The plants and animals that share the same environment are part of an ‘ecosystem’.
Most ecosystems are very complex. The ecosystem of a forest includes many different kinds of birds, plants, trees, insects and animals.
We rely on our environment for 3 essential natural resources; living plants and animals, materials (such as metals, coal, oil, and gas) and energy.
People change their environment to benefit their needs and development purposes. When the environment changes, the ecosystem changes too. Changing the environment for the worse is called ‘pollution’. Pollution can slow down the growth rate of plants and animals and can affect human health. In recent years people have realised how harmful changing, and therefore, damaging the environment is.
Steps have now been taken to prevent pollution through individuals and industries. Derelict buildings have been made into gardens and playgrounds for children, and conservation projects are protecting areas of land, buildings, animals and plants from harm.
This essay looks at various parts of the ecosystem and the environment. It looks at the problems that humans cause such as deforestation, pollution (acid rain, air and river), farming and mining. The essay also discusses why we cause such problems and what measures we are taking to prevent such things from destroying the world we live in.
Farming and Agriculture:
The need for timber and food production has been extremely important factor, as we need food to survive. Therefore there has been mass change in land uses over the years. As the human population increases, demand is constantly creating damage and stress on the fertile land.
The most important environmental impacts on the farm are the use of chemicals, the implications of conservation and the effects on biodiversity.
Fertilisers: Plant nutrients from the soil are taken away when the crop is harvested through leaching into watercourses or by being lost into the atmosphere. If fertilisers are not applied to compensate for this loss, soil fertility will decline. Even though there are organic sources of fertiliser, such as manure, they do not always contain the right amounts or balance of nutrients.
The problem of using fertilisers is that, like the natural nutrients in the soil, they can be leached into rivers and streams where it accelerates the ‘eutrophication’ process. This occurs when there is an excessive content of nutrients and results in too much vegetation growth and decomposition. This deprives the water of oxygen and can result in the death of fish and other aquatic life.
Pesticides: Pesticides can be a threat to the environment in high concentrations by being toxic to plants, fish and animals (including certain useful insects like the natural enemies of the pests). As with fertilisers, pesticides can be leached out of the soil and into rivers and streams.
To decrease the amount of leaching that occurs when fertilisers and pesticides are used, natural fertilisers e.g. manure are being used more often and farmers are planting legumes into their soil to naturally restore the levels of nitrogen in their soil. Biodegradable pesticides are now being used, which break down into harmless compounds after time. A Biological control of pests is also being tested. This involves releasing natural predators of the pest in to the field to feed on them. All of these may slightly less time effective and more expensive but certainly benefit the environment in a huge way.
Biodiversity conservation: Preserving biodiversity is important since all living organisms can be viewed as potential resources that can benefit the society. Aspirin, for example, is the synthetic version of a natural compound found in a plant; if such plants species are eliminated, so too will their potential (and unknown) benefits. Another example is ‘cyclosporin’ derived from an obscure Norwegian fungus. It has shown itself to be a powerful immuno-suppressive agent, which today, is the basis of the entire organ-transplant industry. The Kerry breed of cattle from Ireland, now an endangered species, produces milk that does not cause the same allergic reaction in people who are lactose-intolerant; preserving the species will make the genetic resources of such rare breeds available for future development.
Farmers and the government are now trying to reduce this impact on the environment while still maintaining food production at an adequate level. In some area’s the land is controlled by the law to protect it ‘Areas of Outstanding Natural Beauty’ (AONBs) have been created to protect special landscapes as well as National Nature Reserves and Sites of Special Scientific Interest.
Acid Rain: Acid precipitation (acid rain) contains a higher concentration of hydrogen ions (H+) than of hydroxyl ions (OH-) (McGraw 1992). Data suggests that humans cause 95% of the acid deposition that occurs on the earth. Nitrogen oxide and sulphur oxide from industry and vehicles are major components of acid deposition that become acidic as they react with water in the atmosphere (Gow and Pidwirny 1997).
The aquatic ecosystems found on earth are highly affected by acid deposition. As the acidity of the waters increases, the species richness decreases since only a fraction of the species present are able to survive and reproduce in these conditions.
Godbold 1994 found that acidity in forests enhances abiotic diseases, foliage diseases and root and stem decays, therefore it characterises a decline in forest life.
Pollution in the air: Through respiration, humans, plants and animals all emit CO2. But in general respiration is CO2 neutral (meaning that no more CO2 is taken out of the body by breathing than what is taken in throughout a lifetime). Hence, wood that is burnt, releasing it’s carbon content as CO2, is just emitting what the tree has accumulated in carbon during it’s life span, so this cannot be considered as a source of pollution.
However, the burning of fossil fuels (coal, oil and gas) emits CO2 from carbon that was absorbed millions of years ago and that has accumulated over very long periods of time. Therefore, burning fossil fuels adds massive additional quantities of CO2 into the atmosphere, resulting in an accumulation of the global warming effect.
Humans contribute to CO2 emissions through use of vehicles and power plants. We are now starting to use more public transport to reduce the amount of fossil fuels being burnt. It is also very common nowadays for an average family car to be fitted with a ‘catalytic converter’ which reduces some of the exhaust emissions. Air can be ‘scrubbed’ by fine jets of water, which remove most of the dirt; or an electric current can be passed through. This removes most of the dust particles.
Global Warming: CO2 (carbon dioxide) is a green house gas. It absorbs heat, which radiates from the earth’s surface that would otherwise escape into space. The effects of this is higher tides and water levels due to the melting of ice, which therefore causes more floods in which thousands of homes are destroyed every year. The amount of carbon dioxide in the atmosphere
has increased by a quarter over the past 150 years. This results from burning fossil fuels in industries (power plants) and vehicles.
This problem has been argued over for many years. It is suggested, that to reduce the levels of carbon dioxide released by vehicles, that more public transport should be used, and private vehicles used less. Few of the population have agreed with this idea and have organised walks and use busses a lot more. However, the majority of the population and their way of lifestyle need to use private transport regularly as it is much more convenient and reliable. So what else can be done? Well, nowadays, it is common to see cars fitted with ‘catalytic converters’ to reduce harmful exhaust emissions. The government are also working on new, less harmful fuels to out into cars that release non-harmful compounds into the atmosphere. However, it will be a little while until these vehicles are available readily and at an economical price to buy.
It is evident that increasing exploitation of land for human use greatly reduces the area of each wildlife habitat. Reasons for deforestation include:
> Supplying firewood as fuel
> To make room for houses, industrial buildings, roads and dams
> Removal of trees for pulp and paper
> Cutting trees for timber used in the construction industry
The consequence is decreased species diversity, due to reduced habitable surface area, which corresponds to a reduced ‘species carrying capacity’. It also reduces the genetic diversity of the species living there.
The burning of large areas of forests also produces large quantities of carbon dioxide, which contributes to the global warming effect. Burning trees also significantly reduces the percentage of nitrogen held in the ecosystem. Deforestation causes nutrients to be lost through leaching.
To prevent these problems occurring, new trees are now being planted in replace of ones that are cut down. Ecotourism also takes place now (attracting visitors to natural forest ecosystems to raise awareness for the need of conservation).
Biological Conservation: This aims to maintain the quality of natural environments and their biological resources. Unlike preservation, which tries to prevent human interference, conservation involves actively managing abiotic and biotic components to ensure the survival of the maximum number of species and genetic diversity. In order to survive, populations must have biotic resources (such as food and a mate) and abiotic resources (such as space in which to live and shelter). In many ecosystems, the activities of humans and wildlife are in conflict. To reconcile this conflict, biological conservationists generally adopt a policy of ‘sustainable development’. This is development that can continue indefinitely because it is based on exploiting renewable resources while minimising environmental damage, maintaining the overall integrity of the ecosystem, and conserving animal and plant species.
There is often a conflict between the needs of a country to produce enough food to feed its inhabitants and the need to conserve natural habitats.
This idea can be illustrated in agriculture. Conservationists argue that there are viable non-polluting alternatives to the use of chemical fertilisers. For example, crop rotation or intercropping with nitrogen-fixing leguminous species, which will improve the nitrogen content of soils.
Why conserve at all?
Utilitarian Reasons: Conserving biological resources for their usefulness or economic value. Wildlife supplies us with food, medicines and many industrial products.
Aesthetic Reasons: Conserving wildlife for the pleasure it provides. Some people believe that contact with nature is essential for human well-being. Many countries are encouraging ecotourism. In Kenya, ecotourism is the biggest earner of foreign exchange.
Ecological Reasons: Some people believe that the complex network of relationships that maintain biogeochemical cycles in the biosphere may be disrupted by the extinction of some species or by large-scale destruction of natural ecosystems.
Ethical Reasons: Some think that we have a moral duty to look after the environment and that all species have the right to live. It is therefore morally wrong to destroy ecosystems or to allow species to become extinct.
> Development of national parks and nature reserves – These are habitats legally safeguarded and patrolled by war
> Planned use – On a smaller scale, specific areas of land may be set aside for a designated use. The types of activities permitted on the land are carefully controlled by legislation.
> Legal protection for endangered species – It is illegal to collect or kill certain species. In Britain, the Wildlife and Countryside Act gives legal protection to many plants and animals.
> Commercial farming – The development of farms to produce sought-after goods, e.g. milk farming, deer farming may produce enough material to satisfy the market and so remove the necessity to kill these animals in the wild.
> Breeding in zoos – Endangered species may be bred in the protected environment of a zoo and when numbers have been sufficiently increased they may be reintroduced into the wild.
> Removal of animals from threatened areas- Organisms in habitats threatened by humans, may be removed and settled in more secure habitats.
> Ecological study of threatened habitats – Careful analysis of all natural habitats is essential if they are to be managed in a way that permits conservation of a maximum number of species.
> Pollution control – Measures to control pollution such as smo0ke emissions and over-use of pesticides all help to prevent habitat and species destruction.
> Recycling – The more material that is recycled, the less need there is to obtain that material from natural sources, e.g. mining. These activities often destroy sensitive habitats, through the dumping of waste which is toxic or the development of roads to transport the products.
> Education – It is of great importance to educate people in ways of preventing habitat destruction and encouraging the conservation of organisms.