Rainforests now only account for less than 6% of the lands surface; despite this they are home to nearly half the populations of species found in the world. A rich and diverse habitat provides some exceptionally interesting and unique species of flora and fauna. The dangerous and inhospitable environment has meant that plant and animal species have been able to thrive for thousands of years without human intervention of influence, hundreds, even thousands of years the rainforests were home only to small indigenous communities, living only with the resources provided to them by their natural environment. In recent centuries many events have occurred that have lead to the destruction and exploitation of the world’s rainforests and its people, the cause of the damage is directly linked to human population growth and the knock on effects that come with this. Over-population in local communities, though often blamed was never really the problem, it has been the ever hungry over consumption of rich, developed countries that has lead to mass deforestation and changes in land use, changes which often cripple the land and rob it of a chance at regeneration.
Human Population growthPopulation figures for humans have increased rapidly over just a few hundred years, 2000 years ago human populations stood at approximately 300 million, this figure rose very slowly over a thousand years by just 10 million, the next 800 years populations grew steadily to a milestone1 billion. From the beginning of the 18th centaury the industrial revolution and improvements in health care, sanitation, agriculture, housing and energy supply have allowed populations to soar all over the world: and in just 127 years the population doubled to 2 billion. The time frame for each billion has been getting smaller and smaller since then, it took just 33 years to reach 3 billion and then 13 years to reach 5. The population now sits in the 6 billion mark and is expected to continue to grow.
The rapid growth of human populations has seen a massive reduction in available local resources, despite this human consumption in rich countries continues to grow.
Approximately half the human population live in poverty, in places where there is barley enough resources to survive and as a result the mortality rate is high. Despite the huge numbers of people living in these areas, they have had little impact on the tropical forests of the world; an individual person in a rich country is expected to use sixty times more resources than a single person in an undeveloped country.
Rapid growth of industry and economy over the last 50 years has caused companies and governments to exploit resources from other areas, as they can no longer sustain their own. Colonialists discovered the vast resources of the rainforest and have since exploited its use to the detriment of indigenous individuals. Indigenous people once had their own sustainable methods for managing their environment with low impact farming and utilisation of abundant foods and resources; these have now been displaced by areas of mass agriculture, plantations and logging. Each of these topics have their own effects and impacts on the rainforest and all contribute to the destruction of a very special habitat.
Colonialists also took it upon themselves to start moving indigenous populations around; they believed they could help over-population problems by moving people to uninhabited areas of the rainforest. This soon became a problem as the soils could not sustain the new numbers of people, meaning that areas were drained of nutrients and people had to move on to new places leaving a trail of destruction behind.
Increased levels of tourism have been made possible by continual reductions in the cost of travel, interest in the rainforest has led to resorts and developments being built to accommodate ever growing numbers of people. Tourism is seen as a quick financial solution as it brings in economy that can be used to fund conservation projects, but damage usually occurs before management of the area is put in place leading to further damage.
Animal UtilisationThe rainforests have long been home to many interesting and beautiful species of animal; many of these have been hunted to near extinction for the purpose of man. Though most reduction in species populations is closely linked to habitat loss rather than hunting, it has still however played a large part in the endangerment of certain species.
Fur is a massive trade and although there are many legislations in place to prevent the decline of species for fur, there are still large numbers of species being poached and sold on the black market to be made into coats, bags, hats belts etc. large cats and giant otters are particularly at threat as reduced habitat is making them easier to find.
Ivory has been used throughout history for a range of human items due to its hardness, workability and attractive surface. It has been the basis of many ornamental objects and art works for hundreds of years, the demand for ivory objects became so popular that elephants all over the world were driven to near-extinction; it became illegal to trade in ivory in 1989.
The illegal pet trade is the second biggest threat to rainforest animals after habitat loss; it is actually the third biggest trade in the world and in a multi-million pound industry. There is a keen interest within richer countries to own unusual pets, the vast sums of money available for producing these creatures drives population reductions.
The National Network to Fight Wild Animal Trafficking in Brazil estimates that approximately 38 million animals are trapped and smuggled out of the country on a yearly basis. The process is inhumane and traumatic, most of the animals don’t even make the journey, they die from dehydration, starvation and injuries sustained during the trapping and transport; which just funds the cycle more.
Many tropical animals have close links with ancient medicines and some were used for a range of treatments, aphrodisiacs, and poisons. This interest still exists today at the expense of endangered species. They suffer the same treatment as animals killed for fur, ivory, and most animals trapped for pets.
Plant UtilisationPlants have suffered similar disregard from companies and governments in richer countries with so many species found in the rainforest being drained of resources for use in medicines and food consumed in developed countries.
Many of the foods we eat today originated in rainforests:
Avocado, banana, black pepper, Brazilian nuts, cayenne pepper, cassava/manioc, cashews, chocolate/cocoa, cinnamon, cloves, coconut, coffee, cola, corn/maize, eggplant, fig, ginger, guava, herbal tea ingredients (hibiscus flowers, orange flowers and peel, lemon grass), jalapeño, lemon, orange, papaya, paprika, peanut, pineapple, rice, winter squash, sweet pepper, sugar, tomato, turmeric, vanilla, and Mexican yam. The wild strains still in the rainforests of many of these plants provide genetic materials essential to fortify our existing agricultural stock. Many other rainforest plants have great promise to become other staple foods. (Caufield, Catherine, In the Rainforest)*
Plants are also a basis for many drugs and medicines used everyday in developed countries to treat cancers, leukaemia, Hodgkin’s disease, arthritis, heart conditions, hypertension and birth control to name but a few. Scientist have discovered some very useful chemicals and components in rainforest plants for treating cancer and infact 70% of recognised cancer drugs are derived from plants that are only found in the rainforests.
PollutionPollution is a concern that effects all of the worlds biomes, it is growing issue especially in developed countries where they is more education and media leading to a better understanding of the issue. Pollution has and still is occurring in all areas of the rainforest, the rainforest is know to be a massive carbon storage unit extracting tonnes of co2 and releasing fresh oxygen into the atmosphere and the large areas of forest help to regulate the temperature and climate. Despite all this one of the worlds most delicate biomes is severely threatened by the effects of pollution. Several factors have contributed to the pollution of the rainforests.
OilThe reduction in available fossil fuels has caused oil companies to look further a field for resources, extracting oil from third world and poor countries means that companies can maximise profits through exploitation of resources and people. The effect that oil extraction has on the rainforest and local communities is disastrous leading to sickness and death in people, animals and plants.
The most well known example of the damaging effects of oil extraction in rainforests is in the Amazon. For twenty years the international petroleum and fuel giant Texaco worked alongside the Ecuadorian state Oil Company to extract billions of gallons of oil from the Amazon rainforest. During this time the company did not use the now standard practice of returning waste to the earth where it was extracted, instead they dumped heavy sludge in unlined open pits and flushed 20 billion gallons of waste into near-by streams, rivers and wetlands.
The waste from the pits leached into the surrounding soils and waters, the waterways carried waste out to larger areas spreading contamination over a much larger area. The toxic materials found in oil and oil waste products is extremely dangerous to the health of plants and animals and the constant presence of it in local water sources and soils is passed onto plants and animals through the food chain. The cumulative impact of this is that plants, animals and people are slowly poisoned by continual ingestion of toxic material and because of their circumstances they have no choice but to drink the polluted water and eat the contaminated food they produce.
The soils of the rainforest are already very delicate, being generally nutrient poor means that they suffer dramatically from the effects of heavy chemicals in the soil. Native vegetation suffers as well as the agricultural crops grown for local and mass market, very little will grow on the poisoned soils and soon the land becomes dry, barren and uninhabited.
Despite this oil companies are still pushing to open up new areas all over the rainforest to search for and extract oil. From the extraction, to the burning of fuels for products, to the mass felling of trees to build extraction sites, to the industrial waste that is produced during the from machinery and vehicles, the whole process of oil extraction is highly pollutive and damaging to the rainforests delicate ecology.
Industry, Tourism and Urbanisation The growing industry, tourism and urbanisation that is occurring in developing countries (where most rainforests are found), contributes to the pollution that is absorbed by vegetation and soils in the rainforest. More and more people are being forced to move out from overcrowded urban areas, they are often relocated closer and closer to forest and as the forest shrink populations of people move further and further in. the land around the forest gets built up as houses are built, industry is created and vehicles appear.
Industry, vehicles and the burning of fossil fuels creates toxic gases in the form of sulphur dioxide, nitrogen oxide and hydrocarbons. When released into the atmosphere they react with water and light to form dilute sulphuric acid, nitric acid and ammonium salts. These wash into soils and are absorbed by plants, subsequently many plants cannot tolerate they highly acidic soils and die. Much of the diversity that is lost on a daily basis in the rainforest is due to the increased acid content present in the soils.
Intensified AgricultureIntensified agriculture is a growing concern for the future of the worlds rainforests, as populations grow all over the world a greater demand for food arises, with less space in developed urban areas many countries are importing the majority of their goods. Due to the demand, larger and larger areas of forest are being cleared for growing crops and grazing cattle. A vast amount of the agriculture is owned and controlled by large corporate companies who exploit the local people by paying them barely enough to survive on after robbing them of their own natural resources.
One of the main problems with intensified agriculture is that the soils found in the rainforest are not sustainable for a mass production of crop. The poor soils are low in nutrients, what is there is soon depleted and the crops will no longer grow. The process of harvesting leaves soils exposed to erosion and nutrient leaching from rainwater and drying out in the sun.
The heavy farming is usually accompanied by heavy pesticide and herbicide use, the chemicals leach into the soil and surrounding waters, causing nitrification and depletion of diversity further into the forest, away from the farms and industries.
The burning of rainforests to make way for agriculture and industry produces a range of toxic fumes that are released into the atmosphere, carbon dioxide, nitrous oxides and methane are all released and subsequently enter plants and soils through the water cycle as well as during photosynthesis.
Mineral ExploitationThere are large deposits of minerals hidden in the rainforests of the world and through out history mineral and metal extraction has been the cause of many environmental and social problems. It is here in the third world rainforests that it seems to have made the greatest impact and still continues to do so.
The Amazon basin in Brazil is a store of deposited minerals; it has been heavily mined for gold, bauxite, iron ore, tin ore and diamonds. Large areas of the forest are cleared to build extraction sites and then subsequently drained of resources, polluted and abandoned.
The mineral mining industry is driven by money, with all profits being made by foreign companies and no contribution to the enrichment of local populations. Many of the people have no choice but to be dependant on handouts from mining companies that have taken over their homes and land. The companies actively encourage this behaviour as it means they have more control over the indigenous people and can behave as they please.
Mineral extraction sites are often very violent and constantly he focus of civil wars and violations of human rights, the governments are generally powerless to stop the will of massive industrial companies and the lure of corrupt financial deals attracts officials to turn a blind eye.
The process of mineral extraction is very damaging to the local and wider environments as unwanted by-products (known as tailings) are dumped into local waterways as a means of disposal. The tailings are made up of heavy metals and acids that erode and are released destroying entire ecosystems in certain areas. The mines are left as gapping craters in the landscape void of vegetation and abandoned by the companies, the indigenous people are left to fend for themselves and suffer greatly from the loss of handouts.
As mineral deposits become sparser, the value increases; mines become very hostile and competitive places with opposing mineral companies waging war to gain control of mineral sites. The conflict comes at the expense of local indigenous people who suffer injuries, sickness and death as a consequence.
Timber ExtractionTimber extraction and logging regimes in rainforests is one of the biggest issues circulating debate at the moment. In recent years it has become apparent that the largest damage to rainforests come from intensive logging and deforestation. The 1980s and 90s saw foreign companies make movements into rainforests after depletion of their own natural timber resources. The issue has become highly documented and protective legislation has come into force to try to prevent further degeneration of the world’s rainforests. Despite this illegal unsustainable logging continues in a massive industry that sees mass felling that is unplanned and poorly managed with no environmental consideration.
The disposable attitude of modern developed countries requires a high amount of resources this obviously apparent as nearly all timber felled in rainforests is exported to rich countries to be used for furniture, flooring, ornamental objects and paper. The vast quantities of trees felled during extraction projects takes it toll on the environment not only locally but inter-nationally through changes in climate and loss of species diversity.
Timber extraction offers a limited non-sustainable product, many trees that are felled have taken hundreds of years to reach maturity and regeneration of resources can only occur over a very long period, secondary forests that appear in the after math of heavy logging are considerably different to the original primary forests and do not produce the same timber value as before logging took place.
In many places timber extraction is based on selective logging, in these circumstances specific high yield species are selected for timber sale. The species considered high value for timber are more often than not large well-established species that provide food and shelter to communities of insect, bird and animal. Selective logging is not considered to be as detrimental to wildlife as clear felling of large areas, however it does still have a very dramatic effect on microenvironments within the forest.
A single tree felled in a forest damages surrounding vegetation by pulling out connected root systems and large canopies crash down taking other trees with them that are connected by vines. This leads to a gap in the canopy with increased light availability, which is more vulnerable to wind damage and erosion. The abundance of light damages and kills soil organisms, disabling decomposition and nutrient fixing cycles.
Much of the rainforest is destroyed in transporting and managing cut timber, large areas of unwanted timber is felled to make way for large machinery and vehicles. Roads are built through the forest to make transportation easier whilst numerous skid trails are made from forest to road. The heavy machinery and timber being moves takes it toll on the sallow nutrient poor soils of the rainforest. Constant erosion takes place as tyres pick up nutrients and compact the soil. This makes regeneration even more difficult once logging is abandoned in the area.
Once the logging regime ceases and moves on the disturbed forest is subject to many changes. Rainforests characteristically are places of heavy and frequent rainfall, most of this is self sustained through evaporation from the canopy, the majority of rainfall is absorbed in the canopy and does not ever see the ground, the precipitation that drips from leaves and branches to the floor is soon absorbed into the soil and taken in by plants, which is then evaporated to continue the unique water cycle of the rainforest.
Gaps in the canopy mean that less water is absorbed by trees and subsequently not evaporated as it reaches the ground and is washed away to steams and rivers. The higher levels of disturbance compact soils so mush that no rainwater can leach in to the ground to supply new seeds with moisture. In these areas surface run off is greatest and large amounts of water are removed from the water cycle leading to dryer forests near logged areas.
Most rainforest trees have evolved to store nutrients in their systems, this is because the soil nutrient levels are poor, when trees are logged and removed they not only remove timber but also a store of nutrients that would have eventually been re-invested into the soils when the tree decomposed. The new exposure of the soil allows for more nutrient depletion from surface runoff and wind erosion. The soils are already very shallow, being bound mainly by the root structures of trees; removal of trees allows topsoil to blow away leaving nutrient scarce subsoil. It can take decades for soils to recover from the effects of nutrient removal in which time regeneration will be dominated by a few adaptable species, severely reducing species diversity.
Rainforest trees absorb 11% more light radiation than pasture, the absorbed radiation is emitted as heat, gaps in the canopy reduce the amount of light absorbed and thus the levels of heat, reducing temperatures. The reduction in temperature results in a reduced capacity for evaporation in the forest environment, disturbing the finely balanced ecosystems that exist within it. The overall long-term effects of persistent heavy logging could have a dramatic effect on rainforest climate, which will not be experienced for many years.
Timber extraction has a massive impact on the rainforest as a wildlife habitat; the disturbance then has a range of chain reactions that occur through out the rest of the forest. The rainforests are home to thousands of species of insect, bird, reptile and mammal, all with individual reactions to the effects of commercial logging.
The noisy machinery used to fell and transport timber can be heard for miles, this initially scares and stresses local animals. Primates are particularly susceptible to the effects off logging, the noise drives them away from their own territory into the territory of other communities, this leads to aggression and violence from competition for spaces and food, ultimately one community will suffer, numbers will dwindle and genetic diversity is reduced. Gorillas and orang-utans deal better in these situations as territories usually overlap and species are not so territorial.
Infant mortality rates among primates increase in logged areas as they fall out of trees, are abandoned when community flees an area and have difficulty moving about in open spaces. The open ground makes it easier for predators to target prey, which is why most rainforest species live high up in the canopy as a rule.
The mass felling of trees leads to a sudden reduction in food sources for native fauna, which can have instant impact on population figures. Some species of primate have adapted to eat foods from a select range of tree species that is suddenly removed leading to starvation and increased inter-specific competition for food. Removal of important resources can have huge effects on animal populations that even low level selective felling can have catastrophic consequences. For example strangler figs (as fore-mentioned in 5.3P) are an important source of annual food for many rainforest species, they tend to be found growing around large, high value timber trees, when the trees are removed the unwanted fig dies and a valuable food source is destroyed.
Rainforests are abundant with insect species, many of which have evolved to rely on specific host species of tree and are unable to revert to other food sources and subsequently die out, leading to a reduction of diversity and biomass that reverberates through the food chain.
The regeneration of vegetation from timber extracted sites is known as secondary forest, the increased light levels coming through large gaps in the canopy lead to extensive growth of pioneer light loving species such as vines and climbers, at the expense of tree seedlings used to growing slowly in the shade of mature trees. The level of regeneration is directly related to the level of disturbance and less disturbed sites stand a better chance of similar vegetative regeneration.
The level of damage overall is dependant on the ability of native plant and animal species to adapt to the vast change in environment, some species, such as forest elephant have been able to utilise the canopy gaps by browsing the new growth springing up from the exposed floor. In timber extraction regimes the most specialised species suffer greatest, unable to make the changes necessary to survive in the new changing environment.
The aftermath of large scale timber extraction attract people to inhabit and start to farm the cleared ground which is made easier by all the roads now in place, as communities move further in and spread out into rainforests the effects of agriculture, industry and urbanisation increase the damage and prevent regeneration from naturally occurring.
Loss of Species Through ExploitationWith 58 million square miles of rainforest being cleared every year it is inevitable that plant and animal species will be directly affected by a loss of habitat. It is estimated that a typical four square mile patch of rainforest contains as many as 1,500 flowering plants, 750 species of trees, 400 species of birds and 150 species of butterflies. If the current trend of destruction continues approximately 5-10% of species will become extinct every decade.
The development of the rainforest over a long period has evolved very specific relationships between plants and animals. The loss of one species can have a massive chain effect through the ecosystem resulting in unstable populations in species in surrounding areas. The inability of so many species in rainforests to adapt is a key factor in their decline and extinction.
Tank bromeliads are from the Family (Bromeliaceae) these plants are native to rainforests across the world and are characterised as being able to store water within they’re bodies. Tank bromeliads are utilised by many rainforest species who use them as a water source, over 250 species of insect have been identified as occupying tank bromeliads for food, water and hunting of other species, certain species of mosquito and frog use them as breeding grounds and for rearing young. The loss of these plants through deforestation for whatever reason have a major impact on insect populations and subsequently species that fed on those insects.
On the other side of this coin many tree rely on insects, birds and mammals for reproduction and decline of species will have a knock on effect to areas outside the damage zone. A past example of this occurred with the calvaria tree on the island of Madagascar, the trees hadn’t reproduced in hundreds of years which lead to a scientific investigation that showed that the seeds needed to pass through the digestive tract of the now extinct Dodo in order to germinate; luckily the species was saved by the introduction of turkeys which took up the role. This same effect could easily occur with the exploitation of rainforest resources and animal extinction but without human awareness.
Loss of habitat is the main cause for concern with a reduction of rainforest from 6 million square miles to just 2.1 million square miles over a very short period in history. With rainforests already being densely inhabited by plants and animals, this immense reduction in habitat only serves to increase competition between species for resources essential to their survival.
North-South Resource Consumption DifferentialThe North-South divide is an economic and political division between rich developed countries and poor developing “third world countries”. Wealth developed countries are classed as north and poor countries south. Although most of the north division do occur in the northern hemisphere the divide is not based on geological position but economic value.
There is an unbelievable difference in consumption between the two, with the north being mainly responsible for the vast majority of rainforest destruction. In wealthy developed countries, society strives for improved comforts and quality of living, this normally occurs at the expense of poor underdeveloped societies.
A large contributor to the problem of rainforest destruction arises through the debt burden of countries on the south of the divide. The areas highlighted in yellow on the map indicate a mid level of development and the red areas show very poorly developed countries.
During the 70s and 80s poor countries borrowed large sums of money from developed countries to fund developments and growth of a self-sustaining industry. These countries are still having to repay the debt with high interest rates, an effort that is becoming increasingly difficult when developed countries come in and exploit those countries natural resources.
Developing countries have to pay more money back in debts than they receive in aid every year, this itself drives communities to exploit their own resources and encourage outside developments for small-scale benefit. The pressure of debt means that governments focus more on financial gain by maximising exports rather than addressing important social and economic issues.
Developed counties abuse the situation in under-developed countries to exploit is resources and people through continued large-scale agriculture and timber extraction, of which very little is given to the country. The USA have been accused of manipulating prices for agricultural goods produced by small local communities for export to wealthy countries at the expense of the people producing their product. This activity occurs all over developed countries with multi-national companies making massive profits and their employees are barely provided with enough to survive.
References:
http://www.rainforestinfo.org.au/background/causes.htmhttp://www.nature.org/rainforests/explore/facts.htmlhttp://www.saverfn.org/lessonssymb.htmlhttp://www.globalchange.umich.edu http://www.archipelago.gr*
http://www.ijms-wildlife.co.uk/forest.htmlhttp://www.commondreams.org/headlines05/0427-03.htmhttp://library.thinkquest.org/26993/amazon.htmhttp://www.twnside.org.sg/title/mine-cn.htmwww.rainforestfoundationuk.org/files/LOGGING.pdf
