Effects of anthropogenic environmental changes on amphibian diversity in the rain forests of eastern Madagascar

Abstract

Madagascar has one of the world's highest rates of human population increase, which is coupled with an increase of resource exploitation, particularly food and firewood. Forests are cleared and converted to rice fields or plantations (mainly Eucalyptus or pine). How does deforestation affect the amphibian diversity of the original biotope, the rain forest? To answer this question, the amphibian fauna of intact rain forests was compared with that of secondary forests, Eucalyptus plantations and rice fields. The main consequence of rain forest disturbance was loss of amphibian species. Compared with an intact forest, species richness in secondary forests, Eucalyptus plantations and rice fields were 54%, 46% and 12%, respectively. Species number and individual density increased with increasing structural complexity of the habitat and the presence of water bodies. The reproductive strategy of the species could be decisive for the presence or absence of single species in different habitats. With increasing degradation the percentage of species spawning in water increased. Correspondingly, Hyperoliidae and Raninae were characteristic of degraded habitats, whereas Microhylidae and Mantellinae were representative of natural habitats.