Predicting evolution in response to climate change: the example of sprouting probability in three dormancy-prone orchid species.

Richard P Shefferson,Michael J Hutchings,Ryo Mizuta

doi:10.1098/rsos.160647

Abstract

Although many ecological properties of species respond to climate change, their evolutionary responses are poorly understood. Here, we use data from long-term demographic studies to predict evolutionary responses of three herbaceous perennial orchid species, Cypripedium parviflorum, C. candidum and Ophrys sphegodes, to predicted climate changes in the habitats they occupy. We focus on the evolution of sprouting probability, because all three species exhibit long-term vegetative dormancy, i.e. individual plants may not emerge above-ground, potentially for several consecutive years. The drivers of all major vital rates for populations of the species were analysed with general linear mixed models (GLMMs). High-dimensionality function-based matrix projection models were then developed to serve as core elements of deterministic and stochastic adaptive dynamics models used to analyse the adaptive context of sprouting in all populations. We then used regional climate forecasts, derived from high-resolution general atmospheric circulation models, of increased mean annual temperatures and spring precipitation at the occupied sites, to predict evolutionary trends in sprouting. The models predicted that C. parviflorum and O. sphegodes will evolve higher and lower probabilities of sprouting, respectively, by the end of the twenty-first century, whereas, after considerable variation, the probability of sprouting in C. candidum will return to its current level. These trends appear to be driven by relationships between mortality and size: in C. parviflorum and C. candidum, mortality is negatively related to size in the current year but positively related to growth since the previous year, whereas in O. sphegodes, mortality is positively related to size.

Highlights

The ecological and evolutionary consequences of climate change are of considerable concern for the conservation of species, populations and communities
Predictive models in ecology rarely feature the possibility of Darwinian evolution, originally because evolution was assumed to be irrelevant in shortto medium-term predictive models [12], but more recently because it is considered difficult to incorporate the complexity of evolution into models of ecological processes, because of the need for large amounts of relevant data with which to parametrize models of evolutionary change
This involved the following steps, which are described in detail below: (i) analysis of the key vital rates in each population, including survival, sprouting, flowering and, in Cypripedium, fruiting, to model them as linear functions of density, weather and age or previous life history, (ii) using these functions to develop high-dimensionality population projection matrices, (iii) examination of demographic behaviour for evidence of density dependence, (iv) development and 4 testing of climate-sensitive adaptive dynamics models to predict optimal sprouting probability, and (v) using these adaptive dynamics models to predict evolutionary trends in sprouting probability in response to predictions of future climate at the sites occupied by the species

Summary

Introduction

The ecological and evolutionary consequences of climate change are of considerable concern for the conservation of species, populations and communities. Predictive models in ecology rarely feature the possibility of Darwinian evolution, originally because evolution was assumed to be irrelevant in shortto medium-term predictive models [12], but more recently because it is considered difficult to incorporate the complexity of evolution into models of ecological processes, because of the need for large amounts of relevant data with which to parametrize models of evolutionary change It is recognized, that significant evolutionary and ecological changes can occur over similar time scales [19,20], suggesting that evolution could respond rapidly to climate change [21,22], and two-way interactions between evolution and ecological processes are probably common [20,23]. Predictions of alterations in species distributions, flowering times and species traits may be inaccurate unless evolution in traits that can undergo strong selection in response to climate change is taken into consideration

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Conclusion