Biomes:impact of human activity(the development of economic activities can alter biomes)

Intro

The natural characteristics of the tropical rainforest biome have been altered by economic activities.

Primary economic activities including commercial logging and intensive

agriculture have impacted biomes, industrial development (secondary economic activity) has

impacted biomes, and all of these activities have induced global warming which is also impacting biomes negatively.

Aspect 1:Commercial logging and felling of tropical rainforests

Commercial logging is the major cause of primary rainforest destruction in the South East Asian and African Rainforest Biomes.

Worldwide it's responsible for the destruction of 5 million hectares a year

Logging usually involves the transfer of control of the forests from the local people, who have a vested interest in the preservation, to those who are interested only in destroying them

for short term profit.

Millions of hectares of primary rainforest are being destroyed in South

East Asia by commercial logging.

The driving force of this industry isn't the local population increasing, but increasing international demand for timber as a raw material for processing

and for the paper and pulp industry.

logging

The use of logging roads enables landless people to enter

the forest.

In Africa 75% of the land being cleared by peasant farmers is land that has been previously commercially logged.

In Malaysia during the early 1990's clear cut logging practices have been the main reason for deforestation as logging companies ruthlessly cleared

mile upon mile of primary forest.

Today, commercial logging still forms the most important,direct threat to forests in regions of central Africa.

Aspect 2: Intensive agricultural practices

Biomes are altered by intensive agriculture as soil becomes eroded, and biodiversity (animals

and plants) is therefore effected.

The tropical rainforest biome is impacted by over- cropping/over-cultivation practices leaving the soil infertile

In the past, people have farmed the rainforest, felling trees to allow for cultivation of crops and grazing space for animals, and moving on when the soil loses fertility.

This isn't a threat to the forest, provided it's undertaken in a sustainable manner and that used areas are left to

regenerate for long periods before repeating the process.

However, problems arise when the

land isn't allowed sufficient time to recover. Intensive farming, with increased use of agrochemicals and mechanisation, can lead to soil compaction and also soil erosion.

Furthermore, wen a forest is cleared, the nutrient cycle is destroyed. The remaining soil can be easily washed away by heavy rain.

Brazil

Due to the needs of growing populations, some sources

identify over cultivation as the cause of 70% of deforestation in Africa.

Ranching is a major cause of deforestation particularly in central and South America.

In Central America two

thirds of lowland tropical forest has been turned into pasture since 1950.

Cattle ranching is the leading cause of desertification in the Brazilian Amazon.

Government figures attributed

38% of deforestation from 1966-1975 to large scale cattle ranching.

Brazil is losing 40 hectares of rainforest per minute today.

Furthermore, a significant amount of deforestation is caused by the subsistence activities of poor farmers, who are encouraged to settle on forest

land due to the government land redistribution policies.

The Amazon

Between 1995 and 1998, the

government granted land in the Amazon to approx.

150,000 families. Cutting down the

tropical rainforests for agricultural purposes in an unsustainable manner is causing irreversible damage to soil composition and structure and to native flora and fauna.

In addition, as a result of the high temperatures in this region, exposed soil is baked into a hard,

brick-like surface which cannot support plant growth.

This is known as a laterite soil, which

is useless for farming.

The grass growth on the latosols is so poor that the beef cattle do not

thrive and even more land is cleared to feed them.

Aspect 3: industrial development

Acid rain describes any form of precipitation with high levels of nitric and sulphuric acids.

It can also occur in the form of snow, fog and tiny bits of dry material that settle to Earth.

The biggest culprit is the burning of fossil fuels by coal-burning power plants, factories and

automobiles

When humans burn fossil fuels, sulphur dioxide (SO2) and nitrogen oxides (NOx) are released into the atmosphere.

These chemical gases react with water, oxygen and other substances to form mild solutions of sulphuric and nitric acid.

Winds may spread these acidic

solutions across the atmosphere and over hundreds of miles.

When acid rain reaches Earth, it

flows across the surface in runoff water, enters water systems and sinks into the soil.

Acid rain damages Rainforest Biomes.

Industrial

It robs the soil of essential nutrients and releases aluminium

in the soil, which makes it hard for trees to take up water.

Trees' leaves and needles are also

harmed by acids.

The effects of acid rain, combined with other environmental stressors, leave

trees and plants less able to withstand cold temperatures, insects and disease. The pollutants may also inhibit trees' ability to reproduce.

Some soils are better able to neutralize acids than others.

In areas where the soil's "buffering capacity" is low, the harmful effects of acid rain are much greater

Aspect 4:Global warming

The felling of vast amounts of trees by humans in the tropical rainforests will contribute to global warming.

Deforestation increases the amount of Carbon Dioxide (CO2) and other

trace gases in the atmosphere

When a forest is cut, the carbon content of the trees is released (wood is composed of 50%

carbon).

The release of CO2 enhances the greenhouse effect and this can lead to an increase in global temperatures, a fact related to global warming.

By removing the forest we are

destroying an important 'carbon sink'.

A carbon sink is a thing or place where carbon dioxide is taken from the air and stored for a period of time.

Plants act as carbon sinks as they use

CO2 in the cells of their bodies.

Trees

Trees clean the air by absorbing harmful air dust particles

and gases, including sulphur dioxide, ozone and nitrogen.

Due to the significant loss of

tropical rainforests, overall global air quality standards may decrease.

This will have implications for human and animal populations.

In addition, the accumulation of CO2 in the atmosphere will have very negative impacts on climatic conditions and on glaciers in the Polar Regions.

Changing climatic conditions may result in extreme weather patterns, impact

on agricultural activities and will also effect on the biodiversity of both global and local flora and fauna, and species may not be able to adapt to rapid changes in their environment.