Chris Rowan is a geologist specialising in the dark arts of paleomagnetism, and getting people to pay him to travel to exotic destinations for fieldwork. Having drilled up New Zealand during his PhD, and South Africa in his first post-doc, he now works at the University of Edinburgh.
Anne Jefferson has a love of all things water-related and blends hydrology, geomorphology, geology, and climate change in her work. She has a Ph.D. from Oregon State University and is now an assistant professor at the University of North Carolina at Charlotte.
Chris is not the only one who comes across fascinating things via Twitter. Just yesterday I was introduced to the concept of anthropogenic biomes. In physical geography, biogeography, and ecology classes we learn and teach about biomes - major global ecological communities, classified according to the dominant natural vegetation. But more than 3/4 of the world's ice-free land shows the evidence of human activity - and the remaining 1/4 of the planet supports just 11% of the Earth's terrestrial net primary production. Recognizing these things, Erle C Ellis and Navin Ramankutty of University of Maryland-Baltimore County and McGill University, respectively, have recently advanced the idea of anthropogenic biomes that characterize the human-altered landscape. Their new view of the world is shown below:
Ellis and Ramankutty argue that "anthropogenic biomes are in many ways a more accurate description of broad ecological patterns within the current terrestrial biosphere than are conventional biome systems that describe vegetation patterns based on variations in climate and geology" because such natural patterns are rarely found in large areas outside of the wildland anthropogenic biomes. A few highlights from this view of looking at the world:
- 40% of humans live in dense settlements biomes, 40% live in village biomes (38% urban), 15% live in cropland biomes, 5% live in rangeland biomes, and 0.6% live in forested biomes
- dense settlements and villages cover 7% of the Earth's ice-free terrestial area
- village biomes (dense agricultural populations) cover 1/4 of the Asian continent
- "anthropogenic biomes are best characterized as heterogeneous landscape mosaics, combining a variety of different land uses and land covers"
- wildland biomes are found in the least productive areas on Earth
You can read more about this concept in their 2008 Frontiers in Ecology paper (pdf here) and on their website. You can even print a wall map, or play with the data in Google Earth or ArcGIS. I think anthropogenic biomes are a pretty neat concept and next time I teach my introductory earth science course, I'm going to use them to better tie the required chapter on biomes together with the big themes of the class. What do you think? Is this a useful concept? Or at least a pretty map to look at?
Environment
Life Science
Comments
Very interesting concept - I would definitely use it in teaching - it clearly helps bring home the idea of the human impact on the biosphere without being "preachy" about overpopulation and environmental destruction, and thus is more likely to plant little seeds for future thought in young minds that might desperately need a little light and fresh air to counter what they're getting at home and on Fox news.
Posted by: Knoxville, TN | September 9, 2009 3:35 PM
Wonder how that map would have looked 600 years ago,particularly in light of recent studies suggesting that human involvement with ecosystems on some pretty large scales were possibly more prevalent that previously recognized. Activities such as large scale grass fires, selective permaculture in forest lands, and the creation of the large tracts of modified and amended soils in the Amazon. By the time competent objective descriptions of these seemingly wild (or re-wilded) lands was made by Europeans, sometimes as late as the mid-1800s the long present native populations of indigenous people using ancient practices had been absent a long time, well over a century in some cases, or greatly reduced, leading theorists to think they'd always been pristine and/or only lightly inhabited.
Posted by: doug l | September 9, 2009 7:12 PM
My friend and former colleague Emma Marris did a really nice piece on these and related ideas in Nature recently, "Ragamuffin Earth" http://www.nature.com/news/2009/090722/full/460450a.html (sub required, I'm afraid)
Posted by: Oliver | September 10, 2009 5:28 AM