Many species are shifting their ranges poleward as a response to climate change. Connectivity of suitable habitat is critical to support range expansions, both across protected area networks and across latitudinal gradients. When a landscape in not well connected, some species might not be able to keep up with the pace of climate change on their own.
Hodgson, J.A., Randle, Z., Shortall, C.R. and Oliver, T.H. 2022. Where and why are species’ range shifts hampered by unsuitable landscapes? Global Change Biology. DOI: 10.1111/gcb.16220.
The idea that increased connectivity helps facilitate range expansion makes sense, but is mostly based on coarse-scale simulation models and movement data. There is little empirical evidence that directly tests how landscape configuration contributes to range expansion along with habitat extent, and how configuration can act to encourage (or discourage) movement through the landscape for multiple species.
To address this gap, new research focuses on how habitat configuration affects range expansions using empirical evidence from moths across the UK. The locations of over 50 species of moths were tracked from 1985-2011, and then compared to locations from historical data prior to 1985. The attributes of each species, along with attributes of intervening landcover and climate, were then linked to the rate of colonization northward from baseline to present time.
Results show that regardless of dispersal ability and habitat needs, habitat configuration influences colonization rates and range shifts along with habitat extent. Woodland habitat seems to hamper the range expansion of non-woodland species, and regions of high elevation variance or climatic variance seem to restrict the expansions of species in agriculture or other anthropogenic settings. The results also provide empirical support for the effectiveness of a “conductance” measurement, which can act as a summary metric of the speed of range expansion based on the amount and configuration of breeding habitat.
Range shifts are likely to become more prevalent as climate warming continues, and effective conservation support needs to move beyond a focus on habitat quality. The way in which different habitats are spatially arranged can help some species while acting as a barrier for others, even those that are generalists and highly mobile. Conservation strategies and management plans ultimately can be more effective for the larger community when they incorporate multiple facets of the landscape into the decision-making process.
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