Ecologia trófica de pequenos mamíferos não voadores em uma área contínua de Mata Atlântica
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Data
2013-06-14
Autores
Rodarte, Raisa Reis de Paula [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Ao longo de décadas ecólogos tentam entender quais são os mecanismos que promovem coexistência de espécies. Florestas tropicais abrigam a maior diversidade de pequenos mamíferos do planeta, portanto espécies dentro deste grupo podem compartilhar recursos similares. Nesse trabalho buscamos entender as relações tróficas entre roedores e marsupiais através da análise de isótopos estáveis de carbono e nitrogênio em três áreas contínuas de Mata Atlântica brasileira. Nosso principal objetivo foi compreender como diferentes espécies são capazes de coexistir em uma rica comunidade de pequenos mamíferos em relação a recursos alimentares. Nós verificamos se o tamanho corporal está relacionado às razões isotópicas de carbono e nitrogênio para cada espécie e testamos a hipótese de que espécies de tamanho corpóreo similar apresentam nichos tróficos distintos. Para isso, coletamos amostras de pelos de 57 indivíduos de marsupiais e 204 indivíduos de roedores. Encontramos que roedores apresentam nicho trófico mais amplo com espécies distribuídas em três níveis tróficos (granívoras, onívoras e insetívoras) enquanto os marsupiais estão inseridos em um único nível trófico, alimentando-se exclusivamente de invertebrados. Observamos também alta sobreposição de dieta entre marsupiais e alguns roedores onívoros, provavelmente devido ao consumo de invertebrados e fungos. Em geral, não houve correlação entre o tamanho corporal e os valores isotópicos dos marsupiais, mas para três espécies de roedores (Euryoryzomys russatus, Thaptomys nigrita e Trinomys iheringi) houve correlação significativa entre o tamanho do corpo e um dos isótopos. Para os marsupiais, a dieta por si só não explica a coexistência entre espécies, que parece estar mais relacionada à separação de uso do espaço vertical. Por outro lado, para os...
For many decades ecologists try to understand what the mechanisms that promote species coexistence are. Tropical rainforests support the greatest diversity of small mammals in the world, therefore species within that group may share similar resources. In this paper we seek to understand the trophic relationship between rodents and marsupials through the analysis of stable carbon and nitrogen isotopes within three continuous areas of the Atlantic forest of Brazil. We were particularly interested in understanding how different species are able to coexist in a rich small-mammal community with respect to sharing food resources. We verified if body size is related to carbon and nitrogen stable isotope ratios for each of the species and tested the hypothesis that species with similar body size have distinct trophic niches. We collected hair samples for isotopic analysis from 57 individuals of marsupials and 204 individuals of rodents. We found that rodents have a broad trophic niche with species distributed in three trophic levels (granivores, omnivores and insectivores) while marsupials are mainly within one trophic level, feeding exclusively on invertebrates. We found a strong diet overlap among marsupials and some omnivorous rodents, probably due to consumption of invertebrates and fungi. In general, there was no correlation between body size and isotopic values for marsupials, but for three species of rodents (Euryoryzomys russatus, Thaptomys nigrita and Trinomys iheringi) there was significant correlation between body size and one of the isotopes. For marsupials, diet by itself does not seem to explain species coexistence. Marsupials seem to be more related to different vertical use of space. On the other hand, for rodents diet together with body size was sufficient to elucidate the high number of coexisting species because we could... (Complete abstract click electronic access below)
For many decades ecologists try to understand what the mechanisms that promote species coexistence are. Tropical rainforests support the greatest diversity of small mammals in the world, therefore species within that group may share similar resources. In this paper we seek to understand the trophic relationship between rodents and marsupials through the analysis of stable carbon and nitrogen isotopes within three continuous areas of the Atlantic forest of Brazil. We were particularly interested in understanding how different species are able to coexist in a rich small-mammal community with respect to sharing food resources. We verified if body size is related to carbon and nitrogen stable isotope ratios for each of the species and tested the hypothesis that species with similar body size have distinct trophic niches. We collected hair samples for isotopic analysis from 57 individuals of marsupials and 204 individuals of rodents. We found that rodents have a broad trophic niche with species distributed in three trophic levels (granivores, omnivores and insectivores) while marsupials are mainly within one trophic level, feeding exclusively on invertebrates. We found a strong diet overlap among marsupials and some omnivorous rodents, probably due to consumption of invertebrates and fungi. In general, there was no correlation between body size and isotopic values for marsupials, but for three species of rodents (Euryoryzomys russatus, Thaptomys nigrita and Trinomys iheringi) there was significant correlation between body size and one of the isotopes. For marsupials, diet by itself does not seem to explain species coexistence. Marsupials seem to be more related to different vertical use of space. On the other hand, for rodents diet together with body size was sufficient to elucidate the high number of coexisting species because we could... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Mammals, Mamífero, Isótopos estáveis, Nicho (Ecologia), Roedor, Marsupial, Mata Atlântica, Partilha de recursos (Ecologia)
Como citar
RODARTE, Raisa Reis de Paula. Ecologia trófica de pequenos mamíferos não voadores em uma área contínua de Mata Atlântica. 2013. 42 f. Dissertação - (mestrado) - Universidade Estadual Paulista Júlio de Mesquita Filho, Instituto de Biociências de Rio Claro, 2013.