Modelling red squirrel population viability under a range of landscape scenarios in fragmented woodland ecosystems on the Solway plain, Cumbria

To assess the viability of the red squirrel Sciurus vulgaris in fragmented woodlands on the Solway Plain we used a combination of Vortex population viability analysis and BEETLE (Biological and Environmental Evaluation Tools for Landscape Ecology). Habitat fragmentation and the expansion of the North American grey squirrel S. carolinensis have had a detrimental effect upon red squirrel populations in the UK; assessing the viability of the remaining populations can guide in conservation management decisions. The initial field work showed red squirrels to use 5 of the 23 woodland fragments on the Solway Plain at a density of 0.65 squirrels ha-1, with a minimum dynamic area of 91 ha of red squirrel woodland habitat being identified using Vortex. Red squirrels may use more than one woodland fragment in its home range as long as fragments are connected functionally with the land cover between fragments producing a low cost for the squirrel. The functional connectivity of these woodland fragments was modeled within BEETLE to create habitat networks. Vortex was then used to identify which habitat networks would hold a viable population. Two areas were identified which could, if the correct landscape management is prescribed, potentially hold viable populations of red squirrels on the Solway Plain. This combination of behavioral, demographic and landscape modeling allows scenario building and has application across a wide range of conservation area design problems.