DISSERTATION RESEARCH: Integrating Biogeography, Cytology, Niche Modeling and Phylogenetics to Understand the Evolutionary History of Endemic Campanula Species in the Mediterranean

University Of Florida, Gainesville FL

Investigators

Abstract

Accurate delimitations and estimates of species diversity are critical aspects for many areas of biology, including biogeography, ecology, and conservation. This research focuses on improving our understanding of species diversity in the Mediterranean Basin - one of the most biologically diverse areas in the world. As threats to biodiversity mount, due mainly to climate change and human pressure, accurate assessments are increasingly important for conservation efforts. To study fine-scale evolution and biogeographic patterns and processes, the researchers have identified a poorly understood group of bellflowers (the Campanula erinus species complex) that can serve as a model for understanding the drivers of evolution in this highly diverse area. This project will focus specifically on inferring the evolutionary history and providing an accurate assessment of species diversity in this group of plants. Results will have important implications for understanding the origins of Mediterranean biodiversity, designing successful conservation efforts, and anticipating possible responses to future climate change. The researchers will employ a next-generation sequencing approach, involving targeted enrichment of numerous nuclear loci across populations of both the widespread Campanula erinus and the narrow endemic, Campanula creutzburgii. Though sequencing will focus on the Campanula erinus species complex, the nuclear probe set will be designed such that it will be useful across the Campanulaceae (more than 2400 taxa). This targeted sequencing technique, in conjunction with morphological data, and recent coalescent and model-based methods, will serve as a model for future studies integrating traditional systematic and genome-level data for evaluating species boundaries and detecting cryptic speciation in vascular plants. The probe set developed during the course of this study will be made available to the scientific community, facilitating future evolutionary studies within the family. Studying the Campanula erinus complex in a phylogenetic and biogeographic framework will illuminate the drivers of diversification and persistence of species and allow the researchers to relate these mechanisms to factors such as ecology, geologic history, and climatic fluctuations. Three hypotheses will be tested regarding these taxa: i) Cryptic taxonomic diversity is present within the Campanula erinus aggregate; ii) Historical sea level changes contributed to allopatric speciation; iii) Polyploidy (genome duplication) has been an important historical factor in this group and polyploids may represent species distinct from their diploid progenitors. An understanding of these evolutionary processes will be especially critical in this biodiversity hotspot, where conservation efforts are expected to be most challenging but likely give the highest payoff.