Monday, August 3, 2009 - 2:10 PM

OOS 7-3: Anthropogenic biomes in the global ecosystem

Erle Ellis, University of Maryland, Baltimore County


Humans have transformed more than three quarters of the terrestrial biosphere into croplands, rangelands, villages, settlements and other anthropogenic biomes (anthromes) including managed and recovering woodlands.  Most of the remainder is either arid, frigid, or otherwise undesirable for human use.  While the process of anthropogenic ecosystem transformation and management has been sustained for thousands of years on every continent except Antarctica, there is still a tendency for ecological scientists, educators and policymakers to portray the terrestrial biosphere as a natural place just recently disturbed by humans.  Portraying the terrestrial biosphere in this way may convince the public that action to "save the biosphere" is urgent.  However, this portrayal is neither scientifically accurate nor a means toward sustainable management of the biosphere in the future.  This presentation examines the current state of the terrestrial biosphere and the long-term trajectory by which most of it came to be managed or otherwise transformed by humans and applies these observations towards better understanding our management options for a sustainable biosphere.


As of 2000, close to 90% of earth's terrestrial primary productivity and its most plant-species-rich regions were located within anthromes.  Even in 1700, anthromes were already more extensive than "wild" biomes (lands without evidence of human occupation or land use).  Yet most primary productivity and plant species richness were in seminatural woodlands- the anthromes least influenced by humans.  Moreover, even in the most ancient and intensively managed cropland and village anthromes, substantial areas of seminatural woodlands and other less disturbed ecosystems are embedded within mosaics of harvested, cultivated, settled and other managed lands . These global and local patterns demonstrate that sustained coexistence between human populations and both managed and unmanaged ecosystems is not only possible, but that it has been the norm for most ecosystems globally for centuries.  While rapid change in human systems may not be ecologically sustainable over the long-term- and recent rates of land use intensification are clearly unprecedented, there is little evidence that human interactions with ecosystems are in themselves unsustainable.  On the contrary, virtually all of earth's terrestrial ecosystems have already been irreversibly altered by sustained interactions with humans and management interventions are now needed to sustain even the most wild-seeming natural places and species that remain. The biosphere can no longer be saved from us- all we can do is manage it better.