Treesearch

Interrelationships between flooding and climax woody vegetation in riparian ecosystems of the desert Southwest are discussed. The lack of succession in woody desert upland and desert riparian plant communities results from opposite stresses, the former from aridity, the latter from flooding. Today's "wet riparian big five" are northern tree species of hydroriparian and mesoriparian (wet riparian) ecosystems; remnants of the Arcto-Tertiary Geoflora. The "dry riparian big five" are tree or subtree constituents of xeroriparian ecosystems occurring as Madro-Tertiary remnants at the northern...

The Clark Canyon riparian demonstration area was established in 1984 within the East Walker River subbasin of Mono County, California. Destabilization of the meadow sections of the stream and the upper stream reaches contributed to an increase of suspended sediments, turbidity, and stream channel widening in the lower stream reaches where a viable population of rainbow trout is found. Several different treatments have been implemented to (1) restore meadow riparian areas to high levels of productivity, (2) stabilize active erosion and gully development (headcutting), (3) improve aquatic...

Typical cattle use on two range units of hardwood rangeland (annual rangeland) at the San Joaquin Experimental Range, Madera County, California, left 50 percent of riparian area with less than optimum amounts of residual dry matter (RDM) for promoting seedling growth and soil protection. By relocating supplemental feeding sites away from water sources and into areas of high amounts of RDM, the impact of cattle on riparian areas was greatly reduced. In Range Unit 1, where supplemental feeding sites were relocated, only 1 percent of the riparian area was left with low amounts of RDM. In...

The basic tenet of annual range management in California is that perennial grasses are unable to effectively compete with the naturalized alien annual species. Evidence from the field in northern California is not consistent with this thinking. An alternative view that perennial grasses are restricted in importance from overgrazing and excessive rest is presented. Implications for range productivity and stability in riparian zones and uplands are outlined from a rancher's perspective.

Given time and proper management conditions, degraded rangeland streams can often produce by natural means the same results that we expect from streambank stabilization and fisheries enhancement structures. Advantages of using vegetation and natural recovery processes include: 1) costs are likely to be lower and 2) a wide range of benefits can accrue to a recovered stream. Structures tend to lock a stream channel in place whereas vegetation allows incremental changes in channel characteristics as flow and sediment loads vary. Healthy riparian vegetation can replace itself in perpetuity,...

Increasing demands for Pacific yew bark, a source of an anticancer agent, have generated interest in defining the yew resource and in exploring strategies to conserve this species. The distribution, riparian requirements and ecosystem functions of yew populations in coastal and inland forests of northern California are outlined and alternative approaches to conserving this resource are identified. Efforts to obtain additional information on genetic diversity of yew populations and to insure careful management of the species are essential for the protection of this resource.

The Bakersfield District of the Bureau of Land Management conducted an inventory of rangeland riparian systems using a new method developed by a Bureau-wide task force to inventory, monitor and classify riparian areas. Data on vegetation composition were collected for 65 miles of streams and entered into a hierarchical vegetation classification system. Ratings of hydrologic function, vegetative structure, and vegetative use by grazing animals were employed to measure impacts by land uses and potential for recovery with proper management. The data for each of 116 stream reaches was entered...

Grazed Sierra Nevada stringer meadow systems were sampled on Blodgett Forest Research Station in northern California between 1977 and 1987 to determine cattle use, and to examine changes in production and species composition over time. Utilization of meadow species averaged 61 percent over the 10 years, but use increased to more than 80 percent utilization after 1985. Production averaged 2733 kg/ha but has significantly declined in recent years. Relative species composition has not changed, nor has total vegetative cover between 1979 and 1986. Range condition models based on changes in...

Historic use of many stream riparian areas and associated watersheds has impaired the capacity of riparian vegetation and floodplains to reduce stream energy and trap sediments. As low-gradient streams with erodible banks increase in width and change their pattern, they approach a threshold of instability. Once a stream exceeds a threshold, it must proceed through a process of geomorphic gully evolution that includes degradation, widening, and aggradation phases. Opportunities for enhancing and maintaining favorable conditions of stream morphology and associated riparian values vary...

The management and recovery of degraded riparian systems is a major conservation issue. Presently there are many grazing management strategies being applied based on the name of the technique with little incorporation of basic stream processes. Managers must understand the exact workings of grazing strategies and the individual processes of each stream before prescribing solutions to degraded riparian systems.