Seite - 14 - in options, Band summer 2021

Concentrated solutions These sentiments are confirmed by two recent studies involving IIASA researchers. One looked at restoring cropland and pastureland back into natural habitat. The authors mapped converted land, calculating the local impact of restoration on carbon and species extinction risk based on field data from similar sites. They then modeled global outcomes from restoring 15% of all converted land, amounting to 4.3 million km2. A linear programming algorithm found the optimum choice of conversion sites, for various weights given to extinction risk, carbon, and cost. One restoration scenario, designed to optimize carbon and biodiversity, prevents 60% of extinctions that would otherwise be expected, and locks up almost 300 gigatons of CO2 – about seven years of global emissions at today’s rate. The second study, led by IIASA researcher Martin Jung, looked at conservation, calculating its effect on biodiversity, carbon, and clean water provision. Unlike earlier studies, this included not only animals, but also plants. It concludes that managing just 10% of global land area can improve the conservation status of 46% of species, and conserve 27% of stored carbon and 24% of clean water. A detailed map of local benefits shows where people can get the greatest value for their conservation effort. State of nature Data on biodiversity is essential to guide the campaign, but that is often scarce. “Africa and South America in particular are missing huge amounts of data,” says Ian McCallum, head of the IIASA Novel Data Ecosystems for Sustainability research group. The group is aiming to improve this situation, partly through novel data sources such as citizen science, imaging with drones, and lidar from satellites and aircraft. “We use statistical techniques to harmonize data, in order to put it all together,” says McCallum. McCallum also leads the stakeholder engagement effort of EuropaBON, the EU’s biodiversity observation network project, aiming to identify critical gaps in data. Even though Europe is better covered than much of the world, there are still plenty of weak areas – particularly in aquatic habitats – and this project will help to drive data integration methods. “In data-rich areas you can develop techniques to then scale up and use globally,” he notes. 1, SI Fig. 1), has the potential to improve the conservation status of 46.1% of all species considered, 138 of which 51.1% re plant sp cies, as well as conserve 27.1% of the total carb n and 24.1% of the 139 potential clean water globally. Areas of biodiversity importance notably include mountain ranges 140 of the world, large parts of Mediterranean biomes and South-East Asia (SI Fig. 2) and were overall 141 mostly comparable to previous expert-based delineations of conservation hotspots16, while also 142 highlighting additional areas of importance for biodiversity only, such as the West African Coast, 143 Papua New-Guinea and East Australian Rainforest (SI Fig. 2). The Hudson Bay area, the Congo 144 Basin and Papua New Guinea were among the top-ranked 10% areas for global carbon storage (SI 145 Fig. 3a), while the Easter United States f America, the Congo, Europ an Russia and Eastern 146 India were among the areas with the greatest importance for clean water provisioning (SI Fig. 3b). 147 Overall, top-ranked areas of joint importance of biodiversity, carbon and water were spatially 148 distributed across all continents, latitudes nd biom s.149 150 151 Fig. 1: Global areas of importance for terrestrial biodiversity, carbon and water. All assets 152 were jointly optimized with equal weighting given to each asset (central point in the series of 153 segments in Fig. 2) and ranked by the most (1-10%) to least (90-100%) important areas to conserve 154 globally. The triangle plot shows the extent to which protecting the top-ranked 10% and 30% of 155 land (dark brown and yellow areas on the map) contributes to improving species conservation 156 status, storing carbon and providing clean water. The map is at 10 km resolution in Mollweide 157 projection. A map highlighting the uncertainty in priority ranks can be found in SI Fig 1.158 159 Synergies and trade-offs depend on the relative importance given to conservation of 160 terrestrial biodiversity, carbon storage and water provisioning (Fig. 2a). We explored an array of 161 conservation scenarios each with a range of possible outcomes: at one extreme, priority is given 162 to conserving biodiversity and carbon only, and with equal weight (Fig. 2b). At the other extreme 163 are scenarios that prioritize conserving only biodiversity and water (Fig. 2c). Intermediate options 164 include giving equal weighting to all three assets (Fig. 1). Similar to earlier assessments9,26,27, we 165 found synergies between the conservation of biodiversity and carbon storage (Fig. 2b). However 166 .CC-BY-NC-ND 4.0 International licenseavailable under a was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made The copyright holder for this preprint (whichthis version posted April 16, 2020. ;https://doi.org/10.1101/2020.04.16.021444doi:bioRxiv preprint Gl bal areas of importance for terrestrial biodiv rsity, carbon and water. — Areas of global importance for te restrial biodiversity, carbon, nd water. Jung, et al. 14 Options Summer 2021 www.iiasa.ac.at