Biodiversity is the variability among living organisms including diversity within species, between species and of ecosystems. The reduced abundance of species from overexploitation, the fragmentation and degradation of habitats, pollution and other pressures driving biodiversity loss are constant, and even increasing as a result of development and increasing human populations. Conservation of biodiversity is necessary to ensure the continued survival of species, and ecosystems in general.
Given the importance of biodiversity, ‘No Net Loss’ (NNL) and ‘Net gain’ (NG) approaches for biodiversity use targeted and measureable environmental goals that allow governments and companies to take into account biodiversity when engaging in any type of project. These goals can only be achieved systematically through the application of the mitigation hierarchy, which is a decision-making framework involving a sequence of steps starting with the avoidance of impacts, followed by the minimization of inevitable impacts, on-site restoration and finally, where feasible and necessary, biodiversity offsets.
The correct application of the mitigation hierarchy can potentially limit the adverse impacts of projects on biodiversity, and may deliver additional biodiversity conservation. However, an improper application, especially if implemented with unresolved but fundamental knowledge gaps, and poor corporate, financial and regulatory policy may undermine established approaches to managing biodiversity risk. In certain cases, biodiversity offsets are not appropriate and should not be used.