The response of otters to environmental changes imposed by the construction of large dams

摘要: The number of dams is progressively increasing, but nonetheless there are few examples long-term studies involving otters and these structures. This study assessed how Eurasian otter Lutra lutra responded over time to environmental changes imposed by the construction a large reservoir, Alqueva Dam (250 km2, SE Portugal). Otter distribution was monitored four phases (pre-deforestation/flooding, deforestation, flooding, post-flooding) from 2000 2006 in both flooded surrounding areas. During each phase, presence at two resolutions: 25 km2 (76 survey sites wet dry seasons) 1 km2 (39 sites, every three months). In addition, spraints were collected eight (pre-dam) (post-dam) assess compare diet with prey availability. Otters widespread before dam (>82.4% positive cells), decreased during deforestation (68.5%), particularly flooding phase (33.3%), recovered post-flooding although not level recorded (61.5–83.3%). Otter dominated fish American crayfish Procambarus clarkii pre-deforestation/flooding (56.7% fish, 35.3% crayfish) end (60.7% 33.2% crayfish). Species richness (16 8), as did ratio native/non-native species (1.7 0.3). Changes availability main ecological requirements similar observed area throughout impact phases, some recovery phase. The results emphasize importance monitoring that include several post-impact evaluate response impacts. This will allow better planning mitigation compensation measures. Copyright © 2013 John Wiley & Sons, Ltd.