Impact of otter (<em>Lutra lutra</em>) predation on amphibians in temporary ponds in Southern Spain

Abstract

We report the observation of an event of mortality of ribbed newts (Pleurodeles waltl) and Iberian spadefoot toads (Pelobates cultripes) due to predation by a pair of otters (Lutra lutra) in a temporary pond complex in southern Spain. The peculiar predation mode on ribbed newts, with extraction of soft organs through an incision in the upper part of the thorax, may result in an under estimate of the importance of this species in the diet of otters. The high number of dead amphibians killed by two otters in only several hours suggests that the presence of these predators may pose a serious threat to amphibian populations. The risk is especially high in arid areas, with few ponds, synchronous reproductive migration, and high density of animals. We consider that measures promoting the conservation and population and range increase of otters might have a negative impact on amphibians.