Scale‐dependent complementarity of climatic velocity and environmental diversity for identifying priority areas for conservation under climate change

Abstract

As most regions of the earth transition to altered climatic conditions, new methods are needed to identify refugia and other areas whose conservation would facilitate persistence of biodiversity under climate change. We compared several common approaches to conservation planning focused on climate resilience over a broad range of ecological settings across North America and evaluated how commonalities in the priority areas identified by different methods varied with regional context and spatial scale. Our results indicate that priority areas based on different environmental diversity metrics differed substantially from each other and from priorities based on spatiotemporal metrics such as climatic velocity. Refugia identified by diversity or velocity metrics were not strongly associated with the current protected area system, suggesting the need for additional conservation measures including protection of refugia. Despite the inherent uncertainties in predicting future climate, we found that variation among climatic velocities derived from different general circulation models and emissions pathways was less than the variation among the suite of environmental diversity metrics. To address uncertainty created by this variation, planners can combine priorities identified by alternative metrics at a single resolution and downweight areas of high variation between metrics. Alternately, coarse-resolution velocity metrics can be combined with fine-resolution diversity metrics in order to leverage the respective strengths of the two groups of metrics as tools for identification of potential macro-and microrefugia that in combination maximize both transient and long-term resilience to climate change. Planners should compare and integrate approaches that span a range of model complexity and spatial scale to match the range of ecological and physical processes influencing persistence of biodiversity and identify a conservation network resilient to threats operating at multiple scales. K E Y W O R D Sclimate change adaptation, climatic velocity, conservation planning, environmental diversity, land facets, protected areas, refugia --

Ecological and sociopolitical assessment of congressional and presidential designation of federal protected areas

“…(I) Mean climate refugial index; ranges from 0 to 3.29 in contiguous United States, larger values indicate greater refugial potential (source: Carroll et al. ). (J) Mean LCV score (percentage of pro‐environment votes on environmental legislation) for eight years prior to designation (source: League of Conservation Voters, LCV).…”

“…We evaluated the capacity for PAs to support future biodiversity using an index of climate refugial potential (Carroll et al. ) derived from backward climate velocity (BCV), the rate of movement required for an organism adapted to a location's predicted future climate to reach that location. Areas with lower BCV should be more easily colonized by organisms shifting their distribution to remain within suitable climatic conditions and thus should have greater potential to serve as climate refugia (Carroll et al.…”

Climatic, topographic, and anthropogenic factors determine connectivity between current and future climate analogs in North America

“…However, we found that climate connectivity priorities were robust to uncertainty caused by variation in input data between alternative emission pathways (RCP 4.5 and 8.5) and AOGCMs. Priorities based on centrality derived from different AOGCMs showed less between‐AOGCM variation than did the input climate data or climatic velocity metrics based on that climate data (Carroll et al, ). Conservation planners may place greater focus on sensitivity analyses of the effect of assumptions concerning dispersal behavior and analysis extent, rather than on parameter uncertainty arising from differing climate projections.…”

Detecting microrefugia in semi-arid landscapes from remotely sensed vegetation dynamics

“…There exists much uncertainty over how to identify refugia within landscapes to target management spatially (Ashcroft, 2010). Putative refugia (micro-and macrorefugia) are typically located using simple heuristics, most commonly that areas with high topographic heterogeneity are likely to function as refugia (Ashcroft, 2010;Carroll et al, 2017;Dobrowski, 2011). There is less guidance about identifying refugia in areas of modest terrain (Reside et al, 2014).…”

“…There is growing interest in developing fine-scale grids of micro-or topo-climate, often with ~30 m pixels, via downscaling techniques Dingman et al, 2013;McCullough et al, 2016) or interpolation from dense sensor arrays (Ashcroft, 2010;Frey et al, 2016) to identify microrefugia. An important source of uncertainty is that different measures and different methodological choices identify different sites as candidate refugia (Ashcroft, 2010;Ashcroft et al, 2012;Carroll et al, 2015Carroll et al, , 2017.…”