No 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)

Disturbance is a natural component of ecosystems. All species, including threatened and endangered species, evolved in the presence of, and are adapted to natural disturbance regimes that vary in the kind, frequency, severity, and duration of disturbance. We investigated the relationship between the level of visible soil disturbance and the density of four endangered plant species on U.S. Army training lands in the German state of Bavaria. Two species, gray hairgrass (Corynephorus canescens) and mudwort (Limosella aquatica), showed marked affinity for or dependency on high levels of recent soil disturbance. The density of fringed gentian (Gentianella ciliata) and shepherd's cress (Teesdalia nudicaulis) declined with recent disturbance, but appeared to favor older disturbance which could not be quantified by the methods employed in this study. The study illustrates the need to restore and maintain disturbance regimes that are heterogeneous in terms of the intensity of and time since disturbance. Such a restoration strategy has the potential to favor plant species along the entire spectrum of ecological succession, thereby maximizing plant biodiversity and ecosystem stability.