Scientists also use plots of biomes to help predict changes in Earth’s biosphere.

But a recent study says that there are no longer any ecosystems untainted by human influence.

Published in the journal Science in 2007, the study reveals that even the “pristine” rainforests of the Amazon and Congo show evidence of prehistoric settlements.

In a 2008 paper in Frontiers in Ecology and the Environment, scientists argued that more than three-quarters of Earth’s ice-free land shows evidence of human alteration.

Based on widespread human alteration of Earth’s land surface, the authors of the 2008 study propose a new classification system: anthropogenic biomes or anthromes — ecological patterns caused by human impact.

Such a representation of that classification can be seen in the image to the upper right.

The most common anthropogenic biome apparent on the map is rangeland, areas where livestock graze and human population is low. Rangelands, shown in shades of orange, tend to be in areas where crops don’t grow well — marginal lands — such as the dry desert highlands of the western United States and Central Asia.

The second most common human biome is cropland, shown in shades of green and yellow.

Urban areas and dense settlements appear as red dots scattered across the image, concentrated largely in coastal regions. While more than 80 percent of the world’s population lives in densely populated urban areas or village biomes, cities or towns surrounded by cropland, these areas cover just 7 percent of the planet’s ice-free land surface.

Shown in blue and pink tones, the village biomes are clearly the most common form of settlement in the world. One in four people live in such agricultural settlements, according to the map’s creators.

The remaining land surface in the image is either forested or wildlands. Patches of populated forest appear in the eastern Amazon and through much of Sub-Saharan Africa.

Light and mint greens indicate remote and wild forests, and these predominate in the boreal forests of Canada and Russia. Smaller areas of remote forest occur in the Amazon and the Congo.

Earth’s two extremes—barren deserts and frozen, ice-covered land—are both shown in gray. The Sahara Desert alone constitutes one-third of the barren desert portion of the biome.

Wildlands constitute both the least productive and least populous land areas on our planet. This is not surprising given people’s tendency to seek out, develop and settle the most productive land.

Full story and image: NASA