1. Anthropogenic Biomes
A 21st century framework for ecology & the earth sciences
Erle C. Ellis
Department of Geography & Environmental Systems
University of Maryland, Baltimore County, Baltimore, MD 21250
Navin Ramankutty
Department of Geography & Earth System Science Program
McGill University, Montreal, QC, H3A 2K6, Canada
2. Humans now shape ecological pattern and
process across most of the terrestrial
biosphere.
“Nature” is embedded within human systems.
Ecology needs to move beyond human
footprints, impacts & domination.
3. Overview
Anthropogenic Biomes
• Why care about Biomes?
• Why do we need Anthropogenic Biomes?
– A missing persons detective story
• How to identify & map the biomes
– An empirical approach
• Anthropogenic Biomes of the World
• The way forward….
– A new model for ecological research & education
4. On Biomes…
• Biomes describe global patterns of species
composition and ecological processes
– Basic units in the ecological hierarchy…
• Identified as a function of Climate, moderated
by Altitude (conventionally)
• Basic units for global ecosystem models
– IGBP (17 classes; International Geosphere-Biosphere Programme)
• Core units in ecoregion analysis of biodiversity
–
5. Why Anthropogenic Biomes?
• Humans control biodiversity & ecosystem processes as
much as climate.
Deforestation
Habitat Fragmentation
• Global biome maps are not realistic.
Grazing
– Much of biome area does not even exist (potential vegetation).
– At most includes urban & agriculture (& agriculture+tree mosaic).
Agriculture
Urbanization
• Conventional, climate-based biomes are not static anyway:
– Anthropogenic climate change is altering biome location & etc…
composition.
• Biomes derived from global patterns of human interaction
with landscapes may be a stronger model of global
ecological patterns & processes.
6. Conventional Biomes
ecosystem processes are a function of
macroclimate (latitude, altitude, circulation)
Ecosystem processes = f(C)
C
= Climate
(precipitation & temperature)
7. Anthropogenic Biomes
A Working Hypothesis:
ecosystem processes in anthropogenic
biomes are primarily a function of human
populations and their ecosystem
interactions (land use)
Ecosystem processes =
(in anthropogenic biomes)
P
T
f(P,T)
= Population density
= Land use
(how land & resources are used)
8. Anthropogenic Biomes of the World
Rangelands
*
Ellis & Ramankutty, in press
41 Residential rangelands
42 Populated rangelands
43 Remote rangelands
*Mosaic: >25% tree cover mixed with
> 25% pasture and/or cropland
20. Anthropogenic Biomes of the World
Rangelands
*
Ellis & Ramankutty, in press
41 Residential rangelands
42 Populated rangelands
43 Remote rangelands
*Mosaic: >25% tree cover mixed with
> 25% pasture and/or cropland
21. Anthropogenic biomes
A new framework for ecology
• Only 22% of land and 11% of NPP are wild
• Nature is now embedded within human systems
– It is no longer possible to conserve nature by avoiding
human interactions
• Human interactions with the biosphere go far
beyond a single dimension of impact or domination.
• Beyond the “urban + agriculture + wild” model
– Forests, rangelands & croplands include people!
– A wide range of population interactions.
22. Anthropogenic Biomes: Conceptual Model
Wildlands Forested Rangelands
Croplands Villages
Ellis & Ramankutty, in press
Urban
& dense
23. Anthropogenic Biomes
Results
Anthropogenic Biomes are Mosaics
– Anthropogenic landscapes are heterogeneous
mixtures of different land use and land cover
classes.
– Urban areas are embedded in agricultural
areas.
– Trees mixed with croplands and housing.
– Managed vegetation is mixed with semi-natural
vegetation (e.g. croplands in rangelands and forests).
– Hillslopes & mountains are often islands of
semi-natural vegetation
26. Anthropogenic biomes
A new framework for education
A better story…
The old biosphere story… ecosystems
“Human systems, with natural
“Natural ecosystems with humans disturbing them”.
embedded within them”.
We own the biosphere:
we have altered it irreversibly. Now we control its future.
