posted on 2016-05-02, 08:48authored byLeonardo F.B. Moreira, Luiz A. Solino-Carvalho, Christine Strüssmann, Roberto M.L. Silveira
Land use change has been identified as a major
driver of amphibian decline around the world. Yet we generally lack an
understanding of how conversion to exotic pastures affects freshwater
communities. This study examined tadpole assemblages in areas converted to exotic
pastures and native wooded grasslands in northern Pantanal wetland, Midwestern Brazil.
We tested the differences in site occupancy probability and assemblage
composition during a flood season. We registered thirteen tadpole species, but
only five were detected at levels suitable for occupancy modelling. For most
species, tadpole occupancy was higher at the beginning of the flood season.
Only Scinax fuscomarginatus occupancy was related with vegetation cover.
Occupancy probability for three species (Dendropsophus nanus, Physalaemus
centralis, and Physalaemus cuvieri) was associated positively with
species richness of fish. Multivariate analyses demonstrated that exotic
pastures hosted a different tadpole assemblage than native areas. The
assemblage composition gradient was associated with species richness of fish,
vegetation cover and volume of herbaceous vegetation and leaf litter. These
differences likely relate to specific traits of individual anuran species
(dietary plasticity, reproductive mode, and habitat preference). The study
showed that some generalist species were able to cope with replacement of
native vegetation by exotic species. However, management practices have
maintained many areas in the Pantanal at a stage of a near-pristine wetland ecosystem
and replacement of native vegetation by exotic pastures should be done with
caution.