Distribution and protection of North American climatic refugia

Distribution and Protection of Climate Refugia Distribution and protection of climatic refugia in North America

This page provides links to data that were presented in Michalak et al. 2018 (full citation below). These data represent the distribution of potential climatic refugia and locations with potentially disappearing regional climates given projected mid- and end-of-century climate conditions. Refugia are defined as locations with increasingly rare climatic conditions. 

We identified these locations by tracking projected changes in the total area and distribution of climate analogs over time. Locations with regionally disappearing climates are defined as locations with current climatic conditions with no climate analogs present in the future time period within the specified search radius. We developed two biologically-derived thresholds to define analogs (0.9 and 1.5 PCA units) based on an analysis of climatic conditions with the current range boundaries of over 1,000 North American mammal, bird, amphibian and tree species. The smaller value (0.9) represents species that tolerate a narrower range of climatic conditions (i.e. are more climate sensitive) and the larger value (1.5) represents species that tolerate wider range of climatic conditions (i.e. are less climate sensitive). 

We also limited analog searches using four radial distances to account for dispersal limitations: 0.5, 1, 5, and 10-kilometers annually. We multiplied the annual distance by the number of intervening years so that a dispersal capacity of 0.5-km/year, for example, translates to a search radius of 40-km for the 2050s (0.5 x (2050-1970)) and 55-km for the 2080s (0.5 x (2080-1970)). We identified refugia and disappearing climates using each combination of analog threshold and dispersal radius providing results for eight representative species types. We also generated maps of refugia for all representative species types combined in which any location identified as refugia/disappearing climate for at least one species type is counted as such in the final layer. Further details are given in Michalak, J. L., Lawler, J. J., Roberts, D. R. and Carroll, C. (2018), Distribution and protection of climatic refugia in North America. Conservation Biology. doi: 10.1111/cobi.13130 (pdf available on request from first author).

Fig. 1

Figure 1. The extent and distribution of climatic refugia for at least one representative species type for the (a) 2050s and (b) 2080s. Extents projected for each GCM are overlaid with darker colors representing scenarios with greater warming and precipitation changes projected.
Fig. 2

Figure 2. The extent and distribution of locations classified as having disappearing climatic conditions for at least one representative species type for the (a) 2050s and (b) 2080s. Extents projected for each GCM are overlaid with darker colors representing scenarios with greater warming and precipitation changes projected.

Data

The archives linked below provides results from the study in two alternative zipfile formats. The 7-zip format allows smaller file sizes, but requires the 7-zip software for extraction. 7-zip software is freely available for Windows (link) as well as Mac and Linux systems (link). 

These data have been prepared as part of the AdaptWest project and their development was funded by the Wilburforce Foundation.


Data files
Download
All files, 7-zip format (33MB)
Zipfile: ASCII format
All files, zip format (88MB)
Zipfile: ASCII format
Selected rasters as Databasin map layers

Refugia under GFDLCM3 GCM (RCP 8.5, 2080s, all species types) Map layer
Refugia under INMCM4 GCM (RCP 8.5,  2080s, all species types) Map layer
Refugia under MIROC5 GCM (RCP 8.5, 2080s, all species types) Map layer


Description of data layers 

Raster data layer naming convention:

Refugia/disappearing layers for all representative species types (analog threshold x dispersal radius) combined: for these data layers, any location identified as a refugium/location with disappearing climate for at least one representative species type is counted as a refugium/disappearing climate.

Refugia_RCP_YEAR_GCM_allsptypes
Disappear_RCP_YEAR_GCM_allsptypes

Refugia/disappearing layers for individual representative species types:

Refugia_RCP_YEAR_GCM_THR_RAD
Disappear_RCP_YEAR_GCM_THR_RAD

RCP: RCP85 = Representative Concentration Pathway 8.5.
YEAR: Future time period (2050s = midcentury (2041-2070), 2080s = end of century (2071-2100)).
GCM: Global Circulation Model (GFDL CM3, MIROC5, or INM CM4)
THR: Analog threshold (thr9 = 0.9 PCA units representing a narrow threshold for more climate sensitive species, thr15 = 1.5 PCA units representing a wide threshold for less climate sensitive species)
RAD: Dispersal or search radius (rad05k = 0.5-km, rad1k = 1-km, rad5k = 5-km, or rad10k = 10-km annually).

Data values: 1 = refugia/disappearing; 0 = not identified as refugia/disappearing.
Data resolution: 1-km
Data extent: North America

Projection information:
Lambert Azimuthal Equal Area
Datum WGS 1984
Linear Unit Meter
Angular Unit Degree
False Easting 0
False Northing 0
Central Meridian -100
Latitude of Origin 45
Cell Size 1000