Conservation Genetics

, Volume 18, Issue 1, pp 131–146

A century of landscape disturbance and urbanization of the San Francisco Bay region affects the present-day genetic diversity of the California Ridgway’s rail (Rallus obsoletus obsoletus)

  • Dustin A. Wood
  • Thuy-Vy D. Bui
  • Cory T. Overton
  • Amy G. Vandergast
  • Michael L. Casazza
  • Joshua M. Hull
  • John Y. Takekawa
Research Article

DOI: 10.1007/s10592-016-0888-4

Cite this article as:
Wood, D.A., Bui, TV.D., Overton, C.T. et al. Conserv Genet (2017) 18: 131. doi:10.1007/s10592-016-0888-4

Abstract

Fragmentation and loss of natural habitat have important consequences for wild populations and can negatively affect long-term viability and resilience to environmental change. Salt marsh obligate species, such as those that occupy the San Francisco Bay Estuary in western North America, occupy already impaired habitats as result of human development and modifications and are highly susceptible to increased habitat loss and fragmentation due to global climate change. We examined the genetic variation of the California Ridgway’s rail (Rallus obsoletus obsoletus), a state and federally endangered species that occurs within the fragmented salt marsh of the San Francisco Bay Estuary. We genotyped 107 rails across 11 microsatellite loci and a single mitochondrial gene to estimate genetic diversity and population structure among seven salt marsh fragments and assessed demographic connectivity by inferring patterns of gene flow and migration rates. We found pronounced genetic structuring among four geographically separate genetic clusters across the San Francisco Bay. Gene flow analyses supported a stepping stone model of gene flow from south-to-north. However, contemporary gene flow among the regional embayments was low. Genetic diversity among occupied salt marshes and genetic clusters were not significantly different. We detected low effective population sizes and significantly high relatedness among individuals within salt marshes. Preserving genetic diversity and connectivity throughout the San Francisco Bay may require attention to salt marsh restoration in the Central Bay where habitat is both most limited and most fragmented. Incorporating periodic genetic sampling into the management regime may help evaluate population trends and guide long-term management priorities.

Keywords

Ridgway’s rail Gene flow Fragmentation Microsatellites Population declines 

Supplementary material

10592_2016_888_MOESM1_ESM.pdf (1.6 mb)
Supplementary material 1 (PDF 1669 kb)

Copyright information

© Springer Science+Business Media Dordrecht (outside the USA) 2016

Authors and Affiliations

  • Dustin A. Wood
    • 1
  • Thuy-Vy D. Bui
    • 2
  • Cory T. Overton
    • 2
  • Amy G. Vandergast
    • 1
  • Michael L. Casazza
    • 2
  • Joshua M. Hull
    • 3
  • John Y. Takekawa
    • 4
    • 5
  1. 1.U.S. Geological Survey, Western Ecological Research CenterSan Diego Field StationSan DiegoUSA
  2. 2.U.S. Geological Survey, Western Ecological Research CenterDixon Field StationDixonUSA
  3. 3.Department of Animal Science, Meyer HallUniversity of California, DavisDavisUSA
  4. 4.U.S. Geological Survey, Western Ecological Research CenterSan Francisco Bay Estuary Field StationVallejoUSA
  5. 5.Audubon CaliforniaTiburonUSA

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