Grazing Strategies for Sustainable Ranching Systems in Western Semi-Arid Zones
1. To collect biological, hydrological, management, and economic baseline data for transitional and both management intensive and capital intensive grazing systems designed to maintain or enhance riparian and adjacent upland zone conditions;
2. To monitor performance of variations of the identified ranching systems for two full growing seasons;
3. To determine the impact of alternative grazing strategies on ranch and livestock performance on riparian zone and adjacent upland conditions, and on fish and wildlife habitat;
4. To identify constraints on adoption of "best whole ranch management practices" for ecologically compatible grazing strategies in riparian zones and adjacent upland which may be resolved through either research, user education, and/or through management and policy changes;
5. To develop guidelines for the design and implementation of alternative whole ranch grazing system, grazing intensity, and distribution control strategies; and,
6. To prepare relevant audiovisuals, supporting user-oriented publications, and conduct on- and off-site demonstrations and educational programs on "best management practices" to encourage transfer of viable intensive grazing system technologies.
The study area is located in Grant County, Oregon. Twelve experimental units were identified in the study areas based upon 1) site similarity, and 2) management intensities which were in place for a least five consecutive years. The three treatments consisted of a similar meadow vegetation with woody willow components associated with the riparian zone. Treatments represent a primarily herbaceous vegetation cover currently managed under a summer short-duration/rotation grazing system; and, a primarily continuous woody plant cover currently managed under a fall short-duration grazing system. Four replicates of each treatment were identified.
The concept of "bankfull" was found to be a non-repeatable field measure. It is, therefore, a poor benchmark for a stream classification scheme. Stubble height measurements are a direct indicator of the impact of grazing and haying on the riparian meadow. Analysis of the data showed a significant difference between summer season-long, summer short-duration, and fall short-duration. Forage production in semi-wet low production and semi-wet high production communities were analyzed, as were percent base ground, litter, dominant species, and basal cover. The effect of irrigation practices on stream flow and temperature was analyzed. Non-equilibrium ecological theory satisfactorily represented ecological structure within the herbaceous riparian meadows.
Both bird and mammal communities displayed specific associations with riparian vegetation structure. On a pasture scale, management practices that maintain, restore or enhance willow vegetation will result in the greatest wildlife diversity and abundance.
Based on economic and biological information collected from cooperating ranchers as well as secondary information, the profitability of five grazing plans was evaluated over a six-year period. Although the results showed slight differences in profitability between the grazing plans, the differences were so small and so sensitive to changes in some parameters (in particular forage yields) that the differences cannot be viewed as significant.
Economic sustainability was defined as being established if the rate of long-term returns to ranch investment is at least three percent (one-half of the opportunity cost of capital as measured by the annual yield rate on 10-year U.S. Treasury notes). Given this criterion for economic sustainability and given, further, the then (1993) existing price/cost relationships, the ranch operation was found to be sustainable under all grazing systems examined.
A doubling of grazing fees did not cause the ranch to be economically unsustainable; however, a 30 percent reduction of the public land grazing permit did result in the loss of economic sustainability under all grazing schemes.
In 1995/96, four enterprise budgets were prepared to further examine economic sustainability. The enterprise budgets are for cow/calf operations with 50, 100, 300, and 500 cows, respectively . Production conditions considered are those existing in the mountain region of northeast Oregon. The project site, Bear Valley is located in that region.
One of the four budgets prepared for the mountain region encompassing Bear Valley is representative of the size class prevalent in Bear Valley: the 500 cow (25 bulls, 10 horses) enterprise budget. This budget reveals that the leading per cow annual cost items in the mountain region are winter hay feeding costs ($127.35) and annual family labor costs ($54.00 per cow). Combined, these two cost items account for about 58 percent of annual variable plus cash fixed costs for a representative cow/calf enterprise. Therefore, only it a grazing strategy significantly affects either hay production/feeding of family labor costs is it likely that an alternative riparian grazing management program will significantly influence ranch productivity. These findings confirm the basic conclusions drawn from the ranch survey and whole ranch analysis completed in the previous year.
The budgets reflect the lower cattle prices in 1995/96 (relative to prices in 1993). These prices are approximately 10 percent lower. Given these lower prices and after accounting for the value of family labor ($27,000 per year), the ranch, although returning a positive return to ranch investment, is no longer economically sustainable (if economic sustainability is defined as previously, namely, one-half the opporunity cost of capital as measured by the annual yield rate on 10-year U.S. Treasury notes).
As a pasture level, maintaining or increasing a balance of herbaceous and willow dominated vegetation along riparian areas where the species is absent will increase both the total density of bird species and will increase the diversity of small mammal communities. Haying results in a significant decrease in survival of montane voles, which are competitors for livestock forage.
Grazing systems can be defined so that ecological as well as economic sustainability are achieved. Although recently developed enterprise budgets show absence of economic sustainability due to low prices, long-term sustainability is achieved with the likelihood of higher prices in the long-run.
Because of the close association of western jumping mice to willow habitats we suspect that populations occurring in small isolated patches of willow would be at risk of local extinctions. We predict that occurrence and persistence of nesting bird species would increase with willow patch size; and, that habitat quality, as measured by reproductive success, would increase with willow density and volume for the three riparian shrub obligate nesters identified in this study. As a pasture-level scale, management practices that maintain, restore or enhance willow cover will increase both wildlife abundance and diversity. The contribution of herbaceous riparian pastures for local, watershed, and regional wildlife diversity needs further study. Reported in 1996.