A comparison of survey method efficiency for estimating densities of Zebra Mussels (Dreissena polymorpha)

Abstract

Abundance surveys are a common and practical technique to estimate plant or animal densities. Methods used to conduct these surveys often require jointly estimating uncertainty in both counts and detection probability. The estimation of detection probability requires additional measurements that take time, potentially reducing the efficiency of the survey for high-density populations. We conducted quadrat, removal, and distance surveys of zebra mussels (Dreissena polymorpha) in three central Minnesota lakes and used an efficiency measure to help compare survey designs. Survey efficiency depended on both the survey design and the population density. The efficiency of survey designs that required estimates of detection probabilities (relative to designs that did not) decreased with density, leading to a change in the most efficient survey design at high densities. These results demonstrate that the best survey design may be context-specific, requiring some prior knowledge of the underlying population density and the cost/time needed to collect additional information for estimating detection probabilities.