Olsson Associates


Habitat mapping: Protecting species, protecting communities

Tuesday, September 15, 2015

Stuart Hall, Grand Junction Compliance

The yellow-billed cuckoo; Photo courtesy of the USFWSThe western yellow-billed cuckoo is in trouble. The U.S. Fish and Wildlife Service (USFWS) is currently considering whether it is a threatened species and needs an area—a “critical habitat”—to survive. But before the USFWS claims a broad stroke of critical habitat for the bird—perhaps impacting development for almost half a million acres in the western United States—Olsson Associates is applying practiced mapping techniques to see if those areas can actually support the cuckoo.

The USFWS is in the process of making a final decision about listing the western yellow-billed cuckoo as a threatened species. Part of this decision would include designating 546,335 acres in the western United States as critical habitat. Under the Endangered Species Act, critical habitat must be identified for any species determined to be endangered or threatened. Critical habitats are specific geographic areas that contain features essential for the conservation of a threatened or endangered species. For the western yellow-billed cuckoo, its critical habitat requires the following:

  • Cottonwood trees that are present along a waterway for at least 37 contiguous acres to support foraging
  • Cottonwood trees that are present along a waterway for at least 200 contiguous acres to support breeding
  • A cottonwood tree canopy that provides protection from at least 60 percent of the sun’s rays

Lined with towering cottonwood trees, this portion of the Colorado River in Grand Junction is a potential suitable habitat for the yellow-billed cuckoo.USFWS uses its best available scientific data and considers the economic impact, national security impact, and other relevant impacts of the habitat designation. During the listing process, the USFWS seeks input from local officials and the scientific community to weigh the potential impacts of listing a species.

The designation’s impacts

The USFWS has identified 80 critical habitat units along desert, riparian corridors throughout Colorado, California, Arizona, Utah, New Mexico, Idaho, Nevada, Texas, and Wyoming. This identification is important because a critical habitat’s designation has the potential to impact future development by requiring additional regulatory burden on communities.

Some of the areas identified as critical habitat for the western yellow-billed cuckoo are located within urban communities that may be impacted by a critical habitat designation. Those impacts could include additional permitting or restrictions on future development. Therefore, accurate habitat mapping is vital to ensuring the bird’s habitat can truly be supported.

Gaining a clearer picture

While communities wait for the USFWS to make a final decision regarding listing the western yellow-billed cuckoo as threatened and the critical habitat areas, Olsson is working to help communities use habitat mapping to more accurately identify whether an area generally designated by USFWS as a critical habitat meets the critical habitat criteria.

For example, in Mesa County, USFWS has identified 4,002 acres as critical habitat between the towns of Grand Junction, Palisade, and Fruita along the Colorado River. Olsson is using habitat mapping to more clearly illustrate for the county and for the USFWS whether or not the original USFWS estimates regarding the location of critical habitats are accurate.

Mapping includes the following processes:

  • Combining Geographic Information System (GIS) data, aerial imagery of the area, and other available datasets to create a baseline set of data for habitat mapping
    Performing habitat mapping by delineating cottonwood habitat through visual analysis of aerial imagery
  • Validating habitat mapping with field inspections and existing spatial data (e.g., rafting the Colorado River in Mesa County to photograph the existing cottonwood canopy)
  • Incorporating field data into habitat mapping data, including loading camera images into a software program to calculate tree canopy coverage
  • Providing technical summary reports to describe analysis methods, which summarize all analysis results and depict results in both tabular and map formats

Cottonwood stands in state wildlife areas along the Colorado River in Grand Junction that could serve as potential suitable habitat for the yellow-billed cuckoo.From Olsson’s preliminary work in Mesa County, scientists estimate that cottonwoods in the riparian corridor would have to extend for approximately five continuous miles to provide 37 acres of contiguous trees. Such a long, unbroken stretch of cottonwoods may actually not exist within this USFWS-designated critical habitat area. This more accurate picture of the area may help to remove some areas from the critical habitat designation, while identifying areas that might potentially provide foraging or breeding support for the western yellow-billed cuckoo.

With almost half a million acres and nine states potentially impacted by the pending USFWS decision, communities should consider using habitat mapping to proactively and accurately assess critical habitat areas. At this time, the USFWS has not finalized the critical habitat proposal for the western yellow-billed cuckoo. Although the public comment period is closed, USFWS can accept substantive comments from impacted communities as “entities with standing” in the issue at any time up until finalization, and a scientifically developed, detailed map of existing habitat conditions could form the basis for substantive comments.

For more information, please contact me at shall@olssonassociates.com or 970.263.7800.

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