Assessing and Predicting Distribution Shifts of Canopy-Forming Marine Macrophytes in the Northwest Atlantic with Remote Sensing and Species Distribution Models

Abstract

This thesis quantified the distribution of several ecologically and commercially important canopy-forming marine macrophytes in the Northwest Atlantic using species distribution models (SDM) and satellite remote sensing. Firstly, correlative SDMs and physiological thresholds were used to determine current and projected distributions by 2100 under different climate change scenarios for six seaweed species common to the Northwest Atlantic. Species ranges will shift north with continued warming where fucoids and kelps were projected to have a net loss of latitudinal range, while other species gain latitudinal range. Secondly, SPOT 6/7 imagery was classified with two different classification techniques and modest ground-truthing effort to determine the distribution of eelgrass (Zostera marina) in three bays in Nova Scotia. Only one bay successfully classified eelgrass distribution, highlighting the need for excellent satellite image quality, and clear water. The two approaches can inform conservation and management of canopy-forming marine macrophytes on different spatial and temporal scales.