Diferentes resoluções na análise da dieta afetam nossa interpretação dos padrões de segregação de nicho? Um exemplo com lagartos australianos

Abstract

Understanding the diet of lizards is crucial for comprehending their interactions and the impact of food availability on their survival, growth, and reproduction. Typically, the diet is described using broad taxonomic terms such as orders, resulting in a loss of information as different families and lower taxonomic levels within orders exhibit distinct biological characteristics. This raises the question: Can the loss or variation in resolution of prey items in trophic niche analyses alter our interpretation of ecological patterns in lizard communities? To address this question, we examined the width and overlap of niches in 11 sympatric lizard species in two areas of the Victoria Desert, Australia. Lizards were collected between 1978 and 1979, and prey items present in their stomach contents were identified to the species level.. The diet was analyzed at two resolutions: low resolution (order, approximately 19 prey items) and high resolution (species, approximately 246 prey items). For both datasets, we calculated Pianka's niche overlap index and niche width using Levin's index. The width and overlap patterns among species and communities exhibited a general reduction when higher resolution was utilized compared to lower resolution. These results suggest that the choice of prey item resolution in trophic niche analysis can affect the interpretation of ecological patterns in lizard communities. In low-resolution analyses, overlap may be interpreted as competition among species, whereas in high-resolution analyses, the significant reduction in overlap suggests that species may be effectively sharing resources. For ecological studies of communities, careful selection of prey item resolution in trophic niche analysis is important to obtain a more accurate understanding of species interactions. Detailed and higher-resolution data can help avoid misinterpretations and ensure that trophic niche analyses are conducted in a robust and reliable manner.