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CODEMOCLIM: Species- and community-level demographic responses to past and future climate changes: the role of taxon-specific ecological and phenotypic traits
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.
Inferred (past and present) and predicted (future) effective population sizes (Ne) and population connectivity for a hypothetical assemblage of Pyrenean alpine grasshoppers during different time periods. (a) Last glacial maximum (LGM): high population connectivity and large Ne (NLGM); (b) Current time: range shifts toward higher elevations, disrupted gene flow among isolated populations, and demographic bottlenecks (NCUR); (c) Future scenario of global warming: range shifts toward higher elevations, demographic bottlenecks (NFUT) and local extinctions (red arrows) in areas that do not fulfill anymore the ecological requirements (Grinnellian niche) of the species. (d) In this illustrative example, the two hypothetical species show concordant and synchronous demographic responses to the same events (i.e. Pleistocene climatic oscillations and future climate change).
Six of the taxa considered CODEMOCLIM representative of three communities of grasshoppers distributed at high (blue), medium (green) and low (red) elevational ranges in the Pyrenees. Dots represent the elevation of different localities where each species has been recorded during the field campaigns performed in years 2013-2016.
7. Ortego J, Knowles LL (2022) Geographic isolation versus dispersal: Relictual alpine grasshoppers support a model of interglacial diversification with limited hybridization. Molecular Ecology, 31: 296-312. [PDF]
6. Ortego J, Gutiérrez-Rodríguez J, Noguerales V (2021) Demographic consequences of dispersal‐related trait shift in two recently diverged taxa of montane grasshoppers. Evolution, 75: 1998-2013. [PDF] [On the cover] [Digest by Jessica Fenker et al. - PDF]
5. Tonzo V, Ortego J (2021) Glacial connectivity and current population fragmentation in sky islands explain the contemporary distribution of genomic variation in two narrow-endemic montane grasshoppers from a biodiversity hotspot. Diversity and Distributions, 27: 1619-1633. [PDF]
4. Ortego J, Noguerales V, Tonzo V, González-Serna MJ, Cordero PJ (2021) Broadly distributed but genetically fragmented: Demographic consequences of Pleistocene climatic oscillations in a common Iberian grasshopper. Insect Systematics and Diversity, 5: 2. [PDF] [On the cover] [highlighted in Entomology Today]
3. Tonzo V, Papadopoulou A, Ortego J (2020) Genomic footprints of an old affair: Single nucleotide polymorphism data reveal historical hybridization and the subsequent evolution of reproductive barriers in two recently diverged grasshoppers with partly overlapping distributions. Molecular Ecology, 29: 2254-2268. [PDF]
2. Tonzo V, Papadopoulou A, Ortego J (2019) Genomic data reveal deep genetic structure but no support for current taxonomic designation in a grasshopper species complex. Molecular Ecology, 28: 3869-3886. [PDF]
1. González-Serna MJ, Cordero PJ, Ortego J (2019) Spatiotemporally explicit demographic modelling supports a joint effect of historical barriers to dispersal and contemporary landscape composition on structuring genomic variation in a red-listed grasshopper. Molecular Ecology, 28: 2155-2172. [PDF]
POPULAR SCIENCE PUBLICATIONS
1. Tonzo V, Papadopoulou A, Ortego J (2019) El saltamontes de los Pirineos: cuando dos especies resultan ser la misma. Quercus, 406: 18-23. [in Spanish]
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