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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Environmental DNA exploration of fish diversity in the Balantak River, Central Sulawesi, Indonesia
Introduction: Freshwater ecosystems play a crucial role in supporting human life, providing many ecosystem services. Species diversity is a valuable indicator for evaluating ecosystem health, gaining a broader perspective on ecological richness and ecosystem functions, but data are lacking for many rivers. Objectives: To obtain baseline data on the upstream and downstream ichthyofauna of the Balantak River, Banggai Regency, using environmental DNA (eDNA) with a focus on diadromous species. Methods: We collected, filtered and preserved water samples from upstream and downstream sites on the Balantak River followed by eDNA analysis (DNA extraction, PCR with MiFish 12S rRNA primers, Illumina sequencing, MitoFish bioinformatic analysis at 97 and 99 % identity thresholds) to produce taxonomically assigned Actinopteri amplicon sequence variants (ASVs). Results: Our data are consonant with the expected dominance of diadromous and euryhaline taxa (75 %), high Gobiiformes biodiversity, and differences between upstream and downstream ichthyofaunal communities. Reads were assigned to Actinopteri ASVs from 12 orders, predominantly Gobiiformes, Anguilliformes, and Centrarchiformes. The 15 assigned families included Anguillidae, Eleotridae, Gobiidae, Rhyacichthydae, Kuhliidae, and Terapontidae. Of the assigned genera (17 at 97 % and 25 at 99 %), Anguilla had the most reads (39.9 %), and Sicyopterus had the most ASVs (8). Conclusions: These baseline data demonstrate the usefulness of eDNA metabarcoding for exploring ichthyofaunal biodiversity in small tropical watersheds while highlighting gaps in 12S rRNA sequence databases, reinforcing the need for integrative taxonomic research in Sulawesi watersheds and reliable reference databases. Most assigned taxa are vulnerable to exploitation for food and/or the ornamental fish trade. Four non-native taxa from Cichlidae, Cyprinidae and Clariidae are considered invasive. Implications for conservation include the need to address the unregulated and largely unreported freshwater ornamental trade and introduction of non-native invasive species.
Copyright (c) 2026 Revista de Biología Tropical https://creativecommons.org/licenses/by/4.0
Temporal variation of macroinvertebrate diversity in a high Andean microbasin in the south American tropics
Introduction: The study examines the aquatic biodiversity of macroinvertebrates in the Alambi River, in Ecuador and analyzes how human intervention has influenced the physico-chemical composition of the water and macroinvertebrate communities among 2000 and 2021. Methods: Physical and chemical data were collected, and pH, conductivity, dissolved oxygen, dissolved solids, and temperature were measured. The macroinvertebrates were obtained by means of "Surber", "D" and "kick" type nets. Three indices were used: BMWP, (Biological Monitoring Working Party), ABI (Andean Biotic Index) and (EPT) (Ephemeroptera, Plecoptera and Trichoptera). Cluster analysis, principal components and canonical analyses were also performed. Results: Taxonomic diversity increased significantly between 2000 and 2021, with an increase in the entire group of taxa. Diversity indices varied similarly between years, Simpson from 0.82 to 0.89 in 2000 versus 0.74 to 0.85 in 2021. Shannon in 2000 (2.20 to 2.45) and in 2021 (1.93-2.47). The completeness of the sampling was similar in both years, 81 vs 77 %, respectively. The structure of the macroinvertebrate community was more heterogeneous overall in 2021. There is a change in the sequential pattern in the turnover of communities in the direction of flow, which varies in 2021. The width of the river decreased in 2021. The average speed of the river also decreased from 1.12 m/s in 2000 to 0.52 m/s in 2021. The pH of the water increased slightly (7.8 to 8.1). Dissolved oxygen increased significantly from 66 % to 80 %. Conductivity and dissolved solids increased at all stations in 2021. The physico-chemical variables varied in their importance over the years, the most relevant being dissolved oxygen, total solids, and altitude, associated with good quality indicator families. The quality indicators in general demonstrated good watershed quality maintained over time, despite changes in both land use and human population growth. Conclusion: The Alambi basin has important changes in the composition and structure of aquatic invertebrate communities, however, it generally maintains good physical, chemical and biotic conditions that support the processes for maintaining the integrity of the basin.
Plants that allocate more resources to flower production yield more fruit at local and global scales
Introduction: The internal mechanisms of plants and their interactions with the environment determine flower and fruit production. Several hypotheses have been proposed to explain these processes, emphasizing resource limitations, interactions with pollinators, selective abortion, the characteristics and positions of hermaphroditic flowers, and the influence of environmental variables on plant function. Objectives: This research aims to evaluate whether a high allocation to flowers positively affects the fruit production of hermaphroditic plants, as predicted by the pollinator attraction hypothesis, or whether it negatively correlates, as suggested by the selective abortion hypothesis. Methods: Both a local (Medina, Colombia) and a global database, based on the biomass of flowers and fruits collected using fruit traps were used to determine the possible relationship between the variables. The Medina database included data from 5-10 individuals for each of the seven plant species studied, with entire flowering and fruiting periods monitored. The global dataset encompassed 92 locations across 10 counties in Latin America, 2 in Europe, 2 in Africa, 2 in Asia and 1 in Oceania. This database compiled information on the total biomass of flowers and fruits of different plant species produced over at least one annual cycle. Results: The plant species studied and the global analysis revealed a positive relationship between flower and fruit production, supporting the pollinator attraction hypothesis. Although we did not quantify the biomass of aborted fruits, we found no evidence to suggest that high flower production results in an excess of ovules that cannot develop, as predicted by the selective abortion hypothesis. Conclusions: These findings suggest that plants have evolved allocation mechanisms for flower production that align with the potential for fruit development.
Urbanization as a driver of change: Differential ecological patterns of native and non-native parrots (Psittaciformes: Psittacidae) in an urban tropical city
Introduction: Parrots and related birds (i.e., Psittacidae, hereafter “parrots”) include species that often establish non-native populations in cities. However, little is known about their species-specific ecological patterns to urbanization in tropical cities. Objectives: To analyze changes in species richness, abundance, and composition across different urbanization levels and to compare abundance trends of most abundant species regarding built-up, grass and tree cover at different spatial scales (i.e., 200, 500, 1 000 m) for parrots in Medellín, Colombia. Methods: Parrot surveys were conducted from September 2021 to February 2022 (using transects, n = 10) and July 2023 to August 2023 (using point counts n = 220). Parrot abundance patterns were analyzed with Generalized Linear Models (GLMs), selecting the significant variable and best models based on Analysis of Variance (ANOVA) and Quasi-Akaike Information Criterion corrected (QAICc), respectively. Results: We recorded ten parrot species; six of them were non-native (i.e., outside their natural range of distribution): Eupsittula pertinax, Ara spp. and Amazona spp. The remaining four were native species: Brotogeris jugularis, Forpus conspicillatus, Pionus chalcopterus, and Psittacara wagleri. B. jugularis, F. conspicillatus and E. pertinax were the most abundant species, B. jugularis increased its abundance in areas with higher urbanization levels and F. conspicillatus in areas with lower levels. E. pertinax showed higher abundances in areas with medium to high urbanization levels (51-75 %), but it showed relationships with lower statistical power. Conclusions: Our finding suggest that the parrot assemblage in Medellín is mainly represented by non-native species in richness and composition, but native species are more abundant. Acknowledging these differences in ecological patterns in species can help improve urban wildlife management in tropical cities.
First assessment of the physiological performance of nursery corals in the Galápagos Islands: seasonal impacts on Pocillopora (Scleractinia: Pocilloporidae) growth
Introduction: Coral communities in the Galápagos Islands persist under highly variable oceanographic conditions driven by seasonal upwelling and ENSO-related thermal anomalies, which have historically constrained reef development and recovery. Following the 1982–83 El Niño event (~97 % coral mortality), recovery has been slow and fragmented. Despite this, Pocillopora remains the dominant reef-building genus in the central-southern archipelago and a key target for restoration. However, it remains unclear how seasonal thermal variability influences coral performance in nursery settings. Objective: To evaluate how seasonal thermal variability affects the growth, survival, and condition of Pocillopora corals in nursery settings in the Galápagos, in order to inform restoration strategies. Methods: Coral communities were assessed in Puerto Villamil Bay (Isabela Island), and 12 Pocillopora morphotypes were propagated in rope nurseries. Fragments were monitored using photographic records, and surface area was measured with ImageJ. Absolute, relative, and specific growth rates were calculated, along with mortality and tissue condition (% dead, bleached, and algal cover). In situ temperature data and El Niño 1+2 anomalies were incorporated to characterize thermal variability. Results: The coral community was dominated by Pocillopora (73.6 %, n = 3 569 colonies). Temperatures ranged from 18.7 to 30.1 °C under La Niña conditions. Fragment size increased more than fourfold (from 6.40 ± 2.51 to 27.75 ± 15.85 cm²), with an overall survival rate of 80 %. Growth exhibited strong seasonal patterns: relative and specific growth rates were higher during the warm season, while absolute growth was greater in the cold season. However, the cold upwelling period was associated with reduced overall performance, including higher mortality, tissue loss, and algal overgrowth. Significant differences among morphotypes were observed. Conclusions: Coral gardening is viable in the Galápagos, although seasonal cooling imposes important constraints. Restoration strategies should prioritize resilient morphotypes and account for seasonality to optimize outcomes in marginal reef systems.
coral gardening; thermal stress; La Niña, intraspecific variation; Eastern Tropical Pacific; coral physiological condition.
Beyond the crest: quantifying coastal protection and risk mitigation services of submerged reefs in the Mexican Caribbean
Introduction: Coral reefs function as natural coastal defenses by dissipating wave energy and reducing flooding and erosion. While the protective role of emergent reef crests is well documented, the contribution of submerged reefs remains poorly quantified. This study evaluates the coastal-protection function of two submerged reefs (Manchoncitos I and II) offshore Playa Paraíso, Quintana Roo, Mexico. Objectives: (1) quantify wave height reductions associated with submerged reefs; (2) compare wave propagation under reef and no-reef scenarios; and (3) assess the sensitivity of wave attenuation to changes in reef roughness. Methods: Numerical modeling (WAPO/REFDIF) was used to simulate wave transformation across the reef platform. A high-resolution bathymetric grid (4 × 3 km; 5 m) was developed using multibeam surveys, satellite-derived bathymetry, and in situ measurements. Simulations compared reef and no-reef scenarios and evaluated two Nikuradse roughness values (ks = 0.5 and 1.5 m). Results: The reefs generated local reductions in significant wave height ranging from 0.5 to 1.5 m. Manchoncitos I produced the greatest attenuation, whereas Manchoncitos II exhibited a more heterogeneous response, including localized wave-focusing effects. Increasing reef roughness enhanced wave-height reductions and expanded the spatial extent of wave dissipation. Wave attenuation varied according to reef geometry, roughness, and incident wave direction. Conclusions: Submerged reefs provide measurable coastal-protection services by reducing wave energy reaching the shoreline. Reef morphology and roughness strongly influence attenuation patterns. These findings support reef conservation and restoration to reduce coastal risk.
Coral reefs; wave attenuation; numerical modeling; reef roughness; Nikuradse (ks).
Coral reefs cover only about 3% of the ocean’s surface yet support approximately 33% of marine biodiversity. They also generate substantial economic benefits, with an estimated spillover value of $350,000 per hectare per year (Costanza et al., 2014). Despite their ecological and economic importance, nearly 90% of coral reefs are currently under threat, primarily due to anthropogenic pressures (Souter et al., 2020). This alarming situation has created an urgent need to implement effective policies for their protection and restoration, prompting global initiatives such as the UN Decade on Ecosystem Restoration (UN, 2021).
Early-life history traits of Thalassoma bifasciatum in Culebra, Puerto Rico
Introduction: The study of labrid otoliths has contributed significantly to our understanding of life histories of tropical reef fish. Life history theory is based on the effect on lifetime reproductive success (i.e., fitness), growth, mortality rates, age at maturity, reproductive output, and particularly for reef fish age and size at settlement of pelagic larvae to benthic juveniles. Objective: Quantify age and larval growth at settlement, subsequent length, and body condition of Thalassoma bifasciatum. Methods: Two hundred T. bifasciatum individuals were collected from Punta Maguey, in Culebra, Puerto Rico. One hundred individuals were euthanized for otolith dissection. Results: Otolith analyses revealed settlement ages ranging from 10 to 37 days and estimated standard length of 9–20 mm at settlement. Growth analyses demonstrated a significant positive relationship between age and length, while length – weight regression revealed a negative allometric growth, where length increases at a faster rate than body mass (b < 3). Additionally, Fulton’s condition factor declined with the increasing length. Conclusions: This study highlights early life history and growth patterns in T. bifasciatum in Culebra, PR and underscores the need for further exploration of life history traits to better understand population dynamics of tropical reef fishes. The rapid settlement observed in our study may be attributed to elevated water temperatures, suggesting that environmental drivers play a critical role in shaping recruitment and growth. This emphasizes the importance of incorporating environmental drivers when evaluating recruitment and population structure.
coral reef; otolith; aging; condition factor.
Nature-based solutions for nutrient removal in tourism wastewater: pilot bio-gardens with red mangrove (Rhizophora mangle) and water hyacinth (Eichhornia crassipes) at Iberostar Bávaro, Dominican Republic
Introduction: Wastewater from coastal tourism operations often retains residual nitrogen and phosphorus after conventional secondary treatment, contributing to nutrient enrichment in adjacent marine ecosystems. Nature-Based Solutions (NbS) have been proposed as low-cost polishing strategies that integrate ecological processes into wastewater management. Objective: To evaluate the short-term nutrient attenuation potential of Rhizophora mangle and Eichhornia crassipes in constructed bio-gardens installed downstream of hotel wastewater treatment systems under operational conditions. Methods: Four concrete bio-gardens (3.0 × 1.2 × 0.6 m) were installed downstream of an on-site wastewater-treatment facility in the Dominican Republic. Three units were planted (replicated treatments units) and one was left unplanted (control). Phase 1 evaluated R. mangle under continuous flow using treated effluent. Phase 2 evaluated E. crassipes under similar hydraulic conditions using enriched influent to simulate elevated nutrient loads. Water samples were analyzed for phosphate, total phosphorus, nitrate–nitrogen, and total nitrogen over a 48-hour hydraulic retention period. Results: During Phase 1, R. mangle exhibited limited short-term nutrient attenuation consistent with early-stage system stabilization. In Phase 2, E. crassipes demonstrated substantial short-term phosphorus removal and moderate nitrogen attenuation under enriched conditions, whereas the unplanted control showed minimal change. Conclusions: Plant-based bio-gardens can be physically integrated into hotel wastewater systems and may contribute to nutrient-load reduction when appropriately designed and managed. The contrasting short-term dynamics observed between species highlight functional complementarity under different loading scenarios rather than direct species superiority. These findings support further investigation of NbS as tertiary polishing modules within sustainable tourism infrastructure.
Nature-based solutions; Rhizophora mangle; Eichhornia crassipes; nutrient removal; wastewater treatment; tourism; Caribbean.
Diversity analysis of Chironomidae from the Andean-Amazonian transition (Caquetá, Colombia): a regional perspective
Introduction: The family Chironomidae is one of the most diverse and abundant groups of aquatic macroinvertebrates in aquatic ecosystems. Objective: To analyze Chironomidae's composition and diversity in the Caquetá department's Andean-Amazonian corridor, Colombia. Methods: Three study zones (Andean, Transition, and Amazonian), each with ten sampling stations, were selected. We conducted four field campaigns to collect biological material and record riverscape characteristics. We assessed alpha diversity using Hill numbers, a set of diversity measures providing a unified framework for diversity analysis. We also analyzed beta diversity by considering species richness differences and turnover. Using multivariate RDA analysis, physical and chemical variables of the riverscape contrast with taxonomic composition and beta diversity. Results: 36 chironomid taxa were identified, with the subfamily Chironominae and the genera Cricotopus, Chironomus, Larsia, and Polypedilum standing out. Hill numbers showed differentiation in Shannon-Wiener diversity (q1) and inverse Simpson diversity (q2), but richness (q0) showed less variation across study zones. The most significant component of beta diversity was species richness differences. Current velocity, total dissolved solids (TDS), vegetation cover, and substrates of sandy and vegetative origin (roots, aquatic macrophytes), as well as other components of the riverscape, significantly influenced species composition and beta diversity. Conclusions: Significant genus level information is provided for the Chironomidae family in the Andean-Amazonian region of the department of Caquetá, revealing dissimilarity among the study areas driven by differences in richness, as a measure of taxonomic beta diversity. Moreover, these findings indicate that the transition region functions as an ecotone for Chironomidae, serving as an intermediate zone between the Andes and the Amazon.
Bryophytes of Quindío: community composition, diversity, and structure across altitudinal gradients and heterogeneous habitats
Introduction: Bryophyte diversity in the Northern Andes is high compared with the Central Andes and other tropical regions, yet regional documentation remains uneven; therefore, department-level inventories are essential for biogeography and conservation. Objectives: To update the bryophyte inventory of the Quindío Department (Central Andes of Colombia) and describe species richness, taxonomic composition, substrate preferences, and altitudinal distribution. Methods: We integrated published and herbarium records with field surveys across six municipalities and nine localities. Sampling encompassed four elevational belts (premontane 970–1 600, montane 1 600–2 400, upper Andean 2 400–3 200, and paramo 3 200–4 200 m.a.s.l.) and five substrates (epiphytic, terricolous, lignicolous, rupicolous, and epiphyllous). Microclimatic variables were recorded in situ during sampling using a thermo-hygrometer (air temperature and relative humidity) and a lux meter (illuminance). Taxonomy and nomenclature were standardized using specialized literature and international databases. Results: We recorded 474 species (82 families, 198 genera): 276 liverworts, 195 mosses, and three hornworts, plus eight subspecies and 15 varieties. Richness was highest on epiphytic substrates (303 spp.), followed by terricolous (242), lignicolous (225), rupicolous (113), and epiphyllous (50) substrates. Lejeuneaceae was the most diverse family (76 spp.); among mosses, Fissidentaceae (17 spp.) and the genera Fissidens (13 spp.) and Campylopus (10 spp.) were prominent. Richness was concentrated in montane and upper Andean forests, with pronounced turnover among substrates and elevational belts. Conclusions: The bryophyte inventory of Quindío was updated to 474 species (82 families, 198 genera). Community composition showed high turnover, driven primarily by microhabitat/substrate filters (with peak richness in epiphytes) and, at the regional scale, by the elevational gradient, providing a baseline to guide monitoring and targeted sampling in underrepresented units.
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.
Copyright (c) 2025 Revista de Biología Tropical https://creativecommons.org/licenses/by/4.0
Multi-temporal coral reef structure and health of Tayrona National Natural Park, Colombian Caribbean
Introduction: Coral reefs are biodiversity-rich ecosystems increasingly threatened by disease and, in particular, mass bleaching events driven by elevated sea-surface temperatures. Objectives: To assess spatio-temporal variation in reef structure and coral health across three reef zones within Tayrona National Natural Park (TNNP) from 1998 to 2023. Methods: Coral cover (CC), algal cover (AC), and coral health (CH: bleaching and diseases) were quantified following the protocols of the Colombian Coral Reef Monitoring System. Results: In Gayraca, mean CC was 37.05 %, dominated by massive corals with a declining trend. Mean AC was 43 %, and turf algae increased significantly through time. Black band disease and white plague were recorded with < 2 % incidence. In Chengue, mean CC was 30 % (massive corals), with disease incidence around 2 %, and the mean AC was 44 %. In Granate, mean CC was 28.2 %, largely massive corals with a downward trend, while mean AC was 47 %, dominated by turf algae with an increasing trend. Stony Coral Tissue Loss Disease (SCTLD) was not detected. Conclusions: Bleaching increased sharply in 2023, reaching unprecedented levels. Across bays, we observed a tendency toward lower CC and higher AC in areas closer to human populations. Although disease prevalence across years was high, annual disease incidence remained low and did not track thermal stress, suggesting comparatively high biological robustness of local coral populations.
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.
Copyright (c) 2025 Revista de Biología Tropical http://creativecommons.org/licenses/by/4.0
Epiphytic macrolichen as indicators of environmental changes in a montane forest of Panama
Introduction: Corticolous lichens are organisms that respond to habitat modifications, which is why they are considered model organisms to evaluate environmental changes in different ecosystems. Objectives: To determine the species richness and community composition of corticolous macro lichens in montane forests and forest remnants. In addition, the effect of microclimatic factors in three areas with different degrees of light intensity and density of arboreous vegetation on the species distribution of recorded diversity was evaluated. Methods: The study was conducted in the Volcan Baru National Park, Panama. Three areas with different forest densities and host tree species, Comarostaphylis arbutoides and Quercus spp., were chosen, considering a total of 60 trees, 10 of each species in each area. The canopy's opening close to the host trees and its diameter at breast height were recorded. Linear models and multivariate analysis was used to determine changes in species richness and composition of epiphytic macro lichens. Results: The characteristics of the host trees (e.g. host species and area) conditioned the species richness, while the communities were limited by microclimatic changes (e.g. light) in different areas. Conclusion: The macro lichens communities analyzed responded to changes related to the host tree species and the microclimate, so they can be considered indicators of ecological continuity in tropical montane forests.
communities; corticolous; lichens; light, Lobariaceae; Parmeliaceae; phorophyte; zone
Status of the coral formations of Bajo Nuevo Reef Complex, Western Caribbean, Colombia
Introduction: Although many reefs have been disturbed by the combined effects of climatic and non-climatic stressors, there still are regions largely free from direct human pressures such as runoff, pollution, and maritime traffic due to their geographic remoteness. This suggests that they are replicas of “pristine reefs”, that allow the investigation of relationships between reef communities and their environment. Objective: To evaluate the status of the coral formations of Bajo Nuevo, Seaflower Biosphere Reserve. Methods: The coral health and the relative cover of reef-building organisms and of their main competitors were evaluated. In every station (11), ten photo quadrants of 0.25 m2 were evaluated along a 10 m tape measure combined, along with ~3 min videos. Results: 32 coral species were recorded, 30 of them Scleractinia and two of hydrocorals, with the highest richness in the reef lagoon. In 2021, the reefs in Bajo Nuevo were dominated by non-reef-building organisms (61.7 ± 0.10 %), the building species represented only 23.9 ± 0.10 %; 3.2 ± 0.03 % was coral skeleton with recent and transitional death less than 15 days old. Signs of diseases affected three genera, 13 species and 23.5 % of the colonies evaluated, of which 84.9 % showed one of the four signs related to the stony coral tissue loss disease. Conclusions: With previous expeditions (2010-2011) as a reference, this reef complex registered in 2021 a drop in the cover of hard corals and calcareous algae, and coral richness; an increase in the cover of non-reef-building organisms, with a high prevalence of signs of unhealthiness associated with different coral diseases. This confirms that these reefs are in danger (EN), as suggested by the red list of marine and coastal ecosystems of Colombia.
Diversity and cultural value of the mastofauna associated with coffee plantations in Oaxaca, Mexico
Introduction: The expansion of conventional agriculture has caused the loss of natural habitats for the fauna, but the coffee agroecosystems of Oaxaca can provide an alternative habitat for mammals, which is associated with the cultural value that human communities assign to them. Objective: To assess the diversity and cultural value of medium and large mammals associated with the coffee plantation, and what they represent for the inhabitants of San Gabriel Mixtepec, Oaxaca, Mexico. Method: A mixed method was used. For the diversity analysis, the mammal species were identified through camera traps. To determine the Cultural Importance Index (IIC), semi-structured interviews and participatory workshops were carried out with the residents, who also helped to identify the different uses of the medium and large mammals. Results: A total of 26 species grouped into seven orders, 14 families, and 23 genera were recorded. Alpha diversity was greater in the dry season than in the wet season. Some species were detected in only one of the two seasons. Six hundred and thirty-nine records of cultural uses of mammals were obtained; use as food was the most mentioned. Twelve types of uses were identified. The species with the greatest cultural importance were Odocoileus virginianus (IIC = 0.92), with 11 uses, followed by Dasypus novemcinctus (IIC = 0.61), with 10 uses, Conepatus leuconotus (IIC = 0.60), with eight uses and Didelphis virginiana (IIC = 0.52), with 11 uses. Conclusion: The results show the importance that human residents assign to mammals associated with coffee agroecosystems, both for their use for subsistence and to complement the family economy. Furthermore, the residents themselves emphasize the importance of their traditional knowledge and the need to adopt sustainable management practices for the mastofauna, because they recognize the importance it has in the community and the benefits it can have on the environment.
mammals; Cultural Importance Index (IIC); coffee; agroecology; biocultural
Diversity and vertical distribution of epiphytic orchids and bromeliads in two contrasting forests from Northeast Andes of Colombia
Introduction: Functional traits analysis allows an understanding of the mechanisms that structure plant communities epiphytes. The distribution of taxonomic and functional epiphyte diversity along vertical gradients is a key tool to track epiphytes’ response to environmental changes, especially in biodiversity hotspots, where a high number of endemic species are threatened. Objective: To relate the taxonomic and functional epiphyte diversity and their vertical distribution with forest structural variables of the Montane and Dry Forest ecosystems in the Colombian Andes. Methods: Epiphyte diversity in each study site was recorded in 35 random phorophytes. Alpha and functional diversity were compared for five vertical strata of the canopy (Z1-Z5) and related to forest structural and floristics variables such as tree richness, tree density, diameter at breast height (DBH), canopy height, crown area, and canopy openness. Results: The Montane Forest presented a greater diversity of epiphytes, mainly orchids, with Stelis angustifolia as the dominant species. In contrast, the Dry Forest presented a greater Bromeliad abundance, and Tillandsia recurvata was dominant. Montane forest epiphytes were represented by three functional groups: tank-bromeliads, shallow tank-bromeliads, and ramicauls-orchids, while in the Dry Forest shallow tank-bromeliads and nebulophyte-bromeliads. Positive correlations were found between epiphyte richness, abundance, and diversity with variables related to phorophyte size (DBH and crown area) in montane forest. There was also a different tendency on the preference for some strata between Orchids (Z2-Z3) and Bromeliads (Z3-Z4). Conclusion: Differences were found in the taxonomic and functional diversity of epiphytes between the two forests, where orchids and bromeliads often coexist in similar environments but are distributed in different habitats, resulting from adaptation to specific environmental conditions, which allows them to coexist in different niches within the ecosystem.
Andean forests; ecosystem functions; oak forest; phorophyte; Quercus humboldtii
Density, size and composition of howler monkeys, Alouatta palliata (Atelidae) and white-faced monkeys, Cebus imitator (Cebidae) in dry forest and reduced canopy areas, Costa Rica
Introduction: The size, density, and composition of primate social groups are essential for understanding group dynamics and determining population management plans for primate conservation. Objective: To determine the size, density, and composition of howler monkeys (Alouatta palliata) and white-faced monkey (Cebus imitator) groups in dry forest environments and areas of reduced canopy in Palo Verde National Park, Costa Rica. Understanding how these species respond to different environments has important implications for conservation and reforestation efforts. Methods: Field sampling was carried out during February 2023 during the peak hours of primate activity (6:00-12:00 and 14:00-18:00). The individuals of both primate species were counted, recognizing the groups found in both types of environments (dry forest and reduced canopy areas). Results: Howler monkey group sizes were significantly larger in dry forests and at a higher percent of canopy cover. As for white-faced monkeys, a higher density was recorded in dry forests compared to the last census in 1987. Conclusion: Greater availability of resources (abundance of food and shelter sites) in closed environments favors the presence of a greater number of howler monkeys. Our analyses show that group size in this primate species depends on the type of environment. This study highlights the importance of long-term monitoring and studies of these parameters in wild primate groups.
conservation; management; primates, survey; Platyrrhini
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.
high-altitude peatlands; biodiversity; anthropogenic impact; tropical paramo; Mesoamerican hotspot
Effects of human disturbance on medium and large mammals in primary and secondary tropical forests in Southern Mexico
Introduction: In tropical forests, populations of medium and large mammals are being impacted by human activities. Understanding how species respond to land use conversion, fragmentation, and the encroachment of roads density and settlements is of conservation interest in highly biodiverse regions. Objetive: To assess the effect of human disturbance and environmental variables on trophic guilds of medium and large mammals in the tropical forests of the Sierra Negra-Mazateca in Southern Mexico. Methods: We characterized the landscape (land use and vegetation, number of fragments, and edge density) through supervised classification of Landsat 8 images. We recorded species using camera-trap stations and evaluated the relationship between the presence and relative abundance of species with human disturbance variables using zero-inflated regression models. Results: The landscape of the Sierra Negra-Mazateca is dominated by fragments of secondary forests (48.6 %) with a small proportion of primary forests (9.6 %). We found no differences in the overall relative abundance of species between primary and secondary forests, but differences were observed for omnivore and carnivore guilds. Human disturbances had a disparate effect among guilds, negatively affecting carnivores and positively herbivores. Conclusions: Secondary forests are refuges for tolerant species. Nevertheless, we emphasize the need to conserve primary forests to safeguard medium and large mammals, especially the carnivore guild. Extensive management in secondary forests is recommended to conserve remaining primary forests, alongside community awareness and empowerment for coexistence with wildlife.
carnivores; defaunation; human disturbance; landscape analyses; landsat; montane cloud forest; zero-inflated models
Growth, recruitment and life history parameters of fish in Andean reservoirs
Introduction: The formation of new anthromes such as reservoirs and dams to generate energy for human consumption, provides new environmental scenarios that condition the survival of the pre-existing fish species in the modified system. Objective: To estimate some of the main population attributes in relation to growth and recruitment discussed in the context of the life histories of the species analyzed for a high-Andean river system. Methods: Based on the historical sequence (2005-2017) for the seven species with the highest numerical record and frequency distributions, a typical population parameter estimation analysis was employed following the Growth Model proposed by von Bertalanffy (MCvB) and empirical equations to the respective complementary parameters. Results: A total of 28 651 frequency lengths were analyzed, finding that those species with rapid growth and lower longevity prefer artificial lacustrine environments, species with opportunistic life history strategies (Astyanax microlepis and Roeboides dayi) and with a bimodal recruitment pattern, while species with intermediate growth were seasonal (Brycon henni y Hemibrycon caucanus), registered in tributaries to the reservoir, and in equilibrium (Andinoacara latifrons, Chaetostoma thomsoni and Coptodon rendalli) mainly associated with rivers, reservoirs, and streams or transitional environments to reservoirs. Conclusion: The analysis of information on the population dynamics and live history of fish coexisting in a reservoir and its surrounding environments suggests a spatial segregation of fish species in response to a possible selection of their biological traits and other bioecological characteristics that sustain their local populations.
life history; von Bertalanffy; Porce river; recruitment; ecological filter.
Composition, structure and regeneration strategy of Campnosperma panamense (Anacardiaceae) swamp forests in Darien, Panama
Introduction: Orey swamp forests (Campnosperma panamense) are found on the Caribbean coast of Central America, from Nicaragua to Panama, and in the Pacific of Colombia to Northern Ecuador. In Panama, orey grows in monospecific stands or is the dominant species in inundated mixed forests, mainly along the coasts of Bocas del Toro province and Comarca Ngäbe-Buglé. The species was known to occur in Darien province, in the Pacific, although almost no information on its distribution and forest extension in the region existed. Objective: To describe the structure and floristics of orey forests in Darien, map their extension, and propose a model for their regeneration strategy. Methods: This work is part of a vegetation mapping project of the Matusagaratí complex of wetlands. It includes the use of drones, ground truthing, vegetation sampling through temporary plots, and general plant collecting. A supervised classification of a Landsat satellite image was performed to delimit the orey forest extension. To study the orey forest regeneration strategy, a digitalization of forest gaps in high resolution WorldView-2 and Planet Scope images over years was performed. Gap frequency and turnover time for forest stands were calculated. Results: Several monospecific orey mature forest patches were found in remote areas of the Matusagaratí complex of wetlands, for a total of 1 267 hectares. A description of the floristics and structure of orey forests in Darien is presented. A conceptual model of orey mature forest development and gap regeneration is proposed. Conclusions: Our knowledge of the floristic composition, structure and distribution of orey forests in the Republic of Panama has increased. For the first time, a model about their regeneration strategy is proposed. These forests seem to be evolving to different formations. Finally, some hypotheses are proposed about how they might respond to changing environmental conditions.
Matusagaratí; complex of wetlands; swamp forests; orey; Darien; regeneration strategy
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.
The effect of macrophytes on the presence and population structure of the red swamp crayfish Procambarus clarkii (Decapoda: Cambaridae) in neotropical ecosystems
Introduction: The red swamp crayfish, Procambarus clarkii, is a crustacean species native to Mexico and the United States. It has been introduced around the world, often becoming established as an invasive exotic species. Since its introduction in 1985 in Colombia, no studies have been carried out to determine factors that influence the presence of the species in high mountain ecosystems. Objective: To evaluate the relationship over time between macrophytes and the different stages of development of P. clarkii in a tropical high Andean aquatic ecosystem. Methods: A new collection method called "macrophyte sweep" was standardized. This method ensured the collection of crayfish of all possible sizes, especially juveniles. Sampling was carried out bimonthly for seven months. The morphometry of P. clarkii was evaluated in three macrophytes: Juncus effusus, Ludwigia peruviana, and Polygonum punctatum. Results: A total of 778 individuals were collected, of which 365 were females, 344 males, and 69 sexually indeterminate. The total population density was 6.48 ind/m2. Most organisms were found on P. punctatum (71.9 %), followed by L. peruviana (17.7 %) and J. effusus (10.28 %). The largest and heaviest organisms were recorded in September in all three macrophytes, while the smallest were collected in July and May. P. clarkii exhibited a greater affinity for the macrophyte P. punctatum in its different developmental stages, possibly because it offers greater structural complexity in the submerged zone, providing shelter for juveniles and a food source for adults. Conclusions: Our results highlight that much of the colonization success of P. clarkii is due to the relationship between macrophytes and the development of different life stages in neotropical ecosystems.
The performance of mass testing strategies for COVID-19: a case study for Costa Rica
Introduction: In this article, we derive the behavior of four different mass testing strategies, grounded in guidelines and public health policies issued by the Costa Rican public healthcare system. Objective: To formally develop the changes of each studied mass testing strategy under different contexts related to people’s risk, costs of testing, and accessibility to alternative testing technologies. Methods: We take over a pre-classifier applied to individuals capable of partitioning suspected individuals into low-risk and high-risk groups. We consider the impact of three testing technologies: RT-qPCR, antigen-based testing, and saliva-based testing (RT-LAMP). When available, we introduced a category of essential workers. Results: Numerical simulation results confirm that strategies using only RT-qPCR tests cannot achieve sufficient stock capacity to provide efficient detection regardless of prevalence, sensitivity, or specificity. Strategies that harness the power of pooling and RT-LAMP either maximize stock capacity, detection efficiency, or both. Conclusions: Investing in data quality and classification accuracy can improve the odds of achieving pandemic control and mitigation. Future work will be focused on, based on our findings, constructing representative synthetic data through agent-based modeling and studying the properties of specific pre-classifiers under various scenarios.
mass testing; COVID-19 Costa Rica; RT-qPCR; antigen test; RT-LAMP; pooling; detection strategies
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.
Motile macroinvertebrates and fishes sheltering in burrows with and without the Indo-Pacific Rock-boring Urchin Echinometra mathaei (Camarodonta: Echinometridae), at Mana Island, Fiji
Introduction: Sea urchins of the genus Echinometra are ecosystem engineers that burrow into lower intertidal and subtidal rocks, creating shelter for themselves and a variety of marine animals. Objective: To test the hypothesis that motile macroinvertebrates and fishes shelter proportionately more frequently in burrows with Echinometra mathaei, whose spines potentially offer additional protection, than in burrows without E. mathaei. Methods: We studied the motile macroinvertebrates and fishes sheltering in the burrows of the Indo-Pacific Rock-boring Urchin E. mathaei (Type C) at Mana Island, Fiji. Results: Burrows with E. mathaei averaged shorter in length than burrows without E. mathaei. We observed 42 motile macroinvertebrates of at least eight species and 49 fishes of at least eight species in burrows with E. mathaei (n = 1 127), and four motile macroinvertebrates of three species and one fish of one species in burrows lacking E. mathaei (n = 243). Motile macroinvertebrates occurred with statistically equal frequencies in burrows with E. mathaei (3.6 %) and in burrows without E. mathaei (2.5 %). Fishes occurred significantly more frequently in burrows with E. mathaei (4.3 %) than in burrows without E. mathaei (0.4 %). Conclusion: Fishes, but not motile macroinvertebrates, gain more protection from predators by sheltering in burrows with sea urchins, whose spines offer additional protection, than in burrows without sea urchins.
Structure of fish communities in relation to habitat in Matusagaratí Lagoon, Darién, Panama
Introduction: Matusagaratí lagoon is an ecosystem with diverse habitats and environmental conditions that determine the diversity and distribution of aquatic life. Despite hydraulic connectivity, aquatic habitats generated by this diversity of environmental conditions could determine the composition and structure of fish assemblages. Objective: To understand the structure of fish community in three of these habitats. Methods: Multi-habitat sampling was conducted between March 2022 and September 2023, covering periods of drought and flooding, at 29 sites using different fishing techniques. Results: 1 913 fish from 50 species and 27 families were collected in approximately 320 km2. Three fish assemblages were identified, each associated with a specific habitat. The river corridor of the Tuira River had the greatest diversity, followed by the tidal streams and lagoons. Conclusions: The analysis revealed notable differences between these habitats, with the river corridor dominated by peripheral species, while lagoons showed low diversity with generalized or hypoxia-adapted species. The presence of species such as Hoplosternum punctatum, Ageneiosus pardalis and Pimelodus punctatus in the wetland evidences the influence of the Choco region on Panama´s ichthyofauna. These findings could have important implications for the formulation of wetland conservation strategies.
freshwater fishes; peripheral fishes; Tuira river; Darien province
Protozoos and metazoos present in two wastewater treatment systems and their relationship with the Sludge Biotic Index
Introduction: Sludge Biotic Index (SBI) is one of the most used indices for the characterization of the community of microorganisms present in the activated sludge of wastewater treatment systems. However, this index takes into consideration only the density of the predominant functional groups of protozoa that inhabit this sludge. Objective: To evaluate whether the SBI value can be directly related to the number of protozoos and metazoos species found in the activated sludge of two wastewater treatment systems. Methods: This study was carried out on the wastewater generated by the San Vicente de Paul Hospital in Heredia Province, Costa Rica, during the months of February, March, and April 2022. Physicochemical, environmental, operational, and biological parameters were analyzed in a total of 36 samples from a Conventional activated sludge wastewater treatment system and from a Membrane Bioreactor (MBR) (n = 18 for each treatment system). Results: All the parameters evaluated are related to the abundance of microorganisms in the samples analyzed. The SBI value had an important effect on the number of organisms and can be related to the performance of the treatment system in terms of the percentage of Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) removal, especially for the MBR system. Conclusions: The SBI can be improved so its calculation not only considers functional groups but also includes genus and species of protozoos and metazoos present in the activated sludge. Which in turn would refine its bioindication potential by being more specific in terms of abundance, behavior and specific requirements of each species.
flocs; activated sludge; ciliates; amoebas; rotifers; nematodes