Ground Cover Estimates - Cascabel Watershed

It was on my weekend during 7th and 8th November, 2009 when I joined a group from UofA to Cascabel Watersheds. This watershed is an aggregate of twelve small watersheds on the eastern side of the Peloncillo Mountains in the south-western New Mexico. The area is also identified as Malpai Borderlands in the eastern part of Coronado National Forest, on the western edge of the Animas Valley along the United States-Mexico border.

Photo-1: Cascabel Watersheds

These watersheds, ranging from about 20 to almost 60 acres in size, were established by the Rocky Mountain Research Stations, U.S. Forest Service and its cooperators to evaluate the impacts of prescribed burning on the ecological and hydrologic characteristics of the oak savannas in the region. The aggregate area of these watersheds, called the Cascabel Watersheds, is 451 acres. Each of the Cascabel Watersheds contain between 35 and 45 permanent sample plots that were established along transects located perpendicular to the main stream channel and situated from ridge to ridge. The intervals between the sample plots vary depending on the size and configuration of the watershed under sampling.

I helped the group basically measuring the ground cover and erosion rates. This posting describes about the ground cover measurement. We covered 7 of the total 12 watersheds during this visit.

Photo-2: One of the 7 watersheds

Percentage of plant material, litter, bare soil (including cobble, gravel, and stones), and bedrock on the watershed gives a prediction of hill-slope erosion rates. In each watershed, sample pins were located at certain intervals in different transects. They were symbolized by blue flagging in the field.

Photo-3: Blue Flaggings locating Sample Pin

First the pin was identified. At a distance of 8 feet due north from the pin, a point was noted down as hub.Then first measurement was done directly towards the north of this hub with a quadrat of 12 inch by 18 inch, placing the 12" side facing north. A second measurement at the same pin was made at 3 feet distance and 120 degree from the hub; and a third measurement was done at 3 feet distance and 240 degree from the hub. Thus, three plots were created in each pin along the transects.

Photo-4: Sampling Plots at each Pin

In each sampling plot percentage cover of bare soil, bed rock, litter and plant materials were noted down. This was a relative measurement in terms of how much percentage of the area within the quadrat is covered by bare soil, bed rock, litter and plant materials.

Photo-5: Cover Estimator

The ground cover condition represents a "baseline" for oak savannas of the region. In addition to that, percentage of bare soil and bed rock in comparison to litter and plant materials help in estimating erosion conditions in the area. Vegetative characteristics are good estimates of the capacity of livestock production, quality of wildlife habitats for food and cover, or water related resources.

I chose to join this group as it was a good opportunity to see the south-western watersheds. I had good time understanding the ecological conditions of the watersheds.