Case study Rainforest Ecosystems at Risk
Rainforest: a large, dense forest in a hot, humid region (tropical or subtropical). Rainforests have an abundance of diverse plant and animal life, much of which is still uncatalogued by the scientific community.
Spatial Patterns and Dimension of Rainforests
Rainforests are located in:
·AmazonBasin in South America
·South East Asia
CongoBasin in Africa
·North East Queensland, Australia
Most of the world’s rainforest have been cleared. At the rate of clearing, the estimated survival is to 2050.
Rainforests are usually found in areas with:
·Low latitudes (close to the equator)
·Rain in all seasons (no dry season)
Common Characteristics of Rainforest
Rainforests contain five layers
·The emergent layer : Trees taller than the canopy
·Canopy Layer : Layer of taller trees
·Under Store : Layer of smaller trees
·Shrub Layer: Shrub/Sapling layer
·Forest Floor: Sparse plant growth.
Types of Growth:
·Epiphytes – vine like flora that grow on other plants and trees for structural support only
Lianas – vines
·Emergent – trees growing higher than canopy
·Parasites – strangler figs that take nutrients from host plant
·Fungi – plants that need hardly any sunlight growing on the forest floor
Biophysical Interaction Occurring In Rainforests
Weather and Climate
Temperatures in rainforest need to be constant for the teeming soil fauna. Rainfall must be high – never less than 170cm per year and humidity must also remain high at around 95% so that evaporation does not exceed precipitation. The canopy of the rainforest also help retain water within the closed rainforest system as when water evaporates and gets carried upwards it condenses into clouds which release the water again. Rainforest’s water budget is so efficient that up to 75% of its evapotranspiration is returned.
Weathering and erosion constantly occur within rainforest hydrological system. Weathering and erosion occur constantly as rocks when weathered provide valuable nutrients to the rainforest and maintain fertility on topsoil. Erosion of river banks constantly changes the shape and flow of rivers. Small lakes are created which create microclimates and separate ecological systems within the rainforest.
Recycling Nutrient Stock
Rainforest are also extremely efficient at recycling nutrients through the carbon cycle and nutrient cycle. As carbon is now recognized as a pivotal factor in atmosphere stability is stored by the forest. Virgin rainforest have enormous quantities of nutrients circulating freely between vegetation and soil and very little is lost to the ecosystem through drainage water.
In one particular study near Manaus, Brazil the litter, raining down to the floor of a forest plot contained 18.6kg of calcium. When the rivers near the area was analysed, no calcium was detected. What little nutrients are lost is replaced by weathering of rocks.
Decomposers and fungi also help to replenish the nutrients and carbon lost within the rainforest. These organisms very quickly release nutrients from vegetation debris, animal excretion, and corpses. Most trees growing within rain forests do not have taproots (deep roots) but buttress roots to increase the tree’s nutrient absorption area.
The plant and animal species add to the weather and climate of rainforests. The diversity of flora and fauna keep the cycles within the rainforest going and aiding the survival of rainforest. Partnerships occur between flora and fauna species within the rainforest increasing the amount of pollination and seed dispersal. This is the main cause of biodiversity within rainforests.
Threats To The Rainforest: What Places This Ecosystem At Risk?
According to the Rainforest Action Network (RAN) every minute more than 29 hectares of rainforest are deforested globally.
Today in our world, 54% percent of the rainforest that historically existed have been cleared. Virtually extinct are the rainforest of El Salvador, Haiti, Cote d’Ivoire, Nigeria, Madagascar and the Philippines. Experts predict the Amazon and Congo basins to follow.
Major Threats To Rainforest Ecosystem Include:
·International Logging and Plantation Timbers
·Fuel wood Collection
·Populations, Paper Chase and Other Factors
The world’s population, which has been growing at an exponential rate and the demand for resources, as a result increases by an exponential rate.
Tropical rainforests in many parts of the world are being cleared for agricultural exports to satisfy the demand of mainly resource hungry developed countries. Replacement of rainforests by agriculture destroys the land. In particular, cattle ranching driven solely by developed countries’ demand inexpensive and convenient beef. Cattle ranching are ultimately destructive. By its nature, cattle ranching are the least productive use of the land. Stocking rates are surprisingly low at only one animal per hectare. The soil commonly become unfertile after a few years, trampled to compaction, overgrazed, oxidised, sun baked, and toxic weeds move into pasture and compete more successfully than the grasses.
The processes of Agriculture used in rainforests include “slash and burn” often lead to uncontrolled fires to make way for unsustainable farms. As only the top soil of rainforests are fertile and after a few years the crop yields decrease, this further leads to dispossessed “shifted cultivators” which continue the vicious cycle by clearing more land. Half of the Amazon rainforest has been cleared for agricultural and human uses.
If farms are abandoned, it may take several centuries before all signs of forest succession have disappeared and returned to primary rainforest. This signals an increased need in the increase of sustainable farming.
There is now evidence of contribution of the illicit drug trade toward tropical deforestation, which has been large ignored in the past few years. Peru along has had more than one million hectares of rainforest cleared over the past several decades for coca production (main ingredient in Cocaine). The National Agrarian University in Lima reports that 2 tons per hectare of caustic chemicals and herbicides find their way into the water drainage.
Majority of developed countries have placed some form of restriction on logging. Rainforests contain valuable resources and this has resulted in an accelerated rate of logging to meet world’s demand. With 75% of timber from the Amazon rainforest exported to other countries.
Every year 5.9 million hectares of tropical rainforests are logged. Both illegal and legal logging trade occur.
The consequences of logging include the increased stress placed on commercial species (the particular tree loggers want) and other species as well that relies on commercial species for survival and for the biophysical interaction processes to occur. The decrease in biodiversity is caused by logging and many commercial species have been extinct or facing extinction. Flora and fauna face becoming endangered as their habitats are decreased in size.
Clearing and changing large areas of land within a rainforest can also change the climate and rainfall in that specific area further placing stress on the rest of the rainforest and alters the nutrient cycles which is essential to the survival of a rainforest.
In many developing countries, there is a growing trend to replace deforested rainforests land with commercial high-grade plantation trees. Even though it has less of an environment, impact compared to agriculture or logging, it increases the threat to the biophysical interactions essential for survival of a rainforest.
Environmental problems caused by tree plantations include:
Fuel Wood Collection
Approximately half the world’s population (3 Billion) residing in developing countries rely on fuel wood including charcoal for their household energy needs.
The FAO (Food and Agriculture Organisation of the United Nations) projects that by 2010 the demand for fuel wood will double. Meaning 1.5 billion people in 2010 will be ravaging what little left of the rainforest for fuel.
Consequences include the increased rate at which rainforest’s are logged and destruction of habitat. Burning of fuel wood increases the rate of global climate change.
The Paper Chase, Population and Other Factors
The extraction of mineral resources from rainforests is often accompanied by damage to the rainforest greater than the mining process itself.
The US$5 Billion 900 000 sq km Grade Carajas Project in Brazil’s eastern Amazon pursues Iron Ore, Copper, Manganese, Bauxite and Nickel. Despite the colossal nature of the project, little has been done to alleviate the poverty in the Amazon. But has caused many threats to the Amazon rainforest.
·The 40 000 Brazilian miners employed on the project has brought Malaria which has been responsible for 25% of indigenous tribe deaths.
·Estimated (1000-2000 tons) of Mercury has been released into Brazilian rivers and has affected all commercial food chain.
Hydroelectricity is seen by tropical nations as a way to utilise rivers in the rainforests and reduce the need for fuel wood. Brazil’s “Plan 2010” to reduce reliance on fuel wood and build 136 dams with 22 located within the Amazon and a 11 000 mega watt dam which all together would flood an area within the rainforest the size of United Kingdom
From experiences of building dams, a range of problem has occurred. Colombia’s Anchicaya dam lost a full quarter of its storage capacity within only two years of its completion due to erosion and subsequent siltation. Other consequences include the increases the acidity of the water which corrode and shorten the life of the installation and destroys many flora and fauna which are unable to survive that those levels of acidity.
Reasons For Protection of Rainforests and What Is Lost If Not Protected
There are many reasons for protecting rainforests these include:
The tropical forests are responsible for a conspicuous percentage (up to 69%) of Earth’s biological productivity. Nothing could demonstrate the significance of our dependence on this ecosystem more than to recall the transpiration dynamics of a single large emergent forest tree – pumping some 760L of water per day into the rainforest. Without rainforests the biophysical processes on this Earth would not occur.
The rainforest is home to at least 50% to estimates as high as 90% of Earth’s species. As rainforests are destroyed for various reasons, we reduce the biodiversity and lowering human’s own standard of living.
Rainforests are a wealth of natural resources and but very few of these resources have been discovered and many potential resources are destroyed before knowledge of their potential. As the organism within many rainforests are still unknown to scientists.
The medicinal value of tropical plants has been great. As 50% of medicines used are derived from, plants and 25% of all drugs have their origins in the tropical rainforest. Should the trend of habitat loss continue, we can expect to lose 25% of all potential plants of medicinal value – approximate 60 000 species.
Plants such as Cinchona tree of the Amazon rainforest a life-saving tree used in the treatment of several malaria strains which otherwise would have caused death.
The rainforest contain many foods still unknown to scientist, as edible species within the rainforest could have the potential to feed the ever-growing population without the need to resort to intensive agriculture processes. Manioc for example is a multipurpose rampantly growing tuberous root that serves as a cheap abundant staple food in tropical developing nations.
Indigenous people especially medicine men are a valuable resource and that each time a “medicine man” dies, we lose a lifetime of knowledge and the potential of finding a cure for a lethal disease such as cancer.
Heritage Value and Aesthetic Value
Rainforest especially the Amazon is unique for because of its contribution to Earth’s climate and the biological diversity within the Amazon. Rainforest on this Earth are special and valued by all cultures. The Amazon rainforest supports the lives of indigenous and tribal population living within the rainforest, without the rainforest many would not survive.
Atmospheric and Climatic Stability
Rainforest help regulate the atmospheric balance and temperature through controlling the presence and balance of gases within our atmosphere. Tropical forests are responsible for a major portion of Earth’s biological productivity, which may seem surprising as they hold 6% of Earth’s surface. Rainforests are large producers of oxygen and take in carbon dioxide, which is stored in the form of carbon in trees’ tissues.
The clearing of rainforest and increased use of fossil fuels has contributed substantially to the observed warming over the past 50 years. The heat balance is changed as any other vegetation (other than tropical trees) has a higher albedo because they absorb less of the incident radiation from the sun. The change in albedo affects hydrological cycles and changes regional and global climates.
If the current trend continues, it could lead to melting of ice caps, changing the entire world’s ecological processes. Even the relatively small changes in global climate could produce large changes in the frequency of extreme weather events.
Deforestation of rainforests has seen many diseases and plagues threat. Most of these diseases are spread by flying organisms but are due to human modification and felling of trees in the canopy has caused increased human contact with these flying organisms. Some of them include:
·Malaria – caused by the felling of trees, as the direct connection between Malaria/Deforestation was made by J.W.Mak. Mosquitos prefer the sunlight of the canopy and raise larvae in the water trapped in crotches and hollows of large canopy trees. These natural sites kept mosquitoes high in the canopy and safely out of human contact. When those trees are felled, the mosquitoes find new niches in lower forest strata and increase contact with humans compounded with no access for Malaria treatments has caused Malaria epidemics.
·Elephantiasis – caused by parasites, which prefer sewage water on hill slopes open to light. They are rare in uncleared primary forest but they proliferate when deforestation occurs.
Other diseases caused through deforestation include:
·African Sleeping Sickness
Strategies and Management Techniques Needed For Survival of Rainforest
At the start of the 21st Century, there are no specific strategies or management techniques undertaken by governments of the Amazon rainforest for the survival of the rainforest.
At an ITTO (International Timber Trade Organization) conference on the survival of rainforest, the following strategies all based on the principles of Ecologically Sustainable Development were identified necessary:
Habitat Preservation and Conservation
Habitat Preservation as a management technique is needed for the survival of rainforests and leaving areas intact. This may includes governments turning them into National Parks and wildlife sanctuaries. These national parks need to be set-up with appropriate legislation, some exclusion zones for total conservation and active management.
Increased Understanding of Rainforests as an Ecosystem
Monetary funds are needed from the World Bank for research into rainforest (instead of the World Bank funding/subsidising projects that threaten the rainforest) as rainforests are still at times a mystery to humans. To achieve successful conservation and management strategies, there needs to be more research into ecological and biophysical processes and the catalogue of species. The data from the increased research projects would be used to engage in careful planning and undertaking appropriate management strategies.
Stabilising Migrant Cultivators and Settlers
Shifting cultivators living in rainforests cause the majority of degradation of rainforest land. Policy makers should agree that the current system of free movement be replaced with more frugal and efficient systems to completely stop the loss of rainforest for agriculture use. Innovative ideas discussed at the conference such as a “sustained-yield agro-ecosystem” which uses a cycle of produce that mimic the forest succession instead of resisting the natural forest succession. “Sustained-yield agro-ecosystem” will stop areas of land become unfertile. This idea is implanted will move towards sustainable production, utilisation of rainforest land and lowering the stress.
Reduction of Rainforest Logging
Timber certification needs to be introduced to warn consumers in developing countries of buying a valuable rainforest resource. However, “sustainable development” of tropical forestry has yet to be proven. Enforcement of international responsibility is also needed to stop illegal trading of rainforest-felled timber.
Utilisation of technology is needed to use Super Trees (tree that reach harvest height in 7-20 years due to genetic modification) in plantation timber operation to satisfy the demand without needing to cut down trees located within rainforests.
Education needs to be implemented for the local population of rainforest (including tribes and indigenous people) on the principles of Ecological Sustainable Development and ways of restoring/rehabilitating degraded rainforest land.