Abstract Detail

Systematics

Pantinople, Dexcem [1], Siniscalchi, Carolina [2], Folk, Ryan [3].

Edaphic ecology in island-like systems—a case study in the Heuchera parviflora complex.

Inherently discontinuous habitat requirements, whether montane, edaphic, or otherwise, generate island-like, geographically discontinuous distribution patterns in continental landscapes, with distinct implications for population-level processes and speciation mechanisms. Yet, the implications of these distinct niche and organismal traits for understanding broader biogeographical patterns remain poorly implemented in current paradigms. From the applied point of view, especially in plants, the geographic complexity and lack of study in taxa distributed in ecological islands is likely also to result in cryptic species-level diversity and gaps in conservation effort. Here, I investigate the unique phylogeographic and speciation processes in terrestrial island-like systems using the Heuchera parviflora group (subsect. Villosae, Saxifragaceae). The H. parviflora group, as wide-ranging specialists of rockhouses (shallow caves and cliff undercuts) with diverse edaphic ecology, a highly disjunct distribution, and a relatively established phylogenetic framework, makes an ideal model system for studying island-like continental distribution patterns. As a first analysis to discover phylogeographic structure and to test the current hypothesis of relationships in the H. parviflora group, I ran phylogenetic analyses on a target capture dataset comprising 277 loci and dense population-level sampling, using concatenation in RAxML and coalescent methods in ASTRAL-III. To discover significant predictors explaining species distributions in the group and test whether any phylogeographic structure is mediated by refugial or edaphic mechanisms, I applied a demographic modeling approach using GATK4 and DIYABC, implementing a series of phylogeographic hypotheses based on recognized refugial areas and gridded soil datasets from SoilGrids. Preliminary results identify north-south phylogeographic differentiation between each of the taxa recognized currently in the H. parviflora group, in addition to the phylogenetically deeper west-to-east pattern already known. Initial ASTRAL analyses demonstrate a strong phylogenetic backbone and phylogeographic resolution within several subclades. My work has also generated surprises including a new species and the inclusion of H. villosa within a paraphyletic H. parviflora group, suggesting the need for further investigations on obscure, fragmented habitats.

1 - Mississippi State University, Department of Biological Sciences, 295 E. Lee Blvd., P.O. Box GY, Mississippi State, MS, 39762, USA
2 - Mississippi State University, Biological Sciences, 295 E. Lee Blvd., P.O. Box GY, Mississippi State, MS, 39762, USA
3 - Mississippi State University, Biological Sciences, 295 E. Lee Blvd., P.O. Box GY, Mississippi State, MS, 39762, United States

Keywords:
Heuchera parviflora
Phylogeography
Island-like systems
Edaphic
Refugia.

Presentation Type: Oral Paper
Number: SYST I012
Abstract ID:562
Candidate for Awards:None