A metrics toolbox for measuring gains and losses of biodiversity

The accelerating biodiversity crisis has heightened the demand for robust and comparable tools to assess human impacts on nature and to guide effective biodiversity offset strategies. Achieving no net loss (NNL) or net positive impact (NPI) outcomes require metrics that can measure biodiversity changes across multiple ecological dimensions with scientific rigor and transparency. However, the proliferation of metrics in literature has created uncertainty about which are most appropriate for different contexts. To address this gap, we conducted an extensive literature review and critical analysis of biodiversity metrics developed worldwide for terrestrial and freshwater ecosystems. We identified an initial set of 40 metrics, compiled from published reviews on biodiversity metrics, reports from international organizations, and a systematic review conducted specifically for this study. These metrics were evaluated according to five main criteria: (i) scientific robustness and methodological clarity; (ii) suitability for biodiversity offsetting, focusing on the quantification of losses and gains; (iii) local-scale applicability consistent with project development contexts; (iv) availability of documentation describing the formulation, required parameters and practical application; and (v) representativeness across different dimensions of biodiversity, including attributes (composition, structure, function, and risk) and organization levels (species/population, communities/ecosystems, and landscape). Based on this assessment, using a multi-criteria approach, we selected a subset of 14 metrics that together capture multiple dimensions of biodiversity. This “Biodiversity Metrics Toolbox” enables users to select a combination of metrics tailored to the ecological and operational context of their assessments. Rather than choosing a single metric, we indicate a metric combination to ensure complementarity among biodiversity attributes and organization levels. Built on a structured and transparent process, the toolbox provides a practical and scientifically grounded opportunity to select metrics that will improve consistency, transparency, and ecological relevance of biodiversity offset schemes. The adoption of this toolbox can enhance evidence-based decision-making and strengthen the integration of biodiversity into corporate and policy strategies.