Landscape genetics and dispersal ecology of Pacific Northwest prairie plant species
For my postdoctoral research, I studied gene flow among remnant prairie patches at various geographic scales, for several small flowering plant species. This work is part of a larger, NSF Macrosystems collaborative project with researchers at the University of Oregon, UC Boulder, and Duke. The larger project is focused on modeling how prairie species will respond to climate change, using data from large scale experimental warming plots, replicated at different latitudes, and demographic data from natural populations. In the Cruzan lab, our contribution was to estimate dispersal rates for several species, and understand the different variables influencing dispersal at different scales.
We are using a novel targeted capture array approach to focus on chloroplast sequences, as these are maternally inherited and represent seed dispersal. Using targeted capture allows us to analyze large sample sizes, and study "plastid population genomics". We then use these patterns of cpDNA genetic distance and see how they are correlated to different landscape features, such as plant density, habitat connectivity through swales, and vole pathways through the landscape. We analyze these landscape features by creating resistance surfaces in Circuitscape and optimized in ResistanceGA. Plant species of interest for this project include Lasthenia californica, Plagiobothrys nothfulvus, Ranunculus austro-oreganus, Eriophyllum lanatum, Plectritis congesta, Achyrachaena mollis, and Cynoglossum grande. We are also interested in understanding how different dispersal mechanisms create different seed dispersal patterns.
Another project I lead was comparing pollen flow to seed dispersal in Lasthenia californica, using a genotyping-by-sequencing (GBS) approach. Lasthenia californica forms dense patches on the edges of vernal pools at our study site near Medford, OR, and is pollinated by small native bees and flies. We sampled 20 populations of L. californica in a small (16 hectare) prairie. to understand gene flow on a fine geographic scale..
Effects of forest fragmentation on gene flow in a bat-pollinated tree
For my Ph.D. research in Victoria Sork's lab at UCLA, I studied the effects of forest fragmentation on the ecology and gene flow of a bat-pollinated tree, Crescentia alata (Family: Bignoniaceae).
My field work for this project was conducted in seasonally-dry tropical forest in Jalisco, Mexico, near the Chamela-Cuixmala Biosphere Reserve. I compared bat pollinator abundances and diversity at flowering C. alata trees in fragmented and continuous forest sites. I also surveyed the flowering phenology and fruit set of C. alata trees in sites surrounded by varying levels of fragmentation. My work in the field was supported by grants from a Fulbright Fellowship to Mexico, Bat Conservation International, UCLA's Latin American Institute, UC Mexus, and UCLA's Department of Ecology and Evolutionary Biology.
I developed microsatellites (simple sequence repeats that evolve rapidly) for C. alata, and genotyped multiple seedlings from multiple fruit from the same trees I had observed for pollinator behavior and flowering phenology in the field. I used the genotypes from seedlings from one season of open pollination, and several statistical methods to understand how fragmentation influences pollen flow and connectivity of maternal trees across the landscape. I also examined the patterns of genetic diversity and structure of adult trees, which theoretically lost their co-evolved seed dispersers in the Pleistocene.