Tuesday, May 21, 2013

Is livestock mimicking nature reliable?


For climate change, people always solve the problem of replacing fossil fuels with renewable energy, but fossil fuels, are not the only factor that is causing climate change. Desertification, referring to land turn into desert, is another major cause of climate change. When the soli is damaged and bare, it can evaporate water and give off methane to the atmosphere, just as the results of burning fossil fuels. Almost two thirds of our world land has potential to desertification during months of dryness. People always believe that the major cause of desertification is livestock by overgrazing the plants. The only way to allow new plants to grow is by fire in order to decrease desertification.  However, in the TED talk by Allan Savory, he showed us an unthinkable method. He pointed out that reduce animal numbers and burn grass will both lead to desertification and climate change. The only one option is to stop desertification is to use livestock. The planning process is called holistic management and planned grazing, which develop strategies for planning livestock to mimic nature in order to heal the land. Savory argues that the land tramped gently by livestock can store carbon and break down methane, retaining the ability to mediate relieve climate change. He encourages people to add more cattle to deserts and sell and eat more meat.    
I think the basic principle of holistic management sound pretty reasonable at first. However, many factors need to be taken into account in order for successful work in practice. First of all, nature’s complexity is hard to predict and there are diversity in the bare ground and grassland. Many different factors such as plant types, heights of vegetation are necessary to lead to a perfect symbiosis between plants and livestock. When asked about what the animals ate after they added to the desert, Savory explained there was no need for feeding just depending on movement according to the sigmoid curve. However, some studies show that no grazing method can overcome overgrazing during long term. Cattle will get tired and need supplementary food source. The study in eastern Karoo (http://www.sciencedirect.com/science/article/pii/S0140196303001071) showed that intensive grazing actually decrease grassland cover and reduce the total biomass there.
       Secondly, holistic management only work in a narrow set of conditions and it cannot be applied to larger spatial scales. This method is not useful the desert land type in country such as Russia, eastern Africa, etc, because not all land types are suitable for constantly moving by large herds. Some land in dry years can lead to far more degradation by livestock. In addition, not all bare lands are bad since there are many species depending on the bare land for evolving.
       Thirdly, nature’s complexity is hard to mimic. Savory used the term “mimic” several times in his speech, but this word is easier said than done. Desert or bare land has many co-evolved organisms that are lived symbiosis for over millennia, human-managed “mimicking nature” cannot become a perfect representative of the real nature’s complexity.
       Overall, I think Allan Savory’s method need to evolve and improve by adding more environmental factors into account when treating different types of desert land. In addition, his method is right when several conditions are met, such as high rainfall and frequently movement of cattle. Thus, people need to precisely evaluate environmental conditions in different desert land and find out eligible land that are suitable for holistic management. 



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