Global areas of low human impact (‘Low Impact Areas’) and fragmentation of the natural world

Abstract

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.

Earth transformed: detailed mapping of global human modification from 1990 to 2017

“…Our findings foreshadow trends and patterns of increased human modification, assuming future trends in the next 25-30 years continue as they have recently. Thus, our study reinforces calls for stronger commitments to help reduce habitat loss and fragmentation (Kennedy et al 2019a, Jacobson et al 2019) --which should be considered in conjunction with current commitments (e.g., to reduce CO 2 emissions through the Paris climate accord; Baruch-Mordo et al 2019;Kiesecker et al 2019). We believe that the comparisons of ecoregions and biomes shown in Fig.…”

“…Our overarching goal in producing and publishing these datasets is to support detailed quantification of the rates and trends, as well as the current extent and pattern, to understand the gradient of the degree of human modification across the continuum from low (e.g., wilderness) to high (e.g., intense urban). Beyond the basic findings presented here, we believe there are many potential applications of these datasets, including: examining temporal rates and trends of land modification in and around protected areas (e.g., Geldmann et al 2019a); estimating fragmentation for all ecoregions and biomes (Kennedy et al 2019a, Jacobson et al 2019; and evaluating conservation opportunities and risks (e.g., the conservation risk index; Hoekstra et al 2005). We also note that the human modification approach allows, in a straightforward and logically consistent way, inclusion of additional stressors and higher resolution datasets that may become available over time or may be available for specific, local areas.…”

Unveiling the trap-nesting bees and wasps’ fauna (Hymenoptera: Apocrita) and associated organisms of the Jardim Botânico do Rio de Janeiro, Brazil

“…Habitat loss is a main problem throughout the world (Jacobson et al, 2019). Among the many affected biomes due to deforestation, mainly caused by urbanization processes, stands the Atlantic Forest with less than 30% of its natural cover (Rezende et al, 2018).…”

Active restoration accelerates the carbon recovery of human-modified tropical forests

“…Across the tropics, primary forests continue to be degraded by numerous human impacts, such as timber harvesting, agriculture, and fire. Consequently, more than half of all tropical forests have some human impact, even though many disturbed sites retain high tree cover (3). Loss of tropical forest cover is particularly acute in Southeast Asia, which has the highest deforestation rate in the tropics and where the intensity of logging is increased by the high densities of commercially important dipterocarp trees (4).…”