BRC-BIO: The origin and genetic makeup of rare plants: bridging micro- and macroevolution in the California Floristic Province

This project will examine the origin and genetics of four rare plants in California, a state known for having high biological diversity. In California, there are over 6,000 different plant species, and about a third of them are rare. Often found in only a single county or a few adjacent counties, rare species are those that live in small areas.

Because rare species occupy small areas, any changes to their environment can affect them more relative to widespread species. By studying their genetic makeup and aspects of their morphology and ecology, this study aims to increase our knowledge about rare plants. Understanding how rare plants evolve and how genetically diverse they are will help biologists to manage and protect these rare species.

This study focuses on four rare plants in northwestern California. This area is known for its unique plants but faces important challenges from recent wildfires and prolonged droughts. This project will also provide research experience for college and graduate students in northern California, including for students who are underrepresented in the sciences.

The results of the study will be presented to local indigenous tribes and to regional and national societies.

Hotspots of biodiversity have a high proportion of rare plants: it is estimated that about a third of plant taxa in the California Floristic Province are rare. Recent evidence has shown that budding speciation could be a primary driver of rare species diversity in the California Floristic Province. Despite the apparent relative importance of rare species in the assemblage of biodiversity hotspots, fine evolutionary scale studies that test the predictions of budding speciation are missing, and little is known about the origin and genetics of rare plant species.

Budding speciation is defined as a process in which a widespread species (progenitor) gives rise to a narrowly distributed species (derivative), with the “derivative” species being geographically adjacent or overlapping to the “progenitor” species. This project will study four rare species (Erysimum menziesii, Lupinus constancei, Silene serpentinicola, Wyethia longicaulis) in northwestern California to: 1) test the phylogenetic and genetic predictions of budding speciation, and 2) test for ecological divergence between the “derivative” and its putative “progenitor.” The project will sample hundreds or thousands of DNA regions and multiple individuals per species for aim 1.

Vegetative habit, flower size, flowering period, soil preference, and climatic niche will be compared between the “derivative” species and its putative “progenitor” for aim 2. Knowledge gained from this project will provide valuable input in the evolutionary processes governing rare plant species.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.