A spatiotemporal modelling approach to assessing cumulative land-use and climate change impacts on plant habitat condition in British Columbia

Plant species across British Columbia are being reshaped by the combined influences of climate change and land-use pressures. However, the extent to which these forces jointly influence fine-scale habitat conditions for particular taxa remains poorly understood. This thesis investigates the spatiotemporal interactions between climate change and land-use pressures for three plant species with relatively high cultural salience among some Indigenous communities in British Columbia. I used an integrated modelling framework, combining Maximum Entropy (MaxEnt) habitat suitability modelling with the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) habitat quality model. Habitat suitability was assessed temporally across two 30-year climate normals (1961–1990 and 1991–2020) using bioclimatic variables. In contrast, habitat quality was evaluated using species-specific sensitivity scores and cumulative anthropogenic pressures, with a focused case study of Fritillaria camschatcensis (wild rice root) in the Skeena River watershed. Results indicate that while predicted habitat suitability remained relatively favourable across British Columbia, the magnitude of change varied among the species assessed. Amelanchier alnifolia (saskatoon berry) increased in southern and central regions, Fritillaria camschatcensis (wild rice root) exhibited a modest northeast shift, and Vaccinium ovalifolium (oval-leaved blueberry) remained relatively stable in interior regions. The Skeena River watershed case study suggests that cumulative land-use pressures appear to limit the distribution of high suitable areas resulting in fragmented areas of high-quality habitat for Fritillaria camschatcensis within the study area. Importantly, these projections represent predicted spatiotemporal changes rather than actual change in species’ habitat conditions. Generally, this research highlights the necessity of integrating climate-driven suitability with cumulative anthropogenic pressures to better evaluate habitat condition of plant species in British Columbia.