This map shows the preliminary results of a global prioritization analysis for terrestrial species conservation and carbon storage. Species data used in the analysis were derived from fine-scale range maps of more than 33,000 mammals, birds, amphibians and reptile species (approximately 95% of the species known to science), and a representative proportion (10%) of vascular plant species with existing range maps (131,009, approximately 37.3% of all species known to science). All range maps were refined to areas of habitat (AOHs) based on species habitat affiliations. Carbon data consisted of global maps of soil organic carbon stock at risk from human impact and above-ground biomass carbon. This information was used in a systematic conservation planning framework to jointly optimize for both species conservation and carbon storage in order to rank the value of terrestrial land surface from 0 to 100 globally.
Mammal, amphibian and bird distribution data were obtained from the International Union for Conservation of Nature (IUCN) and Birdlife International (IUCN 2019). Data on the distribution of reptiles was also obtained from IUCN when available, otherwise from the GARD database (Roll et al. 2017). Plant range maps came from a variety of sources, including the BIEN (Botanical Information and Ecology Network) plant database, IUCN, Royal Botanic Gardens Kew (RBGK) and Botanic Gardens Conservation International (BGCI).
The aboveground carbon map was created by overlaying a variety of biomass carbon datasets with the Copernicus global land cover map for the year 2015. The list of datasets included: Santoro et al (2018), Bouvet et al. (2018) Xia et al. (2014) and Spawn et al. (2017).
The map of vulnerable soil organic carbon was created by following IPCC Guidelines for National Greenhouse Inventories to estimate emissions and removals associated with changes in land use (IPCC 2006 and 2019). Hengl and Wheeler (2018) was used as soil organic carbon stock baseline. As above, the Copernicus global land cover map for the year 2015 was taken as baseline and then reclassify to the broader IPCC categories. Soil organic carbon sotk at risk was only estimated for “Forest”, “Grassland” and “Wetland” categories. All other categories we assigned as “No Data”.
This map shows the preliminary results of a global prioritization analysis for the restoration of habitats for terrestrial species and carbon sequestering. Species data used in the analysis consisted in fine-scale distribution maps of more than 20,000 mammals, birds, amphibians and a representative proportion (10%) of vascular plant species with existing range maps (131,009, approximately 37.3% of all species known to science). The carbon-related benefit was measured by the amount of carbon dioxide sequestered following restoration up to a reference ecosystem structure in each geographical zone, considering above and below-ground biomass and soil carbon.
This information was used to build the objective function of an optimization algorithm, selecting the top-priority currently anthropic areas in a hierarchical manner by setting targets ranging from 5% to 100% of the overall anthropic area, using the land-cover maps of the European Space Agency “Climate Change Initiative” (ESA CCI) land use and cover map for 2015. Restoration in each 5 km2 landspace is aimed at restoring the original distribution of natural land cover as computed from the map of 1992, the earliest in the ESA CCI series.
Mammal, amphibian and bird distribution data were obtained from the International Union for Conservation of Nature and Birdlife International (IUCN 2019). Plant range maps came from a variety of sources, including the BIEN (Botanical Information and Ecology Network) plant database, IUCN, Royal Botanic Gardens Kew (RBGK) and Botanic Gardens Conservation International (BGCI). A representative subset of the data was obtained relative to the taxonomic representativeness in a region (according to Kier et al. 2005). This was needed in order to reduce the spatial bias of plant species globally.
We sampled three maps using different approaches for carbon stock estimation (Erb et al. 2018) to obtain mean carbon stock values from remaining native vegetation and then extrapolated these values to restorable areas within the same geographical zone based on the Terrestrial Ecoregions of the World (Dinerstein et al. 2017). Geographical zones were delimited by the Terrestrial Ecoregions of the World, containing 848 Ecoregions, 14 Biomes and 9 Realms. In each of the three current carbon stock maps, we selected planning units that contained 70% of native vegetation cover or more, according to Erb et al. (2007), totaling 2,816,055 planning units. The land-cover classes considered as native were: i) non-productive and snow; ii) wilderness, no trees; iii) unused forests; iv) natural grassland, no trees; and v) natural grassland with trees. we also estimated the potential gains of carbon stocks in the soil based on the most comprehensive dataset of soil organic carbon and the predictions for its distribution in the present (2010) and pre-settlement land use (Sanderman et al. 2017), according to a spatially explicit database of historic patterns of human land use (HYDE-History Database of the Global Environment; Klein Goldewijk et al. 2011). Assuming that the restoration of native vegetation would recover soil carbon stocks to pre-settlement levels, we subtracted the current values from the pre-settlement ones to obtain the potential gains in soil carbon down to a 30cm soil depth.