Anthropogenic Biomes of the World
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Urban

Urban

Urban regions are home to the densest human populations on the planet. All of the major cities in the world fall into this anthrome class.  Characterized by manmade structure and built land cover, the urban anthrome lacks any significant agriculture and generally has a small amount of both tree cover and cultivated land intermixed within the artificial environment.  World wide, 40% of the worlds population live in dense settlements and urban anthromes.  However, these places only cover 7% of the earths total ice-free land area.

Both urban and dense settlements are less influenced by variables that typically describe biomes than other classes.  Three of the top five ecoregions that comprise the urban anthrome fall within the conventional biome of temperate broadleaf forests, which reflects the historic industrialization of Europe and North America and the population booms related to it.  However, cities spring up for different reasons around the world, whether it is access to water ways, roads, or resources; there is rarely one reason for the existence of an urban anthrome in a particular region.  This is reflected in the variation in climatic variables found in each urban anthrome.

Climate

Median* Min Max
Mean Annual Temperature 16.3 °C -9.8 °C 30.5 °C
Mean Annual Precipitation 927
mm/yr
0.4
mm/yr
5018 mm/yr
 
Net Primary Production Global Total Median Min Max
1015g C/yr (%) kg C/m/yr
0.2 (0.4%)
0.45 0 2.08

Population

Global Total Median Min Max
billion persons (%) persons/km
Total 1.87 (29%)
205 336 49,930
Non-Urban 0.2 (6%)
484 0 2471
 

Land Use & Land Cover

 

Global Total
Median Min Max
million km2 (%) (cover %)
Total Land Area 0.6 (0.5%) N/A
Urban 0.3 (41.5%) 30.2% 17.6% 100%
Cultivated 0.15 (1.0%) 7.7% 0.0% 100%
Irrigated 0.1 (3.6%) 0.8% 0.0% 100%
Rice Paddy 0.07 (4.0%) 0.0% 0.0% 100%
Pasture 0.04 (0.1%) 0.5% 0.0% 100%
Tree Cover 0.07 (0.2%) 6.9% 0.0% 57.3%
Bare Earth 0.08 (0.2%) 6.0% 0.0% 100%
*Median, Minimum and Maximum estimates were calculated after removing the top and bottom 2% of cells in each anthrome based on the Euclidean distance across the means of variables used for anthrome classification.
 

Major Ecoregions (Olson)

% cover
Lower Gangetic Plains moist deciduous forests 3.1
Nile Delta flooded savanna 2.9
 Taiheiyo evergreen forests 2.8
Southern Great Lakes forests 2.6
Northeastern coastal forests 2.6

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Photo: Chris73, 12/19/2004, cc-by-sa 2.5 license
http://commons.wikimedia.org/wiki/Image:Osaka_city_view_02.jpg

Created by:

Andrew Petit de Mange & Kelly Kennedy

Based on: Anthropogenic Biomes of the World

Ellis, E. C. and N. Ramankutty. 2008. Putting people in the map: anthropogenic biomes of the world. Frontiers in Ecology and the Environment 6(8):439-447 doi:10.1890/070062. [download]