Understanding how past environmental changes shaped the demography of natural populations is fundamental to predict their responses to different aspects of ongoing global change. Recently, the importance of studying community-level demographic responses has been emphasized, in an effort to comprehend how stable species associations have been across space and time and forecast how entire assemblages of co-distributed species, not only specific taxa, will respond to future environmental alterations. Addressing effectively these questions is of critical importance for guiding integrative conservation strategies aimed to protect entire communities and/or focusing management efforts on those taxa predicted to be more severely impacted by ongoing climate change in terms of range contractions, loss of genetic diversity or reduced population connectivity. The main goal of this project is to fill these gaps in our knowledge of community-level demographic responses to past and future climate changes using as study system three species assemblages of grasshoppers (26 species in total) distributed along an elevational gradient ranging from Mediterranean to alpine ecosystems in the Pyrenees.
In particular, this project aims to integrate genome-wide data (ddRadSeq), state-of-the-art demographic analyses, species distribution modelling and detailed information on taxon-specific ecological traits to: (i) test whether different populations of the same species and multiple taxa within and across different communities present concordant/discordant demographic trajectories and responded synchronously/asynchronously to Pleistocene climatic oscillations; (ii) compare the extent of community-level demographic concordance between species assemblages from alpine habitats submitted to recurrent cycles of population connectivity and isolation and those from Mediterranean habitats that have remained well connected over extended periods of time; (iii) determine whether the demographic trajectories of the different studied species are explained by taxon-specific ecological attributes, including the degree of habitat specialization (generalist vs. specialist taxa), trophic and climatic niche breadth, and certain life-history traits (body size, dispersal capacity); (iv) As a final step, this project will use species-specific demographic parameters inferred from spatiotemporally-explicit demographic models validated with genomic data to make predictions about the future trends of each taxon in terms of genetic diversity and population connectivity under different scenarios of future climate change, which will help to identify those communities and species that are expected to be more sensitive to such human-induced environmental alterations.