COS 306-4 - CANCELLED - How spatial distribution within and between populations impacts genetic diversity through pollen dispersal distance and seed viability.

Thursday, August 10, 2023

4:15 PM – 4:30 PM PDT

Location: B112

Presenting Author(s)

AD

Alissa M. Doucet

Graduate Student
Northwestern University | Chicago Botanic Garden
Evanston, United States

Coauthor(s)

DC

Dylan Cohen

Chicago Botanic Garden, United States
JF

Jeremie Fant

Conservation Scientist/Geneticist
Chicago Botanic Garden/Northwestern University, United States
ST

Sophie Taddeo

Chicago Botanic Garden, Northwestern University, United States
KS

Krissa Skogen

Chicago Botanic Garden, Clemson University, United States

Abstract: The spatial relationship of plant populations can vary over time due to land use change and fragmentation. The spatial distribution of plants within and between populations - such as patch size, flowering plant density, and distance between populations - can impact patterns of gene flow, influencing reproductive factors such as seed viability. Pollen-mediated gene flow tends to homogenize populations, while lack of gene flow causes them to diverge. In clonal species, maternal plants are often closely surrounded by genetically identical individuals; and those with gravity-dispersed seeds are more likely to be surrounded by siblings. Therefore, especially in self-incompatible species, outcrossed pollen deposition (or seed movement) is necessary for producing viable offspring and gene flow. Although changing spatial distribution at different scales (patch, subpopulations, populations) can influence gene flow and reproductive success, research in this area is lacking. For species threatened by habitat disturbance, land managers need guidance on prioritizing populations to maintain gene flow and increase seed viability.

Here, we conduct a three-part study to understand how spatial distribution at multiple scales impacts genetic diversity through pollen-mediated gene flow and seed viability in a desert perennial (Amsonia tharpii) threatened by land use change. We used a ddRADseq approach to conduct population genetic and parentage analyses, along with a seed viability trial. Our results show that larger populations and those with high conspecific floral density are correlated with higher levels of genetic diversity and contemporary pollen-mediated gene flow, which has a positive relationship with seed viability. Further, our preliminary results suggest that spatial distribution influences gene flow and seed viability across multiple spatial scales (i.e. patch, subpopulation, and population). Our findings indicate that conservation decisions for threatened plant populations should prioritize larger patches with high floral density to increase the likelihood of gene flow and viable seed production, ultimately increasing the odds of species persistence.