Improving the selection of salt marsh mapping methods for shoreline change analysis

Introduction Scientists and practitioners routinely track the seaward edge of marsh vegetation to assess marsh vulnerability and track restoration success. While there are clear logistical differences among marsh shoreline data collection methods, we lack guidance on which methods provide suitable estimates of marsh shoreline change under various site‐specific conditions. Objectives We estimated various components of marsh shoreline data errors and investigated the relationships between source data errors, data collection designs, and the accuracy of marsh shoreline change estimates to guide more effective marsh monitoring. Results Subjective user errors contribute greatly to the total uncertainty of high‐precision mapping approaches. However, we demonstrated with simulations that the choice of data collection approach rarely determines the precision of marsh shoreline change rates; rather, the precision of marsh change rates depends strongly on the total duration of the data time series and the number of geographical information system post‐processing cross‐shore transects used in analyses. Conclusion High‐resolution (≤1 m ground square distance) public aerial imagery will often be the preferred method of tracking marsh shorelines by enabling dependable estimates of marsh shoreline movement rates at low cost.