Effects of disturbance on amphibians of conservation concern in Eastern Oregon and Washington

The effects on amphibians of forest insects, tree diseases, wildfire, and management strategies designed to improve forest health (e.g., thinning, prescribed burns, road removal, and spraying with pesticides or biological microbial agents) are discussed. Those species that occur in forested habitats in eastern Oregon and Washington, USA that are considered of concern include the Oregon spotted frog (Rana pretiosa), Columbia spotted frog (R. luteiventris), northern leopard frog (R. pipiens), Cascades frog (R. cascadae), tailed frog (Ascaphus truei), Larch Mountain salamander (Plethodon larselli), and Cope's giant salamander (Dicamptodon copei). Little is known regarding the effects of forest health on amphibians, although tree mortality resulting from insects and disease is unlikely to dramatically affect these species, except for the tailed frog and larch mountain salamander. Both these species depend on overstorey canopy to maintain temperature and moisture conditions; timber harvest in their habitats has rendered them unsuitable. Wildfire and prescribed burning to a lesser extent, may alter the abundance of prey, coarse woody debris, and vegetation, which could influence movements and survival of dispersing amphibians. Spraying with pesticides could negatively affect these species if the abundance of their prey is decreased. Spraying with biological microbial agents is unlikely to affect prey abundance. Additional research is needed to determine if these disturbance agents are contributing to the decline of many of these amphibians.Bull and Wales "Effects of disturbance on amphibians of conservation concern in Eastern Oregon and Washington." Northwest Science. 2001; 75(Special issue): 174-17