Restoration and Grazing Management on Mountain Meadows and Streams
Keywords – livestock distribution, mountain meadows, Sierra Nevada, Cascade, macroinvertebrates, biological integrity, streams, grazing management
Participants – C. Battaglia, Theresa Becchetti, Neil McDougald, David Lile, Don Lancaster, Holly George
Introduction
Livestock grazing on stream associated mountain meadows in California can negatively impact riparian vegetation, stream stability, water quality, and wildlife habitat. However, we have observed degradation at some grazed meadows but not others. This reflects differences in grazing management and meadow/stream resiliency to grazing. We conducted a cross-sectional survey of grazed riparian areas to identify and promote sustainable riparian grazing management.
Project Objectives
- Identify grazing management activities associated with healthy mountain meadow streams.
- Extend these recommendations to grazing managers, regulators, and policy makers.
Study Sites
Fifty-eight grazed meadow – stream riparian areas were enrolled in this cross-sectional survey. Sites were located on both public and private grazing lands across the Sierra Nevada Range, southern Cascade Range, and Modoc Plateau.
Min |
Mean |
Max |
|
| Elevation (ft) | 3,400 |
5,900 |
8,500 |
| Pasture/allotment size (acres) | 800 |
18,000 |
105,000 |
| Herd size (animal units) | 10 |
150 |
670 |
| Total Livestock Distribution Effort (days/yr) | 0 |
9 |
41 |
| Stream Substrate Type (% sites) | Fines |
Gravel |
Cobble |
53 |
27 |
20 |
Descriptive statistics for sites enrolled in this study.
Data Collection
A management survey was conducted with each grazing manager to quantify management activities at each site such as number of head, class of livestock, season of use, time spent herding to distribute livestock, etc.
A first approximation of riparian health was determined for each site using the U.S. EPA Habitat Assessment Field Data Sheet (HAFDS), which assigns a health score of 0 (very poor) to 20 (excellent) based upon an 11 panel site assessment.
Health Score |
Health Category |
0 to 5 |
Poor |
6 to 10 |
Marginal |
11 to 15 |
Suboptimal |
16 to 20 |
Optimal |
HAFDS a health score was based upon an 11 panel site evaluation.
A direct measure of riparian health was made by collection of in-stream macroinvertebrate (insect) samples, taxonomic ID, and calculation of indicators of stream health (e.g., % sample composed if taxa intolerant of pollution, richness, diversity).
Various site characteristics were measured such as stream substrate type (silt/sand, gravel, cobble), solar radiation/canopy cover, channel with and depth, and streambank vegetative cover.
Statistical Correlation of Grazing Management to Riparian Health
Linear regression analysis was used to identify grazing management activities and site characteristics which were positively and negatively correlated with U.S. EPA HAFDS health score (0 to 20).
Negative binomial regression analysis was used to identify grazing management activities which were positively and negatively correlated with 10 macroinvertebrate metrics sensitive to changes in stream conditions (e.g. water temperature, sedimentation). Independent variables were grazing management, and site characteristics.
Results – Grazing and EPA Riparian Health Score
Riparian health score was positively correlated to the time a manager invests to maintain off-stream livestock attractants such as salt, supplemental feeds, and drinking water (p<0.05). The practice of providing off-site attractants was not significant, rather the time invested to insure the distribution practice was effective. Time spent herding to distribute livestock from meadow to meadow, or into uplands was also positively correlated with riparian health score.
| Grazing Management Activity | Correlation to Health Score |
| Time maintaining off-stream attractants (days/yr) | Positive |
| Herding to reduce time near stream (days/yr) | Positive |
| Livestock density (AU/ac) | Negative |
| Frequency of grazing (times/yr) | Negative |
Livestock density (head/ac) on the pasture or allotment containing the meadow was negatively associated with riparian health score. As was the frequency, or number of times per year, the meadow was grazed during a single year. These variables reflect overall grazing pressure applied to the meadow.
Results – Grazing and Macroinvertebrate Metrics
The overall time invested in activities to distribute livestock away from meadows and associated streams was the only grazing activity correlated with macroinvertebrate metrics. Basically, as the amount of time per year spent herding livestock, placing and regularly moving salt/mineral, and checking the working order of off-stream drinking water sources increased there was an associated increase in the macroinvertebrate metrics indicative of healthy riparian conditions. There was also a reduction in the metrics indicative of riparian degradation.
| Macroinvertebrate Metrics | Indicate Riparian Health or Degradation | Correlation to Livestock Distribution Effort (days/yr) |
| No. Ephemeroptera (mayflies) | Health | Positive (p=0.05) |
| No. Plecoptera (stoneflies) | Health | Positive (p<0.01) |
| No. Tricoptera (caddisflies) | Health | Positive (p=0.07) |
| Tot. No. EPT | Health | Positive (p=0.01) |
| Total No. Taxa (richness) | Health | Positive (p<0.01) |
| No. Coleoptera Taxa (beetles) | Health | Positive (p=0.02) |
| % Intolerant to Pollutants | Health | Positive (p<0.01) |
| % Dominant Taxa | Degradation | Negative (p=0.03) |
| % Diptera (true flies) | Degradation | Negative (p=0.10) |
| % Chironomidae (midges) | Degradation | Negative (p-0.09) |
Increased effort to distribute livestock away from meadows and associated streams was correlated with increased macroinvertebrate richness.
Natural decreases in stream substrate size from cobble to fines was associated with decreases in healthy macroinvertebrate indicators.
Management Implications
Management of livestock distribution is a critical management activity to enhance and sustain riparian health in mountain meadow grazing systems. Simple distribution tools such as herding, salting, and off-stream water are effective for protecting riparian areas, but management effort must be invested to assure success. Expectations for stream health based upon macroinvertebrate metrics must account for inherent site differences in stream substrate type.
Supporting Information
Tate, K.W. 2006. Confirmation of Riparian Friendly Grazing Project Results and Development of Achievable, Site Specific Reference Conditions for Grazed Riparian Areas. Final Report to USDA Sustainable Agricultural Research and Education Program. Project # SW03-037. Download
Ward, T.A., K.W. Tate, E.R. Atwill, D.F. Lile, D.L. Lancaster, N.K. McDougald, S. Barry, R.S. Ingram, H.A. George, W.J. Jensen, W.E. Frost, R. Phillips, G.G. Markegard, and S. Larson. 2002. A Comparison of Three Visual Assessments for Riparian and Stream Health. J. Soil and Water Conservation. 58:83-88. Request Reprint
Ward, T.A., K.W. Tate, and E.R. Atwill. Guidelines for Monitoring the Establishment of Riparian Grazing Systems. UC DANR Publication No. 8094. Download
Ward, T.A., K.W. Tate, and E.R. Atwill. Visual Assessment of Riparian Health. UC-DANR Publication No. 8089. Download