Meeting International Biodiversity Targets on Islands: Current Status and Challenges

Biodiversity is declining at alarming rates worldwide despite ongoing conservation efforts. In 2022, the Convention on Biological Diversity identified 23 targets and 4 goals to counter this trend, aiming to achieve them by 2030 and 2050, respectively. Islands are both biodiversity hotspots and particularly vulnerable to biodiversity loss, hosting half of the world’s threatened species and 75% of extinctions since colonial times. Yet, achieving these targets and goals on islands has received little attention to date. Our objectives are to explore historical rates of biodiversity change on islands globally and predict whether current trends align with the biodiversity targets for 2030 as outlined in the Kunming-Montreal Global Biodiversity Framework (KM-GBF). We compiled 303 biodiversity and socio-economic indicators using three main sources (KM-GBF indicators, Geobon indicators, and all indicators listed by Tittensor et al., 2014) and evaluated them against six criteria (relevance, credibility, time span, time resolution, availability, global and island cover). Of these, 36 indicators were included. However, 7 targets (30.4%) lack an indicator. We used the KM-GBF indicators categories (i.e., headline, binary, component, and complementary) to assess how well included indicators correspond to the target (i.e., alignment). The indicator that best aligns with a target was used to assess coverage (i.e., how well a set of indicators measures progress toward a target). Four targets had only poorly aligned indicators and thus poor coverage. We then used time series spanning from 1950 to the present to model current and future trends for each indicator, aggregated by target. Preliminary results indicate that 24 indicators (66.7%) appear to be on track to meet their respective targets. However, almost half of the targets have either poor coverage or no indicators at all (n = 11, 47.8%). Additionally, several limitations exist in quantifying progress toward the KM-GBF targets on islands. We urge the development of missing indicators, as well as the design of indicators and long-term monitoring schemes tailored to islands.