Using airborne laser scanning to predict plant species richness and assess conservation threats in the oil sands region of Alberta's boreal forest

Timely and cost-effective monitoring of biodiversity across large areas is a major challenge, yet an important component of monitoring programs that inform policy and conservation strategies. Recent advances in Airborne Laser Scanning (ALS) provide new opportunities to simultaneously measure vegetation structure and terrain morphology at fine spatial scales. However, there is limited research on whether ALS metrics correlate with biodiversity measures. Here we used vascular plant data from 283 quarter-hectare (50 m x 50 m) plots from the boreal forest in northeast Alberta, Canada, to evaluate the potential for ALS-derived metrics to explain species richness patterns for vascular plants, as well as for four growth forms: herbaceous (including forbs and graminoids) and woody plants. We found canopy height from ALS was the most consistent and important (positive) factor related to local patterns in vascular plant species richness. Multivariate regression models of ALS-derived metrics explained 20-35% of the variation in species richness among vascular plants and the four subclasses. When considering the current distribution of in situ oil sands leases in the region, vascular plant richness inside of the leases is higher than outside. Areas delineated for woodland caribou conservation had lower average plant richness suggesting that it will do little to protect hotspots of vascular plant diversity in Alberta's boreal forest. Our results highlight the value of using fine-scale measures of ALS-derived vegetation structure to explain, predict, and potentially monitor local plant diversity for a high latitude forested ecosystem.