Carnivore conservation in practice: replicated management actions on a large spatial scale

Abstract

Summary1. More than a quarter of the world's carnivores are threatened, often due to multiple and complex causes. Considerable research efforts are devoted to resolving the mechanisms behind these threats in order to provide a basis for relevant conservation actions. However, even when the underlying mechanisms are known, specific actions aimed at direct support for carnivores are difficult to implement and evaluate at efficient spatial and temporal scales. 2. We report on a 30-year inventory of the critically endangered Fennoscandian arctic fox Vulpes lagopus L., including yearly surveys of 600 fox dens covering 21 000 km 2 . These surveys showed that the population was close to extinction in 2000, with 40-60 adult animals left. However, the population subsequently showed a fourfold increase in size.3. During this time period, conservation actions through supplementary feeding and predator removal were implemented in several regions across Scandinavia, encompassing 79% of the area. To evaluate these actions, we examined the effect of supplemental winter feeding and red fox control applied at different intensities in 10 regions. A path analysis indicated that 47% of the explained variation in population productivity could be attributed to lemming abundance, whereas winter feeding had a 29% effect and red fox control a 20% effect. 4. This confirms that arctic foxes are highly dependent on lemming population fluctuations but also shows that red foxes severely impact the viability of arctic foxes. This study also highlights the importance of implementing conservation actions on extensive spatial and temporal scales, with geographically dispersed actions to scientifically evaluate the effects. We note that population recovery was only seen in regions with a high intensity of management actions. 5. Synthesis and applications. The present study demonstrates that carnivore population declines may be reversed through extensive actions that target specific threats. Fennoscandian arctic fox is still endangered, due to low population connectivity and expected climate impacts on the distribution and dynamics of lemmings and red foxes. Climate warming is expected to contribute to both more irregular lemming dynamics and red fox appearance in tundra areas; however, the effects of climate change can be mitigated through intensive management actions such as supplemental feeding and red fox control.

Red foxes colonizing the tundra: genetic analysis as a tool for population management

“…Of these, 32 individuals were included in a previously published analysis of the large-scaled expansion patterns in Fennoscandia (Norén et al 2015). The tundra foxes were obtained as tissue samples from red foxes culled for management purposes (procedure described by Angerbjörn et al 2013) (n = 32) or faecal samples collected at known arctic and red fox den sites during Arctic fox inventories (n = 21) (Johansson et al 2009). For comparison, we included the genotypes of 152 previously published red foxes (Norén et al 2015).…”

“…Also, to increase the efficiency of this action as well as avoiding unmotivated culling, an evaluation of the spatial scale where measures are necessary is highly recommended. Even though predator control has been successful in the case of Arctic fox conservation (Angerbjörn et al 2013), there are examples of unexpected consequences of predator removal (Ruscoe et al 2011). Therefore, continuous assessment of removal strategies and consequences is central.…”

“…For example, the red fox has contributed to alterations in community structure and declines of competitor and prey populations (Hersteinsson and Macdonald, 1992;Smedshaug et al 1999;Angerbjörn et al 2013). In particular, the emergence of red foxes into the tundra region is associated with Arctic fox (Vulpes lagopus) population decline and withdrawal into areas of lower quality (Dalén et al 2004;Angerbjörn et al 2013). The patterns observed in these sympatric fox populations is an example of the expansion-contraction scenarios outlined by Elmhagen et al (2015).…”

“…Previous work has demonstrated that the negative effects exerted by red foxes on arctic foxes can be reduced through intensive culling in specific core areas (Angerbjörn et al 2013). Swedish authorities have included red fox removal as a vital action in the management plan for Scandinavian arctic foxes (Elmhagen 2008).…”

“…Swedish authorities have included red fox removal as a vital action in the management plan for Scandinavian arctic foxes (Elmhagen 2008). The efficiency of red fox culling however varies considerably across different areas and counties (Angerbjörn et al 2013). These actions, however, are both expensive and time-consuming and the practical challenges for working in tundra areas put high demands on well-planned logistics, experienced personnel and large sources of funding.…”