Environmental Issues in the Savanna

Overview:

There are many threats which assail the grassland biome of Savanna, most of which are caused first and foremost by humans and their actions towards this place (most of which are explained in Effects and impact of human progress), although there are still several threats which are caused without any (or with little) human involvement.

Grazing:

One threat to these Savanna biomes is the animals which graze upon it. Other biomes such as Taiga or Rainforest have a high tree quantity which means that less grass is able to grow for animals to graze on. However, since Savannas have few trees and much wide open space than other biomes an herbaceous layer grows much easier.
This can lead to problems because whilst the native animals to graze upon this grass are ok, as it is natural for them to be there, however the many animals brought into the Savannas by humans because of the great grazing conditions should not naturally be there. These animals added with the animals which are already on this grassland provides a great rise in the animal population. This raise in animals lessens the amount of food available and could cause the native animals to be forced to leave or die, upsetting the natural order of things. The lessened amount of grass can also cause a rise in tree growth. The grasses and the trees must compete for water.
If these grasses diminish in number then the trees will no longer need to compete for the water and the number of them will greatly increase. This will be a problem for the animal life because they have evolved to live in an environment with few trees but lots of grass. If the environment suddenly has lots of trees but few grass the animals will have to either change the way which they act (adapt) or they would have to find a better environment to call home. The grasses all being eaten not only reduces competition for the trees but it also for the weeds. The final major affect of grazing on the Savanna is that the hooves of the grazing animals can compact or break up the dirt, as it is no longer protected by the grasses.

Exotic Plant Species:

Another such threat to these magnificent biomes is exotic species of plant. There are many forms of exotic plants species which have been introduced to Savannas all over the world. Many of these are very serious environmental weeds such as the Prickly Acacia, the Rubbervine, the Lantana, the Prickly Pear and the Mesquite. There are also many herbaceous plants which have been introduced to the savanna environment such as Rhodes grass, Giant rat’s tail grass, Buffel grass, stylos and other such legumes. These exotic plant species can harm and alter the environment. Some ways in which these plants do this is to alter the present fire frequency and ferocity by burning better or worse than present plant growth, increase the grazing pressure and compete with the native plants for sunlight and water.

Climate Change:

One very likely and imminent threat to the Savanna biome is climate change. Climate change is a threat which all biomes must face, although some will be affected more so than others. Some people have claimed that because of greenhouse induced climate change the Savanna biomes could become liable to a woody plant encroachment. This would be a drastic alteration to the Savanna environment because at this point in time Savannas are usually areas with few woody plants.