This article highlights the importance of Amazon rain forest to the ecosystem of the world.
Spatial Pattern And Dimensions
The Amazon rainforest is one of the world’s largest tropical rainforest’s covering more than half of Brazil. The Amazon Rainforest is located just below the earth’s equator at 63 degrees south, 3 degrees east. Most of the world’s tropical rainforests are located close to the equator because the climate is hot and humid.
Within the 2.5 million square miles in the Amazon Basin, you can find over 500 mammals and one-third of the world’s bird’s population. The Amazon River accounts for over 16% of the world’s river water. “In Brazil there are three main types of rainforest: the narrow band of tropical rainforest along the east coast, termed the Atlantic forest; the “tropical monsoon” forest covering the extensive plateau to the south-west; and the huge area of forest in the Amazon Basin, running east-west across northern Brazil.”
The government intends on keeping half of the 3.6 million km squared Amazon rainforest covered by natural vegetation. A closer look at the Amazonian map below also highlights key environmental issues such as forest destroyed and tropical forest. It is in the northern part of South America in Brazil, as shown in the maps on the next page.
With all ecosystems, many interactions determine the conditions essential for life. The four biophysical interactions are the relationship between the atmosphere, hydrosphere, lithosphere and the biosphere.
When evaluating the biophysical interactions in the Amazon Rainforest, there are four key topics geographers take into account. They are:
The Dynamics and Impact of Weather and Climate
The distribution of forestry and the natural production of various medicines, foods and other resources depend heavily on the rainfall and temperature. As with any tropical rainforests, the climate is very humid and has a high precipitation rate. This is essential for the Amazon Rainforest, as the forestry needs this specific climate to survive.
The climate of the Amazon Rainforest sets the rate at which the tropical rainforest functions. In the Amazon, precipitation rates and the temperature remain high, this is primarily due to the fact that the Amazon is located so close to the equator. The plant life in the Amazon is highly dependent on high levels of nutrients because of the large biomass and high rates of primary productivity. Decomposers organisms, favored by the hot and wet climate, quickly break down lots of dead waste material, which supply’s the plants thirst for nutrients. The average temperature and precipitation graph figures were taken from a place in the Amazon Basin called Porto Vehlo in 2001.
It is thought that large masses of rainforest, such as those evident in the Amazon play a major role in climate regulation. Many Amazon experts believe that the Amazon controls its own climate, like many other tropical rainforests. Geographers believe that nearly 25% of rainfall is intercepted by the rainforest and evaporates before it ends up on the ground. It is thought that evapotranspiration from the Amazon generates up to 50% of precipitation rates in the Amazon.
“Evapotranspiration is the combination of water that is evaporated and transpired by plants as a part of their metabolic processes.” It is also believed that tropical rainforests like the Amazon contribute to the stability of global cycles of carbon, oxygen and nitrogen. In the United States government’s environment website, they believe that further deforestation of the Amazon can lead to a decrease in rainfall in the US.
Relevant Geomorphic Features and Hydrological Processes
The geomorphic features and hydrological processes that take place in the Amazon are the processes which the make the Amazon rainforest so productive.
The types of soil, which are found in the Amazon, are very poor. This is the sole reason why so many of the farms, which were set up during the mid 1960s, have failed and are no longer present. Although the vast majority of the Amazon region is on poor soil there are a few areas, which lie over richer soils.
Amazon ecologist Felisburto Camargo was the first to suggest agricultural use of the varzea forest, which is annually flooded by the nutrient-rich white water rivers. The flood plain receives alluvial matter and consequently fertilization of the soil by the annual flooding, areas that have already been cleared for agriculture in these areas have and still are successful.
Despite luxuriant growth and the large biomass of the forest, the Amazon is plagued with soils that have very few nutrients making them very poor. The available nutrients are found in the vegetation, not in the soil resulting in lots of recycling of these nutrients.
The nutrient stocks living in vegetation and soil in the abandoned pastures are given the graph below. It gives the socks of major nutrient elements in the living biomass and soil of mature forest, and abandoned pasture following three intensities of use.
For pasture sites, the low-intensity used pasture always has the highest stocks of nutrients. But when these pastures are made by the conversion of forests, there is a large loss in all the nutrients in the living biomass. This is contradictory to the soil where there is a large increase with the conversion of forest to pastures. However, this conversion has a dramatic effect on the total ecosystem stocks of most nutrients. It is these total stocks that must be rebuilt for the forest to become re-established on the pastures. From these results we can conclude that traditional management strategies such as slash on the soil surface replenishes nutrients lost from the soil through leaching and other processes.
Biogeographical Processes And Interactions
There are many interactions between plants and animals and the environment they are living in, mainly because the Amazon Rainforest accounts for more than one million plant and animal species.
Because of the poor soils most of the forests are under nutrient-stress. But the animals and the trees have adapted to these conditions. Animal populations are kept at low densities because of the low nutrients and tree populations have evolved nutrient conservation mechanisms such as thick surficial root-mat which effectively recycles nutrients.
The Amazon Rainforest is not dominated by only one species of tree of animal. There are anything from 87 to 300 species of trees of 10cm diameter or more on a hectare of forest. The diversity causes two major problems. If a species is to be wiped out due to overuse, it is very sparsely distributed throughout the forest. For example, to remove a timber tree, which is scattered throughout, is uneconomical and can cause excessive damage to the forestry. This difficulty has been overcome with clear cutting and the replacement with a one species ecosystem, which places the forest at risk of disease or predator attack.
Many species of fish that are vegetarian depend on the nutrient-rich varzea forest, which bears many fruits on the forest trees. This relationship sustains many of the most important Amazonian fish that reaches the markets and providing protein for the region.
Naturally Induced Changes
There are very few causes that have affected the Amazon Rainforest, naturally. The only naturally induced change, which has affected the Amazon, is global warming, which was originally induced by man-made causes (the use of CFC’s).
Global warming will affect the Amazon Rainforest in years to come because as the temperature gets warmer, it will disrupt the cycle. This is because of the decreasing precipitation rates, which will in turn provide less water for the animals, plants, trees which may cause some of the species to die out because the Amazon species survive on wet and warm conditions.
Nature And Rate of Change Affecting Ecosystem Functioning
The biggest deterrent that is increasing that is changing the forest rapidly is deforestation. Deforestation not only affects the species of tree, which is being wiped out, but the other species as well, who rely on that species as a source of food. Mining is also a problem because it impacts heavily on the environment, inciting pollution mainly through the rivers. The Amazon region is being destroyed, polluted and disturbed by a large number of causes that create unsustainable systems of management for short-term gain.
But there are sign of hope. The destruction phase has caused the complete loss of more than 9% of the Brazilian Amazon forest and the severe disturbance of a much greater area and many of the most useful organisms, but hope remains because of the amount of forest that still remains. During the last decade or so, there has been a significant decrease in the destruction of the forest due to government policies and increasing knowledge about the Amazon Rainforest and what it has to offer.
The Amazonian rainforest has been destroyed by projects of little long-term gain such as temporary cattle pastures. Little thought has been given to sustainable use systems for the region. Since less than 10% of the total area has been clear-cut to date, there is a considerable chance of removing the entire forest.
During the early 1960’s, Brazil was undergoing severe economic problems, especially in the field of agriculture. The negative impacts humans have had on the Amazonian Rainforest all derive from the policies that the Brazilian government have put in place during this time. To achieve economic stability, the government decided to use the Amazon Basin to increase activity in the agricultural industry.
The largest cause of forest destruction has been to create cattle pasture due to the government incentives the Brazilian government once put in place. But since most of the region has extremely poor soils the pastures are mostly not viable in the long term and have a life of only a few years. The fact that these pastures were created by government incentives, the destruction of the forests has been minimized as there are no more incentives for cattle pasture in Amazonian Brazil.