The changing conservation capacity of the North American protection network: a continent-wide vulnerability assessment

Ongoing climate change may undermine the ability of protected area networks to preserve biodiversity and associated ecosystem services. Metrics of climate change, particularly rates and spatial patterns of climatic alteration, can help assess potential threats to this conservation capacity. We compared the baseline climate of the protected area network in North America (NAM) to the projected end-of-century climate (2071–2100) to perform a continent-wide climate change vulnerability assessment. Future climate projections were based on one IPCC emissions scenario (RCP8.5) and one general circulation model (GCM), the MPI-ESM-LR, which represents a “median” climate change projection across 8 different GCMs. We estimated the projected pace at which climatic conditions may redistribute across NAM (i.e., climate velocity); identified future nearest climate analogs to quantify patterns of climate relocation within, among, and outside protected areas; and interpreted climatic relocation patterns in terms of associated land-cover types.
We found that the conservation capacity of the NAM protection network could be severely compromised by a changing climate. The majority of protected areas (~80%) might be exposed to high rates of climate displacement that could promote important shifts in species abundance or distribution. A small fraction of protected areas (<10%) could be critical for future conservation plans, as they will host climates that represent analogs of conditions currently characterizing almost a fifth of the protected areas across NAM. However, the majority of nearest climatic analogs for protected areas are in non-protected locations. Therefore, unprotected landscapes could pose additional threats, beyond climate forcing itself, as sensitive biota may have to migrate farther than what is prescribed by the climate velocity to reach a protected area destination. To mitigate future threats to the conservation capacity of the network, conservation plans will need to consider the existing availability of natural land-cover types outside the current network.
Protection networks are dynamic systems in which distribution patterns and abundance of species can change over time as climate conditions shift. Due to the high potential for climatic relocation, efforts to preserve biodiversity that aim for a static version of the protected biota will fail, as will efforts that ignore the spatial matrix surrounding the protection network. Both current and future inhabitants of the network will continue to need large and diverse protected areas with minimal fragmentation and sufficient connectivity to allow for species movement among them. The computational efficiency, flexibility, and transparency, and the multi-scale character of our framework makes it an effective conservation tool that effectively integrates climate projections and robust metrics of patterns of change to assess the effectiveness of conservation plans and priorities.