Modelling the ecosystem indicators of British Columbia using Earth observation data and terrain indices

Remotely sensed data plays a critical role by acquiring data on ecological conditions over broad spatial scales, providing important information for mapping landscape-scale ecosystem characteristics. The goal of our research is to employ a robust clustering algorithm to provide a transparent method of integrating remotely sensed datasets into homogeneous ecosystem units for conservation planning and monitoring ecosystem condition and change. Using a suite of ecosystem characteristics derived from digital elevation and remotely sensed data at 1 km spatial resolution, we classify the 94 million ha within the province of British Columbia (BC), Canada, into 16 terrestrial ecosystem regions (and a water category) using a two-step clustering approach. Initially, 10 metrics representing the physical environment (elevation and soil wetness potential), available energy (solar insolation and snow melt) and vegetation production (fraction of photosynthetically active radiation) were considered for ecosystem classification, which were reduced to six after analyzing variable inter-correlations. The results provide ecologically unique terrestrial regions: ten of which describe the Northern Boreal, Coastal Mountains and Southern Interior Mountains, and six the coastal lowlands, Georgia Depression, interior, Boreal Plains and Taiga Plains. Analyzing the spatial interaction between the cluster categories revealed that highly dispersed ecosystem types occur most often in the intermediate elevation zone, moderate dispersion at the highest elevations, and homogeneity in the lowland areas where elevation remains relatively constant. When overlaid with BC's standard biogeoclimatic ecosystem classification zones the newly developed regions represent similar ecosystem ranges in the coastal, Taiga and Boreal Plains. However, overall our delineation exhibits a greater level of diversity in the alpine environment, and greater homogeneity in the central and southern interior. The quantitative regionalization approach we present offers a broad-scale assessment of British Columbia's ecosystem diversity that can be used as a supplement to traditional in situ biodiversity assessments to provide detail in under-sampled regions of BC or areas experiencing landscape change.