Project

rare; endemic species; plant distribution; genetic diversity; secondary contact model; Climate Change; Biodiversity; Alpine plants; Adaptation; Refugia; Dispersal; Phylogeography; Pleistocene Glacial Cycles; Ecological Niche Models; Species Distribution Models; Hindcasting; Forecasting; Rare plants; Conservation Biology

Lead
Responding to the twin crises of global warming and biodiversity loss requires a deep understanding of how climate affects the processes that generate and destroy biodiversity, primarily through its effects on the ecology and distribution of species and communities. In this project, we use a combination of ecological niche models (ENMs) and genetic tools to predict the evolution of ecological preferences and distributional ranges from the present, to the past and into the future.
Lay summary
Responding to the twin crises of global warming and biodiversity loss requires a deep understanding of how climate affects the processes that generate and destroy biodiversity, primarily through its effects on the ecology and distribution of species. Recent improvements in our ability to reconstruct the history of biodiversity through timed phylogenies, estimate changes in genetic diversity, and predict the potential distribution of selected species with ecological niche models (ENMs) now allow us to infer the evolution of ecological preferences and distributional ranges at different temporal scales. Our two case studies focus on alpine/arctic regions, because they are among those most endangered by global warming. The first study will use, for the first time, a combination of ENM and phylogeny to test the model of hybrid, polyploid speciation by secondary contact in arctic/alpine plants. We selected Primula sect. Aleuritia (simply Aleuritia, from here on), because our previous phylogenetic work provided clear hypotheses for the parental origins of polyploids, yet the distributions of the inferred progenitors do not currently overlap. Did the ranges of the proposed parents overlap at the time of allopolyploid origins, as predicted by the secondary contact model? To answer this question, we will produce a high-resolution, dated phylogeny of Aleuritia, optimize the ecological preferences of the hypothesized progenitors onto the dated phylogeny, and project their past distributional ranges onto the fine-resolution climatic scenarios recently developed for the Pleistocene. In the second case study, we will try to explain how small populations persisted on summits in the past and how they are affected by current and future climate change. Here we selected Saxifraga florulenta, a rare, endemic species of the Maritime Alps, because hypotheses of its phylogenetic relationships are available from our previous work, it occurs exclusively above 2000 m, and has very narrow ecological requirements. Consequently, if current trends of global warming continue, the strict ecological adaptation of S. florulenta to siliceous substrates at the highest altitudes of the Maritime Alps may represent a serious extinction risk. We will investigate whether the phylogeographic history, genetic diversity, climatic niche and dispersal mode of S. florulenta can explain its long persistence in the Maritime Alps, a hot spot of biodiversity, and predict its future survival or extinction on mountain tops. We will use a combination of genetic analysis and niche modeling to reconstruct changes in the niche, geographic distribution, and genetic diversity of this cold-adapted species.

Direct link to Lay Summary

Last update: 14.03.2013

Active participation

Communication	Title	Media	Place	Year

Title	Year

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Responding to the twin crises of global warming and biodiversity loss requires a deep understanding of how climate affects the processes that generate and destroy biodiversity, primarily through its effects on the ecology and distribution of species and communities. Recent improvements in our ability to reconstruct the history of biodiversity through timed phylogenies, estimate changes in genetic diversity, and predict the potential distribution of selected species with ecological niche models (ENMs) now allow us to infer the evolution of ecological preferences and distributional ranges at different temporal scales, from the present, to the past and the future. Newly trained scientists are thus in a unique position to influence the future of biodiversity with this new integrative knowledge, as long as they are also trained in communication and policy skills. We believe that the two Ph.D. students working on our research module will have a special opportunity to learn: (i) the theoretical and practical skills necessary to explain changes in species richness at different temporal and spatial scales and (ii) how to apply this scientific knowledge for conservation purposes in a way that benefits society as a whole through the specialized courses on environmental policy and communication offered by the Pro-Doc program of the Plant Science Center.Our research focuses on alpine/arctic regions, because several studies have shown that they are among those most endangered by global warming. Case Study 1 will use, for the first time, a combination of ENM and phylogeny to test the model of allopolyploid speciation by secondary contact in arctic/alpine plants. We selected Primula sect. Aleuritia (simply Aleuritia, from here on), because our previous phylogenetic work provided clear hypotheses for the parental origins of the hexaploid P. scotica and the octaploid P. scandinavica. However, the current areas of distribution of the inferred progenitors of the polyploids do not overlap. Did the ranges of the proposed parents overlap at the time of allopolyploid origins, as predicted by the secondary contact model? To answer this question, we will produce a high-resolution, dated phylogeny of Aleuritia, optimize the ecological preferences of the hypothesized progenitors onto the dated phylogeny, and project their past distributional ranges onto the fine-resolution climatic scenarios recently developed for the Pleistocene. Additionally, we will test, also for the first time, whether island colonization by species with specialized breeding systems (i.e. the heterostylous P. farinosa) is associated with a shift of the ecological niche, reduction of genetic variation, and change of reproductive strategy (from heterostylous/obligate outcrossing, to homostylous/facultative selfing).While in the first case study we use arctic islands to understand how climate change in the past may lead to a change in reproductive strategy, Case Study 2 will focus on islands in the sky (i.e., mountain tops) to explain how small populations persisted on summits in the past and how they are affected by current and future climate change. Here we selected Saxifraga florulenta, a rare, endemic species of the Maritime Alps, because hypotheses of its phylogenetic relationships are available from our previous work, it occurs exclusively above 2000 m, and has very exacting ecological requirements. Consequently, if current trends of global warming continue, the strict ecological adaptation of S. florulenta to siliceous substrates at the highest altitudes of the Maritime Alps may represent a serious extinction risk. We will investigate whether the phylogeographic history, genetic diversity, climatic niche and dispersal mode of S. florulenta can explain its long persistence in the Maritime Alps, a hot spot of biodiversity, and predict its future survival or extinction on mountain tops. We will use a combination of genetic analysis and niche modeling to reconstruct changes in the niche, geographic distribution, and genetic diversity of this cold-adapted species.The two case studies will also allow us to compare the effects of climate change on the future distributions of widespread vs. endemic species and of species with specialized breeding systems (i.e. heterostyly). The results will thus contribute to: (a) develop a new theoretical framework for the influence of climate change on speciation mechanisms and reproductive strategies in plants; (b) generate an improved modeling framework that incorporates critical population size and evolutionary processes into ENM projections; and (c) inform conservation strategies with sound knowledge of the evolutionary and ecological potential for adaptation to changing environmental requirements in arctic/alpine plants.