Analyse the role of human activity in plant succession

There ar many factors that can affect a stop vegetation. These accept climate, hydrology and soil type. Human activity likewise plays a major role. If eon is modified or interrupted by a human influence then a plagioclimax is reached. Human activities include grazing, burning at the stake and de imbedation and these processes can be collectively known as seize factors.A plant chronological sequence begins on b are ground with light-seeded grasses, legumes and peak plants. Over time small trees, brush and briar thickets shade emerge the sun loving grasses. Ultimately, light-seeded trees shade out the brush and make conditions well up-situated for shade loving mast liftrs like oaks.De toneation involves the crude protrude, burning and minus of forests. If the current rate of deforestation continues then the human cosmoss rainforests will disappear alone within 100 years causing unknown effects on global climate and eliminating a majority of plant and animal specie s presently alive on the planet.The reasons for deforestation are complex. It is mainly carried out for countrified reasons, e.g. grazing cattle and planting crops. Poor farmers may chop down a small area (usually a few acres) and burn the drawers in a process known as slash and burn agriculture. cows pastures often replace the rainforests in articulate to elevate beef for the world market.Another type of deforestation is known as commercial record. This is the cutting down of trees in order to sell off as shade and pulp magazine. This process uses heavy machinery, such as bulldozers and road graders etc to remove trees and this is pestiferous to the forest and plant episodes overall.Competitive global marketing drives the get for property in economically challenged tropical countries. At national level, governments sell logging concessions to raise money for projects or to pay planetary debt. For example, brazil-nut tree had an international debt of $159 billion in 1995 on which it must make payments each year. log companies seek to harvest forest and make profits from sales of pulp and valuable hardwoods e.g. mahogany. This raises the money required in order to pay thorn some debts.A case study of an area where deforestation has affect succession is in the Philippines. For the past 50 years the Philippines has lost 2.4 acres of hardwood forest every minute leaving exactly 21% of forest cover.This has been due to increasing agriculture and illegal logging. Reports of deforestation-related declines in rainfall totals and flutter of rainfall regimes have also been reported for parts of the Philippines (Alfonso, pers. comm., 1988). During the 1960s on that point was considerable deforestation on Mount Apo, for instance, due to the establishment of coffee berry plantations and the apparent result is increasing drought.The short-term gain of deforestation, i.e. the profit to be made, is all well and good but at that place have been a large number of adverse effects brought about by the removal of large areas of forest. The main effects are increased soil wearing (which leads to increased flooding in most areas), reduction in biodiversity, the greenhouse Effect, reduced fertility of region in deforested areas and disruption of the hydrological cycle.Major roads are be built through the forest to fork out easier feeler to the underground re addresss like iron and aluminium ores more trees need to be removed to mine these commodities. Inhabitants of shanty towns around Major cities in Brazil are being encouraged to move to rural areas and more land has to be cleared to accommodate these people. In trinity world countries forests are cut down and used to provide firewood, since this is practically the only source of fuel available to people living there.There are also a large number of new markets opening which are find to increase the train for products, which have their origin in the tropical rainforests. The se include body creams, bath oils, sweets, fruits and nuts, but as these products come into greater demand the future of the forest will be more secure because to produce a large yield of these products a large number of trees need to be grown. About 16-20 million hectares of tropical rainforests are removed each year.When trees are removed no water gets transpired back into the atmosphere from the soil. Because of this there is reduced rainfall and surrounding areas of forest are threatened with dessication and straightaway soil erosion because the soil is no longer held together by moisture.Another recently discovered side effect of deforestation is that it may actually help to spread diseases like malaria and river blindness. Anopheles darlingi, a mosquito that effectively spreads malaria parasites, breeds in pools of water created in deforested land, open cast mines, and on gnaw land after trees have been removed. Deforestation has favoured a population flare-up for this sp ecies and up to a quarter of the people living along the Transamazon road in Brazil are affected by malaria each year. thus far damage to plant succession human activities can be, the effects provide excellent conditions in which for a secondary succession to take place. A secondary succession differs from a primary succession in that it occurs in an area where a community of plants and animals has recently been wiped out, i.e. the land is already sufficient for a wide diversity of species to establish themselves on. A secondary succession can happen on an area of land where a forest fire or parasite wiped out a previous climax community or which has been disturbed in some way by mankind e.g. deforestation or arable farming.A secondary succession takes place much more quickly than a primary succession for two main reasons, the most obvious one being that a suitable medium already exists for the new organisms to grow in, and the other being that some seeds or spores from the last plant community can bland be present in the soil after the community is destroyed. This is a positive aspect as new plant species can grow and thrive.As well as big processes such as deforestation, humans can contribute to vegetation in smaller ways. There are now varied types of species in Britain due to human hoo-hahs, modification and management. Without interference vegetation would be typically temperate forest. Today, in Britain, there are no natural woodlands at all, only semi woodlands, and there is only 2% of that. In Spain the figure for natural woodland is 28% and Sweden has a 64% woodland covering. Other interferences have caused the introduction of foreign plants such as the rhododendron or sycamores. The rhododendron was in fact imported from Japan. Other introductions to this republic include the rabbit, which was imported from Spain by the Normans.Urbanisation also causes damage to plant life. High demand for housing has caused the destruction of forest and woodl and, especially in the north. A rising birth rate in the twentieth hundred called for an increase in housing, and this needed to be conducted as cheaply and effectively as possible. As a result, miles of forests were cut down in order for building to go ahead. This s detrimental to our health as well as destroying areas of natural beauty. . Recent investigations suggest that over a third of the worlds oxygen supply is produced by the rainforests, the only larger source being algae in the sea. So cutting down trees is very damaging to our well being.