Mortality of game mammals caused by an extreme flooding event in south-western Poland

We examine mortality in five terrestrial species of game animals resulting from an extreme flood event in Central Europe in July 1997. We present species-specific mortality rates and collate them with local abundances to show the susceptibilities of the different species to flood mortality. We also compare mortality rates in areas inundated by the main river and by its tributaries. Data were collected in the catchment area of the Odra River, south-western Poland. Mortality was estimated by surveying for drowned animals in flooded areas of 50 hunting districts (2,876 km²). Total mortality amounted to 3,613 individuals, mostly of roe deer Capreolus capreolus and brown hare Lepus europaeus. Relative to estimates of abundance, mortality was disproportionately high in hares. Drownings of roe deer and wild boar, Sus scrofa were proportional to local abundance. Young individuals were particularly affected. Mortality was low in foxes, Vulpes vulpes, and red deer, Cervus elaphus. The mortality rate increased with the proportion of area flooded and the duration of flooding and was four times higher along the Odra River than along its tributaries. Our data specify, for the first time, direct losses in wild, large animals in response to an extreme flood event. Despite high overall losses, negative long-term effects on populations seemed unlikely. Nevertheless, to lessen the impact, river management focused primarily on human safety should also integrate the needs of wildlife.