Applying genomic approaches to identify historic population declines in European forest bats

Anthropogenically-driven environmental changes over the past two centuries
have led to severe biodiversity loss, most prominently in the form of loss
of populations and individuals. Better tools are needed to assess the
magnitude of these wildlife population declines. Anecdotal evidence
suggests European bat populations have suffered substantial declines in
the past few centuries. However, there is little empirical evidence of
these declines that can be used to put more recent population changes into
historic context and set appropriate targets for species
recovery.  This study is a collaboration between academics and
conservation practitioners to develop molecular approaches capable of
providing quantitative evidence of historic population changes and their
drivers that can inform the assessment of conservation status and
conservation management. We generated a genomic dataset for
the Western barbastelle, Barbastella
barbastellus, a globally Near Threatened and regionally
Vulnerable bat species, including colonies from across the species’
British and Iberian ranges. We used a combination of landscape genetics
and approximate Bayesian computation model-based inference of demographic
history to identify both evidence of population size changes and possible
drivers of these changes.  We found that levels of genetic
diversity and inbreeding were related to broadleaf woodland cover around
the colony location. Genetic connectivity was impeded by artificial lights
and facilitated by the combination of rivers and broadleaf woodland
cover.  The demographic history analysis showed that both the
northern and southern British barbastelle populations have declined by 99%
over the past 330–548 years. These declines may have been triggered by
loss of large oak trees and native woodlands due to shipbuilding during
the early colonial period. Synthesis and applications. Genomic
approaches can be applied to provide a better understanding of the
conservation status of threatened species, within historic and
contemporary context, and inform their conservation
management. This study shows how we can bridge the implementation
gap and promote the application of genomics in conservation management
through co-designing studies with conservation practitioners and
co-developing applied management targets and recommendations.