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Identifying adaptive genetic variation is a challenging task, in particular in non-model species for which genomic information is still limited or absent. Here, we studied distribution patterns of amplified fragment length polymorphisms (AFLPs) in response to environmental variation, in 13 alpine plant species consistently sampled across the entire European Alps. Multiple linear regressions were performed between AFLP allele frequencies per site as dependent variables and two categories of independent variables, namely Moran's eigenvector map MEM variables (to account for spatial and unaccounted environmental variation, and historical demographic processes) and environmental variables. These associations allowed the identification of 153 loci of ecological relevance. Univariate regressions between allele frequency and each environmental factor further showed that loci of ecological relevance were mainly correlated with MEM variables. We found that precipitation and temperature were the best environmental predictors, whereas topographic factors were rarely involved in environmental associations. Climatic factors, subject to rapid variation as a result of the current global warming, are known to strongly influence the fate of alpine plants. Our study shows, for the first time for a large number of species, that the same environmental variables are drivers of plant adaptation at the scale of a whole biome, here the European Alps.

Ecologists have long been interested in how communities change over time. Addressing questions about community dynamics requires ways of representing and comparing the variety of dynamics observed across space. Until now, most analytical frameworks have been based on the comparison of synchronous observations across sites and between repeated surveys. An alternative perspective considers community dynamics as trajectories in a chosen space of community resemblance and utilizes trajectories as objects to be analyzed and compared using their geometry. While methods that take this second perspective exist, for example to test for particular trajectory shapes, there is a need for formal analytical frameworks that fully develop the potential of this approach. By adapting concepts and procedures used for the analysis of spatial trajectories, we present a framework for describing and comparing community trajectories. A key element of our contribution is the means to assess the geometric resemblance between trajectories, which allows users to describe, quantify, and analyze variation in community dynamics. We illustrate the behavior of our framework using simulated data and two spatiotemporal community data sets differing in the community properties of interest (species composition vs. size distribution of individuals). We conclude by evaluating the advantages and limitations of our community trajectory analysis framework, highlighting its broad domain of application and anticipating potential extensions.

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The possible postglacial dispersal of freshwater fishes in the Québec peninsula is described. We tested the hypothesis that fish dispersal was controlled more efficiently by movements of the earth crust and by morphological peculiarities of the peninsula than by upland divides presently found between river basins. Based on the actual distributions of 109 species of freshwater fishes, the presence and absence of these species was noted for each of 289 one-degree-square pixels of the peninsula. A geographical intermediate-linkage clustering was run with a spatial constraint, that is, only neighbouring pixels were allowed to cluster. Five main ichthyogeographic regions and 21 subregions were thus defined. The regional limits seem to be highly correlated with climatic, vegetational, and geomorphological limits or gradients. Knowing the fish species present in each subregion made it possible to deduce their pattern of postglacial dispersal, after computing a coefficient of dispersal direction between neighbouring subregions. The pattern of fish dispersal so derived assumes that the stenohaline species have crossed the centre of the peninsula. This can be explained by the isobasic movements since the end of the Wisconsin Ice Age, and also by a network of river headwater interconnections still extant today.

The discovery of deep-sea hydrothermal vent fauna, kilometers deep in the oceans, is a great achievement of 20th-century marine biology. The deep-sea hydrothermal food web does not directly depend on the sun energy. Vent communities rely primarily on trophic associations between chemoautotrophic bacteria and consumers. A small number of endemic taxa are adapted to this highly toxic environment distributed along ridge crests. Where they appeared and how they dispersed is among the important questions ecologists must answer. Here, by statistical analysis of the most comprehensive data base ever assembled about deep-sea hydrothermal fauna, we delineate six major hydrothermal provinces in the World Ocean, then we identify five significant dispersal flows between adjacent provinces and derive a hypothesis about the center from which that fauna has dispersed to the oceanic ridges of the world. Our data-driven conclusion can be tested by phylogenetic studies and completed by surveys of less explored fields.