Confirming their predictions, hormone levels in adult frogs was lower in suitable habitat (forest litter), compared to unsuitable matrix habitat (ploughed soil). These results provide support that physiological parameters can be used as a proxy of the resistance an individual may experience while moving through certain habitat types. Interestingly, stress levels in juvenile toads seemed unaffected by substrate, which the authors attributed to either experimental design, differences in sensory perception, or differences in cognitive processes between adults and juveniles (I propose a fourth hypothesis, that there may be a hormonal basis in juvenile frogs’ dispersal drive).
Janin, A, J-P Lena, S Deblois, and P Joly. 2012. Use of stress-hormone levels and habitat selection to assess functional connectivity of a landscape for an amphibian. Conservation Biology 26:923-931. (E-mail: pierre.joly@niv‐lyon1.fr)