Beaver facilitation in the conservation of boreal anuran communities

A rapid loss of species and habitats is occurring globally. Amphibians and wetlands are important components of this overall decline. Wetlands in the boreal region are frequently constructed by damming activities of an ecosystem engineer, the beaver (Castor sp.). The authors investigated the anuran fauna in ten such ‘beaver ponds’, ten ‘non-beaver ponds’ and eight temporary ponds in Finland. All three anuran species present in the region occupied the beaver ponds, including a species absent (the moor frog Rana arvalis Nilsson, 1842) in natural waters (non-beaver ponds and temporary ponds). Moor frogs obviously benefitted from pond construction and removal of trees by beavers leading to a plentitude of shallow water and a wide belt of emergent vegetation. The results
show that beavers offer high-quality habitats for anurans and facilitate the occurrence of moor frogs. It is suggested that these ecosystem engineers could be used in ecosystem restoration. The beaver clearly represents a species that promotes amphibian conservation.