Habitat area, quality and connectivity: striking the balance for efficient conservation.
Population viability can depend on habitat area, habitat quality, the spatial arrangement of habitats (aggregations and connections) and the properties of the intervening non-breeding (matrix) land. Hodgson et al. [Journal of Applied Ecology 46 (2009) 964] and Doerr, Barrett & Doerr (Journal of Applied Ecology, 2011) disagree on the relative importance of these landscape attributes in enabling species to persist and change their distributions in response to climate change. A brief review of published evidence suggests that variations in habitat area and quality have bigger effects than variations in spatial arrangement of habitats or properties of the intervening land. Even if structural features in the matrix have a measurable effect on dispersal rates, this does not necessarily lead to significant increases in population viability. Large and high-quality habitats provide source populations and locations for colonisation, so they are the main determinants of the capacity of species to shift their distributions in response to climate change because populations must be established successively in each new region. Synthesis and applications. Retaining as much high quality natural and semi-natural habitat as possible should remain the key focus for conservation, especially during a period of climate change.