The introduction in 1998 by the USDA of the continuous Conservation Reserve Enhancement Program  provided crop producers with the opportunity to reestablish some of the structure and function of former riparian areas . CREP is a voluntary land retirement program intended to help agricultural producers protect environmentally sensitive land, decrease soil erosion, restore wildlife habitat, and safeguard ground and surface water. Where this program applies to lands bordering waterways, the stream must provide current or historical habitat for threatened or endangered fish species and must not be located above a permanent barrier to fish passage. The program also applies to any area with a completed agricultural water quality management area plan, as well as reservation and tribal trust lands. Eligible practices include planting and maintaining riparian forest buffers, filter strips, wetland restoration, fencing, off-site watering and others. Contracts are generally 10 to 15 yr in duration. CREPs are designed by the USDA-Natural Resources Conservation Service  and funded through the USDA-Farm Service Agency .

Technically, CREP projects are not considered ecological restoration, because native and non-native species are used , but are known instead as rehabilitated production systems The first CREP project in northeastern Oregon was established in 1999. After initial post-implementation evaluation by NRCS of the sediment filtering effectiveness of the seeded grasses and establishment success of shrubs, CREP projects are visited periodically to assure compliance with contractual agreements. Few systematic plant community, soil sampling, or soil erosion studies are conducted in RPS to evaluate project success in terms of structure and function, although numerous studies on larger ecological issues have used data gathered from these sites . For example, much of the research has been conducted as habitat evaluations of Conservation Reserve Program , e.g., . Systematic studies of individual CREP projects, particularly in the Pacific Northwest, are lacking,mobile grow system although a statewide evaluation was recently conducted in the state of Washington . The objective of this research was to conduct a multi-year vegetation observational study to describe plant community development in the Gerking Flat CREP. Target-nonnative species comprised significantly more of the vegetation composition than all other classes , during 2000 and 2001, but non target species increased substantially in 2007 and 2008 . This increase was predominately by Eurasian annuals typically found in disturbed semiarid and arid landscapes .

These species are exceptionally well adapted for invading disturbed areas where soil conditions and lack of seed sources reduce competition from native plants. Once established, these communities of invasive species tend to persist unless there is substantial management intervention . Management options in CREP are limited to light soil surface disturbance , mowing, burning, and limited herbicide use. The producer managing Gerking Flat mowed the site after the first year to control seed production from nonnative annuals. An attempt at disking part of the site was judged counterproductive, and the producer opted for burning some portion of the site each spring thereafter. Burning eliminated accumulating dead material, but apparently had no effect on slowing the increase in non target-nonnative species. In Mississippi, Greenfield et al.  were able to improve bobwhite habitat by disking or burning a 10 yr old CRP field, but the improvement was short-lived and plant community composition was unaffected. Disking, mowing, and burning are effective if applied at the appropriate plant phenological stage, i.e. before seed set.

But such timing is likely to interfere with critical wildlife use, such as nesting. Grazing has been proposed as a means of upland weed suppression , and can contribute to nutrient cycling advantageous to target species . However, grazing is restricted in most CREP contracts, and many of the CREP projects on the Columbia Plateau are managed by single commodity producers without the animal or managerial resources needed for grazing. The project on Gerking Flat met the basic objective of Table 4. Trees and shrubs found in zones 1 and 2  in a September, 2008, census. Species Number Willows  279 Pacific willow  Scouler willow  Coyote willow  Dusky willow  Booth’s willow  Woods rose  15 Snowberry  15 Red osier dogwood  5 Black cottonwood  4 providing ground cover, >90% in 2008, to conserve soil. A continuous canopy of willows now covers the channel in the lower one-third of the project. Increased root and stem biomass slows erosion, both within and outside the stream channels, and traps soil eroded from surrounding fields and borrow ditches .