Revista de Biología Tropical

Complete chloroplast genome of the Jewel Orchid, Anoectochilus formosanus (Orchidaceae) and its relatives

Viet The Ho — Tue, 21 May 2024 00:00:00 -0600

Introduction: Anoectochilus formosanus is a highly valuable herb known for its efficacy in treating a wide range of diseases. However, the current methods used to differentiate this species from others within the same genus are not effective due to the high similarity in morphological characteristics and DNA barcode sequences among these species. Objective: Characterization of chloroplast (cp) genome in order to identify potential molecular markers to distinguish this plant at species or isolation levels is necessary. Methods: The complete cp genome was sequenced using next-generation sequencing technology, annotated, and compared with published cp genomes of various species within the Anoectochilus genus. Results: The complete cp genome of A. formosanus is 152 658 bp in size, consisting of a large and small copy of 82 692 bp and 17 346 bp, respectively, separated by reverse repeats of 26 310 bp. Within the cp genome, there are a total of 141 genes, including 92 protein-coding genes, 10 rRNA genes, and 39 tRNA genes. This genome contains a total of 80 simple sequence repeats, with 50 long repeats. Through phylogenetic analysis, a close relationship was observed between A. formosanus in Vietnam and A. formosanus samples originated from China (NC_061756.1). However, genomic comparisons highlighted significant differences between the two cp genomes, specifically in their reverse repeat sequences. Conclusions: These findings reveal distinct variations in the cp genome of A. formosanus in Vietnam, offering valuable insights for the taxonomy, plant identification, breeding, and conservation programs related to this herb in Vietnam.

Elaeis guineensis (Arecaceae) residue as a fuel sorbent for passive application in fire-fighting engineering

Hazel Aragón, Paula Calderón-Mesén, Julio F. Mata-Segreda — Wed, 14 Feb 2024 00:00:00 -0600

Introduction: Spills of flammable liquids can lead to serious accidents, mainly in industrial plants and on roads. To prevent the spread of spills, various forms of collection are used, such as absorption with porous solids. Agroindustrial waste can be used as sorbent materials for flammable liquids. Objective: To determine the sorption capacity of the residual empty-fruit bunch of oil-palm (Elaeis guineensis) and the macaw palm (Acrocomia sp.) nutshell for four organic flammable liquids. Methods: The residual biomasses of E. guineensis and Acrocomia sp. were assessed as sorbents for spilled fuels (diesel, jet fuel, commercial kerosene, and gasoline). Volumetric measurement of liquid-fuel absorption at 24 ºC was taken during a week. Desorption was measured at 50 ºC as the drying kinetics, by using moisture scales. Results: The sorption capacity of the Acrocomia sp. material was not satisfactory, compared to the E. guineensis residual material, due to differences in the residual architecture of the organic material. This last can absorb 2.4 ± 0.2 cm³ g^-1 at 24 ºC, during a one-week period. Diatomite absorbs greater quantities of the organic liquids but, the fluids diffusion at 50 ºC is 0.26 ± 0.09 times more slowly in the mineral matrix, because of the greater pore tortuosity in this mineral matrix. Conclusions: The oil-palm empty fruit bunch of E. guineensis, showed lesser but adequate performance than the sorbing behavior for fire hazard mitigation of diatomite. The nutshell of macaw palm (Acrocomia sp.) did not prove to be useful for this recovery operation.

Trypanocidal activity of five Latin American plants

Tue, 21 May 2024 00:00:00 -0600

Introduction: Chagas disease is caused by a hemoflagellate parasite called Trypanosoma cruzi, distributed mainly in Latin America. Countries like Mexico are affected by this parasite, and it is estimated that one million people carry the disease. Currently, the treatment focuses on benznidazole and nifurtimox, which, when applied in the acute phase, is effective but not in the chronic phase and is difficult to access. Therefore, alternatives that can provide new treatments are sought; one option is plants, since they produce secondary metabolites with various biological activities, including antiparasitic. Objective: To evaluate the trypanocidal potential of methanolic extracts collected in some Mexican states from various Latin American plants. Methods: The five plant species under study were obtained in Mexico from the states of Jalisco, Aguascalientes, and Nuevo León; the samples were dried, and the methanolic extracts were obtained. Two strains of T. cruzi were used to evaluate its trypanocidal activity; the Ninoa strain and a wild strain obtained in Calvillo, Aguascalientes. Concentrations of the extracts from 1 000 to 10 ppm were evaluated using a microdilution method. Results: The extracts showed an inhibitory concentration between 1 418.74 ± 6 ppm and 14.1 ± 5 ppm; the extract that presented the best activity was the Arctostaphylos pungens (pinguica) leaf. Conclusions: A. pungens is a plant used in traditional Mexican medicine, and this study has shown that it is a source of compounds against T. cruzi. Future studies could determine its toxicity and cytotoxicity to be applied as a possible treatment for Chagas disease.

Phylogenetic relationships of the Mangrove Hummingbird, “Amazilia” boucardi (Apodiformes: Trochilidae) of Costa Rica

Federico J. Albertazzi, Ghisselle Alvarado, F. Gary Stiles — Mon, 29 Jan 2024 00:00:00 -0600

Introduction: A recent revision of the generic classification of the Trochilidae based on DNA sequences revealed many inconsistencies with the current generic classification, largely based on plumage characters subject to homoplasy, especially in the Trochilini, the largest tribe. A thorough generic reorganization brought the classification into accord with the phylogeny, but due to lack of genetic data, two species remained unclassified. One of these was the Mangrove Hummingbird, “Amazilia” boucardi, endemic to Costa Rica and included in the IUCN red list of threatened species. Objective: To obtain molecular evidence to clarify the generic relationships of “A.” boucardi. Methods: We isolated DNA from tissues of this species and amplified 4 nuclear and 4 mitochondrial fragments and compared these with homologous fragments from 56 species in the Trochilini, constructing phylogenetic trees with maximum likelihood and Bayesian methods. Results: Our phylogenetic analyses confirmed the placement of boucardi in the Trochilini and definitely excluded it from Amazilia but placed it with high confidence in the genus Chrysuronia Bonaparte, 1850, within which its closest relative is C. coeruleogularis, which also inhabits mangroves. Conclusions: Our genetic data based on nuclear and mitochondrial regions clearly indicate the relationship of A. boucardi and L. coeruleogularis. Moreover, it is also support by their habitat distribution in the mangroves of the Pacific coast of Costa Rica and Western Panama. Therefore, we suggested to exclude A. boucardi as "incertae sedis".

Distribution of Ambystoma altamirani (Caudata: Ambystomatidae) in relation to biotic and abiotic factors in its habitat

Ana Citlali Vargas-Gómez, Diego de Jesús Chaparro-Herrera — Fri, 15 Nov 2024 00:00:00 -0600

Introduction: The mountain stream axolotl (Ambystoma altamirani) is an endemic amphibian of Mexico cataloged as a priority species for conservation with a very restricted distribution in the Sierra de las Cruces. Anthropogenic activities currently endanger it. Objective: To determine the habitat factors most associated with its presence to propose conservation strategies. Methods: Four sites in Villa del Carbon, State of Mexico, were sampled monthly for one year (September 2022 to August 2023) with the presence and absence of A. altamirani. Environmental, physicochemical, bacteriological, physicochemical, and biotic parameters of the water were randomly analyzed. Results: A total of 1 186 organisms were censused, and it was determined with a CCA that the variables most related to the populations were solar radiation, total coliforms, percentage of oxygen saturation, UV radiation, fecal coliforms, and temperature. It was observed that the habitat is not being adequately conserved. The populations studied showed a decline during the study. The sites with the highest population abundance showed an increase in the presence of adults, mainly females. It is essential to focus conservation actions on this umbrella species and maintain the variables mentioned above with little disturbance to allow the prevalence of the species. Conclusion: This information can be useful in developing conservation actions for the habitat, which it shares with other endemic and endangered amphibians. 1) It is urgent to protect this species due to the fragility of its populations and rapid decline; 2) It is necessary to propose conservation strategies that are adapted to the localities studied and 3) This will help to prioritize the protection of microendemic species in local environments.

The role of neophobia in a pioneer olfactory enrichment for amazons, macaws, and toucans

Carmen Hernández, Isabel Barja — Tue, 23 Jan 2024 00:00:00 -0600

Introduction: Despite sensory enrichment being critical for ensuring the well–being of captive wild animals, smells are not being included in enrichment protocols for birds. For this group, neophobia can be a problem when it comes to implementing new enrichment devices. Objective: To explore how participation in an olfactory enrichment and latency times varies between bird taxonomic groups (Amazona spp. / Ara spp. / Ramphastos spp.). Methods: We exposed 257 birds to a scent enrichment, and we recorded which individuals engaged with it and the time they took to interact with it. Results: We discovered that participation by toucans in the enrichment was higher compared to amazons and macaws. Furthermore, latency time to interact with the enrichment was higher in amazons that in the other species. Our findings could suggest that toucans are neophilic species which could benefit from higher exploration rates. Amazons on the contrary seem to be particularly neophobic, possibly because of their less opportunistic feeding habits compared to toucans and their higher vulnerability to predation compared to macaws. Conclusion: These results point out that toucans would be more inclined to engage in environmental enrichments, while a more natural design using smells inside familiar objects could be a more successful enrichment for psittacids

Notes on the natural history and identity of the pelagic sea snake Hydrophis platurus (Serpentes: Elapidae) from Golfo Dulce, Puntarenas, Costa Rica

Alejandro Solórzano-Lopez, Mahmood Sasa — Wed, 18 Sep 2024 00:00:00 -0600

Introduction: The pelagic sea snake Hydrophis platurus has the broadest distributional range of all the snakes and is the only sea snake of tropical waters off the west coast of the Americas. Within the variation in the color pattern of this species, completely yellow specimens were considered very rare or occasional. However, a yellow pattern dominates a population established in the interior of the Golfo Dulce in the Southern Pacific of Costa Rica. Objective: We studied the abundance, activity patterns, morphometry, and feeding behavior of the yellow H. platurus within the Golfo Dulce. Methods: Between February 2009 and July 2018, we conducted surveys for sea snakes from a boat within the perimeter of the Golfo Dulce. Results: Adults from the gulf population are smaller than the bicolor oceanic population, with females having larger bodies. Sea snakes within the gulf float and move with surface currents without being linked to drift lines and debris. These snakes are mainly found in clean, calm waters with little turbulence. They feed on a wide diversity of small fish, which they capture using passive stalking predatory behaviors floating on the surface. Prey are quickly captured and swallowed alive. This species has an almost total absence of predation, a pattern that extends to this yellow population. Conclusions: The characteristics of the gulf and the direction and strength of the surface currents at its entrance might restrict the transit of this yellow population to the outside and the entry of the bicolored snakes of the oceanic population. We do not consider making taxonomic changes in this Golfo Dulce population prudent. This yellow population is relatively common within the basin. However, the high tourist traffic and other activities are risk factors for its conservation. Protection policies must be created to preserve and protect this small population of yellow sea snakes unique within this species' distribution range.

Taxonomic identification using multivariate morphometric statistics in Panamanian Carollia bats (Chiroptera: Phyllostomidae)

Tue, 05 Nov 2024 00:00:00 -0600

Introduction: Carollia is characterized by the challenge of identifying individuals of different species. In Panama, no investigation has been conducted on this genus’s accurate classification and identification. However, molecular and phylogenetic studies have been conducted in other regions of the Americas, demonstrating the difficulty of morphological differentiation. The taxonomic keys for identifying this genus tend to vary, making it difficult in Panamanian localities. Objective: To evaluate the external morphometric and morphological characteristics of Carollia specimens using multivariate statistical techniques to facilitate species identification. Methods: We used previous data matrices, which were updated in the field from October 2022 to January 2023 using mist nets. External morphometric measurements (tail, forearm, hand wing, tibia, calcaneus, tragus, hair colour, and body size) and individual characteristics were recorded. 263 specimens of the four species reported for Panama were recorded. We used univariate statistics to compare each of these characteristics between species. Multivariate analyses, such as principal component analysis (PCA), linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), and partial least square discriminant analysis (PLS-DA) were then performed to identify the species based on external morphological and morphometric characteristics. Decision trees were also used for species classification. Results: Linear discriminant analysis (LDA) and decision trees proved to be the best option for classifying the species with up to 99 % efficiency. The most relevant characters for such classifications are the length of the tail and forearm. Conclusion: Morphometric characteristics alone do not provide adequate species discrimination. However, by analysing the parameters using multivariate models, the accuracy of the discriminatory capacity is significantly improved.

Digestive proteases of Morelet’s crocodile (Crocodylus moreletii) in three life stages

Tue, 16 Apr 2024 00:00:00 -0600

Introduction: Morelet’s crocodile (Crocodylus moreletii) is a species distributed in the Mexican southeast and threatened due to multiple pressures. Objective: To characterize the digestive proteases in the acid phase (stomach) and alkaline phase (intestine) of three life stages of C. moreletii in captivity (hatchling, juvenile, and adult). Methods: Total alkaline and acid protease activities were quantified using casein and haemoglobin as substrates. Trypsin, chymotrypsin, leucine aminopeptidase, and elastase activities were quantified using synthetic substrates. Protease profiles were analysed by SDS-PAGE and Native-PAGE. Results: The specific activity of acid and alkaline proteases showed differences between the three stages, finding the highest activity in the juveniles. Trypsin, chymotrypsin, leucine aminopeptidase, and elastase activities were higher in hatchlings. There were differences in optimum pH and temperature of acid and alkaline proteases, trypsin, and leucine aminopeptidase between the three stages, demonstrating the diversification of the enzymes according to different stages, as well as the presence of specific isoforms in each stage of C. moreletii. The acid phase zymogram showed four bands with pepsin-like acid activity in the hatchling and juvenile crocodile, while in the adult only two of the four bands were detected. The alkaline zymogram showed that the hatchling had the highest number of activity bands compared to the other stages, corresponding to the high specific activity reported in the alkaline phase. Conclusions: Digestive proteases of Morelet’s crocodile differ in their biochemical characteristics and the number of proteases between hatchling, juvenile, and adult. This could help in the future design of balanced diets as well to the sustainable management and production of this species.

Multi-temporal analysis of avian biodiversity at the Centro Universitario Regional del Norte (Tolima, Colombia)

Thu, 22 Aug 2024 00:00:00 -0600

Introduction: More and more studies include functional diversity to understand biodiversity patterns. However, in Tolima department, little research has been conducted on this aspect in bird communities, creating a knowledge gap to this important facet of biodiversity. Objective: To determine changes or patterns in the taxonomic and functional diversity of bird communities at the Centro Universitario Regional del Norte (CURDN) for eight years. Methods: The data were organized to identify changes in the bird community over time and during different climatic periods (high and low precipitation). Several indices of taxonomic and functional diversity (alpha and beta) were used. Non-Metric Multidimensional Scaling (NMDS) and Non-Parametric Analysis of Similarity (ANOSIM) were applied to evaluate the impact of climatic periods and temporal variation. Results: During the sampling, 2 691 individuals were recorded. We found that there was no difference in the taxonomic and functional alpha diversity. However, the results of these two facets of biodiversity revealed opposing patterns that are structuring bird communities. The partitioning analysis of taxonomic beta diversity revealed a process of species turnover, while functional beta diversity revealed functional nestedness. Conclusions: Functional diversity suggested that anthropogenic activities in the CURDN act as filters that structure bird communities. These findings highlight the importance of considering these two facets of biodiversity to determine changes or patterns in bird communities over a long period.

Physiological and anatomical responses of Passiflora tripartita var. mollissima (Passifloraceae) in water deficit

Thu, 11 Jul 2024 00:00:00 -0600

Introduction: Passiflora tripartita var. mollissima (banana passionfruit) is one of the most promising exotic tropical fruits from the diversity of the Passifloraceae family in South America, because of its organoleptic properties and antioxidant activity. Objective: To evaluate the physiological and anatomical responses of banana passionfruit plants under water deficit to better understand the mechanisms that mitigate this stress and affect the production of crops subject to climate change and global warming. Methods: Three-month-old seedlings of banana passionfruit were subjected to a soil water deficit through an irrigation reduction at 70 % for 49 days under greenhouse conditions. Morphology (leaf area, height, and number of leaves) and physiological (stomatal conductance, Fv/Fm, total chlorophyll content) measurements were made through time, and after the irrigation treatments were measured biomass parameters and anatomical foliar traits. Results: The plants experienced a decrease in height, leaf area, number of leaves, leaf area index, and relative water content, that are common responses in plants subjected to reduced irrigation. Additionally, the plants exhibited certain mechanisms that can be attributed to water deficit tolerance such as higher root: shoot ratio, stomatal closing, an increase in stomatal density, a reduction in mesophyll tissue thickness, and a decrease in the number of vessels and its diameter as they enable the banana passionfruit to reduce water loss and decrease the probability of cavitation in xylem vessels. Conclusions: banana passionfruit plants could implement strategies against water scarcity, allowing them to survive and endure challenging environmental conditions

The influence of age on the phenolic contents and lignins of Gmelina arborea (Lamiaceae)

Fri, 19 Jan 2024 00:00:00 -0600

Introduction: Melina (Gmelina arborea) is a tree species of great interest for its wood and medicinal properties. In Costa Rica, there are genetically superior clones that are propagated without knowledge of the ontogenic and physiological age of the materials.

Objective: To evaluate how age influences the content of phenols and lignins in leaves, petioles, stems, and roots of melina plants.

Methods: The total phenolic and lignins contents were determined using Folin-Ciocalteu colorimetric method and alkaline extraction method, respectively. Plants of five different ages were chosen for the investigation (in vitro plants “year 0” and trees of a year and a half, four, seven and 20 years). Sampling was done in March and April 2021.

Results: All parts of the plant analyzed contain phenolic compounds and lignins, regardless of their age. There was no positive correlation between age and phenol and lignin content for any development condition, since the highest values were not obtained in the oldest trees. Leaf extracts from in vitro plants and seven-year-old trees showed, respectively, the highest phenol and lignin contents for all conditions (P < 0.05). The lowest average values of phenolic compounds for all conditions were obtained in four-year-old trees. Regarding lignins, the lowest content occurred in the oldest roots, although the trend was not maintained for the rest of the plant parts.

Conclusions: This study provides the first results of the content of phenolic compounds and lignins present in different tissues of a forest species of different ages. Therefore, they are the first reference values about the biochemical commitment for phenolic synthesis according to the age and the specific developmental stage of a woody plant.

Yeasts of Pichia (Pichiaceae) dominate the mycobiome of Hermetia illucens (Diptera: Stratiomyidae) larvae during urban composting

Mónica Vallejo-Arróliga, Keilor Rojas-Jimenez — Tue, 17 Sep 2024 00:00:00 -0600

Introduction: Hermetia illucens is a fly found worldwide in tropical and temperate regions that feeds on decaying organic matter in its larval stage, which makes them useful to accelerate composing processes. Bacterial component on the larval guts that helps to degrade organic matter is well studied, however fungal communities information is more scarse, specially in tropical regions. Objective: To determine fungal communities in the gut of H. illucens larvae naturally occurring during urban composting processes in a tropical region. Methods: ITS sequencing was employed to characterize fungal communities present in H. illucens larval gut. Results: The analysis of amplicon sequence variants (ASVs) unveiled a notable dominance of Saccharomycetales, being yeasts of the genus Pichia the most abundant. Other relatively abundant yeasts were Candida and Galactomyces and the genus Archaeospora from Archaeosporales. The last two groups not being reported in H. illucens before. Conclusions: Yeasts of the genus Pichia are the most abundant group, this result is in concordance with previous studies which suggest a stable insect-yeast relation. The description of previously unreported fungal groups highlights the importance of continuing to explore the mycobiome dynamics of this larva. This study offers insight into the mycobiome of naturally occurring H. illucens larvae in a tropical region.

Ectomycorrhizal fungi associated with Coccoloba uvifera (Polygonaceae) in coastal ecosystems of Eastern Cuba

Tue, 05 Nov 2024 00:00:00 -0600

Introduction: Coccoloba uvifera, named also seagrape, establishes symbiotic relationships with many ectomycorrhizal fungi. However, in Cuba, these fungi have been little studied. Objective: To characterize the diversity of sporocarps and ectomycorrhizae of ectomycorrhizal fungi associated with C. uvifera in three coastal ecosystems of Eastern Cuba. Methods: Four samplings of sporocarps and ectomycorrhizae were carried out at three-week intervals during the rainy season, from June to September, in 2018 and 2019. Ectomycorrhizae were collected from three mature trees and 30 young individuals per tree. The samples were transferred to the Abiotic Stress Laboratory of the Center for Plant Biotechnology Studies of the University of Granma and the Laboratory of Plant Biology and Physiology of the University of French West Indies for processing and subsequent identification. Results: Five species of ectomycorrhizal fungi were identified from sporocarps collected under C. uvifera in the three sampling sites (Scleroderma bermudense, Russula sp., Cantharellus sp., Inocybe sp., and Amanita sp.). Using internal transcribed spacer sequencing, six taxa of ectomycorrhizal fungi were identified from ectomycorrhizas of mature trees and seedlings (S. bermudense, two Tuber spp., Tomentella sp., Inocybe sp., and Thelephora sp.). Only S. bermudense coincided (similarity 99-100 %) with sporocarps. S. bermudense was the most frequent ectomycorrhizal fungus in the ectomycorrhizas and sporocarps collected. Mature trees and C. uvifera seedlings shared between 75 and 100 % of the ectomycorrhizal fungal communities, being able to form potential common ectomycorrhizal networks. Conclusions: At the three collection sites, sporocarp weakly reflected the belowground ectomycorrhizal fungal community, ectomycorrhizal fungal diversity is quite limited, and S. bermudense was the only ectomycorrhizal fungus that overlapped in sporocarps and ectomycorrhizae.

Microsporogenesis and ultrastructure of pollen grains of the Andean blackberry Rubus glaucus (Rosaceae)

Tue, 14 May 2024 00:00:00 -0600

Introduction: Studies on the microsporogenesis of Rubus glaucus are non-existent and little is known about the ultrastructure of the pollen grains. Objectives: To describe the microsporogenesis process, and ultrastructural aspects of the pollen grains in Rubus glaucus. Methods: Flowers at different developmental stages were embedded in paraffin. Sections were stained with Safranin-Alcian Blue, PAS-Amidoblack and Lacmoid or included in resin and stained with toluidine blue. Ultrathin sections were examined by transmission electron microscopy (TEM). For scanning electron microscopy (SEM) observation, the material was fixed and dehydrated in 2.2 dimethoxypropane, then with Hexamethyldisilazane (HMDS), and the samples were coated with gold. Results: Anthers are differentiated by a cellular mass at the ends distal to the staminal filaments. During development, the anther wall presents several cellular layers and at maturity, they are reduced to the epidermis and the endothecium. Microsporocytes undergo simultaneous meiosis and form tetrahedral tetrads. The tapetum develops secretory activity until pollen grains are released, then the cellular content undergoes autolysis. During sporodermis formation, the exine is first deposited and then the intine in a centripetal form. The pollen grains are tricolporate, isopolar, oblate to peroblate, with radial simetry, circular in outline with blunt apices in polar view, ellipsoidal in equatorial view. The exine is thick, tectated, striate perforate. The sporodermis presents an ectexine formed by a tectum interrupted by perforations and thick columellae. Colpus membrane presents small exine granules and orbicules on the surface. The intine develops known structural patterns. Pollenkitt is inconspicuous. Conclusion: Anthers structure and development follows the known patterns of angiosperms. Simultaneous microsporogenesis and centripetal deposition of the sporodermis, as well as ornamentation patterns, have been previously described for the Rosaceae Family.

Precipitation explains Wood Thrush (Hylocichla mustelina) occupancy patterns in Northern Costa Rica

Natalie Viviana Sánchez, Katherine Bonilla Badilla, Cesar Augusto Estevo — Thu, 29 Feb 2024 00:00:00 -0600

Introduction: The Wood Thrush is a migratory bird that has experienced dramatic declines in its populations in recent decades. This species overwinters in forest fragments with intermediate levels of habitat modification in Central America. However, more studies detailing the use of remnant forests through time are needed to elucidate the threats this species faces in the wintering grounds.

Objective: To understand the effects of environmental and forest structure variables on the occupancy of Wood Thrush in Northern Costa Rica.

Methods: The study area was the Área de Conservación Guanacaste (ACG), located in Northern Costa Rica, in December 2016, and during the 2018-2019 migration season. We estimated Wood Thrush occupancy and detection probability in four locations of ACG (dry forest, cloud forest, and two locations in the wet forest) using single-season occupancy models. We also estimated Wood Thrush occupancy and probability of persistence in different months in three vegetation types (open area, secondary forest, and old-growth forest) in the wet forest of ACG using a multi-season occupancy model approach.

Results: Wood Thrush occupancy was best described by precipitation in the four locations of the ACG; the probability of occupancy increased with precipitation. The average occupancy of Wood Thrushes varied with vegetation type: open area with shrubs and forest edge (0.69 ± 0.09), secondary forest (0.46 ± 0.1), and old-growth forest (0.61 ± 0.1). Wood Thrush probability of persistence responded partially to changes in precipitation, with an unexpected increase in persistence when the rainfall continued decreasing in the season.

Conclusion: Wood Thrush occupancy was best predicted by changes in precipitation considering a larger spatial scale. Its probability of persistence partially varied with precipitation. An increase in persistence closer to Spring migration might be explained by the start of the breeding season of resident birds, potentially reducing territorial conflicts and conserving energy before migration. The long-term protection of wet forests in Northern Costa Rica is of paramount importance for the conservation of Wood Thrushes in their wintering grounds.

Fish stocking as fishing management strategy and its role in delaying the management of aquatic ecosystems

Wed, 23 Oct 2024 00:00:00 -0600

Introduction: Fish stocking has been one of the most applied management actions worldwide for managing declining fisheries. However, worldwide, technical requirements have been identified to carry out these activities and improve their effectiveness, which in the Colombian case have been included in the fishing regulations since 2017. Objective: To discuss the role of restocking as a fisheries management strategy in delaying the management of inland aquatic ecosystems. Methods: For the period 1990-2023, we searched for technical and scientific publications in electronic media, using the keywords "repoblamiento pesquero" and "fish stocking". We researched and requested fishing landings and fish restocking data from Colombia. We calculated total and by species releases for the reported systems and tested their efficiency by correlating releases with one year lag fish landings. Results: There are different terms to describe the intentional release of fish into aquatic ecosystems as a management practice. Its use might vary according to the objectives of fish releases or due to translation difficulties from English to Spanish. The origin of the practice is associated with freshwater integrity loss in which species of commercial and economic interest inhabit but does not replace the management actions of the impacted ecosystems. We found no relationship between fish releases and fish landings. Conclusions: Stocking has not been effective as a fisheries management measure, since it has been used to artificially increase fish populations impacted by low integrity of their habitats. Without real impacts on fisheries, it supports a misleading idea of action, leading us down an evasive and dilatory path of our environmental responsibilities.

Environmental sympatry through time: spatio-temporal distribution and conservation status of two sympatric anuran species (Leptodactylidae) in South America

Mon, 29 Jan 2024 00:00:00 -0600

Introduction: Leptodactylus latinasus and Physalaemus cuqui are sympatric anuran species with similar environmental requirements and contrasting reproductive modes. Climatic configuration determines distribution patterns and promotes sympatry of environmental niches, but specificity/selectivity determines the success of reproductive modes. Species distribution models (SDM) are a valuable tool to predict spatio-temporal distributions based on the extrapolation of environmental predictors. Objectives: To determine the spatio-temporal distribution of environmental niches and assess whether the protected areas of the World Database of Protected Areas (WDPA) allow the conservation of these species in the current scenario and future. Methods: We applied different algorithms to predict the distribution and spatio-temporal overlap of environmental niches of L. latinasus and P. cuqui within South America in the last glacial maximum (LGM), middle-Holocene, current and future scenarios. We assess the conservation status of both species with the WDPA conservation units. Results: All applied algorithms showed high performance for both species (X̅_TSS = 0.87, X̅_AUC = 0.95). The L. latinasus predictions showed wide environmental niches from LGM to the current scenario (49 % stable niches, 37 % gained niches, and 13 % lost niches), suggesting historical fidelity to stable climatic-environmental regions. In the current-future transition, L. latinasus would increase the number of stable (70 %) and lost (20 %) niches, suggesting fidelity to lowland regions and a possible trend toward microendemism. P. cuqui loses environmental niches from the LGM to the current scenario (25 %) and in the current-future transition (63 %), increasing the environmental sympathy between both species; 31 % spatial overlap in the current scenario and 70 % in the future. Conclusion: Extreme drought events and rainfall variations, derived from climate change, suggest the loss of environmental niches for these species that are not currently threatened but are not adequately protected by conservation units. The loss of environmental niches increases spatial sympatry which represents a new challenge for anurans and the conservation of their populations.

Spatial and temporal dynamics of the primate community in a regenerating forest of the Manu Biosphere Reserve, Peru

Tue, 14 May 2024 00:00:00 -0600

Introduction: Amazonian forests with varying degrees of anthropogenic disturbance in the process of natural regeneration harbour many sympatric primate species. However, studies on their usage by primates are still lacking. Objective: To comprehensively study the spatial and temporal dynamics within the primate community in a regenerating forest within the Manu Biosphere Reserve. Methods: Two sets of historical data from Crees Foundation for Manu were analyzed, comprising records from January 2011 to February 2023 and corresponding to data obtained through incidental data and Terrestrial In-line Transects in three types of forest with different degrees of historical disturbance. Results: Lagothrix lagothricha and Ateles chamek showed a preference for less disturbed forests; Plecturocebus toppini, for more disturbed forests; and the other species did not show a clear preference. Regarding vertical stratification, A. chamek, L. lagothricha and Alouatta sara showed a preference for the upper stratum, P. toppini, Saimiri boliviensis and Sapajus macrocephalus showed a preference for the middle and upper strata and Leontocebus weddelli and Aotus nigriceps, for the middle stratum. According to the temporal activity of each species, seven species (A. chamek, S. macrocephalus, S. boliviensis, P. toppini, L. lagothricha, L. weddelli, and A. sara) were observed during the day, four were similar. Conclusions: The primate community varies according to disturbance gradient due to the preferences of some species. The recorded primates make a differentiated use of the vertical strata and most of them show diurnal activity.

Proposal for ecological corridors for the protection of the jaguar in Western Ecuador

Cristian Barros-Diaz, Julián Pérez-Correa — Wed, 13 Nov 2024 00:00:00 -0600

Introduction: Biodiversity conservation and ecosystem preservation have become a challenge today due to increasing habitat loss and forest fragmentation. Objective: To propose an ecological corridor for the recolonization of the jaguar (Panthera onca) and its prey. Methods: Western tree cover was calculated using Hansen Global Forest Watch data in Google Earth Engine, then Wallace was used to make potential distribution models with data on the presence of four species of jaguar prey (Cuniculus paca, Dicotyles tajacu, Mazama gualea and Odocoileus virginianus) and then mapped in Qgis. Results: The tree cover of Western Ecuador has experienced a loss of 406 145 hectares in the last 21 years. Of the 80 models generated in 2022, the Quadratic 3.0 model was chosen as the best. Overlaying the model in QGIS and using the shapes of the protected areas of Western Ecuador, the proposal of the corridor was plotted. The study proposes an ecological corridor focused on areas with high habitat quality and ecological connectivity, considering the results obtained in tree cover and the modeling of jaguar dams will serve as a guide for organizations and national authorities and as a proposal to generate ecological corridors closer to the reality of habitat availability in other countries. Conclusion: This ecological corridor is necessary to facilitate the movement and dispersal of species that could benefit from its existence, both between different habitats and protected areas, which would be expected to favor the recolonization of the jaguar and contribute to the maintenance of the genetic diversity of the populations.

Supralittoral isopod (Oniscidea) diversity at three ecoregions along the Colombian Caribbean: useful data for environmental management

Thu, 22 Aug 2024 00:00:00 -0600

Introduction: Terrestrial isopods (Oniscidea) play important roles in the ecological processes of the soil in tropical ecosystems and are employed as indicators of environmental impact. Despite their importance, studies on the ecology of this suborder in the Neotropics are scarce. Objective: To assess spatial changes in alpha and beta diversity of Oniscidea in the supralittoral zone across Archipiélagos Coralinos (ARCO), Magdalena (MAG), and Morrosquillo (MOR) ecoregions in the Colombian Caribbean. Methods: We conducted Direct Intuitive Searches of specimens and measured soil temperature and moisture in 19 transects with logs, leaf litter, coral remains, and decomposing plant material. Results: A total of 1 970 individuals representing 17 species were collected, with Tylidae, Halophilosciidae, and Ligiidae being the most abundant families. Alpha diversity orders were higher in ARCO than MAG and MOR ecoregions. MAG and MOR differed in observed richness. The structure of the assemblage varied in dominant species and abundances. In ARCO, the indicator species were Tylos niveus, Littorophiloscia denticulata, Halophiloscia trichoniscoides, and Ligia baudiniana; in MOR, it was Tylos marcuzzii, and in MAG, it was Littorophiloscia tropicalis. High beta diversity (> 60 %), with significant differences in the assemblage structure among ecoregions, was confirmed by the NMDS, which distinctly separated each group. CCA analysis revealed a negative relationship between most species with soil temperature and moisture, with a positive relationship observed with T. marcuzzii. Conclusions: This is the first effort to describe spatial changes in the diversity of oniscideans in the supralittoral zone of the Neotropical region, providing a baseline for future studies. This information could be instrumental in identifying priority areas for conservation efforts.

Sustainability of dual exploitation (fry and adults) of the fish Semaprochilodus laticeps (Characiformes: Prochilodontidae) in Colombia

Tue, 16 Apr 2024 00:00:00 -0600

Introduction: Semaprochilodus laticeps is a freshwater fish species native to the Orinoco Basin that is exploited in Colombia at two different stages of its life cycle: fry (for the ornamental trade) and adults (for the consumer market). This double exploitation of juveniles and adults raises concerns about the population stability of the species. Objective: To evaluate the sustainability of the exploitation of the species in these two life stages. Methods: 1 277 specimens of S. laticeps were sampled between June and December 2017. Population parameters were estimated from length-frequency data using ELEFAN 1 routine of the FISAT II package. Length at first maturity (Lm) and length at maximum yield (Lopt) were determined using the Froese and Binohlan equations. Virtual population analysis was performed based on Jones length cohort analysis. Results: Population parameters were as follows: K = 0.75, L∞ = 53.1 cm LE, Z = 2.92 yr-1, M = 1.24 yr-1 and F = 1.68. Lm was estimated to be 29.6 cm SL and Lopt at 33.4 cm SL. Of note, 96.3 % of the fish caught in the consumer fishery exceeded Lm and 80 % exceeded Lopt. The results of the virtual population analysis suggested that a very low proportion (0.85 %) of the population was caught as fry, possibly due to natural mortality. Conclusions: Based on the results, as no indicators of overexploitation were identified, it is recommended to continue with the dual use of S. laticeps. It is recommended to maintain the existing conservation measures, such as the closed season during the reproductive period, to ensure sustainable fishery exploitation. The results obtained can serve as a reference to analyze the situation of other species currently fished for both the ornamental (fry) and food (adult) markets.

Species distribution models and conservation status of threatened bats in the Tumbesian region of Ecuador and Perú

MSc. Carlos Avila, PhD. Daniel Griffith, PhD. Carlos Iván Espinosa — Mon, 29 Jan 2024 00:00:00 -0600

Introduction: Biodiversity is being lost at an accelerating rate because of global change. Tools such as species distribution models (SDMs) have been widely used to improve knowledge about species’ conservation status and help develop management strategies to mitigate biodiversity loss. SDMs are especially important for species with restricted distributions, such as endemic species. Objective: To determine how potential distribution predicted by SDMs for eight threatened bat species differed from the distribution maps reported by the IUCN. Also, to infer the area of distribution and state of endemism of each specie, and to evaluate the importance of the Tumbesian region for their conservation. Methods: Based on presence records across the species' entire ranges, we used SDMs to assess the conservation status of these eight species in the Tumbesian region of Ecuador and Peru. Results: The areas estimated by SDMs were 35-78 % smaller for four species (Eptesicus innoxius, Lophostoma occidentale, Platalina genovensium and Lonchophylla hesperia) and 26-1 600 % larger for three species (Amorphochilus schnablii, Promops davisoni and Rhogeessa velilla) than those reported by the IUCN. For Tomopeas ravus, the area estimated by the SDM and IUCN was similar but differed in spatial distribution. SDMs coincided with areas of endemism reported by previous authors for E. innoxius, R. velilla, and T. ravus, but were different for A. schnablii, P. genovensium, P. davisoni, and L. hesperia, due in part to projected distributions for these latter species in dry inter-Andean valleys according to the SDMs. Conclusions: The region represents a significant portion (40-96 %) of the predicted distribution of seven of the eight species studied, underscoring the importance of this region for bat conservation. Our results show likely distributions for these species and provide an important basis for identifying research gaps and developing conservation measures for threatened bats in the Tumbes biodiversity hotspot.

Spatio-temporal variation in the diversity of Geadephaga beetles (Coleoptera: Carabidae, Cicindelidae), in the tropical dry forest of the Colombian Caribbean

José Daniel Sarmiento-Roa, Anderson Arenas-Clavijo, Neis José Martínez-Hernández — Tue, 23 Jan 2024 00:00:00 -0600

Introduction: The use of arthropods in ecological studies in the tropical dry forest (TDF) of Colombia focused mainly on spiders, butterflies, ants, and dung beetles; therefore, it is necessary to understand the seasonal dynamics of the other groups such as Geadephaga in this ecosystem. Objective: To evaluate the spatiotemporal variations and the effect of environmental conditions on the diversity of the Geadephaga communities in two TDF fragments in the Colombian Caribbean. Methods: This study was conducted during four sampling events between February and June 2018, each lasting four days, and four nights. Four sampling stations were selected in each locality (Reserva Campesina La Montaña = RCM and Reserva La Flecha = RLF), separated 350 m one from another, with square plots of 50 × 50 m. A light trap was installed in the center of each square, while pitfall traps were installed in the four vertices, and manual capture, beating sheets and leaf litter sieve were carried out. Results: A total of 348 Carabidae and 114 of Cicindelidae were captured. In both fragments, the richness and abundance presented the lowest values in dry season, while the highest values were observed during the rainy season. Tetracha affinis (Dejean, 1825) was the most abundant species in RCM during rainy season. Conclusions: The richness variation and abundance of Geadephaga corresponds to a seasonal pattern at both locations. A high dissimilarity between the communities of Geadephaga from the two fragments was found, despite having similar environmental conditions.

Habitat structure influences the diversity of diurnal butterflies (Lepidoptera: Papilionoidea) in high-montane ecosystems in Colombia

Alejandra Clavijo-Giraldo, Carlos F. Álvarez-Hincapié, Gabriel Colorado — Tue, 16 Jul 2024 00:00:00 -0600

Introduction: Recent ecological studies have found a positive correlation between habitat structure and animal communities that inhabit them. Generally, such studies try to test the hypotheses that animal species diversity increases in complex and heterogeneous habitats since they may provide more potential niches that structurally simpler habitats. Objective: In this research, the effect of habitat complexity and heterogeneity, and structural habitat characteristics on the butterfly community (Papilionoidea) inhabiting three vegetation covers (shrubs, highland forest and paramo) was evaluated in high-montane ecosystems of the Central Cordillera, Antioquia department, Colombia. Methods: From January to July 2012, butterflies were systematically sampled using Van Someren Rydon traps. Simultaneously, complexity, heterogeneity, and vegetation structure were quantified using 0.04 ha circular plots established around the traps. Results: We reported 108 species, 48 genus and five families of butterflies. Butterfly richness and abundance were sensible to both complexity and heterogeneity of the vegetation covers, as well as to changes in the vegetation structure, showing strong correlations with habitat characteristics. Butterfly diversity was highest in the shrub habitat (¹D = 25.02; ²D = 11.97), followed by the highland forest (¹D = 15.83; ²D = 9.42) and paramo (¹D = 12.36; ²D = 7.86). Moreover, richness and abundance of butterfly species were positively associated with the increase in canopy cover and vegetation density in horizontal and vertical strata. Conclusion: These findings underline the importance of preserving the heterogeneity of habitats and vegetation structure in the Andean high-montane ecosystems to maintain the diversity and abundance of butterflies, highlighting the need for conservation and management policies that consider the complexity and diversity of these ecosystems.

Activity of bats (Chiroptera) in extensive livestock systems in the Colombian Caribbean

Julio Javier Chacón Pacheco, Car Luis Pacheco Guerra, Jesús Ballesteros Correa — Tue, 11 Jun 2024 00:00:00 -0600

Introduction: Extensive cattle ranching in tropical dry forest areas (TDF) has caused the transformation of natural ecosystems and altered the behavior of associated organisms, generating variation in activity patterns. In bats, the activity pattern is affected by the composition and vegetation structure of the ecosystem, and by the climatic season (dry and rainy). Objetive: In this study, the effect of conventional management systems (CS) and silvopastoral (SPS) of extensive livestock management on the bat activity patterns in the Colombian Caribbean was determined. Methods: The activity pattern of bats in TDF fragments associated with CS and SPS was compared within an annual cycle. The daily activity patterns of 11 species with records of more than 10 days in within management systems were determined. Results: Greater bat activity was recorded during the rainy season. We found that although bats show behavioral adaptation to the different management systems, in TDF fragments associated with SPS there is greater bat activity throughout the year, compared to the activity recorded in CS. Species with higher energetic requirements and degree of specialization (Phyllostomus hastatus, P. discolor and Glossophaga soricina) modified their activity patterns between CS and SPS management types. Conclusion: The TDF fragments associated in SSP, due to the vegetation composition and structure, probably favor the constant supply of resources suitable for the bats assemblage stability.

Influence of behavior and habitat on wildlife roadkill: the case of vertebrates on peri-urban roads in the Colombian Andes

Wed, 04 Sep 2024 00:00:00 -0600

Introduction: Urban development and expansion have led to the loss and transformation of Andean ecosystems. However, remnant forests that maintain biodiversity still exist around Colombia's major cities, but these forests are threatened by the road infrastructure. Road ecology in the Neotropics has been focused specifically in documenting the effects of roadkill from a taxonomic and functional point of view, mainly in rural areas. Objective: To evaluate ecologically and spatially, the collision of fauna on roads located in areas of urban expansion in the Northern Colombian Andes. Methods: We assessed vertebrate mortality rate and identified the critical areas of roadkill by taxonomic and functional groups. This was achieved through spatial ecology analysis, specifically Kernel density analysis and hotspot spatial statistical analysis. Additionally, we identified landscape features associated with road mortality and assessed the role of roads as resistance and permeability factors Results: A total of 279 roadkilled animals belonging to 64 species were found, accounting for 28 % of the 273 vertebrate species recorded in the reserve near the studied roads. The average mortality rate for vertebrates was estimated from 42 to 170 individuals annually. Differential patterns were detected in roadkill density across taxonomic and functional groups, where nocturnal species and the trophic guilds are the most vulnerable. Likewise, it was found that the sections of the roads close to the forest have a greater roadkill species richness with greater ecological requirements. These sections constitute an important resistance to species movement in the area. Conclusions: Road mortality in the study area exhibits heterogeneous spatial patterns not only at a taxonomic but also at a functional level, suggesting the deterioration of protected ecosystems in adjacent peri-urban areas.

Avian diversity in river levee forest: the effect of microscale heterogeneity

Wed, 11 Sep 2024 00:00:00 -0600

Introduction: Levee forests exhibit a vertical stratification that may contribute to structural complexity allowing a great diversity of birds to thrive on the islands. In deltaic ecosystems there is scarce or no data to prove it. Objectives: To assess variations in the composition of the bird community within levee forests. Methods: Two areas of protected wetlands belonging to the Paraná River Delta in Argentina were sampled for three years. A comparative analysis of richness, abundance, and diversity was performed in different levee forests using the point count method. Results: Three distinct types of levee forests -open, intermediate, and closed- were identified based on the structure of their vegetation, hosting a total of 85 bird species. Variation in avian community structure among forest types revealed greater diversity in open forests during winter (3.26 ± 0.13, P < 0.01) and spring (3.58 ± 0.05, P < 0.01), and greater richness in autumn (35.33 ± 3.01, P < 0.01). The closed forests exhibited increased diversity during autumn (3.16 ± 0.13, P < 0.05) and summer (3.24 ± 0.06, P < 0.05), along with elevated abundance in autumn (114 ± 13.70, P < 0.05) and richness in spring (39.17 ± 4.71, P = 0.01). Due to the evolutionary history between sites, significant variation was observed in the most recently created national park, influencing abundance in winter (141 ± 22.06, P < 0.01) and spring (176 ± 12.83, P < 0.01), as well as diversity in winter (3.25 ± 0.10, P < 0.01) and spring (3.50 ± 0.10, P < 0.01). Conclusions: The microhabitat in the different levee forests allows the birds to organize differently. Focusing on microspatial dynamics is key to a deep understanding of the biological processes within subtropical islands and to plan conservation strategies and demonstrate the transition of a recovering riparian forest towards its natural state, where the pulse of the river and the effect of seasonality do not stop operating.

Morphological aspects of Sticholecitha serpentis (Plagiorchiida: Plagiorchiidae) in a new Viperidae host in the Brazilian Amazon

Wed, 18 Sep 2024 00:00:00 -0600

Introduction: Sticholecitha serpentis is a poorly studied parasite of the snakes’ esophagus, with an unclear taxonomy. Currently, there are few records of S. serpentis in snakes in Brazil. Although it has been recorded in snakes of the family Viperidae, it has not yet been reported in Bothrops atrox. Objectives: To present new morphological characters, as well as ecological and parasitic relationships of S. serpentis with B. atrox. Methods: The samples were obtained in a dryland area in the Tapajós National Forest, Pará State, Brazil. Ten specimens of B. atrox were examined manually with the aid of tweezers, and three were positive for trematodes identified as S. serpentis in the oral cavity. Results: We provide scanning electron microscopy images, with detailed images of the S. serpentis tegument and its spines, as well as details of the dorsal keel using light microscopy methods. Moreover, we report the first record of S. serpentis parasitizing an Amazonian viperid, with infection frequency data of 30 %. Conclusion: We emphasize that the new morphological data presented in this manuscript provide additional information to facilitate the identification of this trematode in future studies.

Impact of Collared Peccaries Dycotiles tajacu (Artiodactyla: Tayassuidae) on understory vegetation in the tropical rainforest of the Nogal-La Selva Biological Corridor, Costa Rica

Thu, 29 Feb 2024 00:00:00 -0600

Introduction: Evidence suggests that herbivores, such as peccaries, shape vegetation structure and diversity through predation, trampling, dispersal, and rooting behavior. Objective: To evaluate the impact of peccaries (Dycotiles tajacu) on the understory vegetation of the tropical rainforest in the Nogal-La Selva Local Biological Corridor, Costa Rica, comparing a site with the absence of peccaries to another with the presence of these animals. Methodology: From June to November 2021, 20 experimental exclusions and 20 free access plots, each measuring 2 m² were used to quantify herbivory, the number of leaf blades, damaged leaves, healthy leaves, sapling height, and fallen biomass at both sites. Results: A higher sapling density was found in the Nogal Reserve, but a lower sapling diversity, while in La Selva there was a higher sapling diversity, but a lower density of seedlings. Herbivory and sapling height in La Selva exceeded those in Nogal. The exclusion of peccaries reduced seedling damage but did not affect the dynamics of fallen biomass. Conclusion: For the design, implementation, and evaluation of the effectiveness of biological corridors, it is crucial to consider plant-animal interactions to enhance the flow of ecological processes through functional and structural connectivity, analyzed from interactions such as those presented in this paper.

Acoustics of an assembly of anurans in the geographical Cauca River Valley, Colombia

Natalia Mejía-Cepeda, Óscar Murillo-García, Wilmar Bolívar-García — Fri, 28 Jun 2024 00:00:00 -0600

Introduction: Acoustic communication is essential in anuran communities, particularly for reproduction. However, the acoustic space is limited, and bioacoustic interferences, such as competition for mating and resources, impact the effectiveness of communication. The tropical dry forest in Colombia hosts resilient anuran species that have endured significant reduction, fragmentation, and transformation over the past decades. The scarce research on this topic underscores the importance of acoustically characterizing anuran assemblages to understand species coexistence, monitor changes in the community, and evaluate the impact of both invasive species and human activity on the ecosystem. Objective: To acoustically characterize an anuran assemblage in the Cauca River Valley. Methods: From September to November 2022 (rainy season), acoustic recordings were obtained using passive and active acoustic sensors from an anuran community in the geographical Cauca River Valley, on the western flank of the Central Cordillera in Colombia. Anuran advertisement calls were analyzed in three dimensions: spectral parameters, temporal patterns, and acoustic activity. Results: Five anuran species were recorded, exhibiting high overlap in activity but significant structural differences in their calls. The species were predominantly nocturnal, except for one from the dendrobatid family. Conclusions: Each species presents a distinct acoustic niche, avoiding overlap in acoustic signals. These findings establish a baseline for assessing future changes in the assemblage.

Aboveground biomass in a post-mining forest succession in the Colombian Pacific

Jhon Jerley Torres Torres, Harley Quinto Mosquera , Mayira Guerrero Machado — Wed, 21 Aug 2024 00:00:00 -0600

Introduction: Mining is one of the main drivers of deforestation of tropical forests. This activity affects the storage of aboveground biomass of these ecosystems; therefore, their ability to contribute to the mitigation of global climate change. Objective: To assess the influence of soil properties on the aboveground biomass storage of post-mining forests in the Colombian Pacific. Methods: Plots were established in areas post-mining and with different successional ages (12-15 years, 30-35 years, and mature forest). The aboveground biomass and physicochemical parameters of the soil were measured. Results: An aboveground biomass of 15.58 t ha^-1, 35.17 t ha^-1, and 178.32 t ha^-1 was recorded at 12-15 years, 30-35 years, and mature forests, respectively. The species with the highest biomass content in post-mining forests were Cespedesia spathulata and Clidemia septuplinervia. The aboveground biomass was positively correlated with organic matter (OM), calcium (Ca), magnesium (Mg), CICE, total nitrogen (N), and silt. In contrast, the relationship was negative with sand, aluminum (Al), and potassium (K) content. It was evidenced that the relationship between aboveground biomass and soils differed in each successional age. When evaluating the changes of aboveground biomass and soils in the succession, it was observed that the aboveground biomass and total N increased with the recovery time. At the same time, the P and K decreased with succession. On the other hand, the contents of OM, Mg, Al, Ca, and CICE showed curvilinear tendencies since they increased in the first stages and then decreased in the advanced successional stages. Conclusions: Aboveground biomass increases with forest recovery time in the study area. This increase is influenced by the presence of two dominant species shared among the investigated ecosystems and by the soil's N, P, and K content.

Production and germination of acorns from the Andean oak Quercus humboldtii (Fagaceae) affected by recurrent fires

Tue, 16 Apr 2024 00:00:00 -0600

In recent decades, changes in use and increased wildfires have led to the disappearance of 60% of the surface area of Colombia's Andean forests and their increasing fragmentation. Among these forests are Quercus humboldtii oak forests, the only South American Fagaceae species of high socioeconomic and biodiversity interest. The reproductive response of this species will condition its regeneration capacity and the persistence of the oak forests. However, our knowledge of the effect of fire on the production and germination of acorns in Q. humboldtii is incipient. Objective: To evaluate the production and germination of Q. humboldtii acorns in oak forests affected by recurrent wildfires. Methods: We monitored acorn production and germination in Q. humboldtii trees from fire and non-fire-affected forests (central Colombia Andes, Boyacá, Iguaque massif) for fourteen months. We also evaluated fire incidence, tree size, precipitation, temperature and other site characteristics. Results: Acorn production began 34 months after the fire. In burned oaks, the production of incompletely developed acorns (abortions) was almost nine times higher than that of mature acorns. In addition, Oaks with larger scar areas or many scars were more likely to produce aborts. Conversely, oaks of larger size, especially in the crown, tend to produce more acorns. The few mature acorns from burned trees had smaller sizes and lower germination rates than unburned trees and the literature. The unburned trees in this study did not produce mature acorns, but abortion production is ten times lower than in the burned trees. Therefore, it is feasible that Q. humboldtii presents masting, and the unburned trees are in a low production cycle. Conclusions: Fire, tree size, and masting control acorn production in Iguaque oak forests, , which could affect the recruitment of the species due to a possible limitation in the source.

Local and landscape constraints of adult population of Anastrepha obliqua (Diptera: Tephritidae) in mango orchards

Wed, 11 Sep 2024 00:00:00 -0600

Introduction: The West Indian fruit fly, Anastrepha obliqua (Macquart), is one of the most economically important pests of mangoes in Mexico and the Neotropics. Objective: To analyze adult population patterns of A. obliqua and their relation to local and landscape factors. Methods: We selected 11 “Manila” mango orchards along the middle part of La Antigua River, which were characterized to determine their biophysical structure and landscape configuration considering their distance to six different land uses/land covers. Anastrepha obliqua population was estimated by collecting adult flies in colorless polyethylene plastic bottle traps baited with a protein for three weeks in June 2022. Results: A total of 1 869 adults of A. obliqua were trapped, of which 75 % were females and 25 % were males. Abundance varied from 68 to 490 adult flies per orchard, while capture frequency from 0.36 to 1.8 flies/trap/day. Abundance increased in highly shaded orchards, and capture frequency decreased in orchards with highly soil compaction. Abundance and the frequency of capture increased in orchards near isolated trees of Spondias spp. and decreased in orchards near sugarcane plantations. Shade management in mango orchards may be used as an effective strategy to promote biotic interactions to naturally regulate A. obliqua populations, meanwhile, soil compaction represents a limiting ecological condition, which might severely impact fruit fly larvae survival. Conclusions: Adult population of A. obliqua depends on several local and landscape factors because they indicate resource availability and ecological conditions. These findings could be considered for control strategies in the integrated management of this pest to promote protection and improve the fruit quality of mango crop.

Unveiling activity patterns of the deer Odocoileus virginianus (Artiodactyla: Cervidae) and its predators in Mexico's Arid Region

Tue, 09 Apr 2024 00:00:00 -0600

Introduction: Size, predator presence, and habitat nutritional quality influence herbivorous species' activity patterns and resource utilization. Objectives: This study aims to determine the relative abundance and activity patterns of white-tailed deer (Odocoileus virginianus) and their main predators.

Methods: The study was conducted in the WMU "Bienes Comunales Santa Cruz Nuevo" in Totoltepec de Guerrero, Puebla, Mexico. Twenty-two quadrants were randomly selected, and camera traps were installed. Over a two-year period (2018-2020), wildlife visits were recorded to estimate the relative abundance index (RAI), activity patterns, and overlap coefficient (Dhat1) of white-tailed deer and their predators based on their activity schedule.

Results: The estimated RAI for deer was 7.2%, while it was 3.4% for coyotes (Canis latrans), 2.3% for bobcats (Lynx rufus), and 0.14% for pumas (Puma concolor). White-tailed deer were observed in 31% of the camera traps, while coyotes were captured in 68% of them. The overlap of the activity schedule, Dhat1, between deer and coyotes was 0.18. In contrast, the activity overlap between foxes and deer was higher (Dhat1: 0.2979; EE 0.037) based on the analysis of variance. The activity pattern of coyotes indicated they were crepuscular, with increased activity during the afternoon and night. However, an increase in activity synchronized with deer's patterns was also observed. The bobcat coincided with deer in 10% of the cameras, but due to the limited number of observations, it was not possible to estimate the activity overlap between these species.

Conclusions: The activity overlap between white-tailed deer and foxes is more significant than that of deer and coyotes in this region. The activity overlap between deer and coyotes is lower compared to other parts of the world.

Correlation Abundance Networks for Analyzing Biological Interactions during Cyanobacterial Blooms

Florencia Alvarez, Claudia Borja, Liliana Moraña, Veronica Lozano — Wed, 03 Apr 2024 00:00:00 -0600

Introduction: Blooms of cyanobacteria are becoming increasingly common, and understanding their dynamics can be crucial for proposing appropriate management strategies. While physical and chemical parameters influencing blooms have been widely studied, less attention has been paid to the susceptibility of biological communities. Objective: The purpose of this study was to analyze phytoplankton abundance networks during cyanobacterial blooms at different intensity levels and how they interact and/or affect the phytoplankton community. Methods: We used 22 samplings conducted in El Limón reservoir located in northern Argentina, known for recurrent cyanobacterial blooms. Each sampling was classified into four levels based on cyanobacteria abundance (cells/ml): Level 1 (10 000-30 000); Level 2 (30 000-50 000); Level 3 (50 000-100 000); and Level 4 (> 100 000). For each level, abundance correlation networks were constructed considering all species. Results: A pattern of decreasing statistically significant abundance correlations was observed as bloom intensity increased: 219 correlations at Level 1; 144 at Level 2; 80 at Level 3, and only 33 at Level 4. Blooming cyanobacteria showed few correlations with other species at all levels, indicating a certain independence from the community. An increase in bloom intensity appears to disconnect the phytoplankton abundance correlation network. Conclusion: The analysis of abundance correlation networks should be a valuable tool for understanding the dynamics and development of cyanobacterial blooms, as well as identifying key species in this process.

Chironomidae (Insecta: Diptera) in three high Andean tropical streams in Colombia: altitudinal and temporal changes

Mayra Geraldine Rojas Céspedes, Giovany Guevara, Gladys Reinoso Flórez — Wed, 18 Sep 2024 00:00:00 -0600

Introduction: The Family Chironomidae is recognized for its great abundance and diversity in freshwater ecosystems around the world. However, taxonomic knowledge of this family is limited, particularly in Colombia. Objectives: To estimate the abundance and diversity at the genus level and its spatiotemporal dynamics in three streams, tributaries of the Combeima River in central Colombia. Methods: This study describes the taxonomic and ecological evaluation of chironomid larvae present in three high Andean streams (Tolima, Colombia), called Las Perlas (PE), La Plata (PL) and Cay (CA). Between 2015-2016, six sampling campaigns were conducted in contrasting climatic periods, at nine sampling points (three per stream: upper, middle, and lower). The collections were made with Surber net on different substrates. Results: 15 594 larvae were recorded, corresponding to three subfamilies and 20 genera. The most abundant subfamily was Orthocladiinae with 13 698 larvae (87.84 %), dominated by Cricotopus spp. (66.19 %), followed by Chironominae with 1 367 individuals (8.77 %) and Polypedilum spp. (5.18 %), and Tanypodinae with 530 organisms (3.40 %) and Pentaneura spp. (2.91 %). The highest abundance was found in PL3 (lower part; 27.84 %), followed by CA2 (middle part; 20.47 %) and PE1 (upper part; 1.93 %). The three streams presented the highest abundance during February 2016 (25.93 %; transition to the rainy season), followed by November 2015 (20.59 %; low rainfall) and October 2015 (3.94 %; high rainfall). Conclusions: The results obtained expands the taxonomic lists of chironomids in high Andean areas (1 419-2 586 m), and the detailed characterization of the 20 genera recorded in the selected streams, which constitute relevant contributions for the recognition of these dipterans and their ecological role in the aquatic systems of the Colombian Andes.

Methanogenesis in sediments of a tropical coastal wetland: a culture-dependent method

Tue, 16 Apr 2024 00:00:00 -0600

Introduction: Methanogenic archaea (MA), participate in the anaerobic mineralization of organic matter in mangrove sediments, their activity is related to atmospheric warming due to the production of methane; several environmental variables can influence the presence of MA and methane production in these sediments. Objective: To analyze, through culture-dependent techniques, viable methanogenic archaea (VMA) in the sediments, and the production of methane from acetate in different climatic periods in the mangrove El Morro-La Mancha, Veracruz, Gulf of Mexico. Methods: From May to November 2019, following a salinity transect, sediment samples from El Morro-La Mancha mangrove were collected at three locations, in three different climatic seasons, dry (May), rainy (October) and northern (November) (N = 9). VMA in the sediments was quantified using the Most Probable Number (MPN) technique with acetate and methanol as substrates. The influence of sulfate on methane production was analyzed from acetate in microcosm by gas chromatography and the chemical variables of salinity, pH, Eh, carbohydrates, organic content, and carbonates in the sediments were evaluated. Results: The abundance of VMA was 10² to 10⁸ MPN/g of wet sediment, higher than that reported in other studies, this abundance was higher when methanol (10⁴-10⁸ MPN/g sediment) was used as substrate, compared to acetate (10²-10⁵ MPN/g sediment); methane production in the microcosms increased in sulfate-free conditions (29.78-929.75 nmol CH₄/month) and in the sediments of the rainy season. Conclusion: The influence of the chemical conditions of the mangrove sediments on the methanogenic dynamics is highlighted, determining that in the rainy season, the decrease in salinity, more electronegative Eh, and the increase in organic fractions favored the methanogenesis.

Objetive: To analyze, through culture-dependent techniques, the abundance of MA and the production of methane in different climatic periods in the mangrove El Morro-La Mancha, Veracruz, Gulf of Mexico.

Methods: From May to November 2019, following a salinity transect, sediment samples from El Morro-La Mancha mangrove were collected at three sampling locations, in three different climatic seasons, dry (May), rainy (October) and northern (November) (n=9). The methanogenic abundance in the sediments was quantified using the Most Probable Number (MPN) technique with acetate and methanol as substrates; methane production was analyzed from acetate by gas chromatography and the chemical variables of salinity, pH, Eh, carbohydrates, organic content and carbonates in the sediments were evaluated.

Results: The abundance of MA was 10² to 10⁸ cells/g of wet sediment, higher to that reported in other studies, this abundance was higher when methanol (10⁴ - 10⁸ cells/g sediment) was used as substrate, compared to acetate (10² - 10⁵ cells/sediment); methane production increased in rains with 13% compared to dry.

Conclusion: Highlighted the influence of the chemical conditions of the mangrove sediments on the methanogenic dynamics, determining that in the rainy season, the decrease in salinity, Eh more electronegative and the increase in organic fractions favored both methanogenic abundance as methane production.

Plankton interactions and instability in four tropical reservoirs with different trophic status

Silvia Lucía Villabona González — Thu, 23 May 2024 00:00:00 -0600

Introduction: Reservoirs are conceived as a set of interactions in which physical, chemical, and biological instability determine changes in the density of planktonic communities.

Objective: To evaluate the instability of phytoplankton and zooplankton, and their interactions with environmental factors in four tropical Andean reservoirs with different trophic status.

Methods: Physical and chemical variables and phytoplankton and zooplankton densities were measured between 2010-2018 in the oligotrophic reservoirs Punchiná and San Lorenzo and between 2013 and 2015 in the hypereutrophic reservoir Porce II and in the eutrophic Porce III reservoir (n = 248). The Factor Shaping Community Assemblages (FCA) was used to calculate environmental and biotic instability as well as their interaction.

Results: High environmental and biological instability was observed in the studied reservoirs. Oxygen saturation, pH, total nitrogen, water temperature, nitrites, total phosphorus (only for zooplankton) and total solids were the abiotic variables with the greatest contribution to planktonic instability. Particularly, Cryptomonas sp., Aulacoseira sp., Cyclotella sp., Dinobryon sp., Nephrocytium sp., Tetraëdron caudatum and Oscillatoria sp. had the greatest influence on the instability of various rotifer taxa and some copepods.

Conclusions: Regardless of trophic state, pH dynamics, nutrients availability, amount of suspended solids and the availability of gases, such as dissolved oxygen, mainly determined the instability of phytoplankton and to a lesser extent that of zooplankton. In the oligotrophic reservoirs, zooplankton instability was mainly influenced by highly palatable algae with no toxicity, and in reservoirs highly enriched, the instability was influenced by algae with low nutritional quality and difficult to ingest and manipulation.

Iron and Manganese concentrations in leaf tissues of Rhizophora mangle (Rhizophoraceae): implications for energetic metabolism

Thu, 22 Aug 2024 00:00:00 -0600

Introduction: Iron (Fe) and manganese (Mn) are bioessential micronutrients for plants but can impair the energetic metabolism when present at high levels. Objective: To assess the photosynthetic performance and oxidative damages in Rhizophora mangle L. leaf tissues at low and high concentrations of Fe (74 and 195 mg kg^-1; Fe_leaf) and Mn (65 and 414 mg kg^-1; Mn_leaf). Methods: Photosynthetic pigments, chlorophyll a fluorescence, leaf CO₂ assimilation and gas exchange and DPPH^• radical scavenging capacity were sampled in R. mangle growing in estuarine forests in the North region of Espírito Santo State and the extreme South of Bahia State (Brazil) showing low and high Fe_leaf and Mn_leaf. Results: Effects of high Fe and Mn were not identified on pigment levels. The increase in Fe_leaf and Mn_leaf at the levels observed in this assessment had a positive effect on the number of reaction centers and on the efficiency of the oxygen-evolving complex, evaluated as K-band, while no changes were found in the parameters related to the excitation trapping efficiency at the active center of photosystem II. Distinct interference patterns of Fe and Mn on the functional processes of photosynthesis were identified, especially on CO₂ assimilation and reactive oxygen species metabolism, with major effects on CO₂ assimilation and carboxylation efficiency of Rubisco at high Mn_leaf. Conclusion: These findings demonstrate the efficiency of R. mangle in positively regulating the electron transport chain in response to high Fe and Mn, at least in terms of the preservation of structure and functionality of the plant photosynthetic apparatus. Moreover, interference of high Mn_leaf in R. mangle occurs at non-stomatal and biochemical levels. There is an antagonistic interference of these trace elements with the physiology of R. mangle, which is a dominant species in Brazilian mangroves.

Spatio-temporal composition of aquatic birds community in Juluapan Lagoon, Colima, Mexican Central Pacific

Tue, 23 Jan 2024 00:00:00 -0600

Introduction: Aquatic birds (AB) are usually associated with wetlands, which provide refuge, food, and/or nesting sites for resident and migratory species. Despite their ecological importance, there is little knowledge on AB in some tropical environments, such as those found on the Colima coast. Objective: To investigate the spatial and temporal composition of the AB community in Juluapan Lagoon, Colima, Central Mexican Pacific. Methods: Monthly counts were conducted between June 2017 and May 2018 during low-tide conditions to record habitat use by AB. Species richness and bird counts were obtained to compare sampling areas; mean richness and number of individuals were compared between seasons. Results: We detected 53 species and 5 750 individuals. The highest species richness and relative abundance values were obtained in winter at the lagoon area farthest from the connection with the marine system, where anthropogenic activity is lower. Diversity was greater in zones 2 and 3 in spring, summer, and fall. Muddy flats were the most used environment, and the most frequent activity was resting. Nesting activity was only recorded in the middle of the lagoon at the mangrove during spring. Shorebirds and waders were the most dominant groups in the bird community of the Juluapan lagoon. Conclusions: This coastal wetland is a site of great biological importance for aquatic birds; thus, conservation measures should be implemented, and there should be a continuous study of the effects of anthropogenic pressure.

Environmental controls on bioluminescent dinoflagellate density, in Laguna Grande, Fajardo, Puerto Rico

Yogani Govender, Mark Jury — Tue, 13 Aug 2024 00:00:00 -0600

Introduction: Bio bays in Puerto Rico play an important socio-economic role and declines in dominant bioluminescent dinoflagellate Pyrodinium bahamense are concerning. Studies show erratic blooms with is weak correlation to in situ environmental factors. Our study examines shorter field and longer proxy records on dinoflagellate density at Laguna Grande de Fajardo (LGF). Objectives: To quantify temporal changes in dinoflagellate density in a long-term monitoring study, understand how the marine environment modulates those changes, and determine the wider impacts of a fluctuating climate and extreme events on proxies for dinoflagellate density. Methods: Bimonthly samples were collected from 2016 to 2021 at three sampling sites in LGF. Dinoflagellates density was estimated by Sedgewick Rafter counting cells. Environmental conditions were obtained from Rio Fajardo 5007100 station and NOAA buoy 41056. Marine climate and biotic proxies were obtained from remote sensing measurements. Kruskal Wallis, Spearman correlations and cross-correlations in the shorter field and longer proxy records were used to evaluate environmental controls on LGF dinoflagellate blooms. Results: Six years of field monitoring densities found a low period in 2016-2017, frequent and intense blooms in 2018-2021 punctuated by hurricanes. Generally low values were recorded in late winter in contrast with higher values in late summer (Aug-Nov). Light winds and mixed layer response to seasonal warming in the form of high tides and low salinity, were found to sustain dinoflagellate reproduction. Conclusions: Bioluminescent dinoflagellates are vital to coastal tourism and require resource management. LGF results show that: 1) dinoflagellate counts fluctuate widely, 2) fluorescing dinoflagellates are sensitive to environmental conditions because of limited seasonality and narrow physiological range, 3) hurricanes play a role by ‘raking and refreshing’ the coastal lagoon for subsequent biotic reproduction, and 4) intra-seasonal fluctuations of density and proxies relate to air-sea thermodynamic conditions, the salinity budget and sea level.

Diversity of longicorn beetles (Coleoptera: Cerambycidae) associated with a mangrove swamp in Tabasco, Mexico

Tue, 21 May 2024 00:00:00 -0600

Introduction: The mangrove is one of the most important ecosystems on the planet, due to the ecological role it plays on coastlines, it provides development, protection, and feeding areas for various species. Objective: To determine the diversity and annual fluctuation of the cerambycid community, as well as the vertical distribution of species richness associated with the edge and interior of a mangrove in Tabasco, Mexico. Methods: The sampling was carried out from August 2016 to July 2017. The capture of insects was performed with interception traps baited with ethanol 70 % at 1.5, 6, and 12 m height, on the edge and interior of the mangrove. Results: A total of 382 specimens were collected, belonging to three subfamilies, 25 genera, and 36 species; Laminae was the subfamily most diverse with 24 species, followed by Cerambycinae with 11 species. At the edge of the mangrove 31 species were captured, and 21 in the interior. The 1D index determined that the edge was 2.51 more diverse than the interior, with a similarity of 61 %, sharing 16 species. The fluctuation of the communities on the edge and interior presented remarkable differences during the sampling year. On the edge, the greatest species richness was recorded at 6 m height and in the interior at 1.5 m and 6 m. Conclusions: Studies related to the vertical distribution of this group of insects, together with the increase in collection time and using complementary techniques, could give better results to inventory a larger number of species in the ecosystems.

Phytoplankton from a brackish lagoon in the central region of Veracruz, Mexico

Wed, 21 Aug 2024 00:00:00 -0600

Introduction: The brackish lagoons are ecosystems with great diversity and possibilities for human use. Therefore, the knowledge about phytoplankton needs to be improved to understand its real impact. Objective: To relate the Mandinga's Lagoon phytoplankton to the limnological conditions during the dry and wet seasons. Methods: The material was collected in three stations: Isla Conchas (ICO), Mandinga Chica (MCH) and Isla del Amor (IA) during the dry (March 2018) and wet (September 2017 and 2018) seasons. The limnological analysis included ten abiotic variables, and the phytoplankton was analyzed by the Utermöhl method. Data was analyzed with the Shannon index (H´) and Canonical Correspondence Analysis (CCA). Results: 136 species were identified: 68.4 % Heterokontophyta, 22.8 % Dinoflagellata, and 5.9 % Cyanobacteriota; with 40 euryhaline and 96 stenohaline. The most abundant species were: Bacillaria paxillifera, Chaetoceros compressus, Coscinodiscus rothii, and Chaetoceros atlanticus. The highest abundance was in ICO (dry) and the lowest in MCH (wet), with 307 x 10³ and 76 x 10³ cells/ml, respectively; the H´ ranged from 1.31 to 0.70 bits/ind. The CCA showed a relationship between salinity and dissolved oxygen with C. rothii and Ceratoneis closterium. The phosphates were associated with B. paxillifera, C. atlanticus, and Podosira stelligera. The nitrate, water temperature and pH were related to Tripos hircus, T. furca, Diploneis bombus, and Merismopedia elegans. In contrast, Skeletonema costatum, Cocconeis scutelum, and Nitzschia bicapitata did not correlate with the limnological variables. Conclusions: The Mandinga's Lagoon is a shallow, euryhaline and well-oxygenated ecosystem. The dominance of diatoms and dinoflagellates was evidenced by their ability to survive in different salinities and temperatures. It is recommended monitor phytoplankton, in particular Microcystis wesenbergii, B. quinquecornis, Pseudo-nitzschia cf. pungens, and P. cf. pseudodelicatissima as they are harmful algae.

Geographical distribution model of the fish Coryphaena hippurus (Perciformes: Coryphaenidae) according to climate change in the Pacific Oriental Tropical

Estefania Isaza-Toro, John Josephraj Selvaraj, Alan Giraldo — Tue, 16 Apr 2024 00:00:00 -0600

Introduction: Coryphaena hippurus is a species of commercial interest with a high migratory capacity, a characteristic that places it in tropical and subtropical environments, preferring areas with a temperature range between 21 and 30 °C and salinity close to 31 ppt. Although the population trend of C. hippurus is stable, the fishing of this resource is increasing and occupies important positions in the economy of the Eastern Tropical Pacific coastal countries, which demonstrates the need to design and strengthen conservation strategies for the adequate use of this resource. Given its location in tropical and subtropical environments, its availability and distribution could be affected by climate change. Objective: To analyze the current and future potential distribution of C. hippurus under climate change scenarios. Methods: Ten algorithms were used to model the potential distribution and current habitat suitability index of C. hippurus as a function of sea surface temperature, current salinity and velocity, and these results were then projected under the most extreme climate change scenario. Results: There were good performances with all the algorithms used, but the model generated with BIOCLIM (AUC: 0.89) was chosen because it also solves the problem of spatial and temporal bias found in the records of the species. The region of greatest habitat suitability for C. hippurus matches the oceanic fronts of the Eastern Tropical Pacific. Under future conditions of extreme climate change, the species distribution pattern indicates a contraction, relocation, and expansion of habitat south of the equator. Conclusions: Under conditions of extreme climate change, the distribution model for C. hippurus suggests a process of topicalization of marine ecosystems in the Eastern Tropical Pacific by 2100.

A life controlled by the current: rheotaxis behavior of the river prawn Macrobrachium tenellum (Decapoda: Palaemonidae)

Fri, 05 Jul 2024 00:00:00 -0600

Introduction: The currents of streams and rivers are natural signals that influence the migrations in the life cycle of amphidromous shrimp. Objective: To evaluate the rheotaxis behavior in juveniles and adults of Macrobrachium tenellum, in relation to their response capacity to different water currentspeeds in a closed-loop experimental system. Methods: A PVC pipe system was used, with a tub for water recirculation and a backwater placed in the middle of the system. Water flows of 10-30 cm/s were tested to establish the experimental conditions. Rheotaxis behavior without backwater (SR) and with backwater (CR) was evaluated; three water flows were tested: FI, 14 cm/s; FII, 18.7 cm/s; and FIII, 22.1 cm/s, and a control FC flow, 0 cm/s, with 40 juveniles, 40 females and 40 males per flow. Three main behaviors were identified: positive rheotaxis, negative rheotaxis, and no reaction. Results: For both SR and CR, water flows stimulate positive rheotaxis and the behavioral response is different depending on the speed of the water flow and whether they are juveniles, females, or males. In CR there was a greater response of the prawns to continue swimming against the current when they entered the pool. At a straight angle, the constant flow of water greater than 23.2 cm/s makes it difficult for this species to swim against the current Conclusions: The positive rheotaxis response was the most prevalent in juveniles, females, and males of M. tenellum.

Biotic integrity of the Mar Muerto lagoon, Mexico, based on fish

Mon, 24 Jun 2024 00:00:00 -0600

Introduction: The Mar Muerto lagoon is an ecosystem characterized by high productivity upon which various inhabiting organisms depend. Additionally, it is a system susceptible to environmental impacts. Consequently, indices have been developed to determine the degree of disturbance caused by natural and/or anthropogenic factors. Objective: To assess the degree of disturbance in the Mar Muerto lagoon using a Biotic Integrity Index (BII) based on ichthyofauna. Methods: From December 2019 to March 2021, 12 sampling stations were established in the lagoon. The Biotic Integrity Index was developed by collecting data on hydrological variables (salinity, dissolved oxygen, pH, electrical conductivity, suspended solids, temperature, nitrites, nitrates, phosphates, and transparency) and classifying fish species based on their composition and richness. This was followed by a Water and Habitat Quality Index (WHQI) derived from the characterization and classification of sampling stations based on physicochemical variables. The correlation of the two indices allowed for the evaluation of the effectiveness of the BII. Results: 65 species were reported for the lagoon, with Lile gracilis, Oligoplites altus, Eucinostomus currani, and Gerres simillimus being the most frequently recorded. Only station 10 exhibited poor biotic integrity (BII = 26), while the rest displayed regular biotic integrity (BII = 30 – 44), with station nine presenting the highest calculated value (BII = 42). The assessment of the lagoon's BII demonstrated an average biotic integrity considered "regular." Conclusion: Through this study, the functionality of the modified BII for the Mar Muerto lagoon was verified, allowing for the evaluation of the present conservation status and comparison with previous studies.

Diversity of Leptohyphidae (Ephemeroptera) nymphs in the Quenane-Quenanito river, Colombian plain foothills

Tue, 06 Feb 2024 00:00:00 -0600

Introduction: Various anthropic pressures affect the aquatic ecosystems of the foothills of Colombia. The response to environmental stressors is still unknown in bioindicator organisms such as Leptohyphidae. Objective: To determine the diversity of Leptohyphidae nymphs of the Quenane-Quenanito river, in two contrasting hydrological periods and its relationship with some physicochemical variables. Methods: In December (2014) and February (2015), organisms were collected with a Surber net at six stations along the current. Alpha and beta diversity was analyzed and redundancy analysis and generalized linear model were applied to establish the relationship between taxa and environmental variables. Results: Were identified 369 organisms belonging to four genera (Amanahyphes, Traverhyphes, Tricorythopsis, and Tricorythodes), two species, and eight morphospecies. Amanahyphes saguassu is reported for the first time for the Meta department. High diversity of Leptohyphidae nymphs was recorded in the transition to drought season and greater abundance in drought. Beta diversity indicated that the configuration of the assemblage changes spatially and temporally. Conclusions: Leptohyphidae organisms prefer fast habitats, particularly in the dry period where they find food (leaf litter, detritus) and shelter to establish themselves successfully; anthropic activities such as urbanization notably affect diversity. The high diversity recorded in this small stream in the foothills of the plains reflects the need to increase this type of works and collection efforts of study material in the region.

Infestation of ectoparasite of Probopyrus (Isopoda: Bopyridae) in Macrobrachium amazonicum (Caridea: Palaemonidae) in the Amazon River

Wed, 11 Sep 2024 00:00:00 -0600

Introduction: Macrobrachium amazonicum is widely distributed in South America, occurring in the Orinoco, Amazon and Paraguay river basins, being used as an important source of protein for feeding riverside populations. This prawn is host to the crustacean ectoparasites Probopyrus pandalicola, Probopyrus floridensis and Probopyrus bithynis (Bopyridae) that infest the gill cavity of the species. Objective: To report the prevalence and abundance of ectopasites (P. pandalicola, P. floridensis and P. bithynis) and the condition factor in M. amazonicum from the Amazon River, Eastern Amazon. Methods: The prawns were collected from May 2017 to April 2018, with the artisanal trap matapi in the municipalities of Mazagão (state of Amapá) and Santarém (state of Pará), Brazil. Results: 216 prawns infected with ectoparasites were captured, 133 in the Mazagão region (53 P. pandalicola, 48 P. bithynis and 32 P. floridensis) and 83 in the Santarém region (45 P. pandalicola and 38 P. bithynis). In Mazagão, the highest prevalence values were recorded in May (1.98 %) for P. floridensis, July (2.18 %) for P. bithynis, and March (1.93 %) for P. pandalicola. In the Santarém region, the highest prevalence values were recorded in February, 3.47 for P. pandalicola and 2.89 for P. bithynis. Regarding the abundance of parasites, there was no difference between the species grouped between the regions (t = 0.32, p = 0.739). Parasitized prawns from Mazagão and Santarém presented condition factors below expectations, with an average of 0.85 ± 0.55 for Santarém and 0.88 ± 0.44 for Mazagão. Conclusions: During the study it was found that P. pandalicola, P. bithynis and P. floridensis were present in M. amazonicum throughout the year. Furthermore, there was an effect of parasitism on M. amazonicum in the study areas.

Aquatic macroinvertebrate community and water quality in River Tambo, Arequipa region, Peru

Tue, 21 May 2024 00:00:00 -0600

Introduction: The River Tambo basin is one of the main hydrographic systems of the Peruvian western watershed, being a source of development for agriculture, agroindustry, livestock, and domestic use in the Tambo Valley and Arequipa City. Objective: To analyze the structure of macroinvertebrates in River Tambo, Perú and assess the water quality through this community. Methods: Five sampling events were conducted between December 2018 and November 2019 in 12 stations, using a Surber net (500 μm). Macroinvertebrates were identified at a family level. To assess community structure, richness, Simpson’s dominance index (D), Pielou’s evenness (J’), and true diversity of order 1 were determined. A nMDS based on the Bray-Curtis index was used to evaluate dissimilarity. To check for differences in community structure, ANOSIM and two-way MANOVA were used. SIMPER was used to establish family contribution to sample similarity. Relations between physicochemical and biological variables were determined by CCA. ABI index was applied to assess ecological quality. Results: 32 families were recognized, being the most abundant: Baetidae, Chironomidae, Leptohyphidae, Simuliidae, Hydroptilidae, and Elmidae. The middle and low zones of the basin showed the highest and lowest diversity respectively. There were significant differences (P < 0.05) in the community structure indices among the 12 stations differed. There was a higher similarity among the 12 stations in December. ABI scores increased from the low to the middle part of the river, which showed the highest ecological quality. Conclusion: Macroinvertebrate communities from River Tambo reflect ecosystem conditions. Environments impacted by human activities show lower diversity and ecological quality, due to the structure, habitat, and water quality of the river being altered.

FIRST PAGES

Laura Solís — Fri, 15 Nov 2024 00:00:00 -0600

IN MEMORIAN - El legado del biólogo conservacionista Carlos Guindon Standing (1956-2023)

J. Edgardo Arévalo, Karen Masters — Fri, 15 Nov 2024 00:00:00 -0600

A new type of nest in the genus Quindina (Opiliones: Nomoclastidae) with hypotheses about its origin and a new species for Colombia

Héctor Lancheros, Daniel Arias Cuellar, Ricardo Pinto da Rocha — Tue, 24 Sep 2024 00:00:00 -0600

Introduction: Parental care is a phenomenon that has been recorded for several clades of the order Opiliones, but nest building has only been reported in the Neotropical genus Quindina Roewer, 1914 (Nomoclastidae). Objective: To describe a new type of nest used in parental care by a new species of Quindina and determine its placement in the phylogenetic tree of the genus, to propose hypotheses about the origin of the two types of nests reported so far. Methods: Specimens and nests were collected in La Calera, Cundinamarca, Colombia. Observations of parental care were made both in the field and in terrariums. A new species was described based on somatic characters and penis structure. A phylogenetic analysis was carried out, consensus methods with equal weights, implicit weighting, and successive weighting were used. Results: We describe a new case of parental care with a new type of disc-shaped nest, which we call "pendular disc nest". The nest is built by males of Quindina pendula sp. nov.; this species can be recognized externally by the absence of white spots, the presence of a mushroom-shaped set of patches in the middle part of the prosoma, and the presence of a dark yellow background around most of the tubercles. Results of the phylogenetic analysis showed Q. pendula sp. nov. is sister to all Quindina species except Quindina marginata. Based on the tree, obtained by successive weighting, seven phylogenetic hypotheses, related to the possible origin of the two types of nests recorded in the genus Quindina, were proposed. Conclusions: This study presents a new case of egg guarding and the building of nests in arthropods, which is not very common in nature.

Morphometric variations in the reef crab Plagusia depressa (Decapoda: Plagusiidae) in the Western tropical Atlantic

Anne Karolline Costa, Lira, Simone, Silva, Lucas, Schwamborn, R — Fri, 08 Nov 2024 00:00:00 -0600

Introduction: The reef crab Plagusia depressa is widely distributed in tropical oceans. In the Atlantic Ocean, this species is distributed in geographically distant regions with different environmental pressures, which may lead to morphological divergence. Objectives: To explore morphometric differences in Plagusia depressa populations between coastal reefs and an oceanic island in the Western tropical Atlantic. Also, to examine the potential link between the species' phenotypic plasticity and environmental and geographic factors. Methods: A total of 194 crabs were sampled from four Brazilian coastal and oceanic sites (Suape: n= 52, Tamandaré: n= 53, Barra Grande: n= 44, and Fernando de Noronha Archipelago: n= 45) from 2020 to 2022, under distinct anthropogenic and environmental influences. Linear and geometric morphometric analysis employed seven linear measurements and specific landmarks on the carapace, abdomen, and right chelae to pinpoint significant morphometric differences among these areas. Results: The westernmost coastal population exhibited striking differences from the other regions. Male crabs in this population had a pronounced carapace rostrum, while females showed a narrower abdomen, longer telson, and chelae thinning and elongation. It is possible that the pronounced isolation in this area, along with patterns of changes in ocean currents, may influence our results. Female crab carapaces from the island area showed lateral enlargement and pronounced rostrum depressions. Furthermore, being farther from the mainland, this site has oceanic island environmental features, affecting the population through desiccation and air exposure. For male crabs, different right chelae shape across areas showed an impact of food capture and interaction with other organisms on their phenotypic plasticity. Conclusion: Environmental factors such as tidal exposure and habitat composition might affect the phenotypic plasticity of tidal crabs. Moreover, a biogeographical barrier in Northeastern Brazil, which was hitherto given little consideration, holds important implications for the biogeography of the Western tropical Atlantic.

A new vector emerges? Aedes vittatus mosquito (Diptera: Culicidae): habitat and current and future potential global geographic invasion

Tue, 21 May 2024 00:00:00 -0600

Introduction: The Aedes vittatus mosquito is an important vector of yellow fever in Africa, with vectorial competence for dengue, chikungunya and Zika. Its presence has been reported in some places in Africa, Asia, Europe and – recently – America. However, such information is scattered and with little description of the characteristics of the areas where it inhabits. Objective: Therefore, the aim was to compile records of its occurrence, describe the ecological characteristics of its habitat and estimate its current and future potential global invasion. Methods: A dataset was formed with the first records and global records of the mosquito, which were the basis for describing the habitat of the areas where it is found and together with layers of bioclimatic variables were implemented to estimate, through an ecological niche model (ENM), the areas of potential invasion using the MaxEnt algorithm. Since the native range of A. vittatus is unknown, two hypotheses were proposed for the calibration of accessible áreas, Africa and Asia, based on the genetic information available so far. Results: It is suggested that, regardless of its native area, A. vittatus is currently distributed in all continents in both tropical and subtropical zones, where at higher emissions and high time periods, it could expand into subtropical climates colonizing colder climates. Conclusions: It is estimated that the mosquito can be found on all continents at altitudes between 0 – 2500 m and at temperatures between 15 – 30 °C, being found mainly in tropical coverages and in urban areas being favored probably by transcontinental and terrestrial passive transport networks allowing the invasion of new locations.

Ant Communities (Hymenoptera: Formicidae) in a Protected Urban Park in Northeast Mexico

Madai Rosas-Mejía — Fri, 14 Jun 2024 00:00:00 -0600

Introduction: The creation of protected natural areas within urban environments has played an essential role in providing small reservoirs of native vegetation and refuges for endemic species. Objective: To analyze, through ant communities, the influence of urbanization in a protected natural area (PNA) located in an urban zone. Methods: From April to July 2022, using bait traps and pitfall traps along 100 m transects, the presence of ant species was recorded in the El Refugio State Park Natural Area in Tamaulipas, Mexico. Alpha diversity was assessed using Hill numbers, while beta diversity was evaluated using the Jaccard index. Additionally, indicator species were identified through the indicator value (IndVal). Multiple correspondence analysis was conducted to associate the presence of species with environmental variables and vegetation types, and contingency tables were created to relate ant presence to vegetation cover size. Results: Species richness and diversity decreased in sites with low vegetation cover, such as in Tamaulipan thornscrub; moreover, secondary vegetation retained greater species richness. Indicator species were found in secondary vegetation and grassland areas, mainly composed of species that tolerate high temperatures and generalists such as Forelius mccooki and Tetramorium spinosum, while lowland jungle species were the only indicator species. The presence of these species is primarily associated with temperature, humidity, and vegetation cover. A significant relationship between the presence of ant species and vegetation cover size in El Refugio State Park was evident. Conclusion: The structure and composition of ant communities vary according to the type of vegetation structure, particularly in areas that have undergone greater anthropogenic damage. Therefore, the conservation of landscapes, as well as monitoring of these areas, should be considered in future research.

Keywords: green areas; formicids; conservation; indicator species; community ecology.

Genotypic dynamics and dispersion in Colombian biomes of kdr mutations associated with resistance to pyrethroids in the Aedes aegypti mosquito (Diptera: Culicidae)

Tue, 16 Apr 2024 00:00:00 -0600

Introduction: In Colombia, Aedes aegypti is present in 80 % of the country and little is known about the kdr mutations related to pyrethroids (PY) resistance, as well as the influence of different biomes (mainly temperature) and passive ground delivery transport on maintaining and disseminating populations with these mutations. Objective: To model the behavior of genotypic frequencies associated with the kdr Val1016Ile + Phe1534Cys mutation in A. aegypti populations, considering vector population movement between Colombian biomes through passive ground delivery transport. Method: We obtained data from the literature regarding population dynamics, mosquito life cycle parameters associated with temperatures for each Colombian biome, and ground cargo transportation, including truck transport. We also evaluated the impact of the evolutionary cost for the kdr Val1016Ile and Phe1534Cys mutations on oviposition and death rates. Results: Population behavior is influenced by the evolutionary cost of resistant genotypes and passive cargo transport. Once resistant genotypes arrive in a biome through truck-mediated mosquito transport, they persist. Conclusion: Passive migration through land cargo transport is essential for the dissemination of individual resistance carriers between different regions or biomes. Evolutionary cost plays a critical role in the dynamics of kdr mutations in A. aegypti populations.

Microstructure of the labial palps in the genera Aphrissa and Rhabdodryas (Lepidoptera: Pieridae, Coliadinae) from Mexico

Isabel Vargas-Fernández, Jorge Enrique Llorente-Bousquets — Fri, 01 Nov 2024 00:00:00 -0600

Introduction: We studied the labial palps in three species belonging to two pierids from the Neotropical region. Our examination was based on ten male and eight female specimens from Mexican fauna. Objective: We describe the microstructure of the palp focusing on the Reuter's sensitive patch and the Palp-pit organ. Additionally, we aim to characterize the type, dimensions, and distribution of the sensilla. We aim to discern any variations between sexes and species. Methods: The labial palps were separated from the head and their scales were removed. Subsequently, the palps were mounted for observation under the scanning electron microscope. Micrographs were captured of both the bare and scaled palps. We measure the three segments and sensilla using Photoshop CS3 tools. Results: In both genera, the basal and mesial segments exhibit lateral flattening, whereas the distal segment is spherical or cylindrical. Significant differences were observed in the dimensions of the distal segment among the females of the two Aphrissa species compared to their male counterparts. The sensilla on the outer surface of the segments are chaetic and, while those at the base of the Palp-pit are coeloconic. The sensitive patch has numerous smooth, cone-like microtrichia, located on the basal segment and with lower density on the upper section of the Palp-pit, reaching the apex of the distal segment. Conclusion: The morphology displayed by the coeloconic and chaetic sensilla of the labial palps in Aphrissa and Rhabdodryas is consistent with that described for the coliadine butterfly Prestonia, as well as other previously studied genera. This suggests that the labial palps could serve as a system of microstructural characters in taxonomy.

Invertebrates as disturbance bioindicators in the Manu Biosphere Reserve

Mon, 24 Jun 2024 00:00:00 -0600

Introduction: Monitoring bioindicators is crucial for conservation in natural protected areas, such as the Manu Biosphere Reserve. Different taxa have been used as bioindicators due to their specific characteristics, including ease of sampling, varied responses to disturbances, association richness with other species, and accessible taxonomy. Objectives: To compare the potential of four taxa (Chilopoda, Scarabeidae, Carabidae, and Pompilidae) as bioindicators in a disturbance gradient, considering their ease of collection, presence of changes in community composition, species with marked disturbance preferences, and diversity correlated with other groups. Methods: The study was conducted at the Manu Learning Centre Biological Station within the Manu Biosphere Reserve, a self-regeneration forest with varying degrees of disturbance. Specimens were collected using pitfall traps, yellow pan traps, Malaise traps, and monoliths. Specific richness, abundance, similarity analysis, non-metric multidimensional scaling, Bray-Curtis distance, Bray-Curtis beta diversity partitioning, correspondence analysis, Williams' G goodness-of-fit, and Spearman's correlation index were measured. Results: Among all taxa, the most collected specimens belonged to the Scarabeidae family, with 217 individuals, while Pompilidae exhibited the highest richness with 39 species. Differences in all three forest types were detected only in Chilopoda through similarity analysis. Non-metric multidimensional scaling revealed distinctions in both Chilopoda and Scarabeidae. All taxa exhibited changes in community composition. Conclusions: Each group responds differently to disturbance levels. Scarabeidae and Chilopoda demonstrate more favorable characteristics, though other taxa also hold potential for highlighting distinct ecosystem features.

La Planta: estructura y función, un hito en la literatura científica tropical. Flores-Vindas, E. (2024). La planta: estructura y función (5a ed.). Editorial Tecnológica de Costa Rica

Gerardo Avalos — Wed, 03 Apr 2024 00:00:00 -0600

El análisis de la anatomía y morfología vegetal resulta esencial para comprender la diversidad de estrategias adaptativas de las plantas frente a la variación ambiental. El conocimiento de la variabilidad en la estructura y función de las células, tejidos, órganos, sistemas y organismos vegetales implica explorar la anatomía interna de la planta, así como analizar su diversidad morfológica a lo largo del desarrollo mediante procesos de morfogénesis y diferenciación.

A response to: Evaluating the reliability of DNA Barcoding for Central American Pacific shallow water echinoderms identification

Spencer Kelvin Monckton, Dirk Steinke, Kevin Charles Robert Kerr — Tue, 13 Aug 2024 00:00:00 -0600

Introduction: Chacón-Monge et al. (2024) sought to test the accuracy of DNA barcoding for species identification in Pacific Central American shallow water echinoderms. They used cytochrome c oxidase I (COI) sequences derived from new material collected as part of the BioMar-ACG project in Costa Rica. Using their set of 348 echinoderm sequences, they compared species identification results from two online platforms: the National Center for Biotechnology Information (NCBI) GenBank using the nucleotide Basic Local Alignment Search Tool (BLASTn), and the Barcode of Life Data Systems (BOLD) Identification Engine. Objective: The present article is a response to their results and conclusions. Methods: We reinterpreted the results from the authors’ Appendix 2 to enable an objective comparison between the BOLD Identification Engine and BLASTn in GenBank. Results: While the authors found that both platforms were limited by the number of reference sequences available in their respective databases, they concluded that GenBank outperformed BOLD for identification; however, we identify several methodological flaws in their analysis. These include pseudoreplication amongst query sequences, contaminated sequences stemming from sampling errors, and a lack of standardization when interpreting results from the two platforms. Their assessment of the BOLD Identification Engine was also limited by improper selection of a reference database. Conclusion: Addressing these errors, we reinterpret their results and demonstrate that there is no difference in performance between the two platforms.

Biomass and bioethanol production of the shrub Ulex europaeus (Fabaceae) estimated with remote sensor imagery in the Andean paramos

Diego F. Osorio-Castiblanco — Tue, 16 Apr 2024 00:00:00 -0600

Introduction: Gorse (Ulex europaeus, family Fabaceae) is an evergreen shrub native to Europe and invasive in the Andean high-mountain tropical paramos. Objective: To quantify the extent of a biological invasion within a paramo near Los Nevados National Natural Park in Tolima, Colombia, and evaluate bioeconomic solutions to encourage shrub eradication while promoting the local economy and industry. Methods: An object-based supervised classification approach was conducted using UAS (Uncrewed Aircraft Systems)-based RGB imagery and a Planet-derived NDVI (Normalized Difference Vegetation Index) layer, both from 2022, to quantify the area invaded. This value, the height obtained from a UAS-derived nDSM (Normalized Digital Surface Model), and a pair of allometric equations found in the literature were employed to estimate the gorse aboveground biomass (AGB) and aboveground available fuel, also known as fuel load. Then, documented bioethanol production estimations were applied to calculate its potential extraction based on the AGB values. Results: The invaded area was quantified to be 66 465 m², with an overall accuracy rate of 85.3 %. Furthermore, the fuel load was found to be approximately half of the AGB, which poses a high risk of fire in the ecosystem. The findings also suggest that up to USD 88 933.7 could be generated if all gorse in the study area is exploited to produce bioethanol. Conclusions: This study underscores the urgency of managing the biological invasion of gorse in the Andean paramo and suggests the potential for bioeconomic solutions to mitigate the impact of these invasions.

Complementing biological inventories through open data in a semiautomated method

Sergio A. Cabrera-Cruz, José Luis Aguilar-López, Rafael Villegas-Patraca — Wed, 16 Oct 2024 00:00:00 -0600

Introduction: Surveys are the best way to document the biological richness of any given place, but efforts to do so can be limited. We asked whether the species richness documented through fieldwork can be complemented with open data from digital platforms. Objective: To analyze whether species occurrence data available in the Global Biodiversity Information Facility (GBIF) can complement species lists reported in the literature obtained through fieldwork. Methods: We compared bird species lists published in peer-reviewed articles and those generated with information from GBIF for the same study areas using the Sorensen dissimilarity index (β_sor) and its two components (turnover β_sim and nestedness β_sne). Results: GBIF reported more species (n = 26-232) than 14 of the 24 lists consulted, but fewer (n = 12-114) than the other 10. The sum of species documented by both sources represents an increase between 1.6 and 464 % compared with the number of species in the articles alone, showing the potential for complementation between both sources. β_sor ranged between 0.15-1, showing differences between all species lists. In no instance β_sim = 0 or β_sne = 1, indicating that one source of information always listed species absent in the other source and that species nestedness between sources of information was never total. We provide R code that can be adapted to download and clean GBIF data for any biological group and place. Conclusion: Species occurrences available in GBIF can complement the information collected in the field but this, in turn, can also complement the records of GBIF, so we highlight the importance of continuing documenting the biological richness through fieldwork, especially in little-explored areas.

Geospatial patterns of morbidity due to covid-19 in Costa Rica: March 2020 to May 2022

Wed, 18 Sep 2024 00:00:00 -0600

Introduction: The COVID-19 epidemic has manifested geographically as clusters of high morbidity (hot zones) and as cold spots of low incidence, which have been explained based on social variables. Objective: To characterize morbidity patterns due to COVID-19 in Costa Rica from March 2020 to May 2022 and to explain them through social determinants of health in the geographical context. Methods: An ecological study at the district level was designed with data on vaccination against COVID-19, weekly reports on speed of advance of the epidemic, development level, and other demographic data. Thematic maps were constructed, and spatial morbidity patterns were identified and characterized, which were explained using linear and geographically weighted regression models. Results: In the Greater Metropolitan Area and surrounding area, clusters of hot spots were identified, and cold spots flanked these high-incidence areas. The linear regression model, built from the variables: average number of vaccines per person, speed in weekly case reporting, social development in its economic, educational, and health dimensions, as well as the proportion of overcrowded homes and people born in the outside, explained more than 70 % of the spatial variations of the incidence of cases (crude and standardized by age and sex). The geographically weighted model corrected autocorrelation problems, improving the explanatory capacity to 82 %. Conclusions: morbidity during the COVID-19 epidemic until May 2020 was configured spatially through well-established clusters of hot and cold spots. This structure could be explained from the social determinants of health, proving that effects on morbidity are generated, differentiated territorially.