Anthropogenic Biomes: Observing and Modeling Carbon in an Anthropogenic Biosphere

Erle C Ellis, Geography & Environmental Systems, University of Maryland, Baltimore County, ece@umbc.edu (Presenting)

Humans have fundamentally altered ecosystem form and process across the terrestrial biosphere. Given the large and increasing role of humans in patterning net primary production, standing biomass, carbon balance and emissions across the terrestrial biosphere, it is surprising that terrestrial observing and modeling systems are still designed around vegetation cover systems that either ignore humans altogether or simplify human influence into few simple categories. Anthropogenic biomes offer a new way forward by characterizing terrestrial ecosystems in terms of globally-significant ecological patterns caused by sustained direct human interaction with ecosystems, including agriculture, urbanization, forestry and other land uses. Eighteen anthropogenic biomes (anthromes) were identified by empirical analysis of global population, land use, and land cover data at 5 arc minute resolution, including urban, village, cropland, and rangeland biomes. More than three quarters of Earth’s ice-free land showed evidence of alteration by human residence and land use, with less than a quarter remaining wild, supporting just 11% of terrestrial net primary production. Moreover, densely populated anthromes (>100 persons km^-2) covered a greater area of Earth’s ice-free land than did wild forest biomes, and more than a quarter of global tree cover was embedded within cropland biomes, which were responsible for about a third of global net primary production. Anthropogenic biomes offer a strategic opportunity to integrate human and ecological systems into functional units that better reflect the current state of the biosphere than do conventional biome systems, and have a spatial precision relevant both to terrestrial observing platforms like MODIS and to next generation atmospheric remote sensing platforms, such as the Orbiting Carbon Observatory. We therefore hypothesize that anthropogenic biomes will better explain globally observed patterns of carbon sequestration and flux than will conventional biome and vegetation systems, especially where carbon exchange is dominated by agriculture, forestry and household fuel combustion.