How can we achieve biodiversity net gain?

'Biodiversity offsets' are a means of balancing losses due to development with equivalent gains elsewhere (no net loss), or increasingly are seen as a means of reversing biodiversity losses by offsetting more than is lost (net gain) (De Witt et al., 2019, Brownlie et al., 2013). Offsetting can take a variety of forms, and there is considerable debate about the point at which net gain is achieved (Bull and Brownlie, 2017), and whether it really reverses biodiversity losses. For businesses implementing net gain policies, their reputations are thus at stake. Given that 69 countries are known to have national biodiversity policies, with many more being subject to the offsetting requirements of funding banks (Maron et al., 2016), now is the time to establish how to overcome the significant ethical, social, technical and governance challenges associated with the implementation of 'net gain' policies. This study will therefore attempt to answer the questions:
What is the evidence for the efficacy of different net gain policies?
What expectations do different stakeholders, including civil society, have of net gain?
How can a business deliver net gain with least risk to their reputation?

This research benefits from a collaboration with Anglian Water, a large business with a net gain policy (to offset at least 110% of the biodiversity value lost). This provides an ideal case study within which stakeholder and civil society views can be obtained within the context of an existing business plan.

During the first year, the student will conduct a critical review of biodiversity offset policies, including metrics (e.g. value of native and non-native species) and solutions (e.g. habitat restoration or rewilding). The review will include evidence of biodiversity outcomes associated with the application of policies, and will aim to identify successes, failures and controversies. Particular attention will be given to the relative success, and acceptability, of net gain as a step in the mitigation hierarchy for a distinct project, as opposed to net gain delivered more strategically across a suite of projects. The review will encompass academic literature, official legislation and guidance, and media outlets including newspapers. The review provide the basis for conceptualising biodiversity offsets and 'net gain' practice after Bond et al. (2018), allowing for systematic evaluation of practice based on its separation into discernible dimensions.

The student will then use expert elicitation approaches to clarify the ethical, social, technical and governance challenges associated with each of the dimensions of net gain; these will be of global value. This understanding will form the basis of stakeholder engagement associated with Anglian Water's work plan to identify the most acceptable net gain strategies.

The supervisory team has extensive expertise in the evaluation of assessment approaches and in the evaluation of biodiversity. The student will join active research groups funded by NERC and ESRC, with students and Postdoctoral Researchers already using the methods required for successful completion of this research. The student will join the CEEC and the Tyndall Centre research seminars and will be presenting the work annually.