Building evolutionary resilience for conserving biodiversity under climate change

Abstract

Evolution occurs rapidly and is an ongoing process in our environments. Evolutionary principles need to be built into conservation efforts, particularly given the stressful conditions organisms are increasingly likely to experience because of climate change and ongoing habitat fragmentation. The concept of evolutionary resilience is a way of emphasizing evolutionary processes in conservation and landscape planning. From an evolutionary perspective, landscapes need to allow in situ selection and capture high levels of genetic variation essential for responding to the direct and indirect effects of climate change. We summarize ideas that need to be considered in planning for evolutionary resilience and suggest how they might be incorporated into policy and management to ensure that resilience is maintained in the face of environmental degradation.

Keywords: adaptive potential; biodiversity; climate change; conservation; evolution; evolutionary resilience; genetic diversity.

Figure 1

Contour plots presenting median number of generations to extinction as a function of the narrow-sense heritability of the trait under selection and mean intrinsic rate of natural increase (r) for a population of size 1000. The rate of environmental change (k) in this case was set at 0.1, and the width of the fitness function (V_W) was 20. Populations of 1000 flies were predicted to persist well within the approximate ranges of r > 0.5 and h² > 0.29. Modified from (Willi and Hoffmann 2008).

Figure 2

Seed sources future scenarios depend on whether climatic conditions at a site are expected to change and/or whether there are strong genotype–environment interactions for fitness.

Figure 3

Recommendations for provenancing based on dispersal distance from parental plant. For most species, dispersal distance can be described by an exponential decay curve, with the majority of dispersal occurring locally, a smaller proportion occurring at an intermediate distance and a much lower proportion occurring over long distances. The practice of composite provenancing mimics this dispersal kernel in the proportion of locally sourced material (high proportion), intermediate distance–sourced material that is ecologically matched (medium proportion) and material introduced from distant populations that are ecologically diverse (low proportion). Such a strategy retains a core of locally adapted material. However, the intermediate sourcing will mimic medium-range gene flow that may bring in additional adaptive or beneficial genes. The long-distance provenancing allows an opportunity for novel in situ adaptation at the restoration site either through admixture or recombination. This latter material may be maladapted to the planting site and so an increase in sowing or stocking rate may be required, but the ultimate advantage will be the increased adaptive potential of restoration plantings employing this strategy.