Drivers, consequences and perceptions of newly arriving range-shifters in the United Kingdom

Abstract

CONTEXT: Species distributions are rapidly altering in the 21st century. Climate change and other anthropogenic effects threaten historic ranges but also open up new regions for expansion. Distributional changes will create novel biotic interactions that may significantly affect ecosystems, and humanity, both positively and negatively. Range-shifters create conservation conundrums, which may require us to balance the conservation value of newly arriving species against their impacts on existing biodiversity. To tackle these conundrums we will have to understand why and how species are moving, be able to make predictions of what potential effects may be felt in the new range and recognise how species are perceived when they arrive there. APPROACHES: I explore three aspects of species redistribution: processes, consequences, and perceptions. To better understand the redistribution process, I investigate the importance of climate, habitat, and proximity to source populations in predicting 14 range-shifting birds’ distributions in Britain. I explore consequences by estimating effects of a range-shifting damselfly on UK Odonata with dynamic multispecies occupancy (DMSO) models. Finally, I explore perceptions by surveying UK wildlife recorders’ attitudes towards range-shifting species and their management. RESULTS: I found that climate did not predict most analysed range-shifters’ British distributions effectively. Despite being comparatively better, neither habitat nor distance from European breeding sites were good absolute predictors. Counter-intuitively, our DMSO model predicted that 15/17 resident dragonflies were more likely to persist at sites where the range-shifting damselfly established. Survey responses revealed that recorders opposed efforts to either control or support range-shifters, instead favouring non-intervention. IMPLICATIONS: The poor predictive power of climate suggests that we should explicitly study the full potential suite of range-shift processes, including biotic interactions and constraints on species movement. The absence of a negative association between the range-shifting damselfly and most Odonata species should be welcomed, but cautiously as other factors (e.g. habitat) may confound the range-shifters’ effect. Recorders’ averseness to interventions suggests that ecological research focused on the feasibility of both assisted colonisation and range-shifter threat should also seek to understand social contexts for successful conservation. Integrating these findings, I argue that we should use rapidly growing ecological datasets to not just detect but to test and refine theories of range-shift. Future model refinement alongside fuller understanding of stakeholder perspectives will help enable equitable – and ecologically beneficial – range-shift management.