Open Collections

Deenik, Kristina

University of British Columbia

Despite wetlands being critical components of healthy functioning landscapes and providing valuable ecosystem services, they are being lost at alarming rates due to human influence. Their dynamic nature and varying hydrology and vegetation make identification and classification challenging. Recent advancements in satellite remote sensing and light detection and ranging (LiDAR) provide opportunities to predict and map wetland classes at regional scales. In the semi-arid region of the Okanagan Basin, wetlands are rare biodiversity hotspots that provide critical habitat for many species at risk. Building on existing wetland inventories that have limited coverage, a random forest probabilistic model was developed to predict, classify and map wetlands in the Okanagan at a 10 m spatial scale. In total, 22 covariates representing multispectral and synthetic aperture radar metrics derived from Sentinel-2 and Sentinel-1; topography and vegetation derived from LiDAR; and ancillary geospatial data were used to classify wetlands. The model was trained using an existing wetland database and provincial datasets to predict the probability of each pixel belonging to the following six-classes: fen, marsh, shallow-water, swamp, upland, and open-water. Model performance was evaluated using a confusion matrix and had an overall accuracy of 84.8%. The model predicted that 313.9 km² (3.6%) of the 8,635 km² study area represented areas where wetland probability was ≥ 50%. Marshes were the most commonly occurring wetland (159.0 km²) followed by swamp (150.3 km²), shallow-water (3.7 km²), and fen (0.9 km²). The most important predictor variables for wetlands were slope, distance from streams, probability of depression, number of days above five degrees Celsius, topographic position index, seasonal change in the normalized difference vegetation index, standard deviation of vegetation height, and the red band from Sentinel-2. The wetland model developed here identified and classified new wetlands and provided a comprehensive inventory of wetlands in the Okanagan using a replicable approach with publicly available data. The resulting wetland inventory can help inform regional wetland conservation and management and will serve as an important baseline for land use planning and climate change mitigation.

Text

2022-06-06

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/81703

Earth and Environmental Sciences

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/