Sunday, May 19, 2013

Over, over, overgrazing?

According to Savory: More this 

proposed an “unthinkable” idea that he claimed we need to re-educate the public about “overgrazing” causing desertification. Desertification means human activities increase the rate at which land becomes desert and causes macro climate change. Savory proposed if his Holistic Management and planned grazing principle implemented on 50% of the worlds grassland can bring the quantity of greenhouse gases to pre-industrial levels. Holistic management uses very high densities of livestock and quickly moving them between lands to increase the plant biomass and help soil store nutrients. In addition, he claimed this is the only method and option we left as mankind to correct desertification.

In his talk he showed various results that his research team had progressively restored the vegetation and grassland that were suffering from desertification. According to McWilliams’ article (All Sizzle and No Steak), the results were obtained in 1969 and 1975 (the Charter Grazing Trials) and the experiments were performed on only 6,200 acres of semi-arid African lands. The biologists and ecologists worldwide argued that the trials only count for relatively small areas compared with deserts all over the world. A Scientific paper by Joseph et al. evaluated the Charter Grazing Trials research paper and found high similarity between African studies and North American studies. No solid evidence and significant data to prove that holistic management and planned grazing could improve the regeneration of vegetation. The paper also mentioned that the high density of cattle in small areas reduced the cattle performance because of individual stresses within livestock animals. 
Furthermore, fast livestock movement between lands also did not give a chance for livestock carcasses to die on the land and contribute to a complete nutrient cycle.

Moreover, McWilliam pointed out a very good point that Savory did not separate different kinds of deserts in his talk which was a poor mistake because there are two kinds of deserts: deserts that have evolved from a long history and developed a unique desert ecosystem, and bare ground caused by the overgrazing of livestock. Kelt’s ( 2011) paper stated that the formation of deserts throughout the whole world had unique extrinsic (climate) and intrinsic (population density factors). Those deserts have been developing over a long period of time thus species and vegetation have already developed unique adaptations to the desert’s ecosystem. We would be wrong again if we tried to do as what Savory suggested to “mimic natural complexities” and add 400% (to some cases) of cattle to deserts and destroyed unique desert ecosystems.


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