Change in Terrestrial Human Footprint Drives Continued Loss of Intact Ecosystems

Abstract

Human pressure mapping is important for understanding humanity's role in shaping Earth's patterns and processes. Our ability to map this influence has evolved, thanks to powerful computing, Earth-observing satellites, and new bottom-up census and crowd-sourced data. Here, we provide the latest temporally inter-comparable maps of the terrestrial human footprint and assessment of change in human pressure at global, biome, and ecoregional scales. In 2013, 42% of terrestrial Earth could be considered relatively free of direct anthropogenic disturbance, and 25% could be classed as ''wilderness'' (the least degraded end of the human footprint spectrum). Between 2000 and 2013, 1.9 million km 2 -an area the size of Mexico-of land relatively free of human disturbance became highly modified. The majority of this occurred within tropical and subtropical grasslands, savannah, and shrubland ecosystems, but the rainforests of Southeast Asia also underwent rapid modification. Our results show that humanity's footprint is eroding Earth's last intact ecosystems, and greater efforts are urgently needed to retain them.

Where Might We Find Ecologically Intact Communities?

“…The HF is a composite index of eight global pressures and ranges between 0 and 50. HF scores of four or more are considered modified habitat; scores below this are considered as low impact (Venter et al, 2016b;Mokany et al, 2020;Williams et al, 2020), although, in some recent papers, a value of below three is considered low impact (Di Marco et al, 2018;O'Bryan et al, 2020). The HF mainly maps human infrastructure, population or agriculture, but does attempt to predict impacts up to 15 km on either side of linear features (rivers and roads).…”

The importance of Indigenous Peoples’ lands for the conservation of terrestrial mammals

“…These data sets permit the quantification of the extent of intense pressures on individual species (Di Marco et al 2018;Allan et al 2019;O'Bryan et al 2020). We used the most current human footprint map available (2013) (Williams et al 2020), which contains a composite spatial index of key human pressures on natural ecosystems at a 1-km 2 resolution.…”

“…We conducted to our knowledge the first global assessment of the overlap between mapped Indigenous Peoples' lands (Garnett et al 2018) and mapped terrestrial mammal area of habitat (AOH) (Rondinini et al 2011). We also assessed mammal species composition on lowpressure Indigenous Peoples' lands based on human footprint data (Williams et al 2020). These results are relevant to the development and implementation of the post-2020 Global Biodiversity Framework agreement that will emerge from the Convention on Biological Diversity's (CBD) discussions on abating species extinctions and reducing the erosion of ecosystem services (CBD 2018), as well as for countries trying to implement actions to achieve the 2030 United Nation's Sustainable Development Goals.…”

Editorial: Intact Forests

“…This formed one of the foundational concepts of the 1992 Rio Declaration, but has proven difficult to operationalize beyond bottom-up, local approaches (Hansen et al, 2021). However, recent advances in remote sensing, big data and cloud computing have enabled new biome-wide or global metrics to be generated (Grantham et al, 2020;Hansen et al, 2020;Williams et al, 2020;Nicholson et al, 2021). Rapid further developments are anticipated, and these new tools have already helped to build the confidence of the global policy community that ecological integrity can be measured and monitored in practical ways.…”