Fish functional trophic groups in headwater karst streams from the Upper Paraguay River basin

Data obtained by direct observation of organisms in their natural habitats can provide valuable contributions regarding intra- and inter-specific interactions, as well as spatial distribution and trophic relationships. However, relatively few such data are available for the Neotropical ichthyofauna relative to the great species diversity of this region. We present data on the ichthyofauna in karst environments of the Serra da Bodoquena, Upper Paraguay River basin regarding their categorization into functional trophic groups. We used direct observations that focused on the most frequent feeding tactics and their spatial (vertical and horizontal) distribution in the channel. We observed 83 fish species in 17 functional trophic groups. The greatest species richness was concentrated in the Characidae and Loricariidae in the categories Diurnal Backwater Drift Feeders and Grazers, respectively. Regarding horizontal depth stratification, we found a positive relationship between the association of small fish with the shallow marginal habitats. This work represents a contribution to a region known for its high tourist potential and to the important diversity of the entire ichthyofauna of the Upper Paraguay basin region that requires proper conservation strategies for sustaining these species.(AU)

Dados obtidos pela observação direta dos organismos em seus hábitats naturais podem fornecer valiosas contribuições com relação a interações intra e inter-específicas, além de distribuição espacial e relações tróficas. Entretanto, relativamente poucos dados estão disponíveis no que diz respeito à ictiofauna neotropical dada à grande diversidade dessa região. Apresentamos dados sobre a ictiofauna em ambientes cársticos da Serra da Bodoquena, bacia do alto rio Paraguai e a categorização das mesmas em grupos tróficos funcionais baseada em observações diretas relacionadas às táticas alimentares mais frequentes e à sua distribuição espacial (vertical e horizontal) no canal. Assim sendo, observamos 83 espécies de peixes alocadas em 17 grupos tróficos funcionais. A maior riqueza de espécies concentrou-se nas famílias Characidae e Loricariidae, abrangendo as categorias Catadores Diurnos de Itens Arrastados pela Corrente e Pastadores, respectivamente. Com relação à estratificação horizontal, encontramos a relação positiva entre a associação de peixes de pequeno porte com relação aos hábitats marginais. Esse trabalho representa uma contribuição a uma região conhecida pelo seu alto potencial turístico e à importante diversidade da ictiofauna da região da bacia do alto Paraguai que requer estratégias de conservação adequadas para sustentar essas espécies.(AU)

Trophic relationships among three species of ornamental fish from the region of Lake Amanã, Amazon

Abstract The present study objectified to evaluate the trophic relationships and the possible aggressive mimicry involving Carnegiella strigata, Carnegiella marthae and Gnathocharax steindachneri, in lowland forest streams. Samplings occurred in November 2002, March and August 2003 in Amanã Sustainable Development Reserve (ASDR). The total of 943 fish was caught, being 79.43% of C. marthae, 3.18% of C. strigata and 17.39% of G. steindachneri. Stomach contents, degree of stomach repletion, relative volume and frequency of occurrence of food items were evaluated. Thirteen food items were identified, and the presence of terrestrial and aquatic insects indicates the high dependence of these species and the flooded forest. Low feeding overlap was observed between Carnegiella strigata and C. marthae compared to Gnathocharax steindachneri. However, the overlap between the two Carnegiella species was relatively high, which could explain the low frequency of syntopic occurrence among these species, suggesting a possible case of competitive exclusion.

Resumo Este estudo teve como objetivo analisar as relações tróficas e a possível existência de uma relação de mimetismo agressivo envolvendo Carnegiella strigata, Carnegiella marthae e Gnathocharax steindachneri, em igarapés de terra firme. As coletas ocorreram em novembro de 2002, março e agosto de 2003 e foram realizadas na Reserva de Desenvolvimento Sustentável de Amanã (RDSA). Foram capturados 943 peixes, onde C. marthae representou 79,43%, C. strigata 3,18% e G. steindachneri 17,39%. Foram analisados os conteúdos estomacais e verificados grau de repleção, volume relativo e frequência de ocorrência dos alimentos. Foram identificados 13 itens alimentares, onde insetos terrestres e aquáticos denotaram alto grau de dependência destas espécies em relação à floresta alagada. Ocorreu baixa sobreposição alimentar das espécies Carnegiella strigata e C. marthae em relação a Gnathocharax steindachneri. Entretanto, a sobreposição entre as duas espécies de Carnegiella foi relativamente alta, o que poderia explicar a baixa frequência de ocorrência sintópica entre essas espécies, sugerindo um possível caso de exclusão competitiva.

Dynamic of fish trophic guilds in the plateau-plain gradient in the Paraguay River, Northern Pantanal

This study aims to evaluate the dynamics of fish trophic guilds according to the longitudinal gradient of the Paraguay River, northern Pantanal, Brazil. Three river segments were sampled: plateau, confluence and plain. These segments have different physical and biological characteristics, with high water flow in forest areas in plateau and slow flow in meanders, with Pantanal typical vegetation. In total, 26,542 individuals distributed in 130 fish species were collected. The sampled species were characterized in seven trophic guilds. From the seven trophic guilds identified, only three were statistically related to the type of the environment; herbivores were more abundant in the plateau, piscivores in the confluence, and invertivores in the plain. According to values of corrected Akaike Information Criteria, the environmental variable that best explains the abundance of piscivorous fishes in the segments sampled in the Paraguay River was water transparency. For herbivores, the model that explained the variation in abundance was composed by temperature, altitude and dense forest proportion. The variable altitude best represented the abundance of invertivores. Water transparency, temperature, altitude, river width and dense forest proportion were determining factors for the distribution of piscivorous, herbivorous and invertivorous fishes as a response to an environmental gradient that meets its ecological requirements. Understanding the trophic relationships is fundamental for management actions, contributing to the maintenance of ecosystem services of different species. Therefore, future research must be taken into account regarding management and ecological relationships.(AU)

Trophic relationships among three species of ornamental fish from the region of Lake Amanã, Amazon / Relações tróficas entre três espécies de peixes ornamentais da região do lago de Amanã, Amazonas

The present study objectified to evaluate the trophic relationships and the possible aggressive mimicry involving Carnegiella strigata, Carnegiella marthae and Gnathocharax steindachneri, in lowland forest streams. Samplings occurred in November 2002, March and August 2003 in Amanã Sustainable Development Reserve (ASDR). The total of 943 fish was caught, being 79.43% of C. marthae, 3.18% of C. strigata and 17.39% of G. steindachneri. Stomach contents, degree of stomach repletion, relative volume and frequency of occurrence of food items were evaluated. Thirteen food items were identified, and the presence of terrestrial and aquatic insects indicates the high dependence of these species and the flooded forest. Low feeding overlap was observed between Carnegiella strigata and C. marthae compared to Gnathocharax steindachneri. However, the overlap between the two Carnegiella species was relatively high, which could explain the low frequency of syntopic occurrence among these species, suggesting a possible case of competitive exclusion.

Este estudo teve como objetivo analisar as relações tróficas e a possível existência de uma relação de mimetismo agressivo envolvendo Carnegiella strigata, Carnegiella marthae e Gnathocharax steindachneri, em igarapés de terra firme. As coletas ocorreram em novembro de 2002, março e agosto de 2003 e foram realizadas na Reserva de Desenvolvimento Sustentável de Amanã (RDSA). Foram capturados 943 peixes, onde C. marthae representou 79,43%, C. strigata 3,18% e G. steindachneri 17,39%. Foram analisados os conteúdos estomacais e verificados grau de repleção, volume relativo e frequência de ocorrência dos alimentos. Foram identificados 13 itens alimentares, onde insetos terrestres e aquáticos denotaram alto grau de dependência destas espécies em relação à floresta alagada. Ocorreu baixa sobreposição alimentar das espécies Carnegiella strigata e C. marthae em relação a Gnathocharax steindachneri. Entretanto, a sobreposição entre as duas espécies de Carnegiella foi relativamente alta, o que poderia explicar a baixa frequência de ocorrência sintópica entre essas espécies, sugerindo um possível caso de exclusão competitiva.

Trophic relationships among three species of ornamental fish from the region of Lake Amanã, Amazon / Relações tróficas entre três espécies de peixes ornamentais da região do lago de Amanã, Amazonas

The present study objectified to evaluate the trophic relationships and the possible aggressive mimicry involving Carnegiella strigata, Carnegiella marthae and Gnathocharax steindachneri, in lowland forest streams. Samplings occurred in November 2002, March and August 2003 in Amanã Sustainable Development Reserve (ASDR). The total of 943 fish was caught, being 79.43% of C. marthae, 3.18% of C. strigata and 17.39% of G. steindachneri. Stomach contents, degree of stomach repletion, relative volume and frequency of occurrence of food items were evaluated. Thirteen food items were identified, and the presence of terrestrial and aquatic insects indicates the high dependence of these species and the flooded forest. Low feeding overlap was observed between Carnegiella strigata and C. marthae compared to Gnathocharax steindachneri. However, the overlap between the two Carnegiella species was relatively high, which could explain the low frequency of syntopic occurrence among these species, suggesting a possible case of competitive exclusion.

Este estudo teve como objetivo analisar as relações tróficas e a possível existência de uma relação de mimetismo agressivo envolvendo Carnegiella strigata, Carnegiella marthae e Gnathocharax steindachneri, em igarapés de terra firme. As coletas ocorreram em novembro de 2002, março e agosto de 2003 e foram realizadas na Reserva de Desenvolvimento Sustentável de Amanã (RDSA). Foram capturados 943 peixes, onde C. marthae representou 79,43%, C. strigata 3,18% e G. steindachneri 17,39%. Foram analisados os conteúdos estomacais e verificados grau de repleção, volume relativo e frequência de ocorrência dos alimentos. Foram identificados 13 itens alimentares, onde insetos terrestres e aquáticos denotaram alto grau de dependência destas espécies em relação à floresta alagada. Ocorreu baixa sobreposição alimentar das espécies Carnegiella strigata e C. marthae em relação a Gnathocharax steindachneri. Entretanto, a sobreposição entre as duas espécies de Carnegiella foi relativamente alta, o que poderia explicar a baixa frequência de ocorrência sintópica entre essas espécies, sugerindo um possível caso de exclusão competitiva.

Trophic relationships among three species of ornamental fish from the region of Lake Amanã, Amazon / Relações tróficas entre três espécies de peixes ornamentais da região do lago de Amanã, Amazonas

The present study objectified to evaluate the trophic relationships and the possible aggressive mimicry involving Carnegiella strigata, Carnegiella marthae and Gnathocharax steindachneri, in lowland forest streams. Samplings occurred in November 2002, March and August 2003 in Amanã Sustainable Development Reserve (ASDR). The total of 943 fish was caught, being 79.43% of C. marthae, 3.18% of C. strigata and 17.39% of G. steindachneri. Stomach contents, degree of stomach repletion, relative volume and frequency of occurrence of food items were evaluated. Thirteen food items were identified, and the presence of terrestrial and aquatic insects indicates the high dependence of these species and the flooded forest. Low feeding overlap was observed between Carnegiella strigata and C. marthae compared to Gnathocharax steindachneri. However, the overlap between the two Carnegiella species was relatively high, which could explain the low frequency of syntopic occurrence among these species, suggesting a possible case of competitive exclusion.(AU)

Este estudo teve como objetivo analisar as relações tróficas e a possível existência de uma relação de mimetismo agressivo envolvendo Carnegiella strigata, Carnegiella marthae e Gnathocharax steindachneri, em igarapés de terra firme. As coletas ocorreram em novembro de 2002, março e agosto de 2003 e foram realizadas na Reserva de Desenvolvimento Sustentável de Amanã (RDSA). Foram capturados 943 peixes, onde C. marthae representou 79,43%, C. strigata 3,18% e G. steindachneri 17,39%. Foram analisados os conteúdos estomacais e verificados grau de repleção, volume relativo e frequência de ocorrência dos alimentos. Foram identificados 13 itens alimentares, onde insetos terrestres e aquáticos denotaram alto grau de dependência destas espécies em relação à floresta alagada. Ocorreu baixa sobreposição alimentar das espécies Carnegiella strigata e C. marthae em relação a Gnathocharax steindachneri. Entretanto, a sobreposição entre as duas espécies de Carnegiella foi relativamente alta, o que poderia explicar a baixa frequência de ocorrência sintópica entre essas espécies, sugerindo um possível caso de exclusão competitiva.(AU)

Diet composition of abundant fish species in the shallow waters of the Todos os Santos Bay, Bahia, Brazil

Coastal habitats have great ecological importance with estuarine environments providing feeding sites for many fish species, especially during juvenile life stages. This study investigates the diet composition and trophic guild organization of the common and abundant ichthyofauna in shallow areas of the Todos os Santos Bay (TSB), Bahia, Brazil, and their relationships with environmental parameters. Six fish sampling campaigns were carried out in the shallow zones (infralittoral) of the Paraguaçu River estuary which encompasses the inner and outer (marine exposure) reaches of theTSB. The stomach contents of 1231 individualsbelonging to common and abundant species were examined. A total of 32 food items were identifiedand fish were into four trophic guilds: detritivores, zoobenthivores I, zoobenthivores II, and zooplanktivores. The relationship between the guilds and environmental parameters showed that zoobenthivores II and zooplanktivores guilds had a positive relationship with salinity and pH, explaining 86% of data variability, though only the salinity variable was significant. This study provides basic information about the diet composition of common and abundant species in the TSBand their organization into trophic guilds. In addition, demonstrates that shallow waters fish across all guilds have broadly similar diets, comprising food items that are usually associated with bottom waters.

Diet composition of abundant fish species in the shallow waters of the Todos os Santos Bay, Bahia, Brazil

Coastal habitats have great ecological importance with estuarine environments providing feeding sites for many fish species, especially during juvenile life stages. This study investigates the diet composition and trophic guild organization of the common and abundant ichthyofauna in shallow areas of the Todos os Santos Bay (TSB), Bahia, Brazil, and their relationships with environmental parameters. Six fish sampling campaigns were carried out in the shallow zones (infralittoral) of the Paraguaçu River estuary which encompasses the inner and outer (marine exposure) reaches of theTSB. The stomach contents of 1231 individualsbelonging to common and abundant species were examined. A total of 32 food items were identifiedand fish were into four trophic guilds: detritivores, zoobenthivores I, zoobenthivores II, and zooplanktivores. The relationship between the guilds and environmental parameters showed that zoobenthivores II and zooplanktivores guilds had a positive relationship with salinity and pH, explaining 86% of data variability, though only the salinity variable was significant. This study provides basic information about the diet composition of common and abundant species in the TSBand their organization into trophic guilds. In addition, demonstrates that shallow waters fish across all guilds have broadly similar diets, comprising food items that are usually associated with bottom waters.(AU)

Mangrove-associated fish assemblages off the southern Panama Bight region (tropical eastern Pacific)

The Panama Bight ecoregion (PBE) in the eastern Pacific contains probably the best developed mangrove forests in the American continent. Fishes inhabiting the mangrove-estuary mosaic play fundamental ecological roles and sustain the artisanal fishery operating there. Here, using data collected along ~300 km between 2012 and 2017, we examine the spatial dynamics of mangrove fish assemblages that undertake intertidal migrations in the southern part of the PBE (southern Colombian Pacific coast), where the largest and least disturbed mangroves of Colombia are located. Sixty-one fish species used intertidal mangrove habitats in these areas, constituting ~30% of all fishes inhabiting the whole mosaic of mangrove habitats in this ecoregion. Species within Clupeidae, Ariidae, Centropomidae and Tetraodontidae, all common in mangroves of the eastern Pacific, were the most dominant. Half of the fish species found are commercially important to the artisanal fishery. Differences in fish community structure could be related to salinity differences, but other environmental and ecological factors could also play a role in explaining these differences. A better understanding of the ecological role of mangrove fishes in the region could be gained by examining the ichthyofauna of other habitats within the mosaic and their trophic relationships.(AU)

La ecorregión del Panama Bight (EPB) en el océano Pacifico oriental contiene probablemente los bosques de manglar más desarrollados de America. Los peces que habitan el mosaico estuario-manglar juegan papeles ecológicos fundamentales y sostienen las pesquerías artesanales que operan allí. Usando datos colectados a lo largo de ~300 km entre 2012 y 2017, examinamos la dinámica espacial de ensamblajes de peces de manglar que realizan migraciones intermareales en el EPB sur (costa sur del Pacífico colombiano), donde se encuentran los manglares más grandes y menos intervenidos de Colombia. Sesenta y un especies de peces ingresaron en zonas intermareales de manglar, constituyendo ~30% de todos los peces que pueden ser encontrados en el mosaico de hábitats de manglar de esta ecoregión. Especies de Clupeidae, Ariidae, Centropomidae y Tetraodontidae, todas comunes en manglares del Pacífico oriental, fueron las más dominantes. La mitad de los peces encontrados son importantes comercialmente para la pesquería artesanal. Las diferencias en la estructura de la comunidad pueden estar relacionadas con diferencias en salinidad, pero otros factores ambientales y ecológicos podrían también jugar un rol explicando las diferencias encontradas. Un mejor entendimiento del rol ecológico de los peces de manglar de la región podría alcanzarse examinando la ictiofauna de otros hábitats de este mosaico y sus relaciones tróficas.(AU)

Mangrove-associated fish assemblages off the southern Panama Bight region (tropical eastern Pacific)

The Panama Bight ecoregion (PBE) in the eastern Pacific contains probably the best developed mangrove forests in the American continent. Fishes inhabiting the mangrove-estuary mosaic play fundamental ecological roles and sustain the artisanal fishery operating there. Here, using data collected along ~300 km between 2012 and 2017, we examine the spatial dynamics of mangrove fish assemblages that undertake intertidal migrations in the southern part of the PBE (southern Colombian Pacific coast), where the largest and least disturbed mangroves of Colombia are located. Sixty-one fish species used intertidal mangrove habitats in these areas, constituting ~30% of all fishes inhabiting the whole mosaic of mangrove habitats in this ecoregion. Species within Clupeidae, Ariidae, Centropomidae and Tetraodontidae, all common in mangroves of the eastern Pacific, were the most dominant. Half of the fish species found are commercially important to the artisanal fishery. Differences in fish community structure could be related to salinity differences, but other environmental and ecological factors could also play a role in explaining these differences. A better understanding of the ecological role of mangrove fishes in the region could be gained by examining the ichthyofauna of other habitats within the mosaic and their trophic relationships.(AU)

La ecorregión del Panama Bight (EPB) en el océano Pacifico oriental contiene probablemente los bosques de manglar más desarrollados de America. Los peces que habitan el mosaico estuario-manglar juegan papeles ecológicos fundamentales y sostienen las pesquerías artesanales que operan allí. Usando datos colectados a lo largo de ~300 km entre 2012 y 2017, examinamos la dinámica espacial de ensamblajes de peces de manglar que realizan migraciones intermareales en el EPB sur (costa sur del Pacífico colombiano), donde se encuentran los manglares más grandes y menos intervenidos de Colombia. Sesenta y un especies de peces ingresaron en zonas intermareales de manglar, constituyendo ~30% de todos los peces que pueden ser encontrados en el mosaico de hábitats de manglar de esta ecoregión. Especies de Clupeidae, Ariidae, Centropomidae y Tetraodontidae, todas comunes en manglares del Pacífico oriental, fueron las más dominantes. La mitad de los peces encontrados son importantes comercialmente para la pesquería artesanal. Las diferencias en la estructura de la comunidad pueden estar relacionadas con diferencias en salinidad, pero otros factores ambientales y ecológicos podrían también jugar un rol explicando las diferencias encontradas. Un mejor entendimiento del rol ecológico de los peces de manglar de la región podría alcanzarse examinando la ictiofauna de otros hábitats de este mosaico y sus relaciones tróficas.(AU)

Damming in the Madeira River modifies the food spectrum of piscivorous and affects their resource partitioning

Phylogenetic proximity suggests some degree of diet similarity among species. Usually, studies of diet show that species coexistence is allowed by partitioning food resources. We evaluate how visually oriented piscivorous fishes (Characiformes) share prey before and after building the Santo Antônio Hydroelectric Power Plant (HPP) in the Madeira River (Brazil), the largest muddy-water tributary of the Amazon River. Piscivorous species (Acestrorhynchus falcirostris, Acestrorhynchus heterolepis, Hydrolycus scomberoides, and Rhaphiodon vulpinus) were sampled under pristine (pre-HPP) and disturbed (post-HPP) environmental conditions. We analyzed species abundance and stomach contents for stomach fullness and prey composition to check variations between congeneric and non-congeneric species. The percent volume of prey taxa was normalized by stomach fullness and grouped into the taxonomic family level to determine diet, niche breadth, and overlap. Only R. vulpinus abundance increased in post-HPP. There was no significant variation in niche breadth between the periods, while niche overlap decreased in congeneric and non-congeneric species. Our results indicate that river impoundment affected piscivorous fishes in distinct ways and modified their resource partitioning. Therefore, evaluate interspecific interactions is a required tool to understand how fishes respond to river damming.(AU)

A proximidade filogenética pode indicar similaridade da dieta entre espécies e a partilha de recursos alimentares é um mecanismo que possibilita a coexistência. Neste trabalho, avaliamos como peixes piscívoros compartilham presas antes e depois da construção da Usina Hidrelétrica (UHE) Santo Antônio no rio Madeira (Brasil), o maior afluente de águas brancas do rio Amazonas. Espécies piscívoras (Acestrorhynchus falcirostris, Acestrorhynchus heterolepis, Hydrolycus scomberoides e Rhaphiodon vulpinus) foram coletadas em condições ambientais pristinas (pré-HPP) e impactadas (pós-HPP). Nós avaliamos as abundâncias e as dietas para identificar variações entre as espécies congenéricas e não-congenéricas. O percentual de volume de cada presa foi corrigido pelo grau de repleção estomacal e os itens agrupados ao nível taxonômico de família para determinar dieta, amplitude e sobreposição alimentar. Apenas a abundância de R. vulpinus aumentou no pós-HPP. Não houve diferença na amplitude alimentar das espécies após o represamento, contudo a sobreposição de nicho diminuiu para as espécies congenéricas e não congenéricas. Nossos resultados indicam que o represamento do rio afetou os peixes piscívoros modificando sua partilha de recursos. Avaliar as interações interespecíficas, portanto, é uma ferramenta necessária para entender como os peixes respondem ao represamento de rios.(AU)

Damming in the Madeira River modifies the food spectrum of piscivorous and affects their resource partitioning

Phylogenetic proximity suggests some degree of diet similarity among species. Usually, studies of diet show that species coexistence is allowed by partitioning food resources. We evaluate how visually oriented piscivorous fishes (Characiformes) share prey before and after building the Santo Antônio Hydroelectric Power Plant (HPP) in the Madeira River (Brazil), the largest muddy-water tributary of the Amazon River. Piscivorous species (Acestrorhynchus falcirostris, Acestrorhynchus heterolepis, Hydrolycus scomberoides, and Rhaphiodon vulpinus) were sampled under pristine (pre-HPP) and disturbed (post-HPP) environmental conditions. We analyzed species abundance and stomach contents for stomach fullness and prey composition to check variations between congeneric and non-congeneric species. The percent volume of prey taxa was normalized by stomach fullness and grouped into the taxonomic family level to determine diet, niche breadth, and overlap. Only R. vulpinus abundance increased in post-HPP. There was no significant variation in niche breadth between the periods, while niche overlap decreased in congeneric and non-congeneric species. Our results indicate that river impoundment affected piscivorous fishes in distinct ways and modified their resource partitioning. Therefore, evaluate interspecific interactions is a required tool to understand how fishes respond to river damming.(AU)

A proximidade filogenética pode indicar similaridade da dieta entre espécies e a partilha de recursos alimentares é um mecanismo que possibilita a coexistência. Neste trabalho, avaliamos como peixes piscívoros compartilham presas antes e depois da construção da Usina Hidrelétrica (UHE) Santo Antônio no rio Madeira (Brasil), o maior afluente de águas brancas do rio Amazonas. Espécies piscívoras (Acestrorhynchus falcirostris, Acestrorhynchus heterolepis, Hydrolycus scomberoides e Rhaphiodon vulpinus) foram coletadas em condições ambientais pristinas (pré-HPP) e impactadas (pós-HPP). Nós avaliamos as abundâncias e as dietas para identificar variações entre as espécies congenéricas e não-congenéricas. O percentual de volume de cada presa foi corrigido pelo grau de repleção estomacal e os itens agrupados ao nível taxonômico de família para determinar dieta, amplitude e sobreposição alimentar. Apenas a abundância de R. vulpinus aumentou no pós-HPP. Não houve diferença na amplitude alimentar das espécies após o represamento, contudo a sobreposição de nicho diminuiu para as espécies congenéricas e não congenéricas. Nossos resultados indicam que o represamento do rio afetou os peixes piscívoros modificando sua partilha de recursos. Avaliar as interações interespecíficas, portanto, é uma ferramenta necessária para entender como os peixes respondem ao represamento de rios.(AU)

Food habits of the Cougar Puma concolor (Carnivora: Felidae) in the Central Andes of the Colombian Coffee Region

Abstract The feeding habits of the cougar have been scarcely studied in Colombia, despite its importance in the ecosystems it inhabits. In this study, we analysed the diet of the cougar using 53 feces samples collected from several sites in the Central Andes of Colombias Coffee Growing Region. To identify prey species, we examined and compared bone fragments and hairs found in each sample with descriptions published in relevant literature and with specimens from the Natural History Museum of the Universidad de Caldas, Colombia. We found that rabbits (Sylvilagus sp.) provided half of the relative biomass consumed by the cougar (50%). Other preys identified belong to representatives of medium and large mammals such as marsupials (Didelphis: 10%), sloths (Choloepus: 9%), rodents (Coendou: 10%, Cuniculus: 9%), and deer (Mazama: 9%). Of the preys, Coendou rufescens has not, to our knowledge, been previously included in cougar diet literature. The curve of accumulation of species indicated that the number of samples obtained in this work fully describe the diet of this feline. Neither domestic species were recorded in this work, nor were there any relationships between the dry or rainy seasons and the consumption of prey species. The comparison of the information reported in this study and others carried out in the Andes may indicate the general nature of this felines diet and its adaptability to the prey species found in each area, since these vary in each one of them. It is probable that the obtained trophic niche value (0.33) is due to the abundance of rabbits present in the study area. It is also probable that the cougar has not consumed domestic species since, although it is close to cattle ranches, it has enough of wild prey in the area to supply its needs. The results of this study may help to improve our understanding of the feeding habits of this predator and its interaction with other species in this important region of Colombia. This will, in turn, promote major comprehension of the role of cougars in the Colombian Cordilleras and lead actions for their conservation.

Biologia alimentar de Aequidens tetramerus em macrófitas aquáticas de lagos de várzea da reserva de desenvolvimento sustentável Mamirauá, Região do Médio Solimões, Estado do Amazonas, Brasil / Food biology of Aequidens tetramerus in floodplain lake macrophytes in the Mamirauá sustainable development reserve, Mid-Solimões Region, State of Amazonas, Brazil / Biología alimentaria del Aequidens tetramerus en macrófitas acuáticas de lagos de várzea de la reserva de desarrollo sostenible Mamirauá, Región del Medio Solimões, Estado de Amazonas, Brasil

Estudos sobre a alimentação de peixes são fundamentais para compreender as relações tróficas e estrutura de comunidades ícticas. A espécie em estudo Aequidens tetramerus pertence à família Cichlidae que detém mais de 450 espécies para os neotrópicos, sendo que destes, 287 habitam a América do Sul. Objetivou-se com este estudo compreender a dieta e padrão alimentar de A. tetramerus em lagos de várzea nos ambientes de macrófitas aquáticas da Reserva de Desenvolvimento Sustentável Mamirauá (RDSM), Estado do Amazonas. A análise da dieta foi feita a partir da averiguação do conteúdo estomacal de 59 indivíduos. Determinou-se o Grau de Repleção Estomacal (GRE), Frequência de Ocorrência (FO%), Frequência de Biomassa (FB%) e o Índice de Importância Alimentar (IAi %). Segundo o (GRE), 28 espécimes (39,4%) apresentaram estômagos vazios. A dieta de A. tetramerus foi composta por 12 itens alimentares diferentes. Entretanto, poucos foram predominantes com destaque para insetos (12,6% e 42,7%), em FO% e FB%, respectivamente. Pode-se inferir que A. tetramerus possui hábito carnívoro com tendência a insetivoria, pois quando realizado a combinação dos métodos, por meio da determinação do (IAi %) para verificar a importância das 12 categorias que compuseram a dieta, o item inseto também obteve o maior valor (IAi = 0,71%). Este fato pode estar relacionado ao próprio ambiente de macrófitas aquáticas, pois este é um habitat ideal para a reprodução e desenvolvimento de insetos.(AU)

Studies on the feeding habits of fish are key to understanding the trophic relationships and the structure of ictic communities. The species under study, Aequidens tetramerus, belongs to the Cichlidae family which has over 450 species for the neotropics, of which 287 inhabit South America. The aim of this study was to understand the diet and dietary patterns of A. tetramerus in floodplain lakes in the aquatic macrophyte environments of the Mamirauá Sustainable Development Reserve (RDSM) in the state of Amazonas. The diet was analyzed by investigating the stomach contents of 59 individuals. The degree of stomach repletion (DRS), frequency of occurrence (FO%), frequency of biomass (FB%), and dietary importance index (IAi%) were determined. According to DSR, 28 specimens (39.4%) had empty stomachs. The diet of A. tetramerus was composed of 12 different food items. However, only a few were predominant, with emphasis to insects (12.6% and 42.7% in FO% and FB%, respectively). It can be inferred that A. tetramerus has carnivorous habits with a tendency to be an insectivore, since when the combination of methods was performed, by determining the IAi% to verify the importance of the 12 categories that composed the diet, the insect category also presented the highest value (IAi = 0.71%). This fact may be related to the aquatic macrophyte environment itself, as this is an ideal habitat for the reproduction and development of insects.(AU)

Estudios sobre la alimentación de peces son fundamentales para comprender las relaciones tróficas y estructura de comunidades ícticas. La especie en estudio, Aequidens tetramerus, pertenece a la familia Cichlidae que posee más de 450 especies en neo trópicos, 287 de los cuales habitan en América del Sur. El objetivo de este estudio yace en la compresión de la dieta y el patrón alimentar del A. tetramerus en lagos de vega en los ambientes de macrófitas acuáticas de la Reserva de Desarrollo Sostenible de Mamirauá (RDSM), en el Estado de Amazonas. El análisis de la dieta se realizó investigando el contenido estomacal de 59 individuos. Se determinaron el Grado de Repleción Estomacal (GRE), Frecuencia de Ocurrencia (FO%), Frecuencia de Biomasa (FB%) y el Índice de Importancia Alimentar (IAi%). Según GRE, 28 muestras (39,4%) tenían estómagos vacíos. La dieta de A. tetramerus consistió en 12 alimentos diferentes. Sin embargo, pocos fueron predominantes, con énfasis en insectos (12.6% y 42.7%), en FO% y FB%, respectivamente. Se puede inferir que el A. tetramerus tiene un hábito carnívoro con tendencia insectívora, porque cuando se realiza la combinación de los métodos, determinando el (IAi%) para verificar la importancia de las 12 categorías que componían la dieta, el ítem insecto también obtuvo el valor más alto (IAi = 0.71%). Este hecho puede estar relacionado con el propio ambiente de macrófitas acuáticas, ya que este es un hábitat ideal para la reproducción y el desarrollo de insectos.(AU)

Biologia alimentar de Aequidens tetramerus em macrófitas aquáticas de lagos de várzea da reserva de desenvolvimento sustentável Mamirauá, Região do Médio Solimões, Estado do Amazonas, Brasil / Food biology of Aequidens tetramerus in floodplain lake macrophytes in the Mamirauá sustainable development reserve, Mid-Solimões Region, State of Amazonas, Brazil / Biología alimentaria del Aequidens tetramerus en macrófitas acuáticas de lagos de várzea de la reserva de desarrollo sostenible Mamirauá, Región del Medio Solimões, Estado de Amazonas, Brasil

Estudos sobre a alimentação de peixes são fundamentais para compreender as relações tróficas e estrutura de comunidades ícticas. A espécie em estudo Aequidens tetramerus pertence à família Cichlidae que detém mais de 450 espécies para os neotrópicos, sendo que destes, 287 habitam a América do Sul. Objetivou-se com este estudo compreender a dieta e padrão alimentar de A. tetramerus em lagos de várzea nos ambientes de macrófitas aquáticas da Reserva de Desenvolvimento Sustentável Mamirauá (RDSM), Estado do Amazonas. A análise da dieta foi feita a partir da averiguação do conteúdo estomacal de 59 indivíduos. Determinou-se o Grau de Repleção Estomacal (GRE), Frequência de Ocorrência (FO%), Frequência de Biomassa (FB%) e o Índice de Importância Alimentar (IAi %). Segundo o (GRE), 28 espécimes (39,4%) apresentaram estômagos vazios. A dieta de A. tetramerus foi composta por 12 itens alimentares diferentes. Entretanto, poucos foram predominantes com destaque para insetos (12,6% e 42,7%), em FO% e FB%, respectivamente. Pode-se inferir que A. tetramerus possui hábito carnívoro com tendência a insetivoria, pois quando realizado a combinação dos métodos, por meio da determinação do (IAi %) para verificar a importância das 12 categorias que compuseram a dieta, o item inseto também obteve o maior valor (IAi = 0,71%). Este fato pode estar relacionado ao próprio ambiente de macrófitas aquáticas, pois este é um habitat ideal para a reprodução e desenvolvimento de insetos.

Studies on the feeding habits of fish are key to understanding the trophic relationships and the structure of ictic communities. The species under study, Aequidens tetramerus, belongs to the Cichlidae family which has over 450 species for the neotropics, of which 287 inhabit South America. The aim of this study was to understand the diet and dietary patterns of A. tetramerus in floodplain lakes in the aquatic macrophyte environments of the Mamirauá Sustainable Development Reserve (RDSM) in the state of Amazonas. The diet was analyzed by investigating the stomach contents of 59 individuals. The degree of stomach repletion (DRS), frequency of occurrence (FO%), frequency of biomass (FB%), and dietary importance index (IAi%) were determined. According to DSR, 28 specimens (39.4%) had empty stomachs. The diet of A. tetramerus was composed of 12 different food items. However, only a few were predominant, with emphasis to insects (12.6% and 42.7% in FO% and FB%, respectively). It can be inferred that A. tetramerus has carnivorous habits with a tendency to be an insectivore, since when the combination of methods was performed, by determining the IAi% to verify the importance of the 12 categories that composed the diet, the insect category also presented the highest value (IAi = 0.71%). This fact may be related to the aquatic macrophyte environment itself, as this is an ideal habitat for the reproduction and development of insects.

Estudios sobre la alimentación de peces son fundamentales para comprender las relaciones tróficas y estructura de comunidades ícticas. La especie en estudio, Aequidens tetramerus, pertenece a la familia Cichlidae que posee más de 450 especies en neo trópicos, 287 de los cuales habitan en América del Sur. El objetivo de este estudio yace en la compresión de la dieta y el patrón alimentar del A. tetramerus en lagos de vega en los ambientes de macrófitas acuáticas de la Reserva de Desarrollo Sostenible de Mamirauá (RDSM), en el Estado de Amazonas. El análisis de la dieta se realizó investigando el contenido estomacal de 59 individuos. Se determinaron el Grado de Repleción Estomacal (GRE), Frecuencia de Ocurrencia (FO%), Frecuencia de Biomasa (FB%) y el Índice de Importancia Alimentar (IAi%). Según GRE, 28 muestras (39,4%) tenían estómagos vacíos. La dieta de A. tetramerus consistió en 12 alimentos diferentes. Sin embargo, pocos fueron predominantes, con énfasis en insectos (12.6% y 42.7%), en FO% y FB%, respectivamente. Se puede inferir que el A. tetramerus tiene un hábito carnívoro con tendencia insectívora, porque cuando se realiza la combinación de los métodos, determinando el (IAi%) para verificar la importancia de las 12 categorías que componían la dieta, el ítem insecto también obtuvo el valor más alto (IAi = 0.71%). Este hecho puede estar relacionado con el propio ambiente de macrófitas acuáticas, ya que este es un hábitat ideal para la reproducción y el desarrollo de insectos.

Biologia alimentar de Aequidens tetramerus em macrófitas aquáticas de lagos de várzea da reserva de desenvolvimento sustentável Mamirauá, Região do Médio Solimões, Estado do Amazonas, Brasil / Food biology of Aequidens tetramerus in floodplain lake macrophytes in the Mamirauá sustainable development reserve, Mid-Solimões Region, State of Amazonas, Brazil / Biología alimentaria del Aequidens tetramerus en macrófitas acuáticas de lagos de várzea de la reserva de desarrollo sostenible Mamirauá, Región del Medio Solimões, Estado de Amazonas, Brasil

Estudos sobre a alimentação de peixes são fundamentais para compreender as relações tróficas e estrutura de comunidades ícticas. A espécie em estudo Aequidens tetramerus pertence à família Cichlidae que detém mais de 450 espécies para os neotrópicos, sendo que destes, 287 habitam a América do Sul. Objetivou-se com este estudo compreender a dieta e padrão alimentar de A. tetramerus em lagos de várzea nos ambientes de macrófitas aquáticas da Reserva de Desenvolvimento Sustentável Mamirauá (RDSM), Estado do Amazonas. A análise da dieta foi feita a partir da averiguação do conteúdo estomacal de 59 indivíduos. Determinou-se o Grau de Repleção Estomacal (GRE), Frequência de Ocorrência (FO%), Frequência de Biomassa (FB%) e o Índice de Importância Alimentar (IAi %). Segundo o (GRE), 28 espécimes (39,4%) apresentaram estômagos vazios. A dieta de A. tetramerus foi composta por 12 itens alimentares diferentes. Entretanto, poucos foram predominantes com destaque para insetos (12,6% e 42,7%), em FO% e FB%, respectivamente. Pode-se inferir que A. tetramerus possui hábito carnívoro com tendência a insetivoria, pois quando realizado a combinação dos métodos, por meio da determinação do (IAi %) para verificar a importância das 12 categorias que compuseram a dieta, o item inseto também obteve o maior valor (IAi = 0,71%). Este fato pode estar relacionado ao próprio ambiente de macrófitas aquáticas, pois este é um habitat ideal para a reprodução e desenvolvimento de insetos.(AU)

Studies on the feeding habits of fish are key to understanding the trophic relationships and the structure of ictic communities. The species under study, Aequidens tetramerus, belongs to the Cichlidae family which has over 450 species for the neotropics, of which 287 inhabit South America. The aim of this study was to understand the diet and dietary patterns of A. tetramerus in floodplain lakes in the aquatic macrophyte environments of the Mamirauá Sustainable Development Reserve (RDSM) in the state of Amazonas. The diet was analyzed by investigating the stomach contents of 59 individuals. The degree of stomach repletion (DRS), frequency of occurrence (FO%), frequency of biomass (FB%), and dietary importance index (IAi%) were determined. According to DSR, 28 specimens (39.4%) had empty stomachs. The diet of A. tetramerus was composed of 12 different food items. However, only a few were predominant, with emphasis to insects (12.6% and 42.7% in FO% and FB%, respectively). It can be inferred that A. tetramerus has carnivorous habits with a tendency to be an insectivore, since when the combination of methods was performed, by determining the IAi% to verify the importance of the 12 categories that composed the diet, the insect category also presented the highest value (IAi = 0.71%). This fact may be related to the aquatic macrophyte environment itself, as this is an ideal habitat for the reproduction and development of insects.(AU)

Estudios sobre la alimentación de peces son fundamentales para comprender las relaciones tróficas y estructura de comunidades ícticas. La especie en estudio, Aequidens tetramerus, pertenece a la familia Cichlidae que posee más de 450 especies en neo trópicos, 287 de los cuales habitan en América del Sur. El objetivo de este estudio yace en la compresión de la dieta y el patrón alimentar del A. tetramerus en lagos de vega en los ambientes de macrófitas acuáticas de la Reserva de Desarrollo Sostenible de Mamirauá (RDSM), en el Estado de Amazonas. El análisis de la dieta se realizó investigando el contenido estomacal de 59 individuos. Se determinaron el Grado de Repleción Estomacal (GRE), Frecuencia de Ocurrencia (FO%), Frecuencia de Biomasa (FB%) y el Índice de Importancia Alimentar (IAi%). Según GRE, 28 muestras (39,4%) tenían estómagos vacíos. La dieta de A. tetramerus consistió en 12 alimentos diferentes. Sin embargo, pocos fueron predominantes, con énfasis en insectos (12.6% y 42.7%), en FO% y FB%, respectivamente. Se puede inferir que el A. tetramerus tiene un hábito carnívoro con tendencia insectívora, porque cuando se realiza la combinación de los métodos, determinando el (IAi%) para verificar la importancia de las 12 categorías que componían la dieta, el ítem insecto también obtuvo el valor más alto (IAi = 0.71%). Este hecho puede estar relacionado con el propio ambiente de macrófitas acuáticas, ya que este es un hábitat ideal para la reproducción y el desarrollo de insectos.(AU)

Food habits of the Cougar Puma concolor (Carnivora: Felidae) in the Central Andes of the Colombian Coffee Region

The feeding habits of the cougar have been scarcely studied in Colombia, despite its importance in the ecosystems it inhabits. In this study, we analysed the diet of the cougar using 53 feces samples collected from several sites in the Central Andes of Colombia’s Coffee Growing Region. To identify prey species, we examined and compared bone fragments and hairs found in each sample with descriptions published in relevant literature and with specimens from the Natural History Museum of the Universidad de Caldas, Colombia. We found that rabbits (Sylvilagus sp.) provided half of the relative biomass consumed by the cougar (50%). Other preys identified belong to representatives of medium and large mammals such as marsupials (Didelphis: 10%), sloths (Choloepus: 9%), rodents (Coendou: 10%, Cuniculus: 9%), and deer (Mazama: 9%). Of the preys, Coendou rufescens has not, to our knowledge, been previously included in cougar diet literature. The curve of accumulation of species indicated that the number of samples obtained in this work fully describe the diet of this feline. Neither domestic species were recorded in this work, nor were there any relationships between the dry or rainy seasons and the consumption of prey species. The comparison of the information reported in this study and others carried out in the Andes may indicate the general nature of this feline’s diet and its adaptability to the prey species found in each area, since these vary in each one of them. It is probable that the obtained trophic niche value (0.33) is due to the abundance of rabbits present in the study area. It is also probable that the cougar has not consumed domestic species since, although it is close to cattle ranches, it has enough of wild prey in the area to supply its needs. The results of this study may help to improve our understanding of the feeding habits of this predator and...

Food habits of the Cougar Puma concolor (Carnivora: Felidae) in the Central Andes of the Colombian Coffee Region

The feeding habits of the cougar have been scarcely studied in Colombia, despite its importance in the ecosystems it inhabits. In this study, we analysed the diet of the cougar using 53 feces samples collected from several sites in the Central Andes of Colombias Coffee Growing Region. To identify prey species, we examined and compared bone fragments and hairs found in each sample with descriptions published in relevant literature and with specimens from the Natural History Museum of the Universidad de Caldas, Colombia. We found that rabbits (Sylvilagus sp.) provided half of the relative biomass consumed by the cougar (50%). Other preys identified belong to representatives of medium and large mammals such as marsupials (Didelphis: 10%), sloths (Choloepus: 9%), rodents (Coendou: 10%, Cuniculus: 9%), and deer (Mazama: 9%). Of the preys, Coendou rufescens has not, to our knowledge, been previously included in cougar diet literature. The curve of accumulation of species indicated that the number of samples obtained in this work fully describe the diet of this feline. Neither domestic species were recorded in this work, nor were there any relationships between the dry or rainy seasons and the consumption of prey species. The comparison of the information reported in this study and others carried out in the Andes may indicate the general nature of this felines diet and its adaptability to the prey species found in each area, since these vary in each one of them. It is probable that the obtained trophic niche value (0.33) is due to the abundance of rabbits present in the study area. It is also probable that the cougar has not consumed domestic species since, although it is close to cattle ranches, it has enough of wild prey in the area to supply its needs. The results of this study may help to improve our understanding of the feeding habits of this predator and...(AU)

Mixing models and stable isotopes as tools for research on feeding aquatic organisms / Modelos de mistura e isótopos estáveis como ferramentas para pesquisas sobre alimentação de organismos aquáticos

Implementation of mixture models in isotopic analysis has been increasing due to the need to analyze sources and understand their variations in relation to consumers, which requires an accurate determination of their discriminant rate and fractioning. In this context, we presented the main concepts related to the application of stable isotopes and mixing models, with the aim to analyze the benefits and problems of these tools in surveys on nutrition of aquatic organisms. The predominant methods identified included application of the models IsoSource, MixSIR, SIBER and SIAR, with the use of C and N isotopes in research with aquatic organisms. Studies in both freshwater and marine environments were evaluated to determine the relative contribution of the main food items and understand trophic relationships between organisms. It can be concluded that the application of mixing models, with the stable isotope technique, is a promising tool for research on feeding aquatic organisms and understanding issues related to trophic ecology of these organisms.(AU)

Os modelos de mistura nas análises isotópicas vêm sendo cada vez mais utilizados devido à necessidade de analisar as fontes alimentares e compreender suas variações em relação aos consumidores, o que requer uma adequada determinação de suas taxas discriminantes e fracionamentos. Neste contexto, objetivamos apresentar os principais conceitos relacionados à aplicação de isótopos estáveis e modelos de mistura, visando analisar as vantagens e desvantagens destas ferramentas em pesquisas com nutrição de organsimos aquáticos. Foram identificados de forma predominante a aplicação dos modelos IsoSource, MixSIR, SIBER e SIAR, com a utilização dos isótopos de C e N em pesquisas com organismos aquáticos, tanto em ambientes dulcícolas como em ambientes marinhos para determinar a contribuição relativa dos principais itens alimentares e compreender relações tróficas entre organismos. Pode-se concluir que, a aplicação dos modelos de mistura com a técnica de isótopos estáveis compõe uma ferramenta promissora nas pesquisas sobre alimentação de organismos aquáticos e na compreensão de questões relacionadas à ecologia trófica destes organismos.(AU)

Systematics of Clupeiformes and testing for ecological limits on species richness in a trans-marine/freshwater clade

Clupeiformes (herring, sardines, shad, anchovies and allies) are a globally distributed clade with nearly 400 marine, freshwater, and diadromous species. Although best known as filter feeding fishes that form large schools, this group occupies a diverse array of trophic guilds and habitats. Theory suggests that species richness in clades is modulated by ecological limits, which results in diversity-dependent clade growth, a pattern that most clades exhibit. As a trans-marine/freshwater clade that has undergone repeated transitions between marine and freshwaters, Clupeiformes are an excellent system for investigating the interplay between ecological diversity and macroevolutionary dynamics. In this study we review the systematics of Clupeiformes and explore discordance in phylogenetic relationships and divergence times between mitochondrial and nuclear loci. We then use comparative methods to test whether ecological limits regulate diversity in Clupeiformes. We find discordance in phylogenetic relationships at various taxonomic scales, but also considerable agreement between genomes. Our results suggest that trans-marine/freshwater clades are able to circumvent ecological limits on clade growth at regional, but not on local scales. Our study demonstrates that phylogenies are a critical link between ecology and macroevolutionary dynamics, and suggests habitat transitions can play a key role in shaping diversity patterns, particularly in the neotropics.(AU)

Clupeiformes (apapás, sardinhas e manjubas) são um clado globalmente distribuído com quase 400 espécies marinhas, de água doce e diádromas. Embora mais conhecida pela presença de peixes filtradores formadores de cardumes, este grupo apresenta uma diversidade de guilda e habitats tróficos. A teoria sugere que a riqueza de espécies em clados é modulada por limites ecológicos, o que resulta em um crescimento dependente da diversidade, um padrão que a maioria dos clados exibem. Como um clado que sofreu repetidas transições entre águas marinhas e as águas doces, os clupeiformes são um excelente grupo para investigar a interação entre a diversidade ecológica e a dinâmica macroevolutiva. Neste estudo, revisamos a sistemática de Clupeiformes e exploramos a discordância nas relações filogenéticas e os tempos de divergência entre loci mitocondriais e nucleares. Em seguida, utilizamos métodos comparativos para testar se os limites ecológicos regulam a diversidade em Clupeiformes. Encontramos discordância nas relações filogenéticas em várias escalas taxonômicas, mas também considerável concordância entre os genomas. Nossos resultados sugerem que clados que sofreram sucessivas transições entre águas marinhas e águas doces são capazes de contornar os limites ecológicos do crescimento durante a sua diversificação em escala global, mas não localmente. Nosso estudo demonstra que as filogenias apresentam um vínculo crítico entre a ecologia e a dinâmica macroevolutiva, e sugere que as transições de hábitats podem desempenhar um papel fundamental na modelagem dos padrões de diversidade, particularmente no neotrópico.(AU)