Biomes in South Africa free essay sample

Vegetation, vegetation and fire influence positive and/or negative actions imposed on one another. Climate affects vegetation by means of any form of precipitation (rain, snow, fog, etc). Climate also affects the different types of vegetations that will burn after long periods or seasonally due to the variables of precipitation. Fires can be caused through natural impacts or through human endeavors. Fires usually arise after long dry hot periods in windy weather when humidity is relatively low. Under such extreme conditions intense fires occur. These fires can spread to far distances with burning everything in its path. Lightning is another natural way to cause fire. Human activities in contrast either deliberately or unintentionally ignite fires. With respect to the deliberate fuelling of fires, certain biomes require fire to germinate and adapt to living under these conditions, therefore humans have to ignite fires to maintain the routine of fire in fire-scarce biomes. The biomes of South Africa that fire plays the most important role in are the Fynbos, Savanna, and Grassland biomes. There are four other biomes that rarely burn. Fire is the most important in the Fynbos biome; the reasons will be touched upon in the following paragraph. Fynbos (fine-leaved bush) biome This biome describes evergreen scrublands with a deficiency in trees and grasses. There are two major types of vegetation: Fynbos and Renosterveld. There is high endemism of 80%. The range of the mean annual precipitation is between 250-800mm. Due to the high rainfall occurrence fires are then important to allow for the specific fynbos vegetation growth. There are several factors influencing fire dynamics in fynbos: global warming, grazing practices, and fire management. Fynbos must burn between 6 and 46 years of age in order to uphold its plant species. With the above said, plants have become adapted to two ways in which to manage fires: re-seeders or re-sprouters. Re-seeders are mostly practiced. Cones encase seeds that are fire-resistant hence protecting the seeds from desiccation and burning completely. These seeds are then released after the fire. The fire enables the seed to then germinate and become adapted to that environment. Most fynbos are flammable due to them containing flammable oils. These oils come from the seeds of the plant which get their nutrients from the soil and precipitation. The parent plant species die after the fire indicating a low life span and reproduction can only occur with seeds there-on-after. There are also many species that are adapted to re-sprout after the fire. Without the presence of fire, the fynbos species will age and die out. To great extents of fire burning, fynbos can become eliminated. Grassland biome Grasslands are biomes that dominate in large quantities of grass. Grasslands do not get high rainfall therefore they are said to be semi-arid. Precipitation ranges between 400-1200mm per annum. In the grassland biome fire is regarded as a secondary determinant. Fires and grazing are important factors influencing grass dominance given that under wet conditions it helps prevent trees from thriving in this region. In drier areas, trees may not grow but fire still plays a role in allowing other species to grow as well as recycle nutrients to the soil. Burning of grasslands is prescribed in areas of high biomass where grassland curing poses a wildfire threat. Farmers and nature conservators also burn grass masses to provide grazing and is known as a method called maintenance burning. There is great biodiversity in the grassland biome. These organisms are well-adapted to the environment and are fire-tolerant. Savanna biome The savanna biome is identified as a ground layer consisting of grass whilst the upper layer consists of woody plants and a lack of trees. The mean annual precipitation is in the range of 230-1250mm. Grasses fuel fire. The temperatures in savannas are high therefore savannas are only found in warm or hot regions. Due to the hot dry periods fires occur and this does not allow for the growth of trees and other plant species, if fires weren’t present then the savanna would dominate as tropical forests. Other than the grassland biome, fire and grazing are also important in the savanna because these allow for the dominance of grass. Fires in the savanna are also viewed as a cleansing medium in which old growth of grass is burnt-off. Taxa in this region have become well-adapted to living under these harsh conditions therefore they grow back to assist in continuing this vegetation type. Biomes of South Africa where fires rarely occur and are of little importance; namely: forest, succulent karoo, nama karoo and the thicket biomes. Forest biome The forest biome consists of canopy trees and other herbaceous and woody plant species. Vegetation is absent due to insufficient sunlight which is blocked out by the tall trees. The mean annual precipitation is 525mm in winter rainfall areas and 725mm in summer rainfall areas. Fires rarely burn due to the high rate of humidity. When temperatures reach a maximum, forest biomes can completely burn out-destroying the vegetation profile. Succulent karoo Succulent shrubs dominate this vegetation. There is a lack of grasses, trees and tall shrubs. There is low rainfall in the range of 20-290mm per year. This range indicates summer aridity. The aridity without the influence of other factors does not permit for fires to occur. As no fires occur, the biome is regarded as succulent. Nama karoo The vegetation is dominated by grassy shrublands. The rainfall is 100-520mm per annum. It is relatively low. Summer rainfall is a primary determinant. Grasses are needed for the fuelling of fire but in this biome grasses are present to a very small extent. Hence no fires are present. Thicket biome It contains shrubs with low trees and forest characteristics. The mean annual precipitation is 250-1500mm. There is rain throughout the year in the core area. There is summer rainfall. Due to the humidity, no fires occur. It is then said to be succulent with high humidity. Fires are not delimiting factors therefore insignificant in this biome. With the above information, you can conclude that fires are important in specific biomes with some complex and others not so complex influencing factors being mainly climate and precipitation. The other biomes mentioned rarely burn due to delimiting factors that do not necessarily require other certain factors for burning due to the nature of each biome. Whether fire is caused by humans or natural origins, it is not always taken to have devastating effects on certain biomes as these biomes exist in accordance with fire. Author: Kerina Ramparsad