How environmental factors affect the abundance and distribution of two congeneric species of Amazonian frogs

In this study, we test the hypothesis that, at a fine scale, environmental
variables influence differently sister species that live in sympatry and
are phylogenetically closely related. We sampled two Amazonian anuran
species, Phyzelaphryne miriamae and Phyzelaphryne sp., in 11 permanent
sampling modules distributed across ~600 km in the Purus-Madeira
Interfluve between 2013 and 2014. Using mixed generalized linear models,
we found that the species have distinct environmental associations, which
may facilitate their coexistence in sympatry. Phyzelaphryne miriamae was
more frequent in environments with low precipitation and low water tables,
suggesting this species is better adapted to live in drier places. In
contrast, Phyzelaphryne sp. appeared to be a generalist regarding to
habitat and resource use. These patterns are in accordance with the
hypothesis that environmental variables influence sister species
differently on a fine scale. Phyzelaphryne miriamae is larger than
Phyzelaphryne sp., which may make it more resistant to dehydration,
allowing it to explore drier environments. In conclusion, our results are
in concordance with the hypothesis that the evolution of characteristics
resulting from selection may have reduced competition for resources
between closely related species, thus facilitating coexistence in
sympatry.