There are three methods of maintaining grassland, grazing, mowing and scrub clearance. Woodlands which generally are not very diverse are dominated by certain trees can also be maintained by using two different methods, fire clearance and coppicing. (1)
Grazing involves the introduction of grazing animals onto grassland, they eat tree seedlings so the trees are not established. This means that the land does not develop in to woodland but remains as grassland. However, overgrazing may take place after a period of time so desertification begins to take place. This may be overcome by introducing a natural predator of the grazing animals.
Mowing of the grassland is another method used to maintain grassland. The point from where trees grow, the apical meristem is above the mowing level. Therefore when mowing takes place the seedling dies, grasses have meristems above mowing level so they remain undisturbed from the mowing. When using this method as a control great care has to be taken, mowing cannot take place too frequently otherwise this will lead to low biodiversity. If the grassland is mowed every six months then there has been a sufficient amount of time for other plants to grow amongst the grass leading to an increase in biodiversity.
Scrub clearance is used as a final alternative for maintaining biodiversity within grassland that has already started to develop into woodland. Seedlings, bushes, bracken, bramble or any plant species related to woodland are pulled out of the ground by their roots. This is a temporary measure to ensure grassland is maintained.
As woodland is not as biologically diverse as grassland diversity may be increased. Fire clearance involves burning down trees, initially firebreaks are created. These are made by chopping down a certain area of trees so that there is a gap between that trees set on fire and those which are not required to be burnt. The cleared land has more exposure to sunlight and also there is no obstruction for seeds that are falling from the surroundings. This increases the diversity of the plants that grow in the area of land cleared by fire.
Coppicing is the second method used to maintain woodland, it involves cutting a tree down so that a stump still remains. This encourages new growth of branches grow, these are harvested and used for building or for charcoal. The cutting of trees is rotated, this opens up the canopy encourages flowers and other plant species to develop on the woodland floor.
REFERENCES
- Genetics, Evolution and Biodiversity- Adds, Larkcom & Miller
- The Conservation Atlas of Tropical Forests: Africa (information on biological diversity only)- N. Mark Collins, Jeffrey A. Sayer, Timothy C. Whitmore
- Biology for Advanced Level- Toole & Toole
