Biology subjects

Duffus, N. E.

Publications and source records attributed to Duffus, N. E..

2 recordsLinked to original sources

bioRxiv2025

Early outcomes of England's new biodiversity offset market

Nature markets are increasingly being operationalised as a tool for filling the biodiversity finance gap to achieve global biodiversity targets. One example is the off-site market underpinning the requirement for construction projects to achieve Biodiversity Net Gain (BNG) in England. Here, we quantify the outcomes of the market after 16 months of operation, collecting data from Englands offset register and planning portals. We evaluate the habitat diversity being delivered and how it aligns with environmental targets and existing efforts to achieve goals such as 30x30. Current habitat delivery is skewed toward a few habitat types, with other neutral grassland constituting 44% of planned habitat. There is very limited delivery of new wetland and woodland habitats, with most commitments being to improve the condition of existing habitats. Perhaps more importantly, only around 2% of the registered offset area has been sold. Our results demonstrate how the design of the statutory biodiversity metric used to measure BNG is shaping the market through incentives within the metric. The results also give insight into the demand for off-site BNG units in England and the role which government regulation plays in setting demand and therefore scaling the market.

ecology↗

bioRxiv2024

Metrics based on habitat area and condition are poor proxies for invertebrate biodiversity

There is increasing demand for standardised, easy-to-use metrics to assess progress towards achieving biodiversity targets and the effectiveness of ecological compensation schemes. Biodiversity metrics based on combining habitat area and habitat condition scores are proliferating rapidly, but there is limited evidence on how they relate to ecological outcomes. Here, we test the relationship between the statutory biodiversity metric used for Biodiversity Net Gain (BNG) in England -- and as the basis for new biodiversity credit systems around the world -- and invertebrate richness, abundance, and community composition. We find that the combined area-condition BNG metric does not capture the value of arable farmland and grassland sites for invertebrate biodiversity: invertebrate communities were highly variable across sites that had the same type and condition under the BNG metric. We found no reliable relationship between scores under the metric and either invertebrate abundance or species richness, with the risk of the metric undervaluing sites of high invertebrate value. Our results highlight the need to incorporate factors beyond habitat type and condition into site evaluations, and to complement metric use with species-based surveys.

ecology↗