Long-distance Eurasian lynx dispersal – a prospect for connecting native and reintroduced populations in Central Europe

Large-scale assessment of genetic structure to assess risk of populations of a large herbivore to disease

Chronic wasting disease (CWD) can spread among cervids by direct and indirect transmission, the former being more likely in emerging areas. Identifying subpopulations allows the delineation of focal areas to target for intervention. We aimed to assess the population structure of white-tailed deer (Odocoileus virginianus) in the northeastern United States at a regional scale to inform managers regarding gene flow throughout the region. We genotyped 10 microsatellites in 5701 wild deer samples from Maryland, New York, Ohio, Pennsylvania, and Virginia. We evaluated the distribution of genetic variability through spatial principal component analysis and inferred genetic structure using non-spatial and spatial Bayesian clustering algorithms (BCAs). We simulated populations representing each inferred wild cluster, wild deer in each state and each physiographic province, total wild population, and a captive population. We conducted genetic assignment tests using these potential sources, calculating the probability of samples being correctly assigned to their origin. Non-spatial BCA identified two clusters across the region, while spatial BCA suggested a maximum of nine clusters. Assignment tests correctly placed deer into captive or wild origin in most cases (94%), as previously reported, but performance varied when assigning wild deer to more specific origins. Assignments to clusters inferred via non-spatial BCA performed well, but efficiency was greatly reduced when assigning samples to clusters inferred via spatial BCA. Differences between spatial BCA clusters are not strong enough to make assignment tests a reliable method for inferring the geographic origin of deer using 10 microsatellites. However, the genetic distinction between clusters may indicate natural and anthropogenic barriers of interest for management.

Diverging ecological traits between the Balkan lynx and neighbouring populations as a basis for planning its genetic rescue

Selecting appropriate candidates for genetic rescue mostly relies on previous genetic research and monitoring, while ecological and behavioural traits of the remnant and source populations are rarely considered for such conservation measures. Because of their slow recovery, Eurasian lynx Lynx lynx populations in Central and Western Europe have been a repeated target of genetic reinforcements and reintroductions in the past 50 years. Once inhabiting much of south-eastern Europe, the Balkan lynx L. l. balcanicus is now critically endangered and confined to a small population. Long-term isolation has caused loss of genetic diversity and has possibly led to inbreeding depression. Immediate actions need to consider genetic reinforcement to increase the genetic diversity and secure population viability. Here, we compared the Balkan lynx with two neighbouring populations: Dinaric population originating from the Carpathian subspecies (L.l. carpathicus) and Anatolian population of Caucasian subspecies (L.l. dinniki) to determine is better suited source from an ecological standpoint. Main findings suggest that the L.l. carpathicus is ecologically more similar to the L.l. balcanicus and therefore likely better suited for the environment of south-western Balkans on the basis of prey preference (roe deer being the main prey), local prey availability (lower lagomorph and higher ungulate availability) and habitat use (predominant use of the mixed and broadleaved forests). We discuss the contrasting results of genetic and ecological analyses from both the evolutionary and conservation perspective and provide potential solutions that would take into account both aspects to pave the road towards potential genetic rescue of the Balkan lynx.

Genetic structure of Eurasian beaver in Romania: insights after two decades from the reintroduction

Once exploited for fur, meat, and extracting the yellowish exudate called castoreum, the Eurasian beaver disappeared from Romania during the eighteenth century. After, the reintroductions carried out two decades ago are currently thriving in the Danube River basin. Using nine nSSR markers, we analysed samples from 98 individuals, and we found no genetic substructure, suggesting high dispersal and gene flow capabilities. The stepwise mutation model (SMM) indicated the existence of a recent genetic bottleneck, though the Eurasian beaver retains high levels of genetic diversity and population growth facilitated variation in nSSR loci. A fine-scale spatial correlation in females was detected, contrasting with males’ dispersal on longer distances. While the movement and establishment of individuals’ new territories were made under natural predation pressure, the mix following natural expansion improved the fitness and could contribute to a higher genetic diversity than the source population. With any reintroduction, a focus on capturing individuals from various geographic origins, as well as securing many and suitable founding individuals (adults, subadults, and juveniles) with mixed origins, could secure the post-genetic bottleneck recovery and higher genetic diversity. Beyond this conservation success, future management strategies should consider building a National Action Plan (NAP) for the species, including a permanent genetic monitoring programme for Eurasian beaver.