| Popis: |
Natural resource projects are increasingly governed by requirements that biological impacts be balanced by gains from mitigation measures such as avoidance, minimization, reclamation and biodiversity offsets. Losses and gains are typically quantified in terms of the extent and "quality" or condition of the vegetation component within an ecosystem. Existing measurement frameworks share a number of weaknesses including a reliance on expert opinion, failure to incorporate natural variation, and inability to measure uncertainty or control for bias. We present the Vegetation Quality Assessment (VQA) framework, a new approach that measures quality as the overlap between the sampling distributions of ecological indicators at the project site and those of reference (benchmark) vegetation of the same kind. Stratified-random sampling reduces bias and enables inference for entire classes of vegetation at the level of the landscape. Indicators are commonly-measured attributes such as species richness, taxonomic composition, and percent cover by growth form. When combined, the individual indicator scores provide an index of overall vegetation quality, yielding an intuitive and easily-visualized measure of quality in terms of percent similarity to benchmark. We demonstrate the VQA framework at Teck Coal Limited (Teck) mine operations in the Elk Valley of southeastern BC. This information will provide a critical baseline for determining reclamation targets, designing offsets, and assessing progress towards Teck’s vision of aiming for net positive impact on biodiversity in areas where they operate. |
