Atwell Island Restoration Project Activities 2000 - 2010. Central Valley Project Improvement Act Land Retirement Demonstration Project.

摘要

The Central Valley Project Improvement Act (CVPIA) of 1992 authorized the Federal government to retire drainage-impaired lands by purchasing them from willing sellers (US Congress 1992). Retired lands have been restored with native plant communities to enhance wildlife resources. The Land Retirement Demonstration Project (LRDP), through the guidance and management of the Bureau of Land Management (BLM), and cooperation with Bureau of Reclamation (USBR) and Fish and Wildlife Service (FWS), evaluated re-vegetation strategies to determine effective methods for restoring retired agricultural lands within the Atwell Water District. Significant challenges to successful restoration included: Limited existing reference sites to guide restoration efforts; Altered hydrology; Effects of past agricultural activities (e.g., depleted native seed bank); Competitive pressure from non-native invasive species due to large amount of weed seed in seed bank; Low mean annual precipitation and extremely variable precipitation patterns; Constraining site conditions such as variable soil salinity, highly motile silty soils, fine sand inclusions and low topographic variability From 2000 to 2009, BLM planted 67 restoration sites for a total of 3100 acres. Currently 400 acres are being planted each year. Monitoring in the spring of 2010 showed the restoration sites with an average native plant cover of 35.1%; exceeding the 15% native cover performance criterion. Of the 65 sites for which both monitoring and planting data are available, ten sites (15.4%) met the total native cover criterion, but not the shrub cover criterion; five sites (7.7%) met the shrub cover criterion, but not the total native cover criterion; 46 sites (70.8%) met both performance criteria and only four sites (6.2%) met neither criterion.