DOI: 10.5061/dryad.q8d7d
title: Data from: Biotic and climatic velocity identify contrasting areas of vulnerability to climate change

description: Metrics that synthesize the complex effects of climate change are
 essential tools for mapping future threats to biodiversity and predicting
 which species are likely to adapt in place to new climatic conditions,
 disperse and establish in areas with newly suitable climate, or face the
 prospect of extirpation. The most commonly used of such metrics is the
 velocity of climate change, which estimates the speed at which species
 must migrate over the earth’s surface to maintain constant climatic
 conditions. However, “analog-based” velocities, which represent the actual
 distance to where analogous climates will be found in the future, may
 provide contrasting results to the more common form of velocity based on
 local climate gradients. Additionally, whereas climatic velocity reflects
 the exposure of organisms to climate change, resultant biotic effects are
 dependent on the sensitivity of individual species as reflected in part by
 their climatic niche width. This has motivated development of biotic
 velocity, a metric which uses data on projected species range shifts to
 estimate the velocity at which species must move to track their climatic
 niche. We calculated climatic and biotic velocity for the Western
 Hemisphere for 1961–2100, and applied the results to example ecological
 and conservation planning questions, to demonstrate the potential of such
 analog-based metrics to provide information on broad-scale patterns of
 exposure and sensitivity. Geographic patterns of biotic velocity for 2954
 species of birds, mammals, and amphibians differed from climatic velocity
 in north temperate and boreal regions. However, both biotic and climatic
 velocities were greatest at low latitudes, implying that threats to
 equatorial species arise from both the future magnitude of climatic
 velocities and the narrow climatic tolerances of species in these regions,
 which currently experience low seasonal and interannual climatic
 variability. Biotic and climatic velocity, by approximating lower and
 upper bounds on migration rates, can inform conservation of species and
 locally-adapted populations, respectively, and in combination with
 backward velocity, a function of distance to a source of colonizers
 adapted to a site’s future climate, can facilitate conservation of
 diversity at multiple scales in the face of climate change.
description: Biotic and climatic
 velocity for the Western HemisphereThis zip file includes
 raster data representing biotic and climatic velocity for the Western
 Hemisphere for the period 1961 to 2100. We modeled velocity using climatic
 niche models originally published in Lawler et al. 2009. Projected
 climate-induced faunal change in the Western Hemisphere. Ecology
 90:588-597. We used the code in the included R script to model biotic
 velocity for each individual species in Lawler et al. (2009). We then
 summarized velocity across all species in the three taxa groups, and
 further summarized across 10 climate-change general circulation models. We
 also modeled climatic velocity for each of 10 climate-change general
 circulation models. Each data file is a 50-kilometer resolution ESRI ASCII
 grid.velocity.zip