Thursday, December 1, 2011

Current Human Impacts: The Good, The Bad, The UGLY!


Overall, humans’ impacts on the African savannah have been negative.  While humans’ influence has had a few positive consequences, the cons certainly outweigh the pros in the case of this ecosystem.

The Good:
Tourism keeps natural sections of Africa alive.  The money brought in by tourism helps fund conservation reserves and shows the government and local communities that conservation of animals and the landscape is important because millions of people travel thousands of miles to come to Africa to observe and explore these landscapes. 


The Bad: 
For one, humans have overused fossil fuels, and this over consumption of fossil fuels has led to increased levels of carbon dioxide rising to the atmosphere.  The result has been a shift in vegetation from C4 plants to C3 plants.  This is bad because most animal species have evolved with C4 plants.  The shift away from C4 plants has the potential to disrupt the food chain and ecological balance of the ecosystem since smaller organisms and herbivores lower down on the food chain depend on C4 plants for food and shelter, and lack of C4 plants would thus compromise the survival of these organisms and in turn, the survival of omnivores and carnivores higher up on the food chain that eat these plant-eating creatures.  In sum, the shift from C4 to C3 plants has the potential to severely disrupt and dramatically damage the balance of this ecosystem.

The Neutral:
If humans want to transform the land for pleasure purposes, all they need to do is simply turn it into a park; this allows no destruction of the land to be done.



The UGLY:
Another increasingly common problem for the African savannah is agriculture.  Social and economic influences from humans have forced savannahs to be converted into agricultural lands and fields as humans increasingly urbanize wild landscapes.  On top of the loss of rangeland and habitat for animals of the African savannah, increased use of fertilizer and irrigation pollutes the land surrounding agricultural spaces.  At the same time, monoculture cropping (the planting of just one type of crop) severely depletes the soil of nutrients, leading to environmental degradation that changes the makeup of the African savannah.
Furthermore, the introduction of grazing livestock to the savannah lands has led to overgrazing and overcrowding of watering holes; thus depleting the landscape of both vegetation and water.  In fact, livestock is one of the biggest threats to the African savannah because if just three families try to live on the same plot of land, it can immediately become overgrazed.
In addition, humans have further damaged the ecosystem by hunting many species of animals to the brink of extinction or critical endangerment.  Many megafauna have already gone extinct, and many more continue to be poached illegally and in high numbers.  A prime example is illustrated by “The Elephant Problem,” which was when elephant poaching for ivory was so rampant in the 1970’s and 80’s that 2/3 of the African elephant population was killed.  In addition to megafauna, other smaller animals have also been hunted mercilessly.  Most notably, poor Africans in rural villages and destitute towns kill animals for meat – particularly bush meat – and fur, to sell the profits for income.  In this way, humans have removed many native animals from their surroundings.  Extracting key native animals species ruins the ecological balance of the ecosystem.  Thus, when animals that once play an important role in maintaining the ecosystem disappear, if no other animals fill their niches and perform exactly the same or very similar ecological roles, parts of the African savannah begin to change into a different ecosystem, which negatively impacts the remaining animals and floral composition.

 While fires are essential to maintaining natural landscape of the African savannah by removing dead and decaying organic material and thus rebalancing the ecosystem environment, humans increasingly prevent fires to protect pasture and farm lands.  Fire prevention in the African savannah subsequently threatens the ecosystem because without fires, bushes encroach on landscape, changing the makeup of the savannah and turning it into a long-term forested area.  Meanwhile, sans fire, organic matter and litter accumulate to such an extent that when fires do set in, they end up being massive and destructive to the landscape and environment on a large scale.                                   
However, overburning by humans to reduce bush encroachment and natural re-recruitment of trees leads the ecosystem to be more vulnerable to invasion by foreign species, which further transforms and upsets the balance of the land.


 Keep the Savannah beautiful! Save the Elephants!

6 comments:

  1. Hi, I'm currently doing an Extended Project on the conservation of lions, which was what lead me to this. I wondered if it would be possible for you to give me the name of the book/article/site where you learned about the shift from C4 to C3 plants as I would like to reference and read more about it. Thanks, and I love the blog! :)

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  2. Hey so I'm doing a class project where I'm building a model of a savanna. We also have to write an essay and it includes writing about the human impacts on a savanna biome, and this information really helps. Thanks!

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