Relationship of Endangered Amphibians to Landscape Disturbance




Abstract: We examined the density of 2 endangered amphibians, natterjack toads (Bufo calamita) and yellow-bellied toads (Bombina variegata), in 150 breeding pools at each of 2 military training areas in the German state of Bavaria. We selected pools to ensure a wide range of observable ground disturbance resulting from military vehicular traffic during cross-country maneuvers. Both species exhibited significant affinity for pools with high levels of ground disturbance. Natterjack toads preferred pools with 80–100% ground disturbance; yellow-bellied toads preferentially occupied pools with 40–100% ground disturbance. Pools occupied by the target species were characterized by higher levels of bare ground and minimal vegetation. Among other observed amphibians, European edible frogs (Rana esculenta) preferred pools with ≤60% ground disturbance, less bare ground, more vegetative cover, and disturbance >2 years old. Common tree frogs (Hyla arborea), smooth newts (Triturus vulgaris), and alpine newts (T. alpestris) showed no preference for level of disturbance; densities were correlated to parameters apparently unrelated to disturbance. The habitat mosaic created by the heterogeneous nature of military training disturbance may help explain the high biodiversity that often characterizes military training areas. Preservation of native biodiversity is dependent on maintaining an appropriate disturbance regime that, in turn, maintains a habitat mosaic conducive to the presence of native species adapted to a broad disturbance—succession continuum. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):738–744; 2008)