Habitat loss and fragmentation due to human activities is the leading cause of the loss of biodiversity and ecosystem services. Protected areas are the primary response to this challenge and are the cornerstone of biodiversity conservation efforts. Roughly 15% of land is currently protected although there is momentum to dramatically raise protected area targets towards 50%. But, how much land remains in a natural state? We answer this critical question by using open-access, frequently updated data sets on terrestrial human impacts to create a new categorical map of global human influence (‘Low Impact Areas’) at a 1 km2 resolution. We found that 56% of the terrestrial surface, minus permanent ice and snow, currently has low human impact. This suggests that increased protected area targets could be met in areas minimally impacted by people, although there is substantial variation across ecoregions and biomes. While habitat loss is well documented, habitat fragmentation and differences in fragmentation rates between biomes has received little attention. Low Impact Areas uniquely enabled us to calculate global fragmentation rates across biomes, and we compared these to an idealized globe with no human-caused fragmentation. The land in Low Impact Areas is heavily fragmented, compromised by reduced patch size and core area, and exposed to edge effects. Tropical dry forests and temperate grasslands are the world’s most impacted biomes. We demonstrate that when habitat fragmentation is considered in addition to habitat loss, the world’s species, ecosystems and associated services are in worse condition than previously reported.
32Species distribution maps are essential for assessing extinction risk and guiding conservation efforts. Here, 33we developed a data-driven, reproducible geospatial workflow to map species distributions and evaluate 34 their conservation status consistent with the guidelines and criteria of the IUCN Red List. Our workflow 35 follows five automated steps to refine the distribution of a species starting from its Extent of Occurrence 36(EOO) to Area of Habitat (AOH) within the species range. The ranges are produced with an Inverse 37 Distance Weighted (IDW) interpolation procedure, using presence and absence points derived from primary 38 biodiversity data. As a case-study, we mapped the distribution of 2,273 bird species in the Americas, 55% 39 of all terrestrial birds found in the region. We then compared our produced species ranges to the expert-40 drawn IUCN/BirdLife range maps and conducted a preliminary IUCN extinction risk assessment based on 41 criterion B (Geographic Range). We found that our workflow generated ranges with fewer errors of 42 omission, commission, and a better overall accuracy within each species EOO. The spatial overlap between 43 both datasets was low (28%) and the expert-drawn range maps were consistently larger due to errors of 44 commission. Their estimated Area of Habitat (AOH) was also larger for a subset of 741 forest-dependent 45 birds. We also found that incorporating geospatial data increased the number of threatened species by 52% 46 in comparison to the 2019 IUCN Red List, and 103 species could be placed in threatened categories (VU, 47 EN, CR) pending further assessment. The implementation of our geospatial workflow provides a valuable 48 alternative to increase the transparency and reliability of species risk assessments and improve mapping 49 species distributions for conservation planning and decision-making.50 51
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