Phenotypic divergence across populations does not affect habitat
selection in an Amazonian poison frog
Abstract
In polytypic species, where distinct variants occur in separate
populations, few studies to date have quantified intraspecific
differences in habitat selection. This can inform us about habitat
requirements across different areas and populations, with implications
for conservation, and can increase our understanding of the selective
pressures acting upon different populations. Here, we investigated
differences in habitat selection across six populations of the dyeing
poison frog (Dendrobates tinctorius), which are characterized by
great phenotypic variation among them, especially in terms of warning
coloration, body size, and sexual size dimorphism. We hypothesized that
habitat selection differs (1) among populations containing different
variants, predicting that frogs in larger-bodied populations are less
dependent on structures that retain moisture; (2) among disturbed and
pristine areas, predicting frogs in disturbed areas being more reliant
on structural diversity and water bodies; and (3) between males and
females, predicting stronger differences in habitat selection in
populations with greater sexual size dimorphism. We found little support
for these hypotheses, with habitat selection being broadly similar among
populations. Frogs generally selected for proximity to tree falls, dead
woody material (such as fallen/rotting branches, fallen palm bracts,
etc.), presence of water pools (phytotelmata and other small bodies of
water), and avoided areas with extensive ground vegetation and little
canopy cover. We found limited evidence for fine-scale differences in
habitat selection between sexes, with males showing a comparatively
stronger selection for proximity to water pools and females stronger
selection for tree falls. More generally, our results suggest that in
polytypic and aposematic species, habitat selection might be less
influenced by intersexual niche partitioning and predation risk, and
more by resource availability. Our findings provide important baseline
data regarding the habitat selection and requirements of this emblematic
species, which can be relevant for efficient conservation measures in
the future.