Planning for climate change through additions to a national protected area network: implications for cost and configuration.

Expanding the network of protected areas is a core strategy for conserving biodiversity in the face of climate change. Here, we explore the impacts on reserve network cost and configuration associated with planning for climate change in the USA using networks that prioritize areas projected to be climatically suitable for 1460 species both today and into the future, climatic refugia and areas likely to facilitate climate-driven species movements. For 14% of the species, networks of sites selected solely to protect areas currently climatically suitable failed to provide climatically suitable habitat in the future. Protecting sites climatically suitable for species today and in the future significantly changed the distribution of priority sites across the USA-increasing relative protection in the northeast, northwest and central USA. Protecting areas projected to retain their climatic suitability for species cost 59% more than solely protecting currently suitable areas. Including all climatic refugia and 20% of areas that facilitate climate-driven movements increased the cost by another 18%. Our results indicate that protecting some types of climatic refugia may be a relatively inexpensive adaptation strategy. Moreover, although addressing climate change in conservation plans will have significant implications for the configuration of networks, the increased cost of doing so may be relatively modest. This article is part of the theme issue 'Climate change and ecosystems: threats, opportunities and solutions'.