Wildlife conservation in a fragmented landscape: the Eurasian red squirrel on the Isle of Wight

Abstract

Island populations may have a higher extinction risk due to reduced genetic diversity and need to be managed effectively in order to reduce the risk of biodiversity loss. The Eurasian red squirrels (Sciurus vulgaris) in the south of England only survive on three islands (the Isle of Wight, Brownsea and Furzey islands), with the Isle of Wight harbouring the largest population in the region. Fourteen microsatellites were used to determine the genetic structure of red squirrel populations on the Isle of Wight, as well as their relatedness to other populations of the species. Our results demonstrated that squirrels on these islands were less genetically diverse than those in Continental mainland populations, as would be expected. It also confirmed previous results from mitochondrial DNA which indicated that the squirrels on the Isle of Wight were relatively closely related to Brownsea island squirrels in the south of England. Importantly, our findings showed that genetic mixing between squirrels in the east and west of the Isle of Wight was very limited. Given the potential deleterious effects of small population size on genetic health, landscape management to encourage dispersal of squirrels between these populations should be a priority.

Emerging patterns of genetic diversity in the critically endangered Malayan tiger (Panthera tigris jacksoni)

“…A reduction in population size and restricted gene flow typically leads to increased inbreeding compounded by loss of genetic diversity within small and fragmented populations (Frankham et al 2002). This can result in a range of negative genetic consequences, including inbreeding depression (such as loss of population-and individual-level fitness), susceptibility to disease, and a reduced ability to adapt to changing environmental conditions (McManus et al 2015;Kleinhans and Willows-Munro 2019;Labisko et al 2019;Hardouin et al 2021). Through these processes, biodiversity loss has been particularly severe in tropical forest ecosystems in the last few decades (Symes et al 2018;Hansen et al 2020).…”