measured by belt transects. The standard deviation of the mean cover value will be less than 1/4 of the mean.

Performance Standard #3: The forest vegetation will cover at least 3 acres after 20 years with a canopy cover of at least 40% of native species in these 3 acres.

Objective d. The area of open water will provide habitat for at least two species of amphibians within five years.

Performance Standard: The use of the wetland by two species [of] amphibians will be documented by live trapping, and/or observation of egg masses during the breeding season.

  • Los Angeles District's Proposed Guidelines for Riparian Habitat. Los Angeles District's document Special Public Notice; Proposed Riparian Habitat Mitigation and Monitoring Guidelines, distributed for comment between 15 August and 15 September 1997, includes information on topics such as sequencing, site selection, identification of riparian habitat, and compliance assurance. In part “e” of a section on mitigation design and planning, performance standards (called “success criteria” in this document) are briefly discussed, as transcribed verbatim below:

  1. Propose realistic success criteria based on the purpose of the mitigation, design of the site, and the variables and functions found in the HGM. Develop initial HGM scores for the mitigation site after the proposed grading based solely on physical characteristics. Estimate performance curves and time to establish partial and full success of the site based on HGM score. The Corps will be intimately involved with this aspect of the plan.

HGM refers to the hydrogeomorphic approach to wetland assessment. The decision to use HGM in performance standards resulted from studies suggesting that compensatory wetlands could meet performance standards required by earlier guidelines even though they “were unsuccessful at restoration or creation of fully functional, riparian habitat. ” The philosophy behind the HGM approach is described in Smith et al. (1995).

  • Chicago District Mitigation Guidelines. The Chicago District Mitigation Guidelines and Requirements, dated 30 April 1998, describes issues such as site selection, mitigation ratios, long-term management requirements, and enforcement. A section on performance standards for compensatory mitigation focuses on vegetation but also suggests that applicants should propose performance standards for other functions, such as improvement of water quality and provision of wildlife habitat. Use of existing measures, such as the Index of Biological Integrity, is encouraged. Vegetation performance standards include the following:

  1. The mean coefficient of conservatism must be greater than or equal to 3.5. Coefficient of conservatism values for plant species found in the Chicago District are designated in Swink and Wilhelm (1994). These values indicate the degree to which a plant species is representative of an undisturbed native community; a value of 0 is assigned to



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