Spatial and temporal extinction dynamics in a freshwater cetacean

摘要: Geographical range contraction is a fundamental ecological characteristic of species population decline, but relatively little investigation has been conducted into general trends in the dynamic properties collapse. The Yangtze River dolphin or baiji (Lipotes vexillifer), probably first large mammal to have become extinct over 50 years, was believed experienced major collapse during its decline through progressive large-scale and fragmentation. This range-collapse model challenged by new dataset 406 last-sighting records collected from across baiji's historical an interview survey fishing communities. Although regional abundance may varied range, analyses extensive sighting series provide comprehensive evidence that not associated with any geographical middle-lower drainage, even decade immediately before probable global extinction species. Extinction risk therefore seemingly related Baiji apparently underwent periodic seasonal movements their we propose fragmentation be biogeographic characteristics for declining populations mobile connected landscapes.