programs Natural Resources

Plains Spotted Skunk

(Spilogale putorius interrupta)

Background

The historic range of the plains spotted skunk covers most of the central plains in the United States from Texas to Wyoming. The Katy Prairie to the northwest of Houston is home to one of the last known populations in Texas.

Due to potential threats such as habitat loss, reduction of food availability because of pesticide use and vehicle strikes across the spotted skunk’s entire range, the U.S. Fish and Wildlife Service (FWS) is evaluating the species’ status. It plans to make a listing recommendation in 2023.

Between now and then, biologists across the plains states are trying to understand the spotted skunk’s basic habitat needs, distribution, genetics and causes of mortality.

Research Description

The Texas Comptroller of Public Accounts (CPA) contracted with Angelo State University (ASU) in 2014 to conduct basic research on the species across the state. Although the work concluded the species’ broad range of potential habitat covers most of the east, north and central areas of Texas, very few actual spotted skunks were found. Out of 8,065 survey nights, there were 12 detections, which is not unusual for a nocturnal species with low population densities and where there is limited access for surveys.

In 2018 the CPA entered into a second contract with ASU to focus on the Katy Prairie and determine the presence, habitat associations, distribution and mortality causes of the species. The area was not only one of few locations with a relatively high population, but also an area of the state likely to be affected by the rapidly expanding Houston metro area.

For this new work, researchers are using trail cameras, live traps and radio collars to document the extent of the population and abundance of spotted skunks. Researchers will combine the sightings and tracking data to document the habitat types the spotted skunk uses as well as home ranges and maternal habits. Radio collars are also being used to track striped skunks to assess interaction and the differences in habitat usage between spotted and striped skunks. The analysis will estimate known and potential habitats in and near the Katy Prairie ecosystem.

Deliverables Due by Contract End, July 31, 2021

  • Data from all surveys, including GPS coordinates for each collared spotted skunk
  • Report and analysis of surveys results to estimate:
    • Differences in home range size by sex and season over two years
    • Habitat characteristics and land cover usage, and effects of land management practices
    • Presence, occupancy and distribution of spotted skunks in the Katy Prairie
    • Habitat requirements for daytime resting and maternal denning, along with patterns of maternal care, food provisioning and timing of juvenile emergence/dispersal
    • Cause-specific mortality and survivability in Katy Prairie ecosystem and compared to other habitat types
    • Density and relative abundance at sites and estimated across Katy Prairie ecosystem

Why This Research Matters

The plains spotted skunk population in the Katy Prairie occupies the last remaining undeveloped prairie habitat in this region. The ecosystem has been fragmented over time, and the population is under threat of increasing habitat loss as the Houston metropolitan area rapidly expands. Research on separate populations of the plains spotted skunk in other states is likely not applicable to the Katy Prairie population due to differences in habitat. It is also unclear to what degree each threat causes a decline in the population.

There are also productive agricultural lands in this area, which would likely be affected by a listing decision. Because it is not clearly understood if or why the species is endangered, an FWS listing could add regulatory hurdles, potentially change land management practices for ranch owners and result in uncertainty about permits for highway projects near the Katy Prairie.