Download The Amazon rainforest is, according to Greenpeace International

Effects of Deforestation in Amazonia
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The Amazon rainforest is, according to Greenpeace International, the most diverse ecosystem on earth
with “more than 60,000 plant species, 1,000 bird species, and more than 300 mammal species” that are
known to the scientific world. There are, however, most definitely countless more undiscovered species
deeper in the rainforest. For decades the Amazon has been affected by concentrated logging, mining
and construction, cutting huge swathes through the jungle. This poster aims to shed light on the main
effects deforestation causes in the Amazon .
Biodiversity and Soil Degradation
When forests are cut down into smaller blocks the “edge effects alter flora
and fauna within rainforests” (Butler, 2006). Fragmented patches are
exposed to dry winds which cause the number of tree falls to increase. These
gaps in the canopy effect the ability of the rainforest to maintain humidity,
temperature and heat of the forest floor. These effects then influence the
species living there and cause a reduction in diversity. Many rare species
living deep in the rainforest are unable to cope with the new environmental
conditions and are eventually replaced by more common species.
Scientists also suggest that continued rainforest loss could turn the Amazon
into a savannah landscape through processes such as sandification and soil
degradation in deforested areas.
Amazonian soils “consist of up to 80
per cent or even more of fine quartz”
and do not retain nutrients well. This
is because the only clay mineral
present is kaolinite which has a low
absorption capacity. The forest has a
dense mat of roots above the ground
which filters nutrients before they
can enter the soil. Deforestation
Sandification and soil degradation in the Amazon
interrupts this closed system of
http://earthcool.com/deforestation.htm
recycling nutrients and exposes the
soil to rain and erosion. The soil is heated and desiccated in the dry season
which transforms it into a nonporous “dust bowl”. The finer clay particles are
washed away in the rainy season, leaving coarser and heavier sand particles
behind which reduces the soil’s water retention. Tree seedlings cannot develop
in the new sandy soil conditions which prevents the growth of the forest.
The Yanomami Tribe
In 1973 construction began on the
Northern Circumferential Highway as
part of the National Integration Plan
(OoAS, 1985). This involved cutting
down large swathes of the rainforest
to build the new expressway, much of
which fell inside Yanomami territory.
This influx of ‘foreign’ invaders
brought with it a wave of violence and
disease to the previously self
sustaining Yanomami people. The
new
workers
carried
malaria Members of the Yanomami tribe preparing food.
http://edubuzz.org/laurensblog/yanomami-tribe/
infections that the indigenous tribes
had no immunity to and it was estimated that 20% of the Yanomami population,
around 1500, died in the following epidemic (Bier ,2005).
The construction of the road allowed mining and timber companies deeper access
into the jungle and this brought with it its own unique troubles. During the 198090s heavily armed Brazilian gold miners (‘garimpeiros’ in Portugese) and
lumbermen went deep into Yanomami and fought with their resistance. A study
conducted by researchers at the University of Maryland estimates that over 100
Yanomami have been murdered since the discovery of oil in indigenous lands
(MAR)
Hydrological System
Climatic changes caused by deforestation can be a global problem as well as local.
These changes can be measured in precipitation, evapotranspiration and cloud
cover.
The total amount of deforestation in 1988 was 1.5x104 km2/yr (Werth and Avisser,
2002). This caused a reduction in annual precipitation (between 220-640 mm/yr),
a reduction in evaporation (between 164-500 mm/yr) and an increase in surface
temperatures (between 0°C-3°C) (Werth and Avisser, 2002). Figure 2 shows the
“significant decrease in rainy season precipitation” and little change in the dry
season after an area as been deforested. This decrease in precipitation during the
rainy seasons directly affects the
rainforest as it will inhibit the
growth of the next generation of
flora
in
the
Amazon.
Deforestation also causes a
reduction in the “vertical average
moisture convergence” (Werth
and Avisser, 2002) which implies
that there is a connection between
deforestation in the Amazon and
global atmospheric flow. This has Figure 1: Shows precipitation before (blue) and after (red)
been shown to cause large deforestation. A notable decrease is seen in the summer months.
http://lba.cptec.inpe.br/publications/LBA_JGR_Special_Issue_Oct_2
reductions in the total amount of 002/Local_and_global_effects_Amazon_deforestation_Roni_Avissar_
water in the global hydrological JGR_LBA_Oct2002.pdf
cycle and cloud cover.
Deforestation effects are highest at a localised scale and decrease further away
from the source.
Carbon Emissions
Deforestation in the Amazon accounts
for “15-35% of annual fossil fuel
emissions” (Houghton, 2005). The total
amount of emissions are dependent on
the rate of deforestation (see Figure 4)
occurring and the biomass. It has been
calculated that “the amount of carbon
held in trees is 20-50 times higher in
forests than
in cleared
lands”
(Houghton, 2005).
Deforestation causes carbon, originally
held in forests, to be released into the
atmosphere. This is either immediately
through the burning of vegetation or
slowly through the decomposition of soil
and cleared vegetation. It has been
found that greenhouse gas emissions
from deforestation add up to 25% of the
Figure 2: This graph shows deforestation against carbon emissions. A
correlation can be seen
global
anthropogenic
greenhouse
http://www.grida.no/graphicslib/detail/annual-deforestation-inemissions. If the trend continues,
the-amazon-and-resulting-co2-emissions_0d8b#
tropical deforestation will eventually
contribute to “50% of total anthropogenic greenhouse emissions” (Houghton,
2005). Along with carbon release, deforestation also releases methane, nitrous oxide
and other chemically reactive gasses. These extra gases are indirectly released from
deforestation through the conversion of forests to agricultural land, ranching and
mining.
The Seringueiros
A large rural population in the Amazon relies on forest products such as Brazil nuts,
rubber, oils, subsistence agriculture and fishing for survival (UNRISD, 1992). One
such population is the Seringueiros (‘rubber tappers’). Deforestation often had
devastating consequences on the Seringueiros, such as the destruction of rubber
trees, the source of their livelihood. State policies encouraged cattle ranching with
incentives and land ownership changes which deprived the Seringueiros of access to
the rubber trees and often resulted in the people’s expulsion. Similarly, pollution
and restricted access to rivers and game created a decrease in the availability of fish
and meat which was often their only source of protein.
Many Seringueiros had to move to cities after being expelled in land conflicts and
often ended up in the slums of cities such and Rio Blanco and Porto Velho. The
registered population increase in these cities was reportedly “over 10 per cent
annually between 1970 and 1980” (UNRISD, 1992). The slums often lacked health,
education and employment facilities which was due to the rapid urbanisation. Most
of the Seringueiros lacked urban skills so unemployment was common.
References
Bier, S. 2005. Conflict and Human Rights in the Amazon: The Yanomami Available from
http://www1.american.edu/ted/ice/yanomami.htm [accessed 26/04/2012]
Butler, R. 2006. Fragmentation reduces biodiversity in the Amazon rainforest and worsens global warming. Available from:
http://news.mongabay.com/2006/1127-stri.html [accessed 30/04/2012]
Houghton, R. 2005. The Woods Hole Research Center In: P. Moutinho and S. Schwartzman (eds), Tropical Deforestation
Climate Change, Washington: Instituto de Pesquisa Ambiental da Amazônia, pp. 13
The Minorities at Risk (MAR), http://www.cidcm.umd.edu/mar/ [accessed 26/4/2012]
Organization of American States (OoAS). 1985. Available from http://www1.american.edu/ted/ice/yanomami.htm
[accessed 26/04/2012]
Sioli, H. 1985. Effects of Deforestation in Amazonia. The Geographical Journal. 151, pp. 197-203.
The United Nations Research Institute for Social Development (UNRISD). 1992. The Social Dynamics of Deforestation in the
Brazilian Amazon: An Overview. Geneva :UNRISD publications, 23-26 pp.
Werth, D. and Avisser, R. 2002. The local and global effects of Amazon deforestation. Journal of geophysical research, 107,
pp. 1-7.