Do human-induced habitat changes impact the morphology of a common amphibian, Bufo bufo?

Abstract Human activities induce habitat modifications and the intensification of land use including urbanisation and agriculture. Human-modified habitats are often fragmented, generating patches separated by dispersal barriers. In order to cross landscape obstacles, animals need to adapt or show plastic responses allowing effective dispersal and the pursuit of fitness-relevant activities. Due to their limited dispersal capacity and the need for terrestrial and aquatic habitats to complete their biphasic life cycle, amphibians can be expected to be particularly vulnerable to changes in the landscape. Yet data to test these ideas remain relatively scarce. To test whether human-induced habitat modifications impact the morphology of animals with low dispersal ability we measure 15 morphological traits on 137 common toads ( Bufo bufo ) across four habitat types represented by two or three independent sites across the Ile de France region. The results shown morphological differences among habitat types and sexes. Animals show habitat specific morphologies that may allow them to survive in human-modified habitats. Moreover, females have larger heads possibly to avoid trophic resource competition with males. Males, on the other hand show longer limbs possibly related to their greater movements when finding females during the reproductive season. Overall, our results that animals living in different habitat types are morphologically different with differences between natural and urban habitat being the greatest. Whether these differences are due to local adaptation or plastic responses remains to be investigated.