Range Monitoring in the Upper Stony Creek Watershed

Objective 1. Detailed monitoring was conducted in the watershed at the King Ranch to document the effect of grazing systems and resulting stocking densities on annual rangeland ecology. Cattle grazing impacts were investigated with replications of three grazing regimes, a high-intensity-short duration treatment, a no grazing treatment, and a traditional seasonal grazing regime.

The King Ranch is located near the town of Ladoga in Colusa county. The ranch includes rangeland and cultivated land. The cultivated land has been planted with walnut trees. The rangeland is predominantly annual grass oak woodland used for cattle grazing; however in the 1950s the landowner established Harding Grass, Phalaris aquatica on a 70 acre block. Harding grass has persisted in a healthy stand on the site. Two replications of the grazing treatment regimes are located within the 70 acre block of Harding Grass. Three replications of the grazing treatment regimes are located on a slope adjacent to the improved site. Although annual grasses dominate the sloped site, native perennial grasses and some Harding Grass plants are also present.

On the King Ranch the grazing treatments were fenced in 1990 prior to this project being funded. Grazing treatments have been applied each year on this ranch since 1991. Baseline data was collected in 1990 and 1991. Range plant cover, canopy cover, target plant density, soil crusting characteristics were determined for each treatment using the Savory “dart-throw” method. Residual dry matter and soil bulk density were also determined for each treatment. This data has also been collected annually during the project years 1994, 1995 and 1996.

Data analysis compared years and treatments. Within years no treatment differences were found between soil bulk density or ground cover. Most treatment cells consistently had less than 5% bare ground. About 85% of the treatment sites were covered by new or partially decomposed plant litter. Residual dry matter (RDM) varied by year and by treatment. For example, in 1996 RDM averaged 400 lb. per acre for seasonal grazing, 800 lb. per acre for high-intensity short-duration grazing, and 2800 lb. per acre in the ungrazed plots. In 1995 there was no difference between grazed plots which averaged 800 lb. per acre whereas the ungrazed plots had 3000 lb. per acre of dry matter.

In regards to “target” plant species, we were not able to demonstrate an increase of perennial grass plants by the grazing regime; however, more decadent or “overrested” perennial grasses were noted in the ungrazed treatments. In 1996 it was found that 52% of the Harding Grass plants were decadent in the ungrazed treatments with a 5 to 10% basal cover of Harding Grass. No decadent plants were observed in either of the grazed treatments where Harding Grass was the dominate perennial species. “Overgrazed” perennial Harding Grass plants, plants with less than 1/2 inch of stubble remaining, were observed in the grazed treatments. In 1996, 31% of the Harding grass plants in the high-intensity-short duration treatment appeared “overgrazed”. In the traditional seasonal grazing regime treatment, 79% of the Harding Grass plants appeared “overgrazed”. In the grazing treatments on the slope, the native perennial plants and the Harding Grass accounted for less than 2% of the basal cover and analysis of perennial grass condition was not viable.

Although, after 6 years of grazing treatments, we were not able to detect a change in the population of the perennial grasses, it is reasonable to assume that the difference in numbers of “decadent” versus “overgrazed” perennial plants due to grazing treatment could eventually impact population dynamics. It could also be argued that 6 years of grazing treatments is not long enough to detect change in annual rangeland ecology on upland sites.

Similar detailed monitoring of annual rangeland ecology was planned for the Sommerville 4J Ranch, but livestock was not available for the treatment site until the Spring of 1995. The entire treatment site at the Sommerville 4J Ranch was ungrazed for the first two years of the project and for three years prior to funding this project; however, detailed monitoring of riparian profiles was still conducted (Objective 2).

Although our detailed vegetation monitoring did not indicate significant changes in vegetation due to grazing regimes, it did provide us with valuable information for evaluating monitoring methods and establishing a simpler monitoring method. Using the Savory “dart throw” method we collected 33 data points per treatment plot. Although the treatments were only about 1/2 acre, 33 data points proved to be inadequate to accurately assess change in bare ground or perennial grass populations. In addition, we found that there was a significant difference in interpretation of the monitoring dart “hit” by research individuals. Including the years in which baseline data was collected, three different research individuals collected Savory “dart-throw” method on the King Ranch.

The discrepancies in data collection by individuals was recognized during monitoring of the site in the summer of 1994. Although in subsequent years we continued to collect vegetation data using the Savory “dart-throw” method, we also worked to develop and evaluate a different method. We tested a method of determining percentage of ground cover using a reference frame. We found much higher correlations between individual researchers using a reference frame with 10 data spots versus using the “dart throw” method with 33 data points (.53 versus .29). With the addition of a cover estimator reference sheet and at least 15 reference frame data spots we can improve the repeatability and consistency of this monitoring technique. Monitoring vegetation with a reference frame also proved to take less time. Experience from this monitoring study was used to develop a chapter on vegetation monitoring in a “How to” Monitor Handbook (Objective 3).

In the summer of 1995 detailed monitoring was conducted to compare infiltration rate and interill erosion on sites with annual and perennial grasses. Several of the landowners in the watershed have worked to establish perennial grasses as land treatment practice under the PL-566 project, so there was interest in learning if perennial grasses enhanced hydrology. Hydrologic data was collected using a single-nozzle rainfall simulator on 0.5m2 plots. After conducting 30 rainfall simulations on the grazing treatments at the King Ranch, we decided that this study need a more intensive effort. An additional project was developed and funded by the University of California Division of Agriculture and Natural Resources so that best management practices to increase infiltration and reduce interill erosion could be investigated. The data indicated that the presence of perennial grasses enhanced infiltration rates (water applied minus runoff) on annual rangeland. Runoff was less on perennial plots than annual plots (49.5% versus 63.3%, respectively). However, the amount of vegetation or dry matter and soil bulk density were also very important factors in regards to infiltration rate. Interill erosion on all sites was minuscule. Data from the rainfall simulation study is being prepared for a scientific journal.

Objective 2. Detailed monitoring of the riparian profile was conducted in 1990, 1991, 1994, 1995 and 1996 at the Sommerville 4J Ranch. The Sommerville 4J Ranch is located south of Elk Creek in Glenn county. The ranch consists of 4087 acres of range and 113 acres of irrigated pasture. In 1990, 36 stream profile transects were established Because livestock was not available for the study site until the Spring 1995, livestock impact on the riparian profile was not investigated. Instead, transect sites were used to assess the influence of check dams placed in the stream in 1990. Transects were located one meter above and one meter below 18 different check dams. The riparian profile of each transect was measured using a level and rod. One photo point for each transect was also identified. Photo points were photographed each fall prior to the first fall germinating rains.

The exclusion of grazing from the riparian site had significant impacts on the vegetation. Where bare ground covered much of the riparian area in 1990 and 1991, riparian vegetation dominated the site by 1995. The tremendous growth of vegetation made many of our original photo points ineffective. By reviewing the stream profile data and the monitoring photos from year to year, we were able to evaluate each photo point. Information from our riparian profile monitoring was developed into a case study and reported in the “How to” Monitor Handbook (Objective 3). We also used this field experience to develop a Riparian Monitoring Inventory Form for California’s Annual Grassland, Appendix IIIa in the “How to” Monitor Handbook.

Objective 3. At the beginning of this project, a review of literature on monitoring revealed that there was no specific condensed documents on “how to” monitor rangelands. Other University of California Cooperative Extension natural resource/ livestock advisors also recognized this deficiency and were eager to work together to develop a “hands on” handbook on “how to” monitor rangeland. The handbook evolved into a two-level approach. Level 1 instructs ranchers on “how to” monitor range sites with a camera. Our experience with the Upper Stony Creek Watershed Project provided guidance for evaluating text and creating illustrations for Level 1. With funding from this grant, an illustrator was hired to improve the document with high quality hand-drawn illustrations. “How to” Monitor - Level 1 was published in December 1995 with funding from a Renewable Resource Extension Act grant/loan. The handbook has been sold to defray publication costs.

The California Cattlemen’s Association supported the effort to provide education on rangeland monitoring by donating $4,000 to develop a 12-minute video to encourage and demonstrate photo monitoring. A video was created based on “How to” Monitor - Level 1.

After the publication of “How to” Monitor - Level 1 we began work on developing Level II. “How to” Monitor - Level II includes more specific monitoring methods for collecting data on vegetation, utilization, residual dry matter, water quality, and wildlife. Monitoring methodology on vegetation was developed and field tested in conjunction with monitoring in the Upper Stony Creek Watershed Project (Objective 1). Specifically, experience with the “dart throw” method for collecting detailed vegetation data indicated that collecting enough data points was very time consuming. There also appeared to be a high degree of variability between research individuals in determining the precise “hit” of the monitoring point, particularly on annual rangeland. When the “dart throw” method was field tested during a landowner workshop in the Upper Stony Creek Watershed, it was apparent that this method would not be readily adopted. A group of landowners spent over 20 minutes carefully examining the “hit” of their monitoring dart. Although this activity enticed the landowners to look closely at the range, it did not result in quality monitoring data.

As explained in the results for Objective 1, a monitoring method for vegetation using a 1 ft or 3 ft reference frame was developed. This monitoring method was field tested with landowners and has been promoted in the watershed. In the summer of 1995, with funding from the Renewable Resource Extension Act, a 15-minute video was produced illustrating monitoring vegetation cover, utilization and residual dry matter. “How to” Monitor - Level II is currently being published and will be ready for distribution in January 1997.

In order to achieve rancher adoption of range monitoring in the Upper Stony Creek Watershed, we worked closely with landowners participating in the PL-566 Watershed Project. In the spring 1994 we held 5-day short course in the watershed to introduce landowners to ranch planning and monitoring. The short course included field trips to two ranches in the watershed. During a monitoring exercise at one ranch I demonstrated a rocket camera to encourage ranchers to consider photo monitoring. I fired an “astrocam”, a model rocket with a little camera attached to it, over the range site. The rocket was to take an aerial photo of the range site. Although the rocket malfunctioned, the excitement this created among the landowners was tremendous. Fifteen participants completed the short course.

Since our short course in the spring 1994, we have worked individually with 19 landowners in the watershed. We have introduced these landowners to monitoring methods and provided them with a “How to” Monitor Handbook - Level 1 as well as a disposable camera. In addition to helping several of the landowners identify monitoring goals and establish permanent photo points on their ranches, we worked with three of the landowners to establish more advanced monitoring points. At these points we assisted them in monitoring, vegetation cover, residual dry matter, and oak regeneration. Although our success in establishing more advanced monitoring points with landowners has been limited, we have been successful in getting landowners to establish a few permanent photo points on their ranch. These photo points could undoubtedly provide them with valuable insight into landscape or vegetation change occurring on their ranches.

We have had our monitoring methods adopted for use on other projects in the watershed. In 1995 three of the landowners in the watershed began to work with the California Waterfowl Association on projects to improve waterfowl habitat on their ranches. We worked with the landowners and the Waterfowl Association to establish monitoring sites for these projects. Monitoring methods described in the “How to” Monitor Handbook were followed.