Marine biodiversity offsets: Pragmatic approaches toward better conservation outcomes

A novel use of Stereo Baited Remote Underwater Video and Drop-Down Video for biodiversity and marine landscape mapping and prediction

To make the best-informed decisions on managing marine resources whilst also restoring biodiversity, the creation and analysis of benthic maps is highly valuable. This study focuses on benthic mapping to study patch - and landscape - level processes affecting epifauna and demersal species using Stereo Baited Remote Underwater Video (SBRUV) and Drop-Down Video (DDV) surveys. Surveys were conducted within the South Arran Marine Protected Area between 2013-2019 and yielded 554 SBRUV data points and 333 DDV data points. These data were processed to determine proportional coverage of substrata and kriged to produce benthic maps. From this it was possible to estimate the patch scale of substrata to gain a more detailed understanding of the marine landscape, composition structure, and epibenthic biodiversity. The resulting validated maps allowed the number of substrata patches and patch characteristics such as area and perimeter-to-area ratio to be calculated to support management and understanding of the value of this seascapes for benthic and demersal biodiversity. Our approach allowed for the identification of areas of higher biodiversity that may assist during mapping of Marine Protected Areas' (MPA) vulnerable features. These methods should provide better information about site condition and ecosystem service provision than existing methods.

Forecasting land-cover change effects on waterbirds in Xiamen Bay, China: Determining prospective species winners and losers

Waterbirds are vital to coastal wetland ecosystem, and play significant roles in global biodiversity maintenance, cultural and educational services, etc. Waterbirds are particularly vulnerable to environmental change, particularly land-cover change, which has severely degraded their ecological niches. Accordingly, this study developed a waterbird-habitat preference index to quantify waterbird dependence on Xiamen Bay's habitats and a subsidiary waterbird-specific habitat suitability index to predict potential effects of future land-cover change on waterbirds. Results showed that the waterbird-habitat preference index ranged from -9.8 to 18.71, indicating that habitat selection varied greatly among different waterbird species, where tidal flats were the most popular waterbird habitat. Additionally, most waterbird species showed a preference for more than one habitat, which could be indicative of their diverse ecological demands. Effects on waterbirds varied greatly among the three different land-cover scenarios, where positive benefits were predicted under the ecological protection scenario (EPS), while the greatest negative effects were observed under the development and utilization scenario (DUS). Effects also varied among different waterbirds species. Those under the current trend scenario (CTS) (e.g., Tringa brevipes and Calidris ruficollis) could be at risk for species abundance loss (i.e., losers) while others (i.e., Egretta garzetta and Saundersilarus saundersi) could benefit from increased abundance (i.e., winners). Generally, migratory and traveling birds were much more vulnerable than resident birds. Spatially, conservation priority should be given to the Dadeng Waters and those waters adjacent to it (i.e., Tongan Bay and Anhai Bay) because of the highest waterbird loss risk in these areas under a conflict between an urgent need to protect waterbird biodiversity and intense present and future land-cover development. The intent of this study is to provide a useful tool to explore land-cover effects on waterbirds in similar coastal regions, which can provide important information on protection and restoration strategies.

Bycatch levies could reconcile trade-offs between blue growth and biodiversity conservation

Economic activities in the ocean (that is, the 'blue economy') provide value to society, yet also jeopardize marine ecosystems. For example, fisheries are an essential source of income and food security for billions of people, yet bycatch poses a major threat to marine biodiversity, creating trade-offs between economic growth and biodiversity conservation. This Perspective explores bycatch levies as a market-based instrument for reconciling these trade-offs. We outline the theory and practice of bycatch levies to demonstrate how they could incentivize bycatch prevention and raise revenue for compensatory conservation, provided they are well designed, as part of a policy mix for sustainable and equitable ocean governance. We then explore ways forward for mainstreaming bycatch levies into the blue economy. While compensatory bycatch mitigation has been controversial, increasing adoption of net outcome approaches to biodiversity conservation suggests they could become mainstreamed within the next decade. Bycatch levies could raise billions of dollars towards closing global biodiversity financing gaps, delivering net outcomes for biodiversity under the United Nations Post-2020 Global Biodiversity Framework while enabling blue growth, and moving towards win-wins for economic welfare and biodiversity conservation.