A study of avian population response after habitat restoration using remote sensing and community science bird observation data

During the last two centuries, the contiguous United States has lost over half of its wetland habitats. Preserving the remaining wetland habitats and reversing this trend is of critical importance. Fernhill Wetlands in Forest Grove, Oregon is a natural wastewater treatment site that was transformed from unused wastewater ponds to a complex natural wetland habitat in 2014-15. To assess the effect of habitat restoration on biodiversity changes, previous studies involved comparisons of bird populations before and after habitat restoration. In this study, Landsat-8 and Sentinel-2 satellite imagery and PRISM climate data were analyzed using Google Earth Engine to calculate vegetation, water and climate indices for Fernhill Wetlands for the first time for the pre- and post-restoration periods. Then, the summary data was fed into Microsoft Excel and R and quantitative correlations were established between these indices and community science bird observation data from the Cornell University eBird database collected using a protocol developed by Portland Audubon. The study showed the effects of the habitat restoration, both positive and negative, on several species. Shorebirds, marsh birds and others that lived at the water’s edge showed much subtler and sometimes unexpected reactions to the habitat change. Additionally, supervised machine learning classification was used to obtain clarity on land, vegetation and water changes in the region of interest. This study could be of great interest to the Fernhill Wetlands managers to help guide further habitat modifications