Scientists from the Colorado Natural Heritage Program are hard at work crunching data from the 2019 field season and developing methodologies to extrapolate that data (collected from 100 plots over 100 person-hours thus far) across the watershed as a whole to identify areas of high quality habitat for mule deer, elk, and bighorn sheep.
But what factors go into determining what constitutes excellent, good (mid-range), and low quality ungulate habitat? The CNHP scientists take note of the following at each sample plot:
Plant species composition
Plant species cover
Availability and level of browse of focal species
Pellet counts of focal species
Items 1 and 2 above comprise a vegetation-based habitat quality assessment, while items 3 and 4 define utilization of focal species.
At each plot, CNHP scientists collect data on the above four parameters. First, a complete list of plant species in the ecological community of the sample point is compiled to help define vegetation richness.
Next, a random number generator selects a directional value, and a 50m transect tape is laid out in that direction from the sample point. At one meter points along the transect tape, the scientists make note of the ground cover and species that vertically intersect that point. This helps define vegetation cover.
The scientists then make note of both the availability of browse and level of browse for vegetation in three different size classes.
The random sample points for the Study were generated using the “Create Spatially Balanced Points” tool in ESRI ArcGIS. Other considerations were taken into survey site selection in order to ensure that the plots surveyed by CNHP would both compare to and complement existing Bureau of Land Management survey plots.
Here are a few examples of survey transects from the 2019 field season:
Following collection of data in the field, CNHP scientists developed a rubric to assign a score for species richness and vegetation cover for each site, with availability to and use by ungulates applied as modifiers. The final site score for each plot was then calculated using a multi-decision matrix, resulting in each site being assigned a score of: 2 = Excellent Vegetation Quality , 1 = Good (Mid-range) Vegetation Quality , and 0 = Marginal Vegetation Quality.
CNHP Scientists are currently working to refine methodologies to extrapolate the data collected during the 2019 field season across the Watershed using remote sensing data. In the 2020 field season they will both ground-truth their initial findings and collect data at high elevation sample sites to further refine their results.