PS 29-98 - Effects of small-scale habitat restoration on genetic diversity and connectivity in bee populations

Tuesday, August 16, 2022

5:00 PM – 6:30 PM EDT

Located in: ESA Exhibit Hall

Presenting Author(s)

HH

Hannah Hayes, n/a

M.S. Candidate
University of San Francisco
San Francisco, California, United States

Coauthor(s)

CK

Claire Kremen

University of British Columbia, British Columbia, Canada
SJ

Shalene Jha, Ph.D.

Associate Professor and Principal Investigator
Integrative Biology, The University of Texas at Austin
Austin, Texas, United States
SS

Sevan Suni

Assistant Professor
University of San Francisco
San Francisco, California, United States

Background/Question/Methods

Pollination is essential for the health of natural ecosystems and agricultural productivity, with over 75% of crops benefitting from animal pollination. Populations of many bee species are in decline due to a suite of anthropogenic changes including habitat destruction. Habitat destruction is particularly harmful when it results in highly fragmented areas of remaining natural habitat, because it limits dispersal among populations, which is critical for the maintenance of genetic diversity. Past habitat loss can reduce viability of small isolated populations due to inbreeding depression and random fixation of deleterious alleles. In an attempt to promote biodiversity, there have been efforts to restore degraded habitats to a more natural state. We investigated the genetic responses of a wild bee species following small-scale habitat restoration in an intensively managed agricultural area. We assessed the genetic diversity and genetic connectivity of populations of the sweat bee Halictus ligatus in hedgerows of floral enhancements along the margins of large crop fields in Yolo County, CA. To measure genetic diversity and connectivity, we performed double-digest restriction site-associated DNA sequencing (ddRADseq).

Results/Conclusions

We found that both control and recently restored sites had increases in genetic diversity over time, while genetic diversity at mature restored sites did not change over time. Additionally, genetic differentiation (FST) decreased among all sites over time, with no evidence of restricted dispersal geographically. This indicates that the sweat bees not only colonized the recently restored areas, but also utilized resources in the weedy field edges of the control sites. Since the genetic diversity did not change at mature restored sites, but genetic connectivity increased among all sites, it is likely that mature sites served as source populations from which H. ligatus migrated.