The conservation of large carnivores is a formidable challenge for biodiversity conservation. Using a data set on the past and current status of brown bears (Ursus arctos), Eurasian lynx (Lynx lynx), gray wolves (Canis lupus), and wolverines (Gulo gulo) in European countries, we show that roughly one-third of mainland Europe hosts at least one large carnivore species, with stable or increasing abundance in most cases in 21st-century records. The reasons for this overall conservation success include protective legislation, supportive public opinion, and a variety of practices making coexistence between large carnivores and people possible. The European situation reveals that large carnivores and people can share the same landscape.

The fragmentation of populations is an increasingly important problem in the conservation of endangered species. Under these conditions, rare migration events may have important effects for the rescue of small and inbred populations. However, the relevance of such migration events to genetically depauperate natural populations is not supported by empirical data. We show here that the genetic diversity of the severely bottlenecked and geographically isolated Scandinavian population of grey wolves (Canis lupus), founded by only two individuals, was recovered by the arrival of a single immigrant. Before the arrival of this immigrant, for several generations the population comprised only a single breeding pack, necessarily involving matings between close relatives and resulting in a subsequent decline in individual heterozygosity. With the arrival of just a single immigrant, there is evidence of increased heterozygosity, signi cant outbreeding (inbreeding avoidance), a rapid spread of new alleles and exponential population growth. Our results imply that even rare interpopulation migration can lead to the rescue and recovery of isolated and endangered natural populations.

Poaching is a widespread and well-appreciated problem for the conservation of many threatened species. Because poaching is illegal, there is strong incentive for poachers to conceal their activities, and consequently, little data on the effects of poaching on population dynamics are available. Quantifying poaching mortality should be a required knowledge when developing conservation plans for endangered species but is hampered by methodological challenges. We show that rigorous estimates of the effects of poaching relative to other sources of mortality can be obtained with a hierarchical state–space model combined with multiple sources of data. Using the Scandinavian wolf (Canis lupus) population as an illustrative example, we show that poaching accounted for approximately half of total mortality and more than two-thirds of total poaching remained undetected by conventional methods, a source of mortality we term as ‘cryptic poaching’. Our simulations suggest that without poaching during the past decade, the population would have been almost four times as large in 2009. Such a severe impact of poaching on population recovery may be widespread among large carnivores. We believe that conservation strategies for large carnivores considering only observed data may not be adequate and should be revised by including and quantifying cryptic poaching.

Predatory behavior of wolves (Canis lupus) was studied in 2 wolf territories in Scandinavia. We used hourly data from Global Positioning System (GPS)‐collared adult wolves in combination with Geographic Information System (GIS) for detailed analyses of movement patterns. We tested the hypothesis that wolves spend 1–2 days close to larger prey such as moose (Alces alces) and reasoned that 1–2 locations per day would be enough to find all larger prey killed by the wolves. In total, the study period comprised 287 days and yielded 6,140 hourly GPS positions, with an average of 21.4±2.4 (SD) daily positions. Depending on the radius used to define clusters, 4,045‐5,023 (65.9–81.8%) positions were included in 622–741 GPS‐clusters. We investigated all positions within clusters in the field, and 244 (22%) single positions. In total, we found 68 moose and 4 roe deer (Capreolus capreolus) and classified them as wolf‐killed within the study period. Another 10–15 moose may have been killed but not found. The GIS analyses indicated the proportion of wolf‐killed ungulates included in GPS clusters to be strongly dependent on both number of positions per day and the radius used for defining a set of spatially aggregated GPS positions as a cluster. A higher proportion (78%) of killed prey in clusters based on nighttime (2000‐0700) than those based on daytime (0800–1900) positions (41%). Simulation of aerial search during daylight hours for killed moose resulted in a serious underestimation (>60%) as compared to the number of wolf‐killed moose found during the study. The average kill rate, corrected for 14% nondetected moose, in the territories was 3.6‐4.0 days per killed moose. We concluded that the feeding behavior of wolves in Scandinavia was either different from wolves preying on moose and living at the same latitude in North America, or that estimates of wolf kill rates on moose may have been seriously underestimated in previous North American studies.

The difficulty of obtaining pedigrees for wild populations has hampered the possibility of demonstrating inbreeding depression in nature. In a small, naturally restored, wild population of grey wolves in Scandinavia, founded in 1983, we constructed a pedigree for 24 of the 28 breeding pairs established in the period 1983–2002. Ancestry for the breeding animals was determined through a combination of field data (snow tracking and radio telemetry) and DNA microsatellite analysis. The population was founded by only three individuals. The inbreeding coefficient F varied between 0.00 and 0.41 for wolves born during the study period. The number of surviving pups per litter during their first winter after birth was strongly correlated with inbreeding coefficients of pups ( R 2 =0.39, p <0.001). This inbreeding depression was recalculated to match standard estimates of lethal equivalents (2B), corresponding to 6.04 (2.58–9.48, 95% CI) litter-size-reducing equivalents in this wolf population.