Sunday: 2 December 2007
The other day, in this post, I was surly and rude in my review of the work by Erle Ellis and Navin Ramankutty on anthropogenic biomes. I did admire the google maps but did not otherwise rise to the level of civility that I like to maintain. I addressed the institutional press release more than the content of the work, and that was unfair.
The authors sent me a pdf of the paper itself, "Putting people in the map:
anthropogenic biomes of the world", and asked if I would post the following as a comment. I asked if they would prefer it added to another post making a second attempt at a more reasonable assessment, and they were agreeable to that:
The paper makes the strong point that anthromes are not intended to replace biomes, and after reading it through I understand much better the points of the paper. Briefly, Ellis and Ramankutty are augmenting conventional biomes designations to reflect the types of disturbances and encroachments by humans. Their contention is that with unregulated growth, humans now intercept and consume one-third of terrestrial net primary production, are causing global extinctions, and are altering climate. Human influence must be taken into account, since it is now affects the majority of Earth’s land surface, with wild ecosystems diminishing rapidly.
The paper itself is (I believe) currently embargoed until its publication, so I hope I’m not crossing any lines here.
To produce the augmentations and anthromes, the authors divided land surface up into 5 arc-minute grids (86 square km at the equator) and assigned each a large set of descriptors that include within a wild class and a population density class: human population, land use, land cover, and many others. They then performed a cluster analysis to identify natural groupings of descriptors. The results are the maps that can be viewed with Google Earth, Google Maps, Microsoft Virtual Earth, and also in GIS (Geographic Information System) format.
Here, for instance, is a section from the Google Map version of north Georgia, including Atlanta and Athens. Click on the map for a considerably larger version. The pink and red colors indicate urban and dense settlements, and rainfed mosaic villages anthromes. The majority shades of green surrounding the red and pink blocks are various combinations of residential and populated rainfed mosaics and irrigated cropland, and populated forests.
A conventional biome designation for our area would be "temperate forest", or deciduous forest, along with a description of the non-human aspects of that biome. Of course you could get more detailed - our biome could be further subdivided into associations: "oak-hickory temperate deciduous forest", but again little or nothing might be said about the human influence that modifies the ecosystems of the area.
You could spend hours going over the color coded figures in the paper. Figure 2 is a set of bars that correlates conventional biomes designations with anthropogenic biomes - it is essentially a summary of the results of the clustering. So, for instance, there is a bar in Fig 2b that identifies “grasslands”, a conventional biome designation, and above it is a bar that is divided into sections sized and color coded as to anthropogenic use: populated rangelands constitutes more than a third of this bar, followed by residential rangelands and remote croplands, with all the other 17 anthrome designations also indicated by colored sections.
Figure 3 provides a conceptual model and places broad categories of anthromes on a logarithmic scale, structured by presentations of the actual data: population density, land use (forestry, pasuture, buildup, ornamental, etc.), carbon emissions, biodiversity (native and introduced), and more. It’s an extremely graphic and persuasive figure, particularly when you take into account the logarithmic scale.
In the end the authors argue that the usual parameters that go into describing an ecosystem: biota, climate, terrain, and geology, should be augmented with additional factors that include population density and land use. It is not, as I hastily described it, any sort of seal of approval, but rather a recognition that must be taken into account if ecological modeling is to give meaningful information.
There’s a great deal more to the work than I’ve described, and the figures really must be viewed to appreciate them. There’s much more at the Anthropogenic Biomes website. The paper is in Frontiers of Ecology, and a PDF can be read by scrolling down to the Nov 26 entry on this page.
The authors sent me a pdf of the paper itself, "Putting people in the map:
anthropogenic biomes of the world", and asked if I would post the following as a comment. I asked if they would prefer it added to another post making a second attempt at a more reasonable assessment, and they were agreeable to that:
Hi Wayne,
Thank you for taking the time to flame our recent work on Anthropogenic
Biomes! (just kidding- no offense taken.)
We have two responses.
First, anthromes are not intended to replace biomes, they serve as an
alternative view of the biosphere that includes humans. We do state this in
both our EOEarth topic and paper. Conventional biome systems are still very
useful.
We heartily agree that nature has tremendous value for its own sake.
On the other hand, we also feel that basing nature conservation on the view
that only ecosystems untouched by human hands are worth conserving is not
going to serve us well in the long-term.
We address this in detail in our post at the EarthForum entitled:
"Conserving Nature in an Anthropogenic Biosphere"
We are looking forward to your further comments- and it would be great if
you could join in the EarthForum blog on this too.
Thank you again for your contribution.
Best wishes,
Erle and Navin
The paper makes the strong point that anthromes are not intended to replace biomes, and after reading it through I understand much better the points of the paper. Briefly, Ellis and Ramankutty are augmenting conventional biomes designations to reflect the types of disturbances and encroachments by humans. Their contention is that with unregulated growth, humans now intercept and consume one-third of terrestrial net primary production, are causing global extinctions, and are altering climate. Human influence must be taken into account, since it is now affects the majority of Earth’s land surface, with wild ecosystems diminishing rapidly.
The paper itself is (I believe) currently embargoed until its publication, so I hope I’m not crossing any lines here.
To produce the augmentations and anthromes, the authors divided land surface up into 5 arc-minute grids (86 square km at the equator) and assigned each a large set of descriptors that include within a wild class and a population density class: human population, land use, land cover, and many others. They then performed a cluster analysis to identify natural groupings of descriptors. The results are the maps that can be viewed with Google Earth, Google Maps, Microsoft Virtual Earth, and also in GIS (Geographic Information System) format.
Here, for instance, is a section from the Google Map version of north Georgia, including Atlanta and Athens. Click on the map for a considerably larger version. The pink and red colors indicate urban and dense settlements, and rainfed mosaic villages anthromes. The majority shades of green surrounding the red and pink blocks are various combinations of residential and populated rainfed mosaics and irrigated cropland, and populated forests.
A conventional biome designation for our area would be "temperate forest", or deciduous forest, along with a description of the non-human aspects of that biome. Of course you could get more detailed - our biome could be further subdivided into associations: "oak-hickory temperate deciduous forest", but again little or nothing might be said about the human influence that modifies the ecosystems of the area.
You could spend hours going over the color coded figures in the paper. Figure 2 is a set of bars that correlates conventional biomes designations with anthropogenic biomes - it is essentially a summary of the results of the clustering. So, for instance, there is a bar in Fig 2b that identifies “grasslands”, a conventional biome designation, and above it is a bar that is divided into sections sized and color coded as to anthropogenic use: populated rangelands constitutes more than a third of this bar, followed by residential rangelands and remote croplands, with all the other 17 anthrome designations also indicated by colored sections.
Figure 3 provides a conceptual model and places broad categories of anthromes on a logarithmic scale, structured by presentations of the actual data: population density, land use (forestry, pasuture, buildup, ornamental, etc.), carbon emissions, biodiversity (native and introduced), and more. It’s an extremely graphic and persuasive figure, particularly when you take into account the logarithmic scale.
In the end the authors argue that the usual parameters that go into describing an ecosystem: biota, climate, terrain, and geology, should be augmented with additional factors that include population density and land use. It is not, as I hastily described it, any sort of seal of approval, but rather a recognition that must be taken into account if ecological modeling is to give meaningful information.
There’s a great deal more to the work than I’ve described, and the figures really must be viewed to appreciate them. There’s much more at the Anthropogenic Biomes website. The paper is in Frontiers of Ecology, and a PDF can be read by scrolling down to the Nov 26 entry on this page.
