Mar 5, 2016

How do you know if the ecological conditions of your wetland project are aligned with expected rates of improvement? 

Wetland Habitat Development Curves (HDCs) are used to evaluate the rate of habitat development for restoration and mitigation projects, compared to other projects of the same age and wetland type, based on the California Rapid Assessment Method (CRAM). HDCs have been developed for several wetlands types using existing CRAM assessments from wetlands across California.  Each curve represents the expected average rate of wetland development bounded by its 95% Confidence Interval (CI). Projects that are well-designed for their location and setting, and well-managed tend to be on or above the curve.  In general, as projects age, their habitats should mature, gaining similarity to reference sites, such that the project’s CRAM condition scores increase. The expected reference condition range is included on the HDC plots. The underlying CRAM Attribute and Metric Scores, at low performing mitigation/restortation project sites, can be explored to understand and potentially correct habitat developmental problems.

Visit the CRAM website for more information about CRAM.

An HDC can be used to help address the following questions:

  • At what time in the future will the area of assessed habitat achieve the reference condition or other milestones in habitat development? 

The HDC can answer this question if the CRAM score for the assessed area is within the confidence interval of the HDC. The answer is the time in years along the HDC between the current age of the assessed area and the future date corresponding to the intersection of the HDC and the reference condition or other milestone. 

  • Is the area of assessed habitat likely to develop faster, slower, or at the same pace as most other areas of the same habitat type?  

The habitat area is likely to develop faster, slower, or at the same pace if the CRAM score for the area is above, below, or within the confidence interval of the HDC, respectively. 

  • What can be done to improve the condition of the habitat area or to increase its rate of development?

HDCs by themselves cannot answer this question, but possible answers can be inferred by analysis that involves HDCs.

The HDC is available as a separate tab in the Project Information Page and is only visible when a project has a recorded construction end date (groundwork end date), and there are existing CRAM assessments for the project boundaries in the statewide CRAM database. 

Cristina Grosso
Programs and Focus Areas: 
Resilient Landscapes Program
Wetland Monitoring & Assessment