EFFECTS OF HABITAT FRAGMENTATION ON THE ABUNDANCE OF 2 SPECIES OF LEPTODACTYLID FROGS IN AN ANDEAN MONTANE FOREST

We used visual transect surveys to study the effects of forest fragmen tation on abundance of two species of Leptodactylid frogs in an Andean forest of northern Ecuador. We measured the abundances of Eleutheroda ctylus chloronatus and E. trepidotus at various distances from the for est edge in one large forest patch (200 ha) and four adjacent forest f ragments (0.25-5.3 ha). We also collected data on forest characteristi cs (leaf litter thickness, understory density, and number and size of canopy trees) at each site. Abundance of E. chloronatus and E. trepido tus were respectively 3.5 and 2.1 times higher at sites in the large f orest patch than at sites in the small fragments. Abundance of E. chlo ronatus was positively correlated with the log of patch size and inver sely correlated with understory density E. trepidotus abundance tons n ot correlated with either patch size or understory density, but was in versely correlated with distance from the site to the large forest pat ch. The two species thus both appear to be affected by habitat fragmen tation, but through different processes.