Simulating the effects of local adaptation and life history on the ability of plants to track climate shifts.

Emily V Moran

doi:10.1093/aobpla/plaa008

Abstract

Many studies have examined the impact of dispersal on local adaptation, but much less attention has been paid to how local adaptation influences range shifts. The aim of this study was to test how local adaptation might affect climate-driven range shifts in plants, and if this might differ between plants with different life histories. Simulated range shift dynamics were compared for hypothetical annual, perennial and tree species, each comprised of either one plastic genotype or six locally adapted genotypes. The landscape consists of shifting climate bands made up of 20 × 20 m patches containing multiple individuals. Effects of seed dispersal, breadth of the plastic species’ tolerance, steepness of the climate gradient and rate of the climate shift are also examined. Local adaptation increased the equilibrium range size and aided range shifts by boosting fitness near range edges. However, when the rate of climate change was doubled on a steep gradient, locally adapted trees exhibited a higher percent loss of range during the climate shift. The plastic annual species with short dispersal was unable to recover its range size even after the climate stabilized, while the locally adapted annuals tracked climate change well. The results suggest that in most situations local adaptation and longer dispersal distances will be advantageous, though not necessarily sufficient, for tracking suitable climates. However, local adaptation might put species with long generation times at greater risk when climate shifts are very rapid. If confirmed by empirical tests, these results suggest that identifying variation between species in how fitness varies along climate gradients and in these key demographic rates might aid in prioritizing management actions.

Highlights

Many studies have examined the impact of dispersal on local adaptation, but much less attention has been paid to how local adaptation influences range shifts
Initial occupancy During the establishment period, the abundance of the species across the landscape changes and genotypes sort themselves into bands corresponding to their areas of highest fitness (Fig. 3)
As with the other scenarios, the trees re-equilibrated with the new climate gradient within 200 years. The results of this analysis suggest that local adaptation is likely to be more of a help than a hindrance to plant species in tracking climate shifts, at if locally adapted species usually have higher reproductive success at the leading range edge than species that are less locally adapted

Summary

Introduction

Considerable research effort has focused on the impact of gene flow on local adaptation (Kirkpatrick and Barton 1997; Lenormand 2002; Holt et al 2004; Bridle and Vines 2006; Garant et al 2007; Kimbrell and Holt 2007; Kawecki 2008; Räsänen and Hendry 2008; Bell and Gonzales 2009; Bridle et al 2009, 2010; Sexton et al 2009, 2011; Dawson et al 2010; North et al 2010; Kremer et al 2012; Polechová and Barton 2015). Less attention has been paid to how local adaptation affects the potential for range shifts under climate change. It is not clear whether effects would be the same across life history types. Researchers have defined and tested the degree of local adaptation in plants in two ways. The first approach, generally based on a small number of reciprocal transplants, classifies populations as locally adapted if they either perform better in their home site than in other sites or if, within a site, local genotypes perform better than foreign ones (Kawecki and Ebert 2004). The second approach, used most commonly in provenance studies of trees in which many seed sources are planted in multiple common gardens (not including all source sites), defines a population as being locally adapted if it performs

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