California Rapid Assessment Method for Wetlands - State Water ...

California Rapid Assessment Method for Wetlands v. 5.0.2 – Chapter 1
projects (www.wetlandtracker.org) that can be used to assess the cumulative
effect of projects on the extent and overall ambient condition of wetlands. The
State Wetland Inventory, Riparian Inventory, and the Wetland Trackers will aid
wetland conservation planning by showing each wetland in the context of all
others. They will also serve as sample frames for objective, probabilistic surveys
of the ambient condition of wetlands and for assessing the effects of projects
and other management actions on the ambient wetland condition at various
scales ranging from local watersheds to the State as a whole. Through the
statewide Level 1 inventory and the Wetland Tracker, the State can overcome the
obstacle of not having an adequate inventory of wetlands and related projects to
track changes in their extent and condition.
Level 2. Level 2 methods assess the existing condition of a wetland relative to its
broadest suite of suitable functions, services, and beneficial uses, such as flood
control, groundwater recharge, pollution control, and wildlife support, based on
the consensus of best professional judgment. In this regard, a level 2 assessment
represents the overall functional capacity of a wetland. To be valid, rapid
assessments must be strongly correlated to Level 3 measures of actual functions
or services. Once validated, Level 2 assessments can be used where Level 3 data
are lacking or too expensive to collect. Level 2 assessments can thus lessen the
amount and kinds of data needed to monitor wetlands across large areas over
long periods. CRAM is the most completely developed and tested Level 2
method for California at this time.
Level 3. Level 3 provides quantitative data about selected functions, services, or
beneficial uses of wetlands. Such data are needed to develop indicators, to
develop standard techniques of data collection and analysis, to explore
mechanisms that account for observed conditions, to validate Level 1 and 2
methods, and to assess conditions when the results of Level 1 and Level 2 efforts
are too general to meet the needs of wetland planners, managers, or regulators.
CRAM is based on a growing body of scientific literature and practical experience in the rapid
assessment of environmental conditions. Several authors have reviewed methods of wetland
assessment (Margules and Usher 1981, Westman 1985, Lonard and Clairain 1986, Jain et al. 1993,
Stein and Ambrose 1998, Bartoldus 1999, Carletti et al. 2004, Fennessy et al. 2004). Most
methods differ more in the details of data collection than in overall approach. In general, the
most useful approaches focus on the visible, physical and/or biological structure of wetlands,
and they rank or categorize wetlands along one or more stressor gradients (Stevenson and Hauer
2002). The indicators of condition are derived from intensive Level 3 studies that show
relationships between the indicators, high-priority functions or ecological services of wetlands,
and anthropogenic stress, such that the indicators can be used to assess the effects of
management actions on wetland condition.
Existing methods have been used to assess wetlands at a variety of spatial scales, from habitat
patches within local projects, to watersheds and regions of various sizes. Methods that are
designed to assess large areas, such as the Synoptic Approach (Leibowitz et al. 1992), typically
produce coarser and more general results than site-specific methods, such as the
Hydrogeomorphic Method (HGM; Smith et al. 1995, Smith 2000) or the Index of Biotic
Integrity (IBI; Karr 1981). Each scale of wetland assessment provides different information.
4