Forum Article

Biodiversity offsetting and compensation are high-stakes endeavours. Much rests on the process by which an offset or compensation proposal is designed and the tools used to evaluate the proposal, as this has a strong and direct influence on the potential outcomes for biodiversity. Models by their nature are imperfect, but their ecological robustness, and therefore usefulness, can be improved by adhering to well-established principles of good model development.

Two biodiversity models are commonly used by Aotearoa’s terrestrial ecologists to guide habitat restoration and enhancement activities required to offset or compensate for development project impacts. The Biodiversity Offset Accounting Model can be used to assess the adequacy of an offset proposal. A more recent Biodiversity Compensation Model can be used to complement ecologists’ professional judgement on the compensation required. The latter is increasingly used when relevant biodiversity offsetting principles cannot be met with confidence.

Loss of remnant vegetation and landscape complexity through agricultural intensification reduces the abundance and diversity of beneficial insects such as pollinators and natural enemies of pests (predators/parasitoids). The Canterbury Plains (CP), New Zealand, is a highly intensified agricultural region that has lost almost all remnant native woody vegetation.

The official Predator Free New Zealand programme launched in 2016 is based on a hugely inspiring, aspirational ambition to eradicate all invasive rodents (rats Rattus norvegicus and R. rattus but not mice Mus musculus), mustelids (stoat Mustela erminea, ferret M. furo, and weasel M. nivalis) and possums (Trichosurus vulpecula) from throughout New Zealand by 2050. Others had already been doing predator control for years, but this campaign has caught the public imagination as no previous operation ever has.

Natural grasslands are among the most threatened biomes on Earth. They are under pressure from land cover change including afforestation, farming intensification, invasive species, altered fire regimes, and soil amendments, all of which impact native biodiversity and ecosystem functioning. In Aotearoa New Zealand, tussock-dominated native grasslands expanded due to increased fire activity during waves of human settlement. These areas have subsequently been maintained as modified grasslands by agricultural pastoral land management practices and effects of introduced feral mammals.

Biodiversity offsetting and compensation proposals are routinely employed through the resource consenting process to address development-induced indigenous biodiversity losses in Aotearoa/New Zealand. Determining the quantum of demonstrable biodiversity gain required to adequately account for development induced losses is a fundamental component of designing a biodiversity offset. However, trading biodiversity is complex and must account for substantial uncertainties.

Forest restoration is an activity that can be readily undertaken to address both the climate and biodiversity crises. In Aotearoa New Zealand, aspirations for large-scale native forest restoration are growing across governmental and private sectors and a considerable focus to date has been on forest establishment by actively planting native trees.

Indigenous Knowledge (IK) provides effective solutions to environmental threats and pressures. Using approaches that fully include Indigenous concepts, ideas, worldviews, knowledge, process, and practice helps the recovery of threatened species and endangered ecosystems, but it is essential that such work engages with Indigenous Peoples and that engagement is respectful, reciprocal, and meaningful.