Monday, 30 April 2012

Effects of the expanding agriculture frontier in the Bolivian Amazon

ResearchBlogging.orgLast week, a paper published in Nature spurred a lot of debates on the internet about the future of agriculture and our ability to feed the 9 billion people that the world will have in 2050. One important aspect related to this debate is the availability of agricultural land. However, people do not always have a clear idea of what expanding the agriculture land means. Here an example of what is happening in one of the most biodiversily rich places of the world: the Bolivan Amazon. Let’s just have a look at a few Google earth’s images of the Lake Peroto in the Llanos de Moxos (dep. of Beni in the Bolivian Amazon).
Image taken the 17 of May 2003. Land use is extensive cattle ranching. Typical floating vegetation (locally called “yomomo”) is growing along the shores of Lake Peroto.

Image taken the 20th of Nov 2004. Land use is extensive cattle ranching. It is the end of the dry season, and the water level is extremely low. In the greenish areas inside the lakes water is almost completely evaporated. This is normal in the Llanos de Moxos, where seasonality can be extreme
Image taken the 2nd of July 2009. Land use is extensive cattle ranching. We are at the beginning of the dry season, water level is quite high, the water is clearly visible.
Image taken the 8th of August 2011. Land use is extensive cattle ranching plus industrial agriculture. 70 hectares of land in the surroundings of the lake have been used to produce rice.

What happened to the lake in 2011? Now the lake is almost completely covered with vegetation... Is it dry? Or is it the first effect of land use change: eutrophication? Based on my personal experience of having been working in the Llanos de Moxos for more than 10 years now and based on the fact that the nearby Lake Suarez is full of water (photo below) on the 15 of August 2011, I would conclude that Lake Peroto is in process of eutrophication.
Lake Suarez. Image taken the 15th of August 2011. The lake is full.

Industrial agriculture in the Beni is already causing deforestation and threatening archaeological sites (see this). Now it is also affecting lake ecology. Is industrial agriculture what people in the Beni really need? Does this kind of agriculture make any sense in a place with a density population of 1 person per square kilometre? Here, a very important part of the population lives in indigenous communities whose subsistence depends on local natural resources. What will happen to them in ten years’ time if these resources are depleted?

Seufert V, Ramankutty N, & Foley JA (2012). Comparing the yields of organic and conventional agriculture. Nature PMID: 22535250