Unexpected landscape-scale contemporary gene flow and fine-scale genetic
diversity in rural hedgehogs
Abstract
Agricultural intensification is one of the major forces driving
populations of many traditionally common native species into smaller,
fragmented populations which are prone to isolation and loss of genetic
diversity. Identifying the spatial extent and characteristics of rural
systems that support gene flow and promote genetic diversity for these
species is thus essential for their long-term conservation. Here we used
asymmetric autosomal genetic structure between sexes to investigate
current gene flow among four neighbouring suburban populations of
hedgehogs (Erinaceus europaeus) in England, which are separated by
agricultural land. Contrary to expectations, we found that individuals
belonged to a single genetic population despite the populations being
separated by unoccupied agricultural land. Spatial autocorrelation was
significant in adult female hedgehogs, but non-significant in adult
males, revealing male driven contemporary gene flow between local
populations. The results suggest that male hedgehogs are capable of
moving between population patches separated by at least 3 km across the
agricultural matrix. This finding is crucial to aid the development of a
conservation strategy for hedgehogs as, for the first time, it shows the
extent that previously assumed isolated populations across a perceived
inhospitable landscape are connected by current gene flow. Higher within
patch relatedness, and lower allelic richness were found from smaller
suburban patches, largely reflecting local population size, indicating
an early stage of genetic diversity loss due to habitat loss and
associated fragmentation. Our study illustrates that considering current
gene flow and genetic diversity together is important to better
understand habitat effects on genetic variation.