Predation has a greater impact in less productive environments: variation in roe deer, Capreolus capreolus, population density across Europe

Abstract

Aim We aimed to describe the large-scale patterns in population density of roe deer Caprelous capreolus in Europe and to determine the factors shaping variation in their abundance. Location Europe.Methods We collated data on roe deer population density from 72 localities spanning 25°latitude and 48°longitude and analysed them in relation to a range of environmental factors: vegetation productivity (approximated by the fraction of photosynthetically active radiation) and forest cover as proxies for food supply, winter severity, summer drought and presence or absence of large predators (wolf, Canis lupus, and Eurasian lynx, Lynx lynx), hunter harvest and a competitor (red deer, Cervus elaphus). ResultsRoe deer abundance increased with the overall productivity of vegetation cover and with lower forest cover (sparser forest cover means that a higher proportion of overall plant productivity is allocated to ground vegetation and thus is available to roe deer). The effect of large predators was relatively weak in highly productive environments and in regions with mild climate, but increased markedly in regions with low vegetation productivity and harsh winters. Other potentially limiting factors (hunting, summer drought and competition with red deer) had no significant impact on roe deer abundance. Main conclusionsThe analyses revealed the combined effect of bottom-up and top-down control on roe deer: on a biogeographical scale, population abundance of roe deer has been shaped by food-related factors and large predators, with additive effects of the two species of predators. The results have implications for management of roe deer populations in Europe. First, an increase in roe deer abundance can be expected as environmental productivity increases due to climate change. Secondly, recovery plans for large carnivores should take environmental productivity and winter severity into account when predicting their impact on prey.

Incorporating anthropogenic effects into trophic ecology: predator–prey interactions in a human-dominated landscape

“…Wolf extirpation caused eruptions of deer populations in European and American national parks [17,65], and our results suggest that similar wolf reductions and extirpations could have led to increased red deer populations elsewhere in Europe [66]. By contrast, roe deer populations were only suppressed by apex predators in unproductive landscapes, and were more affected by foraging needs and competition for food in Europe [67,68]. Bears had a relatively large (but variable) negative effect on roe deer and not on red deer.…”

Roe deer face competing risks between predators along a gradient in abundance

“…This implies that the recovery of large carnivores, especially lynx ), across Europe is going to induce a change in roe v www.esajournals.org deer mortality schedules, increasing total mortality, especially for yearling and adult females. If not accounted for this could cause declines in harvested roe deer populations, especially in marginal areas (Melis et al 2009(Melis et al , 2010.…”

“…For example, Eurasian lynx, when sympatric with roe deer, are roe deer specialist (Jędrzejewski et al 1993, Jobin et al 2000, Odden et al 2006b) and their kill-rates show only limited variation across a wide range of prey abundance (Breitenmoser and Haller 1993, Okarma et al 1997, Molinari-Jobin et al 2002, Nilsen et al 2009b. Consequently, assuming that lynx density remains stable, lynx predation could be expected to be higher at low roe deer abundance and in areas with unfavorable environmental conditions (Melis et al 2009, Melis et al 2010. On the other hand, red foxes have been well documented to prey upon fawns (Cederlund and Lindströ m 1983, Linnell et al 1995, Aanes and Andersen 1996, Jarnemo et al 2004, but due to their generalist and opportunistic feeding behavior, they have been observed to specialize only when roe deer occur at high abundance and the higher encounter probability makes prey switching behavior profitable (Panzacchi et al 2008).…”

The Importance of Reintroducing Large Carnivores: The Brown Bear in the Pyrenees

“…In Bialowieza, Poland, the wolf and lynx prey significantly on small ungulates, but less on wild boar (Sus scrofa), moose and bison (Bison bison) since their numbers are limited by food availability and weather conditions such as snow (Jedrzejewska and Jedrzejewski 2005). In Norwegian forests, roe deer (Capreolus capreolus) density declined predators were present in the habitat (Melis et al 2009). The population went from 1485 roe deer individuals per 100 km 2 when there were no predators to 605 with one predator (European lynx or wolf) and 167 with both predators.…”