Abstract Detail

Biogeography

Spalink, Daniel [1].

Global phylogenetic, functional, and taxonomic beta-diversity in Carex is mostly driven by climate: implications for a megadiverse genus in a changing world.

Carex is one of the world’s most diverse genera. The tremendous ecological diversity of Carex, coupled with chromosomal lability and high dispersibility, are hypothesized to be key drivers of diversification in the genus. These drivers have led to high rates of fine-scale niche partitioning within lineages and geographic convergence of distantly related species, resulting in hotspots of phylogenetic, functional, and taxonomic diversity and endemism on every continent except Antarctica. Notably, previous work has demonstrated the many Carex species are restricted to narrow bioclimatic conditions and that co-occurring species tend to not be each other’s closest relatives. This suggests that 1) turnover (beta-diversity) in sedge communities may be more tightly linked to climate or soils than to geographic distance; 2) species and functional trait turnover should occur at faster rates than phylogenetic turnover over comparable distances; 3) changing climates can be expected to substantially shift sedge community composition. To address these hypotheses, we integrate a global database of Carex occurrence records with a phylogeny and functional trait dataset. We use general dissimilarity modelling and gradient forest to develop models of phylogenetic, functional, and taxonomic beta-diversity, assessing the geographical, edaphic, and bioclimatic drivers of turnover on local and global scales and predicting the impact of global climate change on within-assemblage compositional turnover. Our results largely support our hypotheses, indicating that species and traits behave very differently than lineages, likely owing to the oversized role of long-distance dispersal in driving global patterns of sedge diversification and assembly. We find that climate change can be expected to drive compositional turnover within assemblages in the near future, though the impacts will vary in severity across the globe.

1 - Texas A&M University, Ecology and Conservation Biology, 534 John Kimborough Drive, College Station, TX, 77802, USA

Keywords:
turnover
Community Phylogenetics
general dissimilarity modeling
distribution modeling
climate change
functional traits
phylogenetic diversity
Cyperaceae
Carex.

Presentation Type: Oral Paper
Number: BIOG II006
Abstract ID:611
Candidate for Awards:None