Thursday, March 7, 2019
Discuss the relative importance of physical and human factors in accounting for changes to vegetation over time within ecosystems in the British Isles Essay
There argon some factors that account for the changes to the phytology over sequence within ecosystems in the British islets, such(prenominal) as homo operation, climate, blemish, slack availability and intensity and internal disasters. The characteristics of the vegetation that ar influenced by these factors are apex, distri thoion, variety of species, adaptations and density of the vegetation. whatsoever of these factors gift relatively little influence on the successiveness development, whereas others surrender a spectacular influence over a retentive plosive consonant of time, such as human activity. These factors, over time, proceeds in the advancement of a succession until the climatic sexual climax vegetation is createed. However, sometimes these factors female genitalia mean that a plagioclimax is reached, as they prevent the succession from progressing any go on and the climatic climax vegetation is never achieved, which in the UK are Oak, Hawthorne and birch trees.This succession results in the development of an ecosystem. An ecosystem is a dynamic, st fit environment which is compose of interacting and functioning biotic and abiotic comp matchlessnts and tail assembly be of any size. There john be composed of variety of successions, such as lithoseres in grass trim and woods battlefields for practice the Isle of Aaron, psamoseres a dogged the coastline or small scale urban successions in urbanised areas. In an ecosystem, all the component are characterised as biotic, for example animals and plants, or abiotic for example climate, pH, reason characteristics or drainage. These biotic and abiotic factors get the changes to the vegetation in the ecosystem overtime as they have a undischarged effect on it, such as flooding and animal grazing. deep follow up the ecosystem, thither are inputs, outputs, stores and flows which transfer minerals, nutrients, water and light vital force. The most distinguished input is light e nergy from the sun, which is the source of any food chain.Producers scar a food chain, but they would not be open to do so without the 2% of energy provided by the sun to allow photosynthesis to occur. 10% of this energy is then transferred with the trophic levels in the food chain, from the autotrophs, with the consumers to the detritivores. Energy is lost at each stage as a result of movement, excretion and heat energy loss. As long as there is sufficient sunlight, consumers will continue to be able to use the vegetation in an ecosystem is a food source, which will have a dramatic affect on the characteristics of the vegetation. In this case, both human and visible characteristics are equally important for accounting to changes in the vegetation. Nutrients in an ecosystem are transferred through the nutrient cycle, a balanced cycle which ensures that there are complete nutrients for the ecosystem to survive.This cycle is represented in a Gersmehl Diagram. An example of an e cosystem is a cold- equable deciduous woodland. The main human factor that affects the development of a temperate deciduous woodland is deforestation. Deforestation occurs for a cast of reasons to use the tonicity for commercial use, to use the land for agriculture or to use the land to build on. Once the land has been deforested, it will never be able to be used for the same environment again as the soil washes a mode in the rain. Therefore, human activity has an extremely large pretend on the development of vegetation as it end result in the environment becoming inhospitable. One of the physical factors that affects the distribution of vegetation is the height and density of the exsisting vegetation.This is because the more dense the canopy layer, te less light will filter through the leaf mosaic to the shrub layer. This agency that only plants that require little sunlight will be able to survive, unless they have adaptations that enable them to absorb as much sunlight as po ssible such as having bread flat grants so that they have a large surface area, or flowering earlier or later than other plants, such as Dogs Mercury and Bluebells. Another physical factor that affects the distribution of vegetation is the climate. If an area receives too little or too much rainfall, the plants will not be able to survive. On average, the temperate deciduous woodland should receive around 750-1500mm of rain per year. If this number is greatly exceeded, then the soil will become saturated and the area will flood, suffocating the plants as they do not have rise to position to sufficient oxygen and coke dioxide.On the contrary, if there is not full rainfall then the plants will to a fault die because they do not have access to a plentiful supply of minerals that the water contains such as nitrogen and magnesium. One type of succession that can body an ecosystem is a lithosere. A lithosere is a plant succession that begins life on a innovatively exposed rock n r oll surface, such as one left bare as a result of glacial retreat, architectonic uplift as in the formation of a raised beach, or volcanic eruption. The lithosere succession is initiated by pioneer plants, such as docile and green algae with colonise the sock as there are into a lot of nutrients available and they have no root systems, so they can survive in the soldieryile conditions.The succession then progresses cod to the pioneer plants dissolving the rock, resulting in a release of nutrients. This then direction that mosses, lichens and liverworts are able to thrive on that ground as the moss can absorb nutrients from rain water and they provide their own energy from photosynthesis. These plants chemically decay the rock by releasing acids, and physically decay the rock as a result of their root systems, leading to an amelioration of the plants so that the lithosere can progress to the next seral stage.Herbs grasses and small flowering plants can at one time colonise in the se conditions, which are followed by ferns, brackens and small shrubs as the soil is now thick enough to support their roots and their seeds become lodged in the cracks made by the moss, so colonisation continues. Once these plants die and decay, they leave humus which adds to the richness of the soil and enables more developed plants to grow in their place. At this stage, the soil is developed enough and contains enough nutrients that it can host small tress, such as Alder and Rowan. Once these trees die, the lithosere is able to reach its climatic climax vegetation of Oak, Birch and Pine.There are galore(postnominal) physical and human characteristics that affect the development of a lithosere. In the Isle of Aaron, there is no vegetation in areas of high relief. This is because the seeds for the plants slide down the slope, and do not colonise the steepest areas but colonise the top and fathom of the slope. Another physical factor which causes a lack of colonisation is the sal tiness spray from the sea. The salt dehydrates the rocks that it lands on, so the area becomes inhospitable to the hardiest of plants. The prevailing winds from the southwesterly west result in a higher wind shakiness factor, therefore temperatures are lower, resulting in niche conditions. The winds also deliver seeds which can colonise the area, if the niche conditions that have been created are an appropriate for their survival.The southerly go about beaches receive more light and heat energy, therefore decreasing the time in which it takes for the succession to reach its climatic climax vegetation. This is because the increased heat energy results in more photosynthesis taking place, as photosynthesis needs carbon dioxide, water and sunlight to occur. As a result, the plant has more energy and so the root systems develop at a fast rate, weathering the rock. In this particular example, the physical factors have a great effect on the development of the lithosere as its developme nt is regulated by factors such as climate, relief of land and pH of the environment.A plagioclimax is when human activity interferes with the succession of a sere and prevents it from reaching its climatic climax vegetation. Human activity which causes a plagioclimax to occur could be deforestation, animal grazing or finish clearance. Conversely, it is not just human activity that can result in a plagioclimax. Natural disasters such as floods and volcanic eruptions can also result in a plagioclimax being reached. However, if the plagioclimax is reached as a result of physical activity then it is mainly not maintained and inessential succession can occur, which is when plants develop on land that has previously been vegetated. An example of a plagioclimax is the heather moorland in the North York Moors.The North York Moors were formerly covered in woodland, and heather would have featured in in truth small quantities. However, as a result of sheep grazing and deforestation, the regrowth of the climatic climax vegetation has been prevented and now heather is the dominant species. To control the uplands and encourage new heather shoots, managed burning is employed every 15 years, a proficiency that eliminates the less fire resistant species, allowing heather to dominate and conserves as many nutrients as possible.To conclude, I think that both physical and human factors comprise a significant role in accounting for changes in vegetation over time in the British Isles. However, I intent that physical factors have a greater impact in the long term that human factors, as physical factors are such that they generally change the environment or habitat on a long-lived basis, such as climate change. Nevertheless, I believe that human factors play a significant role in changes to vegetation over time, but I feel that human intervention is not as long term as a change made as a result of physical factors because humans generally have the control and power to conti nuously change the environment and possibly restore it back to the way in which it was originally, whereas physical factors are not controlled.
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