What should my pastures look like? Interpreting rangeland monitoring data
Conducting rangeland monitoring is an important way for ranchers and others who manage rangelands to understand how their management practices affect plant communities and soil health.
Data from this monitoring helps them know whether they should make any changes in their management practices, a concept known as adaptive rangeland management.
A new collaborative project between Nebraska Extension and cattle producers in the Nebraska Sandhills, the Sandhills Rangeland Monitoring Cooperative (SRMC), connects ranchers, scientists, and the public in a network of ongoing knowledge exchange about rangeland health and management. Hopefully this will help monitoring data on the cooperating ranches become more meaningful and useful.
The SRMC started in 2019 with the aim of conducting monitoring and evaluating monitoring data on a growing number of ranches in the Nebraska Sandhills. Here’s how the project works: Seventy monitoring sites across seven ranches made up the 2019 SRMC monitoring season. Ranches were grouped into two regions, western Sandhills and central Sandhills. Monitoring occurred on four ranches in the western Sandhills with 36 upland study sites, and three ranches in the central Sandhills with 34 upland study sites.
Three to four pastures were selected at each ranch to represent that ranch’s typical grazing management. Within each pasture, three study sites were selected. Each site was about one-fourth of a mile from water, located at an ecological site categorized as sands, and represented upland dune tops and slopes. Lowlands and wet meadows, which are important components of the Nebraska Sandhills ecosystem, were not evaluated due to travel and time constraints.
At each study site, we recorded the GPS location as a middle point and took photo points in three different directions, north, southwest, and southeast (photo 1). Moving away from the center point in the three directions, a monitoring frame was placed every two steps and vegetation and ground cover was recorded for 11 monitoring frame placements per direction. A total of 99 frames were measured for each pasture.
Within each frame, measurements were made of percent ground cover, plant species frequency of occurrence, and plant species dry weight rank. Forage production was also measured on some of the ranches. Other information collected for each site included elevation, aspect, slope, ecological site description, and current and long-term weather data.
Interpreting monitoring data can help detect changes in plant communities over time, and highlight plant response to grazing-management strategies. This data can be interpreted and compared with a target plant community in the USDA Natural Resources Conservation Service state and transition models for the ecological site being monitored. More information on specific ecological sites is at https://edit.jornada.nmsu.edu.
Compiled data of multiple sites in a similar region can also be used to compare a single site’s values with the averages, maximums and minimums in that region. In this way, deviations from specific management goals can be detected early and help in reassessing management decisions.
Percent cover is an important indicator of rangeland health that can be analyzed across seasonal and yearly differences in precipitation and grazing utilization. When bare ground is prevalent or increases over years, it suggests an area may be at greater risk for wind and water erosion.
We quantified ground cover at SRMC sites by identifying what was directly underneath the tip of a cover point (a wood screw) located on the monitoring frame (photo 2). We identified what was observed as either litter, bare ground, or the plant base of live vegetation. If we recorded a live vegetation cover point, we recorded the species. From these observations, we calculated percent ground cover.
When looking at ground cover data, the percent of bare ground in relation to litter or live plants provides valuable information about the amount of ground that may be lacking adequate cover. For example, if a site is reaching 40-50 percent bare ground, and the range management goal is to increase ground cover, then management practices should be employed that leave more litter or improve vegetation diversity and abundance. These management practices might include adjusting stocking rate, increasing rest time or altering timing of grazing.
However, having some sites with more bare ground is not always a negative. Areas with greater amounts of bare ground provide important habitat for wildlife, insects and specific plants, such as Blowout penstemon.
Monitoring rangelands provides critical insight to assist in managing for defined plant conditions in specific areas. The images in photo 3 show two sites in the central Sandhills, one with 9 percent bare ground (left) and the other with 42 percent bare ground (right). The 42 percent bare ground site has soil patches exposed along the monitoring transect visible in the photo.
Yearly photo points at the same location can help monitor the spread or reduction of bare ground at a specific location. Photo points cannot show every detail along the transect but are helpful in comparing year-after-year changes in bare ground under different management strategies. Keeping detailed monitoring records (such as cover and plant species transect) at a few locations will help in monitoring rangelands visually as the rancher drives through pastures at different times of the year.
The SRMC will continue to collect data over the next few years. To learn more about the project and to follow along with the results, visit the SRMC website at https://spark.adobe.com/page/EkDaaEdOVwCXG/.
The site will be updated with more data at the conclusion of each growing season.
Anyone with questions about setting up a rangeland monitoring program or the SRMC project should contact project coordinator Kayla Mollet (email@example.com) or UNL Range and Forage Management Specialist Mitch Stephenson (firstname.lastname@example.org). ❖
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