Revista de Biología Tropical / International Journal of Tropical Biology and Conservation, es una revista de acceso abierto completo de la Universidad de Costa Rica centrada en la biología tropical y la conservación. Todos los números, desde 1953 hasta la actualidad, están disponibles para su descarga gratuita. aquí. NUESTRO ENFOQUE (Objetivo) Nuestra revista publica artículos científicos que aumentan nuestra comprensión de la biología, la conservación y las ciencias biomédicas de la vida en los trópicos. Los criterios de selección son la cantidad y calidad de la nueva información y su interés potencial tanto para el público en general como para los especialistas. Los ecosistemas estudiados, o al menos los organismos, deben ser tropicales. COBERTURA TEMÁTICA Números regulares Damos preferencia a artículos de fondo que incluyen preguntas de estudio comprobables, por ejemplo, estudios con un diseño experimental que evalúe factores que influyen en variables biológicas, o estudios que explican los mecanismos subyacentes a fenómenos biológicos o biomédicos como, por ejemplo, el comportamiento o la fisiología. Los estudios de campo deben presentar patrones temporales o espaciales. También damos la bienvenida a estudios sistemáticos o filogenéticos por encima del nivel de especies, metanálisis y estudios bibliométricos que examinan críticamente lo que se conoce y lo que queda por hacer en cualquier campo de la biología tropical. Los artículos de revisión se publican en su mayoría por invitación del Consejo Editorial a autoridades reconocidas. Otros especialistas interesados en enviar una revisión primero deben enviar un esquema de manuscrito titulado al correo biologia.tropical@ucr.ac.cr. Las propuestas aceptadas reciben la misma evaluación que los manuscritos regulares. Todas las revisiones y metanálisis deben identificar y llenar los vacíos en el conocimiento, presentar avances metodológicos y proponer futuras direcciones de investigación. Nota sobre datos antiguos: Si su trabajo se basa en datos antiguos, recomendamos compararlos con datos más recientes, o usarlos como parte de meta-análisis, para darles mayor valor. Los estudios basados en datos recopilados hace más de seis años deben incluir una justificación de por qué siguen siendo de interés y, en el caso de estudios de campo, deben presentar patrones espaciales o tendencias temporales de importancia histórica. El Comité Editorial evalúa la validez de los métodos y la relevancia de los resultados antes de enviar el manuscrito a revisión. La revista ahora cuenta con un número al año (publicación continua del 1 de enero al 31 de diciembre) y publica los artículos la misma semana en la que se tiene disponible una versión editada. Hasta 2021 publico cuatro números regulares por año: número 1 (enero-marzo), número 2 (abril-junio), número 3 (julio-septiembre) y número 4 (octubre-diciembre). No publicamos notas; comunicaciones cortas; listas de especies; nueva especie única; extensiones de rango; nuevos registros y otros estudios preliminares o breves; o informes técnicos altamente especializados basados en protocolos (por ejemplo, estudios agrícolas, forestales, bioquímicos, microbiológicos, acuícolas, pesqueros o similares que solo aplican técnicas bien conocidas a casos particulares de interés local). NÚMEROS ESPECIALES Los números especiales financiados por organizaciones de investigación se aceptan después de la aprobación del Comité Editorial. Pueden contener una diversidad de tipos de informes, incluidos artículos breves, nuevos registros, nuevas descripciones de especies, listas de verificación, informes técnicos, etc. Para publicar un número especial, comuníquese con biologia.tropical@ucr.ac.cr para obtener una estimación de costos. PÚBLICO META Personas investigadoras con interés en el estudio de todos los campos de la biología tropical. PORQUÉ PUBLICAR EN LA REVISTA DE BIOLOGÍA TROPICAL? Totalmente indexada: Revista de Biología Tropical está incluida en Science Citation Index Expanded, REDIB Journals Ranking, Current Contents, Google Scholar, Biological Abstracts y alrededor de 50 otros índices internacionales. Rápida decisión y publicación (7 días para la primera decisión, 5-7 meses para aceptación definitiva, 6-8 meses desde el envío hasta la publicación). Razonable: utilizamos un sistema de doble ciego para una evaluación justa de los manuscritos. Alto impacto, no solo por su índice de citas, sino también porque es muy leído en países con la mayor biodiversidad tropical, lo que garantiza que su artículo tendrá el mayor impacto en la conservación de la biodiversidad tropical. Factor de impacto de Web of Science de 0.6. Factor de impacto en SJR de 0.28 (Q2). Un trato personalizado por parte de nuestro dedicado personal. Juntas editoriales y científicas de clase mundial. Acceso abierto: Todos los artículos, desde el primer número en 1953 hasta el presente, están disponibles gratuitamente en línea (Archivos), por lo que es más probable que sean citados que los artículos detrás de muros de pago. PUBLICACIÓN GRATUITA: Cada artículo recibe 10 páginas de espacio libre en formato PDF, que es suficiente para la mayoría de los artículos científicos. Se pueden publicar páginas adicionales diagramadas en el pdf a $50 cada una. Material complementario como textos adicionales, figuras, tablas, gráficos y bases de datos con un costo de $60. Póngase en contacto con biologia.tropical@ucr.ac.cr para obtener más información. OAI-PMH: https://revistas.ucr.ac.cr/index.php/RBT/oai
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Biology of an introduced species of Pleco fish (Siluriformes: Loricariidae) in a tropical freshwater ecosystem
Introduction: Loricariid species have been introduced in many countries in the world, causing negative ecosystem effects wherever they invade. Species from this family, also known as Pleco, have been recorded from Lake Nicaragua for several years. Objective: investigate basic aspects of the biology of Pleco in Lake Nicaragua, as an initial step to generating information to contribute to establishing management strategies for this species. Methods: We assessed relative abundance and relative weight, Gonadosomatic index (GSI), Capture optimization Index, Catch composition by Net type, and environmental variables. Results: 23 different species were captured, with the Pleco being the species represented in the greatest number of individuals and weight. Mature ovaries were observed throughout the year, except in July, GSI values were always high between September and June. High number of females were capture in September and October, as well as the period between March and May. The highest values of the capture optimization index were obtained in September and October. Additionally, the loricariids tended to prefer sites and times where water levels were deepest, potentially as a response to increased Río Frio’s flow. This aligns with the strategy of conserving energy by seeking areas of reduced water current. Conclusions: In the southeast of Lake Nicaragua, increases in Pleco (Hypostomus sp.) populations have been matched corresponding declines in the capture of species of commercial interest. As a result, switching to target the Pleco in the area could provide an opportunity for local fishers to extract an abundant resource and avoid the extraction of local species, as long as viable markets are developed for Pleco.
Copyright (c) 2025 Revista de Biología Tropical https://creativecommons.org/licenses/by/4.0
Habitat preferences and simulation of physical habitat availability of Perlidae (Plecoptera) and Corydalidae (Megaloptera) in a neotropical river
Introduction: Habitat preferences represent the distribution and abundance of species among different habitat types. These preferences are highly relevant ecological information because they relate to the feeding strategies, offspring care and predator avoidance refuges of the organisms, therefore potentially influencing their fitness. Objective: To define the habitat preference of the nymphs of Anacroneuria spp. (Plecoptera) and larvae of Corydalus spp. (Megaloptera) with respect to current velocity and depth. Methods: We evaluated the abundance of Anacroneuria and Corydalus with information gathered through 15 field campaigns in three sites of the Savegre River, Costa Rica. Also, we used habitat preferences to create simulations of the physical habitat availability for these species through hydraulic models to determine habitat gain or loss due to variations in flow. Results: Anacroneuria (Plecoptera) nymphs preferred velocities of 0.9 m/s and depths between 23-36 cm, while Corydalus (Megaloptera) larvae preferred velocities between 0.6-0.8 m/s, and depths between 17-29 cm. As a case study, these preferences were modeled to determine optimal, regular or inadequate habitat availability for Anacroneuria and Corydalus given hypothetical flow variations in the Savegre River (Costa Rica). A discharge of < 8 m3/s resulted in a decrease in optimal habitat, mainly because it decreased water velocity below the preferred ranges. Also, a discharge of > 18 m3/s resulted in a decrease in optimal habitat because of the depth increase. Conclusions: This type of information is scarce or even absent for neotropical rivers, though necessary for a description of a healthy habitat. Furthermore, this habitat preference vs. modeled habitat availability approach is highly useful, -both in tropical and temperate rivers- for understanding the potential effects of any water derivation or exploitation.
Bacteria associated with the alga Ulva lactuca (Ulvaceae) from the Colombian Caribbean and their laccase activity
Introduction: Marine macroalgae, their associated bacteria and the environment, interact to produce compounds that aid the holobiont in adapting to biotic and abiotic challenges. These compounds include several novel enzymes with industrial applications and with less environmental impact than industrial chemical reactions. Laccases are an example of enzymes that are of interest due to their wide range applications, and their versatility is a subject of research and exploration. Despite the abundance of macroalgal holobionts in the Caribbean region of Colombia, little is known about the microorganisms associated with these hosts and their potential for biotechnology. Objective: To evaluate the epibiont and endobiont bacteria associated with the macroalga Ulva lactuca present in Santa Marta, Colombian Caribbean, and to search for laccase producers among them. Methods: Culture techniques were used to isolate bacteria from U. lactuca collected on February 27, 2023. The 16S rRNA region was sequenced to determine the identity of the different isolates. Lacase production was screened by inoculating the isolates in guaiacol medium, which was later confirmed in nutrient agar with 0.2 % dimethoxyphenol. Results: 118 isolates were obtained, of which 64 were epibionts and 54 were endobionts. 75 % were identified to genus and species level. The predominant epibiont isolates were Proteobacteria, especially Vibrio, while Firmicutes, with Bacillus, had a higher representation in the endobiont isolates. Laccase activity was found in 42 isolates including Enterobacter, Halomonas, Paenibacillus, Priestia, Pseudomonas, Shewanella, and Vibrio. Among them, endobionts related to Bacillus had the highest number of isolates positive for laccase. Conclusions: Proteobacteria and Firmicutes dominated the culturable bacterial community of U. lactuca. This study indicates that several bacterial genera associated with U. lactuca in the Colombian Caribbean are positive for laccase activity. Further research is needed to explore the potential industrial applications of these enzymes.
Performance of the Weibull individual growth model for weight at age data
Introduction: Knowledge of different functions associated with a probability distribution, as well as their properties, can be translated into functions that provide information about different characteristics of the growth process under study. Objectives: To analyze the relationship between individual growth models and the cumulative distribution functions of continuous random variables. Methods: We compare the flexibility and goodness of fit of the Weibull-type model against the von Bertalanffy weight growth model. We fit these two growth models into two very different sets of age-weight data taken from the literature; the first comprises 22 pairs of Pacific halibut mean weight at age, and the second 900 pairs of striped bass weight-age-data. Results: The Weibull-type growth model had greater flexibility and neglected less information available in the data sets than the von Bertalanffy model. Conclusions: The Weibull model, derived from cumulative probability distribution, is a good choice to fit weight-at-age data as it is more flexible than the commonly used von Bertalanffy model.
Top predator feces: behavioral consequences for coexisting species
Introduction: Deposition of feces in the environment is a key behavior in the ecology of predator carnivores, which promotes behavioral changes in animals, influencing the ecology, abundance, and distribution of the species with which they coexist. Objective: To analyze whether jaguar feces are detected by other jaguars and mammal species and if they have behavioral effects. Methods: We recorded the behavior of jaguar (Panthera onca), puma (Puma concolor), mesocarnivores (Leopardus pardalis, Leopardus wiedii, Herpailurus yagouaroundi), and prey species using camera traps, at marked sites (with jaguar feces; n = 28) and control sites (without jaguar feces; n = 10). Using the records, we analyzed, for rainy and dry seasons: (1) the detection of jaguar feces by animals and (2) whether animals modify their exploration, remarking, vigilance and foraging behavior after detecting jaguar feces. Results: The detection of jaguar feces by jaguars and pumas was similar and the detection was higher in dry season. Regarding the behaviors analyzed, jaguars explored 15 times more and remarked 13 more times, marked sites than control sites. Pumas explored eight times more marked sites than control sites. Mesocarnivores explored marked sites 17 times more than control sites. Prey explored 41 times more and increased their vigilance 24 times more at marked sites compared to control sites times. Conclusions: Jaguar feces are detected by conspecifics and other mammal species, and they have behavioral effects on them. This can trigger changes in the abundance and distribution of populations and may be one of the ways that large predators shape ecosystems.
Rhizospheric bacteria associated with Dryopteris pseudofilix-mas (Dryopteridaceae) at Mount Tláloc, México
Introduction: Plant roots harbor communities of bacteria that can provide benefits to their host through the production of phytohormones, phosphate solubilization, and nitrogen fixation. In Mexico, there are few studies on the richness and diversity of rhizobacteria communities associated with ferns. Objective: To analyze and identify the functional groups of bacteria from the rhizosphere of Dryopteris pseudofilix-mas in Mount Tlaloc, Mexico. Methods: Rhizospheric soil from D. pseudofilix-mas was collected at four sites where this fern occurs naturally. Bacterial populations were quantified by the plate count and dilution method. The isolated strains were characterized and identified using the 16S rDNA gene. Physical and chemical characteristics of the soil were determined and data of soil moisture, temperature and light in the canopy were collected. Results: The total bacteria population was from 30.1 to 92.3 x 104 CFU g-1 soil. Soil pH and phosphorus content influenced the density of bacterial populations. About 108 bacterial strains were isolated, 92 were Gram-negative and 16 Gram-positive. The isolated strains belonged to 20 genera, being the most abundant Pseudomonas and Bacillus. The Sørensen index indicates that the species of bacteria are similar in the four sites; Pseudomonas jessenii was present in the four sites. The bacterial strains presented more than one plant growth promoting activity, being the group of nitrogen fixers the most abundant. Conclusions: The rhizosphere of D. pseudofilix-mas harbors diverse groups of functional bacteria that could potentially be used in biotechnology for ecological restoration or agricultural purposes. The bacterial population of the four sites was dominated mainly by Pseudomonas and Bacillus.
Fern; rhizobacteria; soil microorganisms; diversity; vegetation
Combining environmental DNA metabarcoding and specimen collections to describe fish biodiversity in the Tukakas Bay, Colombian Caribbean
Introduction: Tukakas Bay, located on the border between Colombia and Venezuela, is practically unknown in terms of its marine biodiversity. This lack of knowledge generated the need to carry out an expedition to evaluate the current state of its associated biodiversity. Objective: To describe for the first time fish biodiversity in Tukakas Bay through integrated sampling methodologies. Methods: We combined environmental DNA (eDNA) from seawater with observations and morphological methods, and subsequent mitochondrial DNA barcoding (COI, 16S) to describe fish biodiversity. Water samples for eDNA analysis were concentrated in four transects along the bay and processed in laboratory. Visual censuses were carried out through scuba diving and snorkelling, and fish were collected in 17 stations. Tissue samples were subtracted and preserved for DNA barcoding. Voucher specimens were fixed and preserved for taxonomy. Both specimens and tissue samples are part of reference collections at MHNMC, and their metadata are available in the public domain. Results: We identified 481 ASVs belonging to 95 species, 68 genera, and 52 families from eDNA, visual censuses, and morphology (including DNA barcoding). Detections made with eDNA included solitary species and represented 65 % of all identified fish taxa in Tukakas Bay, from which 15 species were also observed or collected. Specimen collections were effective for the creation of 45 DNA barcodes and 164 DNA sequences, and the confirmation of taxonomic assignations obtained by the other two methods. We improved taxonomic resolution for 20 % of the taxa by combining these three survey methods. Conclusion: Integrating eDNA metabarcoding approaches to traditional fish surveys significantly improves biodiversity assessments specially on remote areas.
Bio Expedition “Lamuuna Neimalu’u”; Wayuu indigenous communities; La Guajira desert; Colombian Caribbean; molecular taxonomy
Biogeographical analysis of the Central American clade of Sechium (Cucurbitaceae)
Introduction: The genus Sechium P. Brown (Cucurbitaceae) includes 11 species, of which two are domesticated and nine grow in the wild. The Central American clade of Sechium has six species distributed in Panama and Costa Rica. These species have characteristics that can be transferred from wild to domesticated species. Objective: To use three machine learning stacking algorithms and multivariate tools to describe geographic distribution, diversity degree, and endemism, to identify major conservation areas and to promote research for the improvement of the domesticated species. Methods: Two hundred and nine occurrence records were retrieved from the Global Biodiversity Information Facility. Raster values extracted from 21 bioclimatic variables were analyzed with descriptive and multivariate statistics. The species distribution algorithms were assembled with the SSDM library from R software. Results: Most species are distributed in type A and C climates, mainly in volcanic soils, with abundant organic matter. These species can grow at altitudes exceeding 2 000 m and tolerate low temperatures and high humidity levels. K-medoids established two groups and a 0.39 average silhouette coefficient, which indicates a low clustering trend. The stacked distribution models recorded good performance in areas under the curve (AUC) (> 0.75) and true skill statistic (> 0.75). Conclusions: The main variables that supported the models were elevation, soil types, and precipitation. The main endemism and species diversity areas were in the Cordillera de Talamanca, the Cordillera de Guanacaste, the Cordillera de Tilarán, and the Central Volcanic Range (Costa Rica). These species thrive under similar environmental conditions; however, the diverse areas have significantly different precipitation and soil types.
domesticated species; machine learning; diversity; endemism; soil types
Spatial variability and trophic structure of aquatic macroinvertebrate communities in the semi-arid Quilca-Chili basin, Peru
Introduction: The trophic structure of macroinvertebrate communities is of particular interest for understanding the functioning of the river ecosystems. Objective: To determine the community structure and functional feeding groups of aquatic macroinvertebrates in the Quilca-Chili basin. Methods: Two sampling campaigns were conducted at 26 stations, distributed across six sectors, from June to October 2022. The community structure was analyzed based on basic ecological parameters, including taxonomic richness, dominance, evenness, and diversity. Spatial variability was assessed through a similarity percentage analysis and non-metric multidimensional scaling using the Bray-Curtis distance index. The relationship with physicochemical variables was determined through canonical correlation analysis. Results: A total of 51 families were identified and assigned to functional feeding groups: predator, shredder, collector-gatherer, scraper, and filterer. The highest and lowest diversity was observed in the Sihuas sector and the Chili and Lluta sectors, respectively. Differences in community structure indices were found between the six sectors of the basin. The most abundant functional feeding groups were scrapers, while shredders and predators were the least abundant. Conclusion: The spatial distribution reflects the complexity and variability among physicochemical parameters and functional feeding groups in this basin.
functional feeding groups; macroinvertebrates; desert; high Andean; rivers
Acoustic characterization of the threatened bat Neoeptesicus innoxius (Chiroptera: Vespertilionidae) and two sympatric species in western Ecuador
Introduction: Bioacoustics allows the study of the ecology and behavior of bats through the analysis of echolocation signals. In insectivorous bats, foraging strategies, prey preference, and habitat use are closely related to the emission patterns of echolocation signals. Identifying significant bat habitats and improving conservation efforts can benefit from understanding these relationships. Objectives: To describe the echolocation signals of an endangered species Neoeptesicus innoxius, and other commonly detected species in the study area, Myotis nigricans and Molossus molossus, to contribute to the construction of a bat echolocation call reference library in Western Ecuador. Methods: Mist nets were used to capture bats, and reference recordings were subsequently obtained using the Anabat Swift ultrasonic detector. Echolocation pulse selection for each species was carried out using Kaleidoscope Pro 5.6.8 and BatSound 4.2.1, measuring the following spectral and temporal parameters of the echolocation signals in the search phase: initial, final, and maximum energy frequency, pulse duration, and interpulse interval. Results: N. innoxius presented the echolocation signals with the greatest variability of the spectral and temporal parameters, emitting pulses with high modulation speed (with one prominent FM component), and of low modulation speed (with one prominent QCF component); M. nigricans emissions were characterized by broadband signals of very short duration; and M. molossus presented alternation in its echolocation signals, where both high and low pulses had very little variability. Conclusions: The acoustic description of an endangered species like N. innoxius alongside the descriptions of other species frequently detected at the same study site, contributes to the construction of a bat echolocation call reference library. This input is the basis of future research of the ecology and behavior of the insectivorous bats that inhabit the Western Ecuador, which in turn is very valuable for designing tools and strategies for bat conservation.
insectivorous bats; echolocation; Isla Santay; Ecuador; Molossidae; Vespertilionidae.
Proximate composition and lipid content of muscle tissue by TLC-FID of seven freshwater fish species collected from Campoma Lake, Venezuela
Introduction: Lipids in fish play a fundamental role in growth, reproduction, and homeostasis, maintaining cellular integrity. Objective: To assess the nutritional quality of seven fish species from Lake Campoma through analysis of their proximate composition and lipid profile. Methods: A total of 10 kg of each species Cichlasoma kraussii, Pimelodus clarias, Hoplias malabaricus, Aequidens pulcher, Hypostomus plecostomus, Hoplosternum littorale, and Centropomus mexicanus were collected through direct fishing in Lake Campoma. Samples were refrigerated and transported to the laboratory, where muscle tissue was dissected for subsequent analysis. Lipid fractions were determined using thin-layer chromatography with flame ionization detection (TLC-FID). Principal component analysis (PCA) was applied to explore the relationships among the evaluated parameters. Results: Centropomus mexicanus exhibited the highest lipid (2.33% w/w) and protein content (24.07%). In all analyzed species, phospholipids were the predominant lipid class (34–85%), followed by free fatty acids (7%), triacylglycerols (4%), and cholesterol (<34%). Water was the major component in the proximate analysis, ranging from 76.5% in C. kraussii to 82.5% in P. clarias, which may increase susceptibility to microbial spoilage if not stored properly. No clear association was observed between species and ash content. Conclusions: The evaluated species demonstrated high nutritional and energy value, supporting their inclusion in human diets. Phospholipids were predominant (up to 85%), followed by free fatty acids (7%) and triacylglycerols (>4%), with cholesterol levels below 37%. C. mexicanus stood out due to its high protein and energy content, while H. littorale and H. malabaricus were identified as the most nutritionally rich. These findings underscore the importance of these freshwater species as valuable sources of macronutrients and essential bioactive compounds.
Proximate composition; freshwater fish; TLC-FID; total lipids; multivariant analysis
Insights from DNA barcoding endangered endemic Caridina shrimps (Decapoda: Atyidae) in Lindu Lake, Indonesia
Introduction: Humanity faces a multidimensional crisis with severe threats to often poorly known freshwater biodiversity. Molecular tools, like DNA barcoding, can aid in biodiversity exploration, monitoring, and conservation. Sulawesian Caridina shrimps are both ecologically significant and endangered yet remain understudied. Objective: To contribute well-documented DNA barcode (COX1 mtDNA) sequences for three Caridina species endemic to Lindu Lake. Methods: We collected 224 Caridina shrimps from three sites around Lindu Lake in August (n = 73), and October 2023 (n = 117), and July 2024 (n = 34). We measured and analyzed morphological traits as dimensionless ratios of total length. We extracted DNA from six specimens (two per species) and COX1 mtDNA barcodes obtained through PCR (primers jgLCO and jgHCO) and Sanger sequencing. We obtained homologous sequences from GenBank (BLAST routine) and BOLD repositories for phylogenetic analyses. All molecular analyses were performed in MEGA 11. Results: One species was identified at each site. Morphological traits differ between species. Three haplotypes with low divergence: one in Caridina kaili, one in Caridina linduensis, and one in both Caridina dali and C. linduensis. Homologous sequences in GenBank and BOLD included very few Sulawesi endemic species; these formed the closest sister clades to Lindu Lake Caridina. Conclusions: We submitted to the GenBank repository the first reference DNA barcodes for each of the Lindu Lake Caridina species. The poor resolution of COX1 mtDNA for Lindu Lake Caridina may be due to recent evolutionary processes. Our study highlights the ongoing need for barcoding freshwater invertebrates, particularly atyid shrimps from Sulawesi, in the Wallacea bioregion.
atyid shrimps; Crustacea; cryptic species; lacustrine; mitochondrial DNA; Wallacea
Light preferences, population structure, and pre-dispersal fruit predation in the reverse-phenology tree Bonellia nervosa (Primulaceae)
Introduction: Bonellia nervosa is a dry forest understory tree with reverse leafing phenology (it produces leaves during the dry season and is deciduous during the wet season). Being a phreatophytic species, it relies on substantial root biomass to access groundwater and flush leaves during the dry season. Objective: assess the population structure of B. nervosa in Santa Rosa National Park, Costa Rica; analyze the relationship between stem diameter and plant height; and examine how canopy structure and light availability influence its local abundance. We also evaluated fruit maturity and pre-dispersal fruit predation during the late wet season to understand its reproductive success. Methods: the study was conducted along the Indio Desnudo trail (6.16 ha). Hemispherical photographs were taken above or near each B. nervosa (n = 33) and at 10 random sites where the species was absent. We used principal component analysis to consolidate seven light and canopy structural variables. The Chapman-Richards model was applied to examine the relationship between stem diameter and height and to identify inflection points. We analyzed fruit weight and seed count and inspected each fruit for the presence of Tortricidae larvae. Results: Adults dominated the population (only three seedlings were found out of 33 individuals). The Chapman-Richards model identified an inflection point at 70.6 cm in height, indicating a shift from relatively rapid to progressively slower growth. Bonellia nervosa sites had higher canopy openness (14.68 %) and transmitted diffuse light (21.05 μmol/m²/s) than sites where the species was absent (12.42 % and 18.22 μmol/m²/s, respectively). Predispersal fruit predation was low (16 % of fruits, n = 39), and was effected by Tortricidae larvae. Conclusions: Seedlings are likely limited by high energy demands for reserve accumulation, vulnerability to drought-related mortality, mechanical damage, and susceptibility to herbivory and pathogens. Their scarcity creates a recruitment bottleneck. The dominance of adults, the low number of seedlings, and specific light preferences limit the plasticity and adaptive capacity of B. nervosa to environmental changes. Although pre-dispersal fruit predation was low, further monitoring is needed to assess its full impact. Future research should focus on the physiological mechanisms underlying B. nervosa’s reverse leaf phenology and its resilience to climate change.
phenological strategies; reverse phenology; predispersal seed predation; tropical dry forests
Predicting of HABs by phytoplankton type and abundance in northern Bone Bay, South Sulawesi, Indonesia
Introduction: Harmful Algal Blooms (HAB) are the rapid growth of algae or cyanobacteria in water that can cause negative impacts on people, animals, or the environment by production of natural toxins. Information about HABs in the bays in Indonesia is limited. Objective: To predict HABs based on the type and abundance of phytoplankton in the northern part of Bone Bay, South Sulawesi, Indonesia. Methods: The study was conducted in four locations, namely Tj Ringgit (TR), Passampa (PS), Siwa (SW), and Barangmamase (BM) between May and July 2024. Various environmental parameters, including nutrients, were measured. Phytoplankton samples were collected by filtering seawater using a 25 μm plankton net and analyzed in the laboratory. Results: The dominant types of phytoplankton were found to be Bacteriastrum, Chaetoceros, Leptocylindrus, Rhizosolenia, Thalassionema, and Ceratium. All of them are classified as Non-HABs. The identified types of HABs include Pseudo-nitzschia, Dinophysis, Prorocentrum, Protoperidinium, and Oscillatoria. Orthophosphate and salinity are two environmental parameters that affect the occurrence of HABs. The proportion of HABs abundance was lower than that of non-HABs in all locations. An increase in the abundance of HABs was detected in two locations: SW and BM. Conclusion: Although the proportion of HABs is lower than that of Non-HABs, the increased abundance of HABs in some locations, such as SW and BM, indicates the potential for future blooms. Monitoring environmental parameters, especially orthophosphate and salinity, is critical to mitigating the impact of the development of HABs, which ultimately affects the ecosystem and human health in Bone Bay. This study emphasizes the importance of sustainable water management to maintain the balance of the ecosystem in the bay.
phytoplankton; harmful algal blooms (HABs); Bone Bay; orthophosphate; salinity; mitigation
Structural analysis and health status of the mangrove forest in the coastal sector Paraguay, Guantánamo, Cuba
Introduction: Manglares are ecosystems that provide numerous benefits and environmental services to society. However, its extension is being reduced due to various human activities such as the change in soil use and coastal development, which is why studies are needed to determine the state of these ecosystems and thus propose actions for their rehabilitation. Objective: Characterize the structure and health status of manglar in the coastal sector Paraguay, Guantánamo, Cuba. Methods: The investigation took place in a mangrove forest in the coastal sector that borders Guantánamo Bay, in the eastern region of Cuba. Plots of 100 m2 aligned, perpendicular to the coast; The structure of the mangle is determined by height, diameter, basal area, volume, density and mortality. The relationship of these variables with the composition of mangle species was carried out through a Canonical Discriminant Analysis. To determine the state of health, the quotient of the number of identified tensors over the total of identified tensors is obtained, the result is the remainder and is multiplied by 100 to express it in complete numbers. Using the value obtained, the health status was classified following this scale: very high (from 100 to 71), high (from 70 to 67), medium (from 66 to 62), low (from 61 to 42) and very low (41 or less). Results: The average height of the head was 6.50 m, with a predominance of Avicennia germinans and average regeneration. New environmental tensors were identified, the majority with anthropic character and low intensity (88% are of anthropic origin and 12% are related to natural events). Conclusion: The health of the studied ecosystem presents a variation that goes from very high to low and is characterized by a low size.
basal area; coastal zone; environmental tensors; natural regeneration; forest structure
Foraging patterns and spatial distribution of synanthropic mammals and their interaction with dogs
Introduction: Synanthropic mammals benefit from food and shelter provided by green urban areas. However, they frequently interact with predators such as dogs which may modify certain behaviours and their spatial distribution, compromising their survival. Objective: To determine the effect of feral dogs’ presence on mesopredator synanthropic mammal feeding patterns by analyzing the spatial distribution of three species, opossum (Didelphis marsupialis), ringtails (Bassariscus astutus), and gray fox (Urocyon cinereoargenteus) in a green urban area in Mexico. Methods: Camera traps and scent stations were used to record foraging patterns and spatial distribution. The habitat was characterized and correlated with duration and frequencies of synanthropic mammal feeding patterns and spatial distribution. Results: Opossums were recorded more frequently inside vegetation compared to other areas of the park, while dogs were recorded in grass-covered areas, on roads, and in recreation zones. Ringtails and gray foxes were recorded inside vegetation and in open spaces. Feeding patterns were not affected by the presence or absence of dogs. However, the presence of dogs affected opossum and gray fox vigilance frequency and was associated with habitat characteristics. Ringtail vigilance was affected by dog presence and habitat characteristics. Conclusion: The interaction between dogs and wildlife may generate species-specific behavioural responses, allowing some species to be tolerant of risk while others may show spatial and temporal segregation. Understanding the spatial distribution of dogs and their effect on wildlife inhabiting green urban areas will help to improve control-impact programs of dogs, reducing predation events and improving the welfare of mesopredator synanthropic mammals.
behaviour; camera traps; exotic predator; feeding habits; mesopredator; predation; scent stations; vigilance
Ex situ conservation of White-footed tamarin Oedipomidas leucopus (Primate: Callitrichidae) in four rescue centers: How are we doing it?
Introduction: Ex situ conservation is essential for the preservation of threatened species, such as the gray titi monkey (Oedipomidas leucopus), an endemic primate of Colombia that inhabits the Magdalena Medio region. Many individuals enter Wildlife Care and Assessment Centers (CAVs) for rehabilitation and eventual release; however, achieving this goal is not always feasible. Objective: To assess the population dynamics of the gray titi monkey in four wildlife CAVs located within the species’ endemic region in Colombia. Methods: Various factors related to the ex situ conservation of the species were analyzed in CAVs in Antioquia and Caldas, including annual intake frequency, mortality, and duration of stay in the center, among other characteristics. Results: Between 2009 and 2021, a total of 282 individuals were managed across the four CAVs (48.8 % males and 51.2 % females). The majority, based on age group, were adults (51.8 %), while juveniles, pre-juveniles, and neonates represented 20.9 %, 22.7 %, and 4.6 %, respectively. The municipalities with the highest intake numbers were Medellín (n = 68), followed by La Dorada (n = 25), Norcasia (n = 15), and Victoria (n = 12). Differences were observed in the duration of stay among individuals, with the longest stays recorded for those who remained in the centers or were released. Conclusion: The population dynamics of the gray titi monkey highlight the extended duration of stay for released individuals, suggesting a need to strengthen rehabilitation strategies for the species.
endangered species; euthanasia; primates; release; Saguinus leucopus, wild life handling
Distribution, richness, and abundance of Lycaenidae (Lepidoptera: Papilionoidea)in the Loxicha Region, Oaxaca, Mexico: A regional analysis on the Pacific slope
Introduction: The Sierra Madre del Sur in Mexico, known for its geological complexity and elevational gradient, hosts diverse ecosystems. The Loxicha region in Oaxaca, with five vegetation types and a 2 500 m elevation range, has the richest documented butterfly fauna on the Pacific slope. This study focuses on Lycaenidae butterflies, exploring their distribution, richness, and abundance along vegetation and elevational transects. Objective: To document geographic, elevational, and ecological patterns of Lycaenidae butterflies on the Pacific slope Loxicha region as part of a larger project on the distribution of diurnal butterflies in the state of Oaxaca, Mexico. Also, to compare Loxicha fauna with other regions to recognize biogeographical patterns at a larger scale. Methods: Spatial and temporal patterns of Lycaenidae diversity are based on systematic sampling conducted between 2005 and 2014 along elevational (80 to 2 500 m) and vegetational transects. Exclusive and characteristic species for each elevation and vegetation type are recognized. Results: A total of 123 species of Lycaenidae were recorded: nine species of Polyommatinae and 114 of Theclinae. The highest species richness occurs in May in tropical semi-deciduous forest. It decreases with increasing elevation. The results are compared with four other butterfly families. Lycaenid community similarity in the Sierra Madre del Sur and Pacific slope is correlated with elevation and vegetation type, though variability within each grouping is significant. Higher elevation faunal isolation also plays a role, as seen in other mountainous Papilionoidea taxa. Conclusions: Lycaenidae is one of the most diverse and least known butterfly families in Mexico. This is the fourth study on the Loxicha Region's lepidopteran fauna, confirming its high diversity among five Papilionoidea families. Systematic studies aid in understanding speciation and endemism, particularly for stenotopic species. The distribution of Lycaenidae in the Loxicha region is the most comprehensive to date for any region in Mexico.
elevational gradient; Eumaeini; phenology; Sierra Madre del Sur
Examining functional diversity in two plant communities under ecological restoration in Farallones de Cali, Colombia
Introduction: Functional diversity is crucial in understanding species performance and monitoring ecological restoration processes. In Valle del Cauca, Colombia, where only a small percentage of tropical dry forest remains, ongoing ecological restoration efforts are vital. However, monitoring of restoration efforts is typically not conducted. Objective: To compare the functional diversity of two plant communities, restored two and eight years ago, in the Loma Larga reserve, Colombia. Methods: We assessed nine functional traits in the five most significant species of each community. The analysis included contrast tests for functional trait differences, as well as functional diversity indices. Results: The 8-year community displayed greater values for maximum height, diameter at breast height, and specific leaf area. Conversely, the 2-year community exhibited higher leaf thickness. Moreover, the 8-year community presented the highest values in the functional indices: richness, evenness, divergence, dispersion, and specialization. Conclusions: Ecological restoration had a positive impact on plant communities, as evidenced by increased functional diversity and structural complexity in the 8-year community compared to the 2-year community. This suggests that ecological succession processes advance significantly over time, leading to more resilient and functionally diverse communities. The analysis of functional traits stands out as an effective tool for monitoring the success of restoration and guiding future efforts in critically threatened ecosystems such as tropical dry forests.
Conservation priority sites for reptiles in the Sierra Madre del Sur with a perspective for the future
Introduction: Reptiles are often overlooked when planning for conservation, as they are typically perceived as a persistent or tolerant group. Nonetheless, recent studies have shown their vulnerability. Identifying priority areas is crucial, and spatial prioritization is an essential analysis to optimize the scarce available resources for conservation. Furthermore, it is of the utmost importance to establish protected area networks that would keep their usefulness in the future, especially considering the enormous environmental changes that are currently occurring. Objectives: To evaluate the performance of the current protected area network (PA) and to identify potential areas for expansion, considering their persistence in time. Methods: We estimated species distributions for 177 reptiles on the Sierra Madre del Sur in Southeastern Mexico. The species were weighed according to their international conservation status, and future land use scenarios were incorporated to identify priority areas with Zonation software. Results: We found coincidences between priority areas for reptiles and zones previously identified for other groups. However, most regions with top priority rankings remain unprotected, considering the current established PA. Federal PA protects the highest percentage of priority areas, followed by areas voluntarily dedicated to conservation and state PA. We emphasize conserving natural land uses since they are the only ones that constitute the highest priority zones for reptiles. Conclusions: Our prioritization for reptile conservation entails efficient outcomes in terms of temporal permanence, amount of area to be protected, and coverage of species distribution, especially for small percentages of expansions to the current network of PA, making it an affordable proposal for implementation. Nonetheless, it is crucial to recognize that it is also important to consider social factors, possible conflicts of interest, and to evaluate the effectiveness of PA over time.
land use, Mexico, protected areas, spatial conservation, species distribution models, Zonation.
The impact of climate change on the distribution of wetland-associated invasive alien plant species in Western province, Sri Lanka
Introduction: Climate change and invasive alien plant species (IAPS) severely threaten natural ecosystems globally. Objective: To identify and assess climate suitability for seven wetland-associated species and predict their future distribution using shared socio-economic pathways (SSPs) 2 4.5 and 5 8.5 for 2050 and 2070. Methods: The species selected were Alstonia macrophylla, Annona glabra, Dillenia suffruticosa, Lantana camara, Leucaena leucocephala, Panicun maximum, and Sphagneticola trilobata. Data on species occurrence were collected by field surveys in the Western province (Colombo, Gampaha and Kalutara districts), and this, together with climate data, were fed into the Maximum Entropy model (MaxEat model). Climate suitability area maps were developed for the seven IAPS for the current climate and four future scenarios. Results: A. glabra, L. camara, and L. leucocephala showed an increase in climate-suitable areas for the years 2050 and 2070 under both climatic scenarios compared to the current distribution. S. trilobata showed a decrease in its range in the future compared to the current distribution. The climate-suitable area for A. macrophylla will also not expand under either scenario except for a modest rise in SSP2 4.5 in 2050. The current distribution of D. suffruticosa and SSP2 4.5 in 2050’s distributions were almost identical, and the other two future scenarios showed comparatively low distribution. For P. maximum SSP2 4.5 indicated a slight increase in climate-suitable areas for 2070 compared to the current distribution. Conclusion: A. glabra, L. camara, and L. leucocephala can become highly invasive as their ranges expand in response to future climate changes. The distribution of S. trilobata will be significantly reduced under future climate scenarios. As suitable areas for IAPS increase in the Colombo district over time compared to other districts in the province, its wetland-associated native plant species may face a greater risk of invasion by IAPS in future climatic scenarios.
temperature; range expansion; exotic; habitat shift; biodiversity.
Morphology, histology and histochemistry of the gastrointestinal tract of the fish Prochilodus magdalenae (Characiformes: Prochilodontidae)
Introduction: The Bocachico Prochilodus magdalenae, an endemic herbivorous/detritivorous fish from the Magdalena River basin, is the region’s most important fishing resource, with high ecological and socioeconomic significance. Its populations have declined significantly due to fishing pressure and anthropogenic environmental stressors, including wastewater discharge, infrastructure projects, and material extraction. Understanding the characteristics of its digestive tract is a crucial knowledge gap, hindering the comprehension of nutritional and physiological processes vital for aquaculture and both in situ and ex situ conservation efforts. Objective: To characterize the morphological, histological, and histochemical features of P. magdalenae’s gastrointestinal tract (GIT) and relate them to its feeding habits. Methods: Fifteen adult specimens from the Sogamoso River (Santander, Colombia) were analyzed using standard morphological measurements and histological and histochemical staining techniques for tissue structure and mucin distribution analysis. Descriptive statistics were used for morphological analysis. Results: Specimens averaged 24.66 cm standard length, 291.77 g weight, and 1.02 condition factor, with a mean GIT weight of 12.02 g. The digestive tract showed four distinct regions: oropharyngeal cavity, esophagus (mean length 1.26 cm), stomach, and intestine (mean length 88.18 cm). The esophagus contained abundant acinar glands, producing neutral and acidic mucins, with acidic mucins predominating. The U-shaped stomach showed simple columnar epithelium with tubular gastric glands producing only neutral mucins. The intestine, lined with simple columnar epithelium, exhibited differential mucin distribution: high neutral mucins anteriorly and predominantly acidic mucins in middle and posterior segments. Conclusions: The gastrointestinal characteristics align with its feeding habits, particularly the elongated intestine and thick pyloric muscular layer. The distinct mucin distribution pattern, especially the carboxylated acidic mucins in the middle and posterior intestinal segments, supports nutrient absorption functions. These findings provide crucial reference points for fish welfare assessment, pathogen response in aquaculture, and environmental impact evaluation in natural habitats.
histochemistry; histology; mucins; mucous cells; detritivorous fish.
Embryogenesis and early larval development of the fish Sorubim cuspicaudus (Siluriformes: Pimelodidae)
Introduction: Sorubim cuspicaudus is a migratory catfish listed as a vulnerable fish. The study of its embryonic and larval development allows the identification of morphological and chronological events necessary to establish adequate management practices. Objective: To describe the main events of the embryonic development and early larval phase of the trans-Andean shovelnose catfish, S. cuspicaudus, under controlled conditions of incubation and larviculture. Methods: Final maturing fish were induced for reproduction with a dose of 10 µg of GnRH/kg of live weight. The embryos were incubated at 28 ± 0.5 °C and were analyzed at early stages (zygote-gastrula) every 5 minutes and late stages (cleavage-hatching) every 15 minutes. Results: Animal pole differentiation occurred at 0.5 hours post-fertilization (HPF), first cleavage at 0.58 HPF, 4, 8, 16, 32, 64 cells at 0.75, 0.92, 1.08, 1.17, 1.33 HPF respectively, blastula 1.5 to 4.37 HPF, gastrula 4.7 at 6.87 HPF, organogenesis 7.37 at 11.37 HPF, pharyngula 11.87 at 13.37 HPF, and hatching at 15.92 HPF. The opening of the mouth happened at 32 hours after hatching (HPH), food consumption at 43 HPH at 26.6 °C, yolk sac depletion 70.5 HPH, barbels at 35.7 HPH, fins at 6 days post hatching (DPH), swim bladder at 10.2 DPH, stomach with glands at 12 DPH, additionally with sensory and locomotion organs. Conclusions: The fingerlings show complete development and escape instinct at 14 DPH. It is suggested that 14 DPH could be the minimum age to carry out restocking programs with this species.
histology; larvae; fingerling; growth; ontogeny; catfish.
Carbon capture in Chondracanthus chamissoi (Gigartinaceae) algal meadows: a case study on the Peruvian coast
Introduction: Algal meadows can significantly contribute to carbon (C) capture; nevertheless, few studies on Peruvian coast reserves are available. Evaluation of these stocks allows proposing better measures for the sustainable use of these habitats and maintaining their ecosystem services. Objective: To estimate biomass distribution and quantify the C captured as standing stock biomass in natural algal meadows of red algae Chondracanthus chamissoi on the Laguna Grande coastal lagoon (Ica-Peru), place of main extraction of these economically important algae. Methods: To calculate the biomass, the area occupied by each patch of algae in each sampling zone was delimited and transects perpendicular to the coast were used in randomly located plots. In the laboratory, the dry biomass and C content were measured (the latter using an elemental analyzer). Results: Monthly variation in the distribution and area was identified. September 2021 presented the highest total biomass (50 416.4 kg; 50.4 t) and C captured (13 t C or 47.58 t CO2) while from February to June no algal biomass was found. Differences were found in the biomass and C capture in the sampling zones, the months of C capture, and the interaction between these two variables. C capture decreases with warm months and more intensive anthropogenic extraction of algae. Conclusions: This study highlights the interaction between the anthropogenic extraction of C. chamissoi and seasonal environmental changes, alongside the net contribution of macroalgal biomass.
assimilation of carbon; blue carbon; red algae; sustainable extraction.
Histological development of fish larvae Piaractus orinoquensis (Characiformes: Characidae) with emphasis on mouthparts
Introducción: El proceso de desarrollo larval es una etapa crítica en los sistemas de producción acuícola por la mortalidad que se presenta, debida a la temperatura, patógenos y la alimentación, entre otros. El suministro adecuado de alimento en cada etapa es uno de los inconvenientes más frecuentes dado el desconocimiento del desarrollo bucal en la transición de larva a juvenil que permita la toma de decisiones sobre manejo alimenticio, eficiencia del alimento y disminución de riesgos de pérdida durante esta fase del cultivo. Objetivo: Describir el desarrollo histológico de larvas de cachama blanca Piaractus orinoquensis con énfasis en el aparato bucal, durante la transición de larvas a alevinos. Métodos: Se tomaron muestras en diferentes estadios desde las 0 hasta las 763 hpe (horas post eclosión), registrando los diferentes cambios morfológicos por medio de histología convencional, microscopía óptica de alta resolución y microscopía electrónica de barrido, para un posterior análisis de imágenes con el software ImageJ®. Resultados: Las cachamas muestran ontogenia indirecta y son especies altriciales, debido a que muestran escasas reservas vitelinas cuando inician la alimentación exógena, como se evidenció a las 187 hpe con cambios significativos en el aparato bucal, pero sin contenido estomacal, posiblemente por inmadurez del sistema digestivo y la falta de suministro de alimento en esta etapa, factores asociados al manejo del cultivo, lo que incrementa el riesgo de mortalidad y escaso crecimiento de las larvas en relación directa con la alimentación. Conclusión: Los productores deben mejorar el proceso de larvicultura, al sincronizar los tiempos de traslado de la incubadora y de preparación del estanque, como estrategias de alimentación temprana para equilibrar la eficiencia económica con el desarrollo y la demanda metabólica de las larvas, mejorando así los índices de supervivencia y el rendimiento en los sistemas de producción piscícola.
larviculture; high-resolution optical microscopy; feeding; jaw.
Population structure of freshwater prawn Macrobrachium amazonicum (Crustacea, Palaemonidae) in two regions of the Amazon River, Brazil
Introduction: Macrobrachium amazonicum is a species of shrimp native to South America, widely distributed and exploited by artisanal fishermen in the North of Brazil. Objective: This study aimed to analyze the population structure of M. amazonicum, with an emphasis on sex ratio, frequency distribution of male and female size, also considering the rainy and dry period in the study areas. Methods: For this, monthly collections were carried out from May 2017 to April 2018 with the help of “matapis” in two locations, Mazagão and Ilha das Marrecas. Results: A total of 6 796 (4 163 females and 2 633 males) were captured, with a monthly average of 531.66 specimens. The sex ratio in both areas was favorable to females with 1.32♀ : 1♂ (x² = 76.58, p < 0.001) in Mazagão and 2.34♀ : 1♂ (x² = 394.26, p < 0.001) in the Ilha das Marrecas. In both Mazagão and Ilha das Marrecas, abundance was strongly related to precipitation. Conclusions: The shrimps of Ilha das Marrecas were longer than those caught in Mazagão. Despite this fishing pressure in Mazagão, the areas proved to be favorable for the growth of the species.
morphometry; sex ratio; white water Amazon shrimp; estuary; river.
Molecular determination of Helicobacter pylori and detection of beta-lactamases in clinical isolates from patients in Antioquia-Colombia
Introduction: Helicobacter pylori exhibit variations in antibiotic resistance in America and Colombia. Despite the use of various treatment regimens containing amoxicillin in the department of Antioquia, Colombia, as well as in several countries across the continent, the pattern of genotypic and phenotypic susceptibility to this antibiotic remains unknown. Objective: To determine the frequency of H. pylori infection by detecting the ureA gene and amoxicillin susceptibility through beta-lactamases in H. pylori isolates from patients with gastroduodenal diseases in Antioquia-Colombia. Methods: Cross-sectional analytical study with 179 patients attending endoscopy units of seven healthcare institutions. Sociodemographic and risk factor data were collected. Moreover, biopsies from the antrum and body were taken for microbiological isolation and molecular detection of H. pylori. The sociodemographic data were assessed through frequency analysis and bivariate statistics. DNA obtained from the biopsies was amplified by PCR for the ureA gene, and beta-lactamase production was evaluated using the nitrocefin test as well as the amplification of the TEM and SHV genes. Results: It was found that 61 % (109 / 179) of patients tested positive for H. pylori; out of 84 isolates obtained by culture, none tested positive for the nitrocefin test. Significant differences were found in socioeconomic status, healthcare system, and geographical location in patients positive for the ureA gene. Two patients tested positive for molecular detection of beta-lactamases from biopsies; however, SHV and TEM genes were not found in any isolate. Conclusions: The frequency of H. pylori for ureA-gene detection is higher than previous studies and similar to other reports in other Colombian regions; consequently, this will become a good diagnostic test in the country. Finally, none of the H. pylori isolates tested positive for beta-lactamases TEM and SHV.
Flora of high mountain tropical peatlands: threats and management measures, Talamanca Range, Costa Rica
Introduction: Tropical peatlands are highly fragile vegetal formations, especially vulnerable to anthropogenic impacts and changes in climatic conditions. Objective: To characterize the flora of the Talamanca peatlands, as well as identify their dynamics, threats, and impacts. Methods: The flora was analyzed in five peat bogs located in the Buenavista Massif, along the Inter-American Highway, at altitudes of 2 400 - 3 100 m, through field sampling. Subsequently, a Floristic Value Index (IVF) was designed to assess the state of conservation. Results: The floristic richness was determined in the peat bogs studied. A lower biological diversity was found in the three peatlands outside the state-protected natural spaces, suggesting the influence of the edge effect and agro-productive activities or their proximity to the Highway. In contrast, the Salsipuedes and Cerro Paramillo peatlands exhibited greater diversity, highlighting genera such as Blechnum, Puya, Chusquea, Myrsine and Vaccinium, in association with the bryophyte genus Sphagnum. A different floral composition was observed along the strip near the Inter-American Highway, characterized by species with lower water demand, especially genera such as Rubus and Pteridium, among others. Conclusion: From the identified floristic composition, the importance of peatlands as part of the mesoamerican hotspot ecosystems was determined, not only as repositories of biodiversity but also as sensitive indicators of human influence and environmental threats in the region associated with anthropic impact and climate change.
Demographic variations of the spotted snapper Lutjanus guttatus (Perciformes: Lutjanidae) along the Pacific coast of Costa Rica suggest the existence of two population units
Introduction: The spotted rose snapper Lutjanus guttatus is one of the commercially most important fish species in tropical and subtropical areas of the Eastern Tropical Pacific. In Costa Rica, L. guttatus is one of the main target species of the artisanal fishery; traditionally, its management has considered a single population that extends along the entire coastal zone. However, there is no evidence that there is only one population unit, which could affect the effective management of this valuable resource. Objective: Determine the population structure of L. guttatus caught on the Pacific coast of Costa Rica through demographic parameters. Methods: A total of 428 specimens, collected in different zones along the Pacific coast of Costa Rica were analyzed, including 190 males and 238 females. The size structure, total length-weight relationship, maturity stages, mean size at sexual maturity, age and growth were estimated, differentiating between the Northern, central, and Southern Pacific of Costa Rica. Results: Demographic variations were observed in size structure, total length-weight relationship, the average size of sexual maturity, and growth rates among the organisms caught in the three sampling regions. Conclusion: The demographic variations of L. guttatus in the different capture areas suggest the probable existence of two separate population units; the first corresponds to the Northern Pacific, and the second includes the central and Southern Pacific areas. The above has important implications for the management of the resource.
Phenotypic differences in sun and shade leaves of Monstera deliciosa (Araceae)
Introduction: Leaves are among the most plastic organs in plants, and their structure, while shaped by phylogeny, can show considerable phenotypic plasticity within a species in response to environmental gradients. Monstera deliciosa, a tropical hemiepiphytic vine known for high leaf heteroblasty, adapts to diverse light conditions. This makes leaf structure a useful proxy for assessing whole-plant resource allocation strategies and adaptations to environmental changes. Objective: To measure the morphological and structural differences in sun and shade leaves using nine leaf traits (petiole length, leaf width and length, effective leaf area, fenestrated area, leaf perimeter, lobulation ratio, stomatal density, and specific leaf area -SLA-). Methods: We selected 20 widely separated M. deliciosa plants on the University of Costa Rica campus in 2022, positioned in contrasting sun and shade conditions, and measured one mature leaf per plant (ten per light environment). Results: Sun leaves had higher fenestrated area, perimeter, and stomatal density, suggesting structural adaptations to high light. These traits may enhance thermal regulation by facilitating heat dissipation. Sun leaves had lower SLA, indicating thicker, denser leaves better suited to high light and wind exposure. Lobulation ratios (leaf dissection) were not different between sun and shade conditions. A principal component analysis explained 82.88% of the variation in the leaf traits, with 39 % of the variation attributed to fenestrated area, leaf perimeter, and effective leaf area. Correlation analyses showed that fenestrated area, perimeter, and stomatal density were positively associated (and negatively related to SLA), emphasizing the functional convergence of these traits, adapting the leaf phenotype to light differences. Conclusions: M. deliciosa modulates leaf morphology and structure to adapt to distinctive light conditions, with fenestration, stomatal density, and SLA emerging as crucial traits. These findings underscore the significance of environmental differences in driving leaf shape and structure.
functional traits; leaf dissection; phenotypic plasticity; plant morphology; stomatal density.