Pilot Study: Do California Highways Act as Barriers to Gene Flow for Ground-Dwelling Mammals?

Details

• Creators:
  Coen, Amanda ; Schreier, Andrea ; Schilling, Fraser
• Corporate Creators:
  University of California, Davis ; University of California, Davis. Institute of Transportation Studies
• Corporate Contributors:
  National Center for Sustainable Transportation (NCST) ; California. Department of Transportation ; United States. Department of Transportation. University Transportation Centers (UTC) Program
• Subject/TRT Terms:
  • Genetics
  • Highways
  • Statistical sampling
  • Wildlife
  • Wildlife crossings
• Publication/ Report Number:
  NCST-201512
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Corporate Publisher:
  National Center for Sustainable Transportation (NCST) (UTC)
• Abstract:
  Roads have the potential to fragment wildlife populations, leading to genetic diversity loss, ; inbreeding, and increased extinction risk for small, isolated populations. In this study, we used ; coyote as a model to investigate how four Northern California highways affect gene flow of ; ground-dwelling mammals. We collected coyote scat samples from opposite sides of a stretch ; of I-580 and I-680 in the Bay Area and I-80 and US 50 in the Sierra Nevada foothills. We ; extracted DNA and genotyped each coyote at 13 microsatellite loci. We estimated genetic ; diversity and determined how that diversity was partitioned across the landscape in each ; region. ; Genetic diversity levels in coyotes were high and comparable to other studies. We found ; significant genetic structure in both the Bay Area and Sierra Nevada foothills, although it didn’t ; always correspond to highway presence. In the Bay Area, two populations were identified and ; although some evidence suggested I-580 was a significant barrier to gene flow, we identified ; migrants across the highway. One of the two populations in the Bay Area contained many ; second order relatives, suggesting limited gene flow into that population. There was evidence ; of dispersal out of that population, however. In the Sierra Nevada foothills, we identified three ; populations. Individuals from one population were sampled across highway I-80 suggesting it ; was not a significant barrier to movement. The most genetically divergent population in the ; Sierra Nevada foothills was also the most geographically distant and therefore it was difficult to ; determine whether gene flow into that population was limited by highway presence or simply ; geographic distance from other populations. ; The conclusions drawn in our pilot study are limited by the small number of samples we were ; able to genotype completely in the timeframe of this project. We are going to continue ; analyzing samples that currently have only partial genotypes and add those to our regional ; datasets. Genetic analysis with these larger samples will allow us to better understand the role ; of highways in structuring coyote populations in the Bay Area and Sierra Nevada foothills.
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• Format:
  PDF
• Funding:
  Agreement No 65A027
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31286/dot_31286_DS1.pdf
• File Type:
  [PDF - 1.97 MB]
• Collection(s):
  University Transportation Centers ; US Transportation Collection
• Main Document Checksum:
  urn:sha256:77be459abe649f61951d3af1b930ee37bca8e4fa03ba83f33212edca956bf250