Conservation Letter: Effects of Global Climate Change on Raptors

Global climate change is an ongoing pervasive global conservation concern, with significant negative impacts for many species and populations. This Conservation Letter provides a scientific review of the effects of global climate change on raptors and concludes by highlighting potential mitigations and research needs. This letter is not intended as an exhaustive literature review. Rather, the intent of the Raptor Research Foundation (RRF) is to provide readers with enough evidence-based examples that they can appreciate the scope and prevalence of climate change impacts, understand their effects on raptor species and populations, and recognize some of the challenges associated with addressing climate change’s effects on raptors across regions. Climate change is caused by the release of atmospheric greenhouse gases (primarily carbon dioxide) resulting in changes in global climate-related parameters, mainly temperature and precipitation. In this scenario, the trend of increasing global temperatures is predicted to continue (Intergovernmental Panel on Climate Change [IPCC] 2021), influencing other climatic parameters and events. Increasing temperatures can impact raptors directly (e.g., Jaffré et al 2013, Dykstra et al. 2021b) and indirectly by driving disruptions to water cycles ranging from more frequent heavy precipitation events (Trenberth et al. 2003, Min et al. 2011, Anctil et al. 2014) to more severe drought (Cook et al. 2018, Smith et al. 2020). Further, the nature of climate events is also changing, encompassing more severe hurricanes and tropical cyclones (Emanuel 2005, 2013, Holland and Bruyère 2014), a poleward expansion of tropical cyclones (Studholme et al. 2022), and shifts in precipitation temporal trends (Dunning et al. 2018), exposing raptors to stochastic events. Climatic changes also alter the distributions of primary producers (Sturm et al. 2001, Tape et al. 2006) creating bottom-up effects that alter ecosystem function (i.e., ‘‘regime shifts’’; Rodionov 2004, Ripple et al. 2014). Moreover, the risk of wildlife extinctions is substantially accelerated by climate change (Urban 2015), and climate warming is related to the recent extinctions of at least one raptor (Sergio et al. 2021). This suggests there may be major negative effects of climate change for raptors (McClure et al 2018). Raptors are valuable and important study systems for investigating the effects of climate change because raptors are widespread, perform important ecological functions and can serve as flagship species for biodiversity (Donázar et al. 2016). As long-lived top predators holding large home ranges and preying on a wide variety of vertebrates and invertebrates, raptors are influenced by the effects of environmental change on lower trophic levels (Meserve et al. 2003, Schmidt et al. 2018) and can serve as biotic multipliers of climate change (Urban et al. 2017). Raptors have been the focus of multiple long-running studies on 1 The editorial processing and review of this paper were handled by Associate Editor James F. Dwyer. 2 Corresponding author: cheryldykstra@gmail.com