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.
  
  
• Format:
  PDF
• Funding:
  Agreement No 65A027
• Collection(s):
  University Transportation Centers US Transportation Collection
• Main Document Checksum:
  urn:sha256:77be459abe649f61951d3af1b930ee37bca8e4fa03ba83f33212edca956bf250
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/31286/dot_31286_DS1.pdf
• File Type:
  [PDF - 1.97 MB ]