Only 5% of the world’s lands are mapped to be unaffected by humans (6.96 million km2), and 44% is in low modification (58.96 million km2). The least modified biomes are tundra, boreal forests, deserts, temperate coniferous forests, and montane grasslands.
The remainder of the world’s lands are in moderate modification (34%, 45.63 million km2) or high modification (17%, 22.62 million km2). Tropical dry broadleaf forests, temperate broadleaf forests, Mediterranean forests, mangroves, and temperate grasslands are the most modified biomes.
Percentage of terrestrial land across the world’s biomes in none (HM = 0, dark green), low (0.00 < HM ≤ 0.10, light green), moderate (0.10 < HM ≤ 0.40, yellow), and high (0.40 < HM ≤ 1.00, red) human modification. Average HM values per biome indicated by black dots.
Percentage of low modified lands within edge-distance classes (km) from disturbed areas across the world’s biomes. Average edge distances per biome indicated by black dots. Given the 1-km2 resolution of the HM map, the 0−1 km edge-distance represents adjacency to modified areas.
Half of the world’s biomes have some cause for concern, either because they have little remaining low modified lands (6 biomes contain ≤ 20%), retain only a handful of low modified ecoregions (6 biomes have ≤ 10), or are vulnerable to fragmentation effects (4 biomes have 60-69% of low modified lands close to disturbed areas).
Notably, four biomes (tropical dry broadleaf forests, mangroves, tropical coniferous forests, and grasslands) have only 1 to 3 low modified ecoregions that remain.
Biomes are large ecological areas of the Earth’s surface with similar abiotic factors, such as temperature, climate, geology, soils, and vegetation. There are 14 terrestrial biomes (7 are forested and 7 are non-forested). For a map of biomes see: http://ecoregions2017.appspot.com/.
The number of low, moderate, highly modified ecoregions across the world’s biomes.