Abstract

High Andean wetlands are crucial for biodiversity conservation, climate change mitigation and adaptation, and the well-being of local communities in the Andes. Although community genetics provides an evolutionary viewpoint on ecological processes and allows for potential new understandings of the mechanisms that influence biodiversity and ecosystem function and their response to environmental changes, no research has yet explored the ecological effects of genetic variation in high Andean species. Here, we searched for single-nucleotide polymorphism (SNP) loci of Carex gayana, an abundant plant species that fulfills crucial ecological functions in high Andean wetlands, that are associated with plant and aquatic macroinvertebrate diversity, and then investigated the spatial distribution of their alleles across a latitudinal gradient of ca. 600 km in Chile's Norte Chico. To identify SNP loci of C. gayana associated with community diversity, we analyzed a genomic dataset of SNP loci obtained through genotyping-by-sequencing of 158 individuals from 17 Andean wetlands using a genome scan approach. We found 30 structure and spatial outlier loci in C. gayana that were also linked with community parameters. We performed spatially-based causal modelling to infer the most probable origin of the observed relationships between SNP allele frequencies and community diversity parameters, resulting in 11 SNP candidates with possible extended effects on communities. The prevalence of alleles linked to greater taxonomic diversity varied greatly across wetlands. Some wetlands exhibited high frequencies of these alleles, while others had very low frequencies. These findings suggest that certain sites may be less resilient to global changes, while others could potentially serve as a source for restoration initiatives. Functional analysis of candidate genes using reference genomes of closely related Carex species allowed the identification of genes involved mainly in plant metabolism, responses to biotic and abiotic stress, defense mechanisms, growth and development, with functions commonly found in high-altitude plant species, and suggests that extended genetic effects of C. gayana genes to high Andean communities could be related to flower/reproductive development, defense mechanisms against herbivore insects and stress response.