Evaluating the development and use of a rapid wetland assessment tool (ABWRET-A) in policy implementation in Alberta, Canada

Abstract

The Alberta wetland policy aims to protect the most valuable wetlands and maintain wetland functions despite unavoidable wetland loss. The Alberta Wetland Rapid Evaluation Tool-Actual (ABWRET-A) was developed to quantify wetland functions in support of policy implementation. We evaluated > 200 wetlands used to calibrate ABWRET-A and > 2000 wetlands targeted for loss under the policy to understand potential biases in the system. We compared the functional value of wetlands targeted for loss to the pool of wetlands used to calibrate ABWRET-A and to the general population of wetlands in Alberta’s settled region. We evaluated ABWRET-A calibration and scoring and found that wetlands used in tool calibration were over 8 times larger (median size = 2.07 ha, n = 207 vs. 0.245 ha, n = 1,782,001), more permanently ponded and distributed approximately 2.5 times closer to roads (median distance = 162.1 m, n = 207 vs. 399.7 m, n = 1,782,001) than the general wetland population. Calibration wetlands also underrepresented bogs and overrepresented fens. This influenced scores, as larger wetlands and wetlands classified as fens receive higher ABWRET-A scores, whereas wetlands close to roads received lower scores. We conclude that scores may underestimate functional value. Wetlands targeted for permitted loss were larger (median size = 0.290 ha, n = 2087) and more road-proximate (median distance = 237.0 m, n = 2087) than the average wetland from the inventory. Crucially, permitted wetland loss is significantly clustered around major cities (using Getis-Ord Gi statistic; p < 0.01), implying permanent loss of wetland functions in peri-urban areas.