SAMPLE DESIGN, EXECUTION, AND ANALYSIS FOR WETLAND ASSESSMENT

Probability-based sample surveys are increasingly being used to assess natural resource condition, yet many of the techniques commonly used in survey sampling are not well known to environmental scientists. Here we discuss several techniques from survey sample methodology that can substantially increase the efficiency of a sample (lower the variance for the same sample size), make the survey more cost-effective, or adjust the analysis to accommodate difficulties in implementation, such as lack of access to all sample sites. The techniques are illustrated with two surveys that were designed to assess wetland condition: one in the Juniata watershed in Pennsylvania, USA, and one in the Nanticoke watershed in Maryland and Delaware, USA.