Trophic ecology of tadpoles in floodplain wetlands: combining gut contents, selectivity, and stable isotopes to study feeding segregation of syntopic species

摘要

Little consensus exists on the role of food partitioning in the organization of tadpole assemblages. We studied trophic ecology of syntopic tadpoles through the analysis of gut contents, selectivity, and stable isotopes to assess the occurrence of food partitioning in tadpole assemblages. Tadpoles (n = 194) were collected in three wetlands and corresponded to four species:Elachistocleis bicolor(Eb),Scinax nasicus(Sn),Physalaemus albonotatus(Pa), andDendropsophussp. (D); and belonged to four ecomorphological groups (EMGs): suspension feeders (Eb), nektonic (Sn), benthic (Pa) and macrophagous (D).Sn, andPashowed low selective diet and a wider trophic spectrum thanEbandD, which mainly consumed one or two food categories. Diet overlap was higher betweenSnandPa. Still,SnandPapresented some differences in the food resources consumed. Stable isotopes analysis showed thatEb,Sn, andPahad a lower trophic position thanD, explained by the high contribution of animal food oligochaete inDdiet, in contrast to the importance of algae in the diet ofEb,Sn, andPa.Diet specialization of some species, combined with the low dietary and isotopic overlap among the ecomorphological groups, suggests that trophic partitioning facilitates coexistence of syntopic tadpoles.