Using Unoccupied Aerial Vehicles (UAVs) to map and monitor changes in emergent kelp canopy after an ecological regime shift

Kelp forests are complex underwater habitats that form the foundation of many nearshore marine environments and provide valuable services for coastal communities. Despite their ecological and economic importance, increasingly severe stressors have resulted in declines in kelp abundance in many regions over the past few decades, including the North Coast of California, USA. Given the significant and sustained loss of kelp in this region, management intervention is likely a necessary tool to reset the ecosystem and geospatial data on kelp dynamics are needed to strategically implement restoration projects. Because canopy-forming kelp forests are distinguishable in aerial imagery, remote sensing is an important tool for documenting changes in canopy area and abundance to meet these data needs. We used small unoccupied aerial vehicles (UAVs) to survey emergent kelp canopy in priority sites along the North Coast in 2019 and 2020 to fill a key data gap for kelp restoration practitioners worki..., Priority survey site selection:
We selected sites for UAV emergent kelp canopy surveys using a prioritization framework for kelp recovery efforts based on data from OAV surveys, subtidal surveys, areas of cultural significance, areas of economic significance, accessibility, and proximity to marine protected areas (MPAs) (1). A total of 37 sites were identified in Mendocino and Sonoma Counties (i.e., the “North Coast”), hereafter referred to as ‘priority sites’. Ten of the sites are in actively managed state MPAs and 27 are in the Greater Farallones National Marine Sanctuary (NMS). Thirty-six of the 37 sites were surveyed with UAVs between 2019 and 2020, with 21 sites surveyed in both 2019 and 2020. The average priority site area was 1 km2 (range 0.2-1.7 km2).       
UAV flights, timing and environmental sources of variation and error
Due to the 90 km stretch of coastline within which the noncontiguous priority sites are located, numerous pilots participated in data collection and we dev..., README 
Data repository metadata for Using Unoccupied Aerial Vehicles (UAVs) to map and monitor changes in emergent kelp canopy after an ecological regime shift 
This repository contains the following data and files: 

The 2019 and 2020 orthomosaics for all surveyed priority sites. These files have been georeferenced and masked to remove the coast with individuals’ homes for privacy purposes. The relevant nomenclature for these files is as follows: SITENAME_YEAR.tif (n = 57) 

The 2019 and 2020 classification layers built off of the orthomosaics for all surveyed priority sites. These files are available as shapefiles that can be opened in QGIS. The relevant nomenclature for these sites is as follows: SITENAME_finalYEAR.shp/.shp.xml/shx/prj/dbf/sbx/sbn/cpg 

The R code and relevant CSV files for the spatial statistics and figures. The relevant nomenclature for these files is as follows: 

Saccomanno_etal_UAVkelp_stats.Rmd (this script is well-commented) 

kelp_landsat_area_FINAL.c...