This study investigates the role of stable isotope ecology in unconsolidated sediment coastal systems, focusing on scientific production and research trends over time. Existing literature is analyzed to identify knowledge gaps and highlight the significance of stable isotope analysis in understanding coastal ecosystems. A comprehensive bibliometric analysis is employed, utilizing Scopus database to collect and categorize relevant publications on stable isotope ecology. Key indicators are focused on, including publication trends, authorship patterns, and the geographic distribution of research efforts. The temporal scale of studies is systematically analyzed, with attention given to methodological approaches used in these publications. Co-authorships networks and co-occurring keywords are examined to explore the intellectual structure of the field and identify collaborative patterns among authors. Over 140 publications are revealed, attributed to more than 400 researchers, with a significant increase in interest noted over time, particularly in trophic studies involving macrobenthos. Mudflats are identified as a focal point, receiving more attention than sandy beaches. The analysis indicates that seasonality is the predominant temporal scale, while mesoscale studies are observed to be more common in spatial investigations. A plateau in publication growth is noted, probably corresponding with the emergence of alternative methodologies for trophic ecology studies. Major contributions are attributed to France, the United States and Australia. Additionally, fragmented collaboration networks are illustrated through the co-authorship analysis, with limited international engagement among developing nations. Overall, the critical importance of stable isotope ecology in understanding coastal ecosystems is underscored, while the need for methodological diversity and increased collaboration in future research efforts is highlighted.

Human societies depend on services provided by ecosystems, from local needs as clean water and pest control to global services like ozone layer and the ocean biological pump. Ecosystem services are intrinsically linked to the states of the ecosystem, which are, in turn, governed by a complex web of ecological interactions. These interactions and, consequently, the services they support, are increasingly under threat from environmental changes driven by human activities. Therefore, safeguarding these vital services require an understanding of how the structure and dynamics of ecological interactions are affected by environmental change. A critical step towards this goal is the development of an integrative theoretical framework that can elucidate how ecosystem services are sustained or impaired by interactions within these complex ecosystems in fluctuating environments. Recent years have seen significant progress in quantitatively characterizing the organization and the dynamics of ecological interactions through the study of ecological networks. However, linking temporally varying network structure in fluctuating environments, the seascapes of ecological networks, and their impact on ecosystem services remains a challenge. We propose an approach based upon merging empirical ecological network analysis with Boolean functions and modeling techniques accounting for fluctuating environments to tackle how ecosystem services are affected by the changing structure and dynamics of ecological networks. The approach aims to contribute to the study of how the organization of ecological interactions affects the persistence of ecosystem services. Specifically, we discuss how this approach can be used provide new insights into how environmental change affect the relationship between ecological networks and ecosystem services. The combination of information on ecosystem services, Boolean networks and fluctuating environments might allow to enhance the research around conservation strategies for preserving biodiversity and ecosystem services in the face of ongoing environmental change.

Resumen Las relaciones entre diversas poblaciones permiten describir diferentes tipos de interacción entre especies, como el consumo, la búsqueda de alimento, el parasitismo, la polinización, por mencionar algunas. Cuando éstas ocurren entre recursos y consumidores se conocen como relaciones tróficas, y el conjunto de relaciones tróficas de una comunidad o un ecosistema describe a una red alimentaria. Estas redes son de importancia ecológica ya que permiten describir la dirección y el flujo de energía dentro del ecosistema, son esenciales para analizar la dinámica y biodiversidad del sistema, y su construcción realista es clave para el estudio de comunidades biológicas. En las últimas décadas, algunos autores han propuesto modelos que reproducen varias propiedades importantes de redes alimentarias. Sin embargo, hasta donde sabemos, la aplicación de dichos modelos no ha sido estandarizada ni puesta a disposición de la comunidad científica en algún repositorio público. En este trabajo presentamos 3 de los modelos más usados para crear redes alimentarias e indicadores representativos que dan información sobre la estructura y composición de la red. Además, compartimos los códigos de los modelos e indicadores para que puedan ser replicados y usados en otras investigaciones.

Abstract The relationships between various populations allow the description of different types of interactions among species, such as consumption, foraging, parasitism, and pollination, to name a few. When these occur between resources and consumers, they are known as trophic relationships, and the set of trophic relationships in a community or an ecosystem describes a food web. These webs are of ecological importance as they outline the direction and flow of energy within the ecosystem, are essential for analyzing the dynamics and biodiversity of the system, and their realistic construction is key for studying biological communities. In recent decades, some authors have proposed models that replicate several important properties of food webs. However, as far as we know, the implementation of these models has not been standardized nor made available to the scientific community in any public repository. In this work, we present 3 of the most used models for creating food webs and representative indicators that provide information about structure and composition of the network. Additionally, we share the codes for the models and indicators so they can be replicated and used in other research.

Abstract. The invasion of non-native species is one of the main threats to biodiversity conservation and the provision of ecosystem services. Mangroves are one of the most vulnerable ecosystems worldwide due to invasive alien species (IAS), as they can destabilize the structure and function of trophic webs and reduce their primary productivity, mainly through competition and predation of native species. In this paper, an analysis of biodiversity information systems and scientific literature were used to determine the presence of IAS within the mangrove forests of the Ria Celestún and Ría Lagartos biosphere reserves in the Yucatan Peninsula, Mexico; the level of risk of IAS was identified according to the rapid invasiveness assessment method, and information was generated on the implications of IAS in mangrove forests. In both natural protected areas (NPAs), 16 IAS were found, of which 56.25% had a "very high" invasiveness risk value, and 43.75% had a “high” invasiveness risk, which implies a danger alert for mangrove forests in the NPAs. The information generated in this study can be used to identify strategies for managing IAS and the conservation of mangrove forests in NPAs.

Resumen. La invasión de especies no autóctonas es una de las principales amenazas para la conservación de la biodiversidad y para la provisión de servicios ecosistémicos. Uno de los ecosistemas más vulnerables a escala mundial por la presencia de especies exóticas invasoras (EEI) es el bosque de manglar, ya que estas pueden desestabilizar la estructura y función de las redes tróficas y reducir su productividad, principalmente por competencia y depredación de especies nativas. En este estudio se realizó un análisis en los sistemas de información de biodiversidad y la literatura científica especializada para determinar la presencia de EEI en los bosques de manglar de las reservas de la biosfera Ría Celestún y Ría Lagartos ubicadas en la península de Yucatán, México; se identificó el nivel de riesgo de las EEI de acuerdo con el método de evaluación rápida de invasividad, y se generó información sobre las implicaciones de las EEI en los bosques de manglar. Entre las dos áreas naturales protegidas (ANP), se encontró la presencia de 16 EEI, de las cuales, 56.25% tienen valor de riesgo de invasividad “muy alto” y 43.75% riesgo de invasividad “alto”, lo que significa una alerta de peligro para los bosques de manglar de las ANP. La información generada en este estudio servirá de base para el planteamiento de estrategias de gestión para la atención de EEI y sobre la conservación de los bosques de manglar en las ANP.

The structure of food webs is a fundamental attribute of ecosystems, and their characterization provides an intrinsic knowledge of the trophic interactions among organisms and of nutrient and energy transfer within ecosystems. Over the last few decades, several chemical and biogeochemical approaches have been proposed to explore different aspects of food webs. In this sense, this study reviews the application of stable isotopes and mercury as main auxiliary tools to the characterization and modeling of aquatic food webs, including analytical and modeling advances, strengths and limitations. The metanalysis performed showed that the most used tools for trophic ecology studies are stable isotopes, and that they can provide better results when combined with mercury and specific chemical molecules such as amino and fatty acids. In addition, the statistical methods applied in the interpretation of results, such as isotope mixing models, have witnessed significant advances in the last two decades. All approaches have premises and limitations when applied to aquatic ecosystems, which must be well understood prior to results interpretation. The use of multiple tracers in trophic studies provides complementary information and in many cases is an appropriate alternative to overcome some limitations, allowing to expand the knowledge of the food webs. ecosystems decades sense acids addition models

Abstract Aquatic macrophytes are the main autochthonous component of primary production in the Amazon Basin. Floating meadows of these plants support habitats with highly diverse animal communities. Fishes inhabiting these habitats have been assumed to use a broad range of food items and compose a particular food web. We employed carbon (δ13C) and nitrogen (δ15N) stable isotope analysis to draw the trophic structure of these habitats and to trace the energy flow by its trophic levels. Fishes and other animals from 18 independent macrophyte meadows of a floodplain lake of the Solimões River (Amazonia, Brazil) were analyzed. The food web of macrophyte meadows consists of four trophic levels above autotrophic sources. In general, primary consumers exhibited a broader range of food sources than the upper trophic levels. Some fish species depended on a large number of food sources and at the same time are consumed by several predators. The energy transfer from one trophic level to the next was then mainly accomplished by these species concentrating a high-energy flux and acting as hubs in the food web. The broad range of δ13C values observed indicates that the organisms living in the macrophyte meadows utilize a great diversity of autotrophic sources. Basin communities δC δ C (δ13C δ15N δN N (δ15N 1 Amazonia, Amazonia (Amazonia Brazil analyzed general predators highenergy high

Resumo Ambientes urbanos apresentam uma heterogeneidade ambiental menor em relação aos naturais, afetando a biodiversidade de morcegos e os processos ecológicos dos quais participam. Desta forma, vamos identificar como a urbanização influência na estruturação das comunidades de morcegos no município de Goiânia, Goiás, Brasil. Comparamos a composição de espécies, guildas e riqueza de morcegos em um gradiente que cruzou áreas urbanas, semiurbanas e naturais no município de Goiânia, contido no bioma Cerrado. Capturamos um total de 775 morcegos de 16 espécies distribuídas em três famílias. Áreas urbanas apresentaram uma abundância maior de espécies, enquanto em áreas semiurbanas tivemos uma riqueza de espécies maior. Os três tipos de ambientes apresentam diferentes composições, sendo o urbano mais homogêneo, a fauna nessas áreas é composta por espécies generalistas, que se beneficiam com esse processo. A diversidade presente nas áreas semiurbanas é consequência do cruzamento entre a fauna urbana e a natural, por isso é necessário que a expansão urbana ocorra de forma planejada para minimizar os impactos desse processo e garantir a manutenção da biodiversidade. participam Goiânia Goiás Brasil Cerrado 77 1 famílias composições homogêneo generalistas natural 7

Abstract Urban environments present less environmental heterogeneity in relation to the natural ones, affecting the biodiversity of bats and the ecological processes in which they participate. In this way, we will identify how urbanization influences the structure of bat communities in the municipality of Goiânia, Goiás, Brazil. We compared species composition, guilds and bat richness in a gradient that crossed urban, semi-urban and natural areas in the municipality of Goiânia, contained in the Cerrado biome. We captured a total of 775 bats of 16 species distributed in three families. Urban areas had a higher species abundance, while semi-urban areas had a higher species richness. The three types of environments have different compositions, the urban one being more homogeneous, the fauna in these areas is composed of generalist species, which benefit from this process. The diversity present in semi-urban areas is a consequence of the intersection between urban and natural fauna, which is why urban expansion needs to occur in a planned manner to minimize the impacts of this process and ensure the maintenance of biodiversity. ones participate way Goiânia Goiás Brazil composition semiurban semi biome 77 1 families abundance compositions homogeneous 7

Resumo Objetivo O semiárido tropical brasileiro é um bioma que possui pequenos ecossistemas de água doce, frequentemente intermitentes, que atuam como um mosaico em constante transformação entre as estações seca e chuvosa. As comunidades meiobentônicas desempenham papéis cruciais nesses ambientes, e compreender seus processos de colonização e sucessão é fundamental para entender como esses organismos se estruturam em um habitat defaunado. Além da abordagem taxonômica tradicional, os traços funcionais oferecem perspectivas valiosas sobre a dinâmica desses processos. Neste estudo, testamos as seguintes hipóteses: i) embora a meiofauna seja composta por organismos microscópicos com dispersão ativa limitada, eles colonizam rapidamente novos substratos, aumentando em abundância, riqueza e diversidade; ii) as características funcionais dos Nematoda de água doce são uma boa ferramenta para observar uma sucessão inicial em substrato artificial duro em um reservatório lêntico. Métodos Colocamos 27 placas de cerâmica em um reservatório no semiárido brasileiro e amostramos aleatoriamente três réplicas a cada semana, ao longo de nove semanas. As diferenças semanais na abundância, riqueza e diversidade da comunidade foram testadas com one-way ANOVA e pairwise PERMANOVA. Resultados Os Nematoda predominaram na primeira semana, com os Rotifera dominando a partir da segunda semana de experimento. Não observamos diferenças na estrutura taxonômica da comunidade de Nematoda ao longo das semanas. Entretanto, houve um aumento na complexidade funcional da comunidade de Nematoda ao longo do tempo, conforme indicado pelo índice de maturidade e pela estrutura trófica. Os colonizadores/persistentes surgiram rapidamente na primeira semana. Os comedores de depósito dominaram, mas observou-se um aumento na diversidade trófica com a presença crescente dos mastigadores ao longo das semanas. Conclusões Este estudo destaca que as características funcionais dos Nematoda representam uma ferramenta robusta para avaliar a sucessão ecológica em ambientes lênticos de água doce no semiárido tropical. intermitentes chuvosa defaunado tradicional hipóteses i limitada substratos abundância ii lêntico 2 semanas oneway one way PERMANOVA experimento Entretanto tempo colonizadorespersistentes colonizadores persistentes dominaram observouse observou

Abstract Aim The Brazilian tropical semiarid is a biome with small freshwater ecosystems, often intermittent, acting as a mosaic in constant transformation between dry and rainy seasons. Meiobenthic communities play crucial roles in these environments, and understanding their colonization and succession processes is essential to comprehend how these organisms’ structure in a defaunated habitat. In addition to the traditional taxonomic approach, functional traits provide valuable insights into the dynamics of these processes. In this study, we tested the following hypotheses: i) although meiofauna consists of microscopic organisms with limited active dispersion, they quickly colonize new substrates, increasing in abundance, richness, and diversity; ii) functional traits of freshwater Nematoda are a good tool for view an early succession on hard artificial substrate in a lentic reservoir. Methods We placed 27 ceramic plates in a reservoir in the Brazilian semiarid and randomly sampled three replicates each week over nine weeks. Weekly differences in community abundance, richness, and diversity were tested with one-way ANOVA and pairwise PERMANOVA. Results Nematoda predominated in the first week, with Rotifera taking over from the second week of the experiment. No differences were observed in the Nematode taxonomic structure over the weeks. There was an increase in the functional complexity of the Nematoda community over time, as indicated by the maturity index and trophic structure. Colonizers/persistents emerged quickly in the first week. Deposit feeders dominated, but an increase in trophic diversity was observed with the growing presence of chewers over the weeks. Conclusions This study highlights that the functional traits of Nematoda represent a robust tool for assessing ecological succession in freshwater lentic environments in the tropical semiarid. ecosystems intermittent seasons habitat approach hypotheses i dispersion substrates abundance richness ii 2 weeks oneway one way PERMANOVA experiment time Colonizerspersistents Colonizers persistents dominated

Resumo Mudanças na paisagem causadas pela construção de barragens hidrelétricas e invasão da agricultura na região ribeirinha têm catalisado alterações na dinâmica da cadeia alimentar de peixes. Os objetivos deste estudo foram investigar o estado trófico e o uso da terra de três rios, um diretamente impactado por uma barragem; a estrutura trófica de quatro espécies de peixes de quatro guildas tróficas; e a relação entre o estado trófico e o uso da terra com a estrutura trófica. Encontramos maior contribuição alóctone total no rio regulado pela barragem em contraste com seus tributários, juntamente com menos cobertura natural na região ribeirinha, mas uma alta porcentagem de vegetação natural nas ilhas. Além disso, observamos uma maior contribuição das fontes ribeirinhas para todos os três rios, independentemente do estado trófico e da cobertura natural do rio. A posição trófica foi maior para os peixes no rio em uma área protegida e menor nos rios com uma alta porcentagem de atividades agropastoris nas áreas ribeirinhas. Esses achados mostram a importância da conservação das zonas ribeirinhas, principalmente em rios regulados por barragens, pois essa vegetação fornece a principal fonte de energia dos peixes. tróficas tributários ilhas disso

Abstract Landscape change caused by hydropower dam construction and invasion of agriculture in the riparian zone has been a catalyst for alterations in fish food web dynamics. The objectives of this study were to investigate the trophic state and land use of three rivers, one directly impacted by a dam; the trophic structure of four fish species of four trophic guilds; and the relationship between the trophic state and land use with trophic structure. We found a greater total allochthonous contribution in the dam-regulated river in contrast to its tributaries, along with less natural cover in the riparian zone, but a high percentage of natural vegetation on the islands. Additionally, we observed greater contribution of the riverine sources for all three rivers, independent of the trophic state and natural cover of the river. The trophic position was greater for the fish in the river in a protected area and lower in the rivers with a high percentage of agropastoral activities in the riparian areas. These findings show the importance of the conservation of the riverine zones mainly in dam-regulated rivers, because this vegetation provides the main energy source by fish. dynamics guilds damregulated regulated tributaries islands Additionally areas

Resumo Relações tróficas moldam a estrutura dos ecossistemas ao regular o fluxo de energia e o ciclo de nutrientes, impactando o consumo de presas e promovendo adaptações comportamentais nas espécies de presas para mitigar riscos. Embora muito seja conhecido sobre o comportamento antipredador de peixes em ambientes marinhos, pouco se sabe sobre essas dinâmicas em ambientes de água doce. Investigamos o comportamento antipredador de um peixe da planície de inundação amazônica, Crenuchus spilurus, em diferentes complexidades estruturais de habitat. Através de experimentos, examinamos como o número de indivíduos (1 e 4 indivíduos) e a complexidade estrutural do habitat (baixa, média, alta e muito alta) influenciam a resposta do peixe à presença de predadores. Grupos pequenos apresentaram maior distância de iniciação de fuga (DIF) do que indivíduos solitários, sugerindo uma estratégia de defesa coletiva contra predadores em aproximação. A complexidade estrutural do habitat não teve um efeito direto sobre a DIF. Além disso, observamos variações no uso de refúgios pelos peixes em diferentes complexidades estruturais de habitat. Esses achados ressaltam a interação entre fatores comportamentais e ambientais na adaptação das presas ao risco de predação em ecossistemas aquáticos. nutrientes riscos marinhos doce amazônica spilurus experimentos 1 ( baixa, baixa (baixa média DIF (DIF solitários aproximação disso aquáticos

Abstract Trophic relationships shape ecosystem structure by regulating energy flow and nutrient cycling, impacting prey consumption and prompting behavioral adaptations in prey species to mitigate risks. While much is known about fish antipredator behavior in marine environments, less is understood about these dynamics in freshwater environments. We investigated the antipredator behavior of an Amazonian floodplain fish, Crenuchus spilurus, across different habitat structural complexities. Through experiments, we examined how the number of individuals (1 and 4 individuals) and habitat structural complexity (low, medium, high, and very high) influence the fish response to predator presence. Small groups showed longer flight initiation distance (FID) than solitary individuals, suggesting a possible collective defense strategy against approaching predators. The structural complexity of the habitat did not have a direct effect on FID. Additionally, we noted variations in refuge usage by the fish across different habitat structural complexities. These findings underscore the interplay between behavioral and environmental factors in prey adaptation to predation risk in aquatic ecosystems. cycling risks environments spilurus complexities experiments 1 ( low, low (low medium high presence FID (FID predators Additionally ecosystems

Abstract. Sandy beaches are among the most extensive coastal ecosystems in Brazil and constitute important buffer zones between terrestrial and marine environments. The present study aimed to analyze the distribution and spatiotemporal variation of the meiofaunal community of an urban tropical sandy beach in northeastern Brazil with a particular focus on nematofauna. We set up 4 transects during 2 sampling periods to evaluate different beach zones. The meiofauna comprised 8 taxa, and the nematofauna consisted of 5 orders, 16 families, and 45 genera. The meiofaunal communities followed the qualitative-quantitative standards of those of other tropical sandy beaches in northeastern Brazil. The nematofaunal community showed variation in its composition and trophic structure between dry and rainy months, which were not significantly correlated with granulometric characteristics. This suggests that other variables may influence the structure of nematofaunal communities in Gaibu Beach. Further research on the biodiversity of the meiofaunal communities on sandy beaches in northeastern Brazil is urgently needed given the lack of available information of these environments and the extreme stress they are currently under.

Resumen. Las playas arenosas son uno de los ecosistemas costeros más extensos de Brasil y constituyen importantes zonas de amortiguamiento entre el ambiente terrestre y el marino. El presente estudio tuvo como objetivo analizar la distribución y la variación espaciotemporal de la comunidad meiofaunal de una playa arenosa tropical urbana con particular énfasis en la nematofauna. Establecimos 4 transectos durante 2 periodos de muestreo para evaluar diferentes zonas de playa. La meiofauna estuvo compuesta por 8 taxones, y la nematofauna consistió en 5 órdenes, 16 familias y 45 géneros. Las comunidades meiofaunales siguieron los estándares cualitativos-cuantitativos de las de otras playas arenosas tropicales en el noreste de Brasil. La comunidad nematofaunal presentó variación en su composición y estructura trófica entre los meses secos y los lluviosos, los cuales no presentaron correlación significativa con las características granulométricas. Esto sugiere que otras variables pueden influir en la estructura de las comunidades nematofaunales en la playa de Gaibu. Se requieren urgentemente más estudios de investigación sobre la biodiversidad de las comunidades meiofaunales en las playas arenosas del noreste de Brasil debido a la falta de información disponible sobre estos ambientes y el estrés extremo bajo al que están sujetas.

Resumen Introducción: La presencia y estructura de la vegetación en áreas urbanas tiene un impacto en la composición de las comunidades de aves. Las áreas verdes con una mayor proporción de vegetación introducida tienden a presentar una homogeneización de avifauna, mientras que las áreas verdes con alta proporción de vegetación nativa presentan mayor diversidad de aves. En varios trabajos realizados en áreas urbanas de México, estos factores no son tomados en cuenta. Por lo tanto, se desconocen las respuestas de las especies en términos de riqueza y diversidad. Objetivo: Analizar la composición de especies de aves en las áreas verdes de Ciudad Victoria, Tamaulipas y evaluar la respuesta de las comunidades de aves en tres áreas verdes con diferente composición de vegetación. Así como analizar la relación entre los gremios tróficos de aves con los elementos de la vegetación en las áreas urbanas. Métodos: El estudio se llevó a cabo en tres sitios de muestreo de Ciudad Victoria, Tamaulipas, México, con base en dos criterios: área similar de muestreo (ha) y diferencias en las características de la vegetación. Los monitoreos se realizaron de enero a diciembre de 2020, con tres visitas mensuales en cada sitio para un total de 108 visitas, utilizando el método visual directo. Resultados: Identificamos 98 especies (11 órdenes, 28 familias). Las especies más abundantes fueron Quiscalus mexicanus y Molothrus aeneus. Hubo diferencias en la riqueza de especies para cada sitio. Las insectívoras y granívoras fueron las dominantes. Se determinó una asociación entre los gremios y los sitios de estudio, donde la mayoría están relacionados con la vegetación mixta, comparado con la vegetación homogénea o introducida. Conclusiones: Las áreas urbanas estudiadas mantuvieron un número notable de aves, y varias de ellas presentaron alguna categoría de riesgo o endemismo. Esto demuestra la importancia de estas áreas verdes como refugio de aves y resalta la necesidad de conservar y proteger dichas áreas dentro de Ciudad Victoria y ciudades similares.

Abstract Introduction: The presence and structure of vegetation in urban areas have an impact on the composition of bird communities. Green areas with a higher ratio of introduced vegetation tend to have a greater homogenization of avifauna, whereas green areas with a high ratio of native vegetation have a greater diversity of birds. In several studies carried out in urban areas of Mexico, the factors of vegetation are not considered. Therefore, the responses of the species to vegetation types in terms of richness and diversity are unknown. Objective: To analyze the composition of bird species in the green areas of Ciudad Victoria, Tamaulipas, and evaluate the response of bird communities in areas with differences in vegetation composition. As well as to analyze the relationship between the trophic guilds in birds and vegetation in urban areas. Methods: Three sampling sites were established in Ciudad Victoria, Tamaulipas, Mexico, based on two criteria: similar sampling area (ha) and differences in vegetation characteristics. Monitoring took place between January and December 2020, with three monthly visits in each site for a total of 108 visits, using the direct visual method. Results: We identified 98 species (11 orders, 28 families). The most abundant species were Quiscalus mexicanus and Molothrus aeneus. Differences in species richness were found for each site. The insectivorous and granivorous were the dominant guilds. An association between the guilds and the study sites was determined, where most were linked to mixed native vegetation, compared to homogeneous or introduced vegetation. Conclusions: The urban areas studied maintained a notable number of birds, and several of them presented some category of risk or endemism. This demonstrates the importance of these green areas composed of native vegetation as a refuge for birds and highlights the need to conserve and protect these areas within Ciudad Victoria and similar cities.

Resumen Introducción: La variabilidad en la estructura de las comunidades acuáticas se atribuye frecuentemente a cambios ambientales, no obstante, en ambientes estables como ríos regulados, las interacciones tróficas podrían ser otro factor ambiental clave determinante de la estructura de estas comunidades. Estas alteraciones podrían provocar un mayor crecimiento de algas y, a su vez, cambios en los grupos funcionales y en la composición de la comunidad de macroinvertebrados favoreciendo la dominancia de determinados grupos de organismos. Objetivo: Identificar el efecto de los cambios ambientales y de la estructura del ficoperifiton sobre la comunidad de macroinvertebrados de ríos Andinos regulados. Métodos: Se analizaron datos ambientales y biológicos recolectados en muestreos trimestrales realizados entre 2010 y 2018 en dos ríos de los Andes Centrales (Antioquia - Colombia), para un total de 27 muestras. La recolección de muestras empleó métodos estandarizados. Se utilizaron diferentes modelos estadísticos para establecer patrones espaciales y temporales de las variables ambientales, de la abundancia y/o densidad y diversidad de ficoperifiton y de los macroinvertebrados, así como las relaciones tróficas que existen entre ellos. Resultados: Se encontró que los ríos regulados presentan relativamente poca variabilidad ambiental. Los parámetros ambientales con mayor variación fueron: temperatura, turbidez y ortofosfatos; las dos últimas variables abióticas fueron las que más aportaron a la inestabilidad bentónica. Conclusión: La presencia de macroinvertebrados raspadores y recolectores fue más afectada por la estabilidad de la densidad del ficoperifiton que por las variables ambientales, evidenciando la importancia de las interacciones tróficas en ríos regulados y el control bottoom up en estos ecosistemas.

Abstract Introduction: The variability in the structure of aquatic communities is frequently attributed to environmental changes; however, in stable environments such as regulated rivers, trophic interactions could be another key environmental factor determining the structure of these communities. These alterations could cause a greater growth of algae, and in turn, changes in the functional groups and in the composition of the macroinvertebrate community favoring the dominance of certain groups of organisms. Objective: To identify the effects of environmental variations and changes in the structure of the phycoperiphyton on the macroinvertebrate community of regulated Andean rivers. Methods: We analyzed environmental and biological data collected in quarterly samples carried out between 2010 and 2018 in two rivers of the Central Andes (Antioquia - Colombia), for a total of 27 samples. Sample collections used standardized methods. Different statistical models were used to establish spatial and temporal patterns of the environmental variables, of the abundance and/or density and diversity of phycoperiphyton and macroinvertebrates, as well as the trophic relationships that exists between them. Results: We found that regulated rivers present relatively little environmental variability. The environmental parameters with the greatest variation were temperature, turbidity, and orthophosphates; these last two were the abiotic variables with the greatest contribution to benthic instability. Conclusion: The presence of scraping and foraging macroinvertebrates was more affected by the stability of the phycoperiphyton density than by environmental variables, showing the importance of trophic interactions in regulated rivers and the bottom up control in these ecosystems.

ABSTRACT Background. Ecological Network Analysis has been used for defining aspects concerning the structure, health, and dynamics of marine ecosystems. Objectives. Evaluate the ecosystem’s structure, organization, and maturity in the shallow rocky reef ecosystem in Yelapa. Also, we determine the most affected functional groups by disturbances simulated and those which generate less resilience in the ecosystem. Methods. A mass-balance trophic model Ecopath with Ecosim, was constructed, and Ascendency›s theory was used to evaluate the ecosystem properties. A Mixed Trophic Impacts matrix was used to assess direct and indirect trophic effects on the network. The functional groups more sensitive to disturbances were determined using Ecosim dynamics simulations in the short and long term with two mortality scenarios (an increase of 25 % and 50 %). Finally, the System Recovery Timewas used as a measure of resilience. Results. The Yelapa rocky-reef ecosystem exhibits the feature of a mature, organized, and developing ecosystem but is less resistant to disturbances. Several fish groups, zooplankton, and phytoplankton produced the most remarkable effects in the trophic network. In addition, the phytoplankton, chlorophyta, and the group of other benthic invertebrates propagated more effects on other model components. Conclusions. Yelapa rocky reef would lose resilience if the functional groups eels & morays, other benthic invertebrates, snappers, and phytoplankton were disturbed.

RESUMEN Antecedentes. Los análisis ecológicos de redes han sido usados para definir aspectos relacionados a la estructura, salud y dinámica de los ecosistemas marinos. Objetivos. Evaluar la estructura, organización y madurez en el ecosistema de Yelapa, un arrecife rocoso somero. También, se determinaron los grupos funcionales que podrían ser más sensibles a perturbaciones simuladas y aquellos que generan menor resiliencia en el ecosistema. Métodos. Se construyó un modelo trófico de balance de masas Ecopath con Ecosim y se usó la teoría de Ascendency para evaluar las propiedades ecosistémicas. La matriz de Impacto Trófico Mixto evaluó los efectos tróficos directos e indirectos en la red. Se determinaron los grupos funcionales más sensibles a perturbaciones usando simulaciones dinámicas Ecosim de corto y largo tiempo con dos escenarios de mortalidad (incremento del 25 % y 50 %). Finalmente, se empleó el Tiempo de Recuperación del Sistema como una medida de resiliencia. Resultados. El ecosistema arrecifal rocoso de Yelapa exhibió características de un ecosistema maduro, organizado y desarrollado, pero a su vez menos resistente a perturbaciones. Diferentes grupos de peces, zooplancton y fitoplancton generaron los mayores efectos en la red trófica. Además, el fitoplancton, clorofitas y el grupo de otros invertebrados bentónicos propagaron los mayores efectos hacia los otros componentes del sistema. Yelapa es menos resiliente cuando son perturbados los grupos funcionales de anguilas y morenas, otros invertebrados bentónicos, pargos y fitoplancton. Conclusiones. Grupos funcionales de distintos niveles tróficos fueron prioritarios para preservar la integridad estructural del ecosistema, las condiciones de madurez, desarrollo y resiliencia. Este estudio representa el primer paso para analizar las propiedades de la red trófica y especies ecológicamente relevantes entre el ecosistema de coral somero y profundo en Yelapa.

Resumen Las interacciones interespecificas entre vertebrados de distintos grupos son comunes, pero también complejas y de gran importancia para la estructura de las comunidades. En particular, la depredación, considerada una interacción trófica, desempeña un papel significativo en la estructura de las redes tróficas y en los efectos selectivos sobre las presas en los ecosistemas naturales. En este trabajo aportamos nueva información sobre la relación trófica entre aves y herpetofauna (reptiles y anfibios) en la compleja y biodiversa cuenca del río Usumacinta, a través de 10 observaciones registradas entre 2012 y 2021. Las observaciones muestran interacciones con fines alimenticios de ocho especies de aves, incluyendo garzas (Tigrisoma mexicanum), charas (Psilorhinus morio), rapaces (Caracara cheriway, Pseudastur albicollis, Harpagus bidentatus, Buteo plagiatus), bucos (Malacoptila panamensis), y patos (Dendrocygna autumnalis), con serpientes (Coniophanes quinquevittatus), tortugas (Chelydra rossignonii, Trachemys venusta), lagartijas (Iguana iguana, Sceloporus serrifer), cocodrilos (Crocodylus moreletii), y ranas (Smilisca baudinii).

Abstract Interspecific interactions between vertebrates of different groups are common but also complex and of great importance for community structure. In particular, predation, considered a trophic interaction, plays a significant role in food webs structure and selective effects on prey in natural ecosystems. In this paper we provide new information on the trophic relationship between birds and herpetofauna (reptiles and amphibians) in the complex and biodiverse Usumacinta river basin, through 10 observations recorded between 2012 and 2021. The observations show interactions for feeding purposes of eight bird species, including herons (Tigrisoma mexicanum), jays (Psilorhinus morio), raptors (Caracara cheriway, Pseudastur albicollis, Harpagus bidentatus, Buteo plagiatus), puffbirds (Malacoptila panamensis), and ducks (Dendrocygna autumnalis), with snakes (Coniophanes quinquevittatus), turtles (Chelydra rossignonii, Trachemys venusta), lizards (Iguana iguana, Sceloporus serrifer), crocodiles (Crocodylus moreletii), and frogs (Smilisca baudinii).