Wetland Assessment Methods: Biological Assessment

Abstract

The central purpose of biological wetland assessment is the quantitative and qualitative description and enumeration of the species, communities, and habitats present. To achieve this, often a basic inventory is needed of the wetland attributes (physical properties, species composition, and structure) and of soil, water chemistry, and hydrological characteristics. Specific aims may be: estimating the nature conservation value at a regional, national, or international scale; determining the need for protective measures; determining the contribution of the wetland to ecosystem services and the scope for exploitation; informing management and restoration strategies; or a comparison to reference conditions. Biological assessment can make use of a wide range of techniques including broad habitat mapping (e.g., terrestrial survey, aerial photography, satellite imagery), detailed community mapping, quadrat and/or transect surveys and phytosociological analysis, population counts of target species (e.g., as indicators of biological integrity or for conservation goals), fixed-point photography, sub-aqua diving surveys, remotely controlled cameras, structured grapnel surveys, and integrated survey systems. Nature conservation agencies have developed rapid assessment methods, which express the biological integrity of the wetland in metrics (indicators) that may support management decisions but can also be used to communicate information about the status of wetlands to the general public. A main future challenge is to develop consistency in assessment approaches and to ensure the availability of basic information, which will improve the comparability of assessment results and their application in policy making.