Hydrogeomorphic Approach to Assessing Wetland Functions: Guidelines for Developing Regional Guidebooks. Chapter 4. Developing Assessment Models.

摘要

In the Hydrogeomorphic (HGM) Approach, assessment models are a simple representation of the functions performed by wetland ecosystems. The purpose of an assessment model is to estimate the magnitude at which a wetland performs a function relative to similar wetlands in the region. Model variables represent attributes and processes of the wetland ecosystem and the surrounding landscape that influence the ability of the wetland to perform a function. They are quantitatively measured or qualitatively estimated in the field using a standard sampling protocol. This chapter introduced the initial steps in the development of assessment models under the HGM Approach. The initial steps considered here include: (1) selection and definition of wetland functions, (2) identification of model variables and field measures, and (3) construction of aggregation equations for deriving functional indices. Other chapters in this volume consider other steps related to the development of assessment models including identification of reference wetlands (chapter 3), collection and management of reference data (chapter 5), analysis of reference data and calibration of assessment models (Chapter 6), and verification and validation of assessment models (Chapter 7).