Remnant vegetation provides genetic connectivity for a critical weight range mammal in a rapidly urbanising landscape

Abstract

Urbanisation is one of the most pervasive agents of contemporary landscape change globally. Rapid land use change and competing land uses pose multiple challenges for biodiversity conservation, particularly in peri-urban fringe areas where suburban development encroaches into natural habitats. The quenda (Isoodon fusciventer) is one of the very few ground-dwelling critical weight range mammals to persist in the peri-urban fringe of the rapidly expanding city of Perth, Australia. We investigated the genetic connectivity of 42 populations of quenda across the Greater Perth metropolitan region using microsatellites and generalised dissimilarity modelling to evaluate the impact of landscape elements on functional connectivity. Spatially-explicit Bayesian cluster analysis indicated quenda exhibit significant population structure across the Perth region, which, at the broadest scale, was associated with hydrological and topographical features. Inter-population genetic connectivity was facilitated by the presence of native vegetation, particularly low vegetation (<1.4 m height) that is the species’ preferred habitat. Surprisingly, measures of urbanisation were not significant predictors of gene flow, potentially as quenda show some characteristics of urban utilizers. Given the rapid pace of development in the region, knowledge on the distribution and population structure of quenda, and understanding the processes that contribute to them, provides a basis for a landscape conservation approach to urban planning. Retention of suitable habitat that facilitates persistence of this important mammal is critical.