SAHARA DESERT
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| http://my.opera.com/nielsol/blog/2010/09/06/niger-floods |
The Sahara Desert is the world's third largest desert after
Antarctica and Arctic, and the largest hot desert. The desert spreads across the
northern part of the continent of Africa with an area of around 1.8 million
square miles and more than 9,000,000
square km. "It covers nearly eleven countries and in terms of area, Sahara desert can be considered equivalent to the
continent of America. The desert divides the continent of Africa into two parts
- North and Sub-Saharan Africa."
6. "The
Sahara Desert." : Wildlife, Plants, People and
Cultures, Interesting Facts. N.p., n.d. Web.
<http://www.desertusa.com/du_sahara_life.html>
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| http://www.sciencedaily.com/releases/2009/11/091111115843.htm |
Topography
In terms of topography, the Sahara desert has a wide variety
of surface types. There are stone plateaus, sand dunes, gravel plains, salt
flats and dry valleys. The area harbors many deeply dissected mountain ranges
that at times form their own smaller ecosystems. Underground aquifers that have
risen above the surface level form magical oases.
Precipitation
The ecological region of the desert is mostly hyper arid
that receives extremely low rainfall (with less than 25 mm of mean annual
rainfall) at sporadic intervals. The major problem with the Sahara desert is
that it lies in climatic divide. The winter rain that falls on North Africa
does not reach south enough to bring rain to the central Sahara. On the other
hand, the rain from at the Intercontinental Convergence Zone moves up south,
but stops way before it can reach the central part of the Sahara. The northern
and southern parts of the desert receive comparatively greater rainfall, and
therefore have more vegetation cover.
Temperature
The Sahara Desert comes under one of the hottest regions in
the world. The average temperature of the desert is in around 86 degree
Fahrenheit. In summers, the temperatures can rise over 110 Fahrenheit, whereas
in winters it can fall below freezing. Since there is extremely limited cloud
cover, the temperatures vary daily to a great extent.
Life
Life
Due to harsh climatic conditions like extreme heat and low
rainfall, the region fosters a limited variety of species. Living organisms
that do survive have adapted to notable extents. The highest concentrations of
plants exist along the northern and southern margins of the desert and near the
oases and drainages. Similarly, the vegetation in the western part of the
desert is more than the eastern part since the western part receives relatively
more rainfall.
For obvious reasons, the Saharan flora is extremely poor
with only 500 or so species. This number is very low in relation to the
geographic area of the region.
On the other hand the fauna of the Sahara Desert is
relatively richer than what it is perceived to be as. There are almost 70
different species of mammal with around 20 being classified to be large
mammals. The Saharan Desert also fosters around 100 species of reptiles and 90
species of resident birds. There are also numerous arthropods like ants.
Historical State of the Ecosystem
"The
history of the desert dates back to 3 million years ago." It has been researched
that only a few thousand years ago the Sahara Desert was a region with
significantly large amount of precipitation and fauna. It is believed that
climatic changes over the past 5000 years, and intense hunting by man over the
last millennium has eradicated the existing faunas. "According to archeologists, the Sahara was much more densely
populated thousands of years ago when the desert's climate was not as harsh as
it is today Earlier, the desert
used to be a fertile area, in which elephants, giraffes and other animals
grazed. Slowly it started becoming drier and the fertile landscape gave way to
infertile region, as we see today. Fossils, rock art,
stone artifacts, bone harpoons, shells and many other items have been found in
areas which today are considered too hot and dry to inhabit. This suggests that
these areas were quite habitable thousands of years ago, but that the climate
of the Sahara has since changed drastically due to natural means. The artifacts
found were located near remains of giraffe, elephant, buffalo, antelopes,
rhinoceros, and warthog, as well as the remains of fish, crocodiles,
hippopotamuses and other aquatic animals which suggests that thousands of years
ago water was quite abundant in the Sahara." (http://library.thinkquest.org/16645/the_land/saha_tp.shtml)
Although
no particular conclusion has been reached as to what was the exact historical
state of the Sahara Desert, it is widely believed that the desert has undergone
some enormous variation between wet and dry over the last hundred thousand
years. During the last ice age, the Sahara Desert was close to what it is
today. However, by the end of the last ice age, the area saw a rise in
precipitation. Since then, climatic changes have led the region to be a desert
like it once was.
 |
| http://www.livescience.com/4180-sahara-desert-lush-populated.html What the Sahara Desert looked like thousands of years ago. |
 |
| http://elkhillspetroleum.com/montana.php?sp=125&mp=120 What the Sahara Desert looks like. |
Current Human Impacts on the Ecosystem
Although the Sahara desert has reached its current status of
a desert due to natural reasons, mankind has made (and continues to make) its
share of impact on the region as well. Most part of the Sahara Desert is a
relatively untouched habitat with sands and rocks and small patches of
vegetation. The major degradation that does occur, takes place in areas where
there is presence of water. Over here, the ecosystems are largely affected by
human activities.
The local pressure on the natural resources of areas with
bodies of water (like oases) is a major threat to the surviving ecosystems of
the Sahara desert. The pressure is put in terms of:
·
Hunting for food
·
Deforestation for fuel and building
·
Overgrazing by sheep and cattle resulting in
plant destruction destroy.
·
Consumption of water for domestic purposes
·
Infrastructure development (building of roads
and houses)
·
Desert Driving over vegetation (for both
domestic and recreation purposes)
·
Solar power farms.
·
Rally car races.
·
Desert farms.
Future Prospects of
the Ecosystem based on Current Human Impacts
In essence, the Sahara Desert is not a well-protected
ecosystem when compared to its counterparts in America and Europe. "Yet, this may be due to the low population and impracticality of defining borders over
this vast area. Fewer than two million inhabitants reside throughout the entire
Sahara Desert. The majority are nomads, predominantly the Tuareg, Tibbu, and
Moors. They survive by nomadic pastoralism, hunting, and trading. Most of these
people are found in the desert margins and they do not often spend much time in
the central hyper-arid portion."
(http://www.eoearth.org/article/Sahara_desert?topic=49460).
As of today, there is only one tiny protected natural reserve area in the Sahara Desert – The Zellaf Nature Reserve in Libya – which stretches only 1000 square kilometers. The development projects that have started in the deserts of Algeria and Tunisia using irrigated water pumped from underground aquifers have led to salinization and soil degradation. This has further destroyed the existing ecosystems. There is an urgent need to create more protected areas as not only will it benefit the wildlife and the habitat but also improve the lives of the local nomadic people by increasing ecotourism and boosting domestic economy.
As of today, there is only one tiny protected natural reserve area in the Sahara Desert – The Zellaf Nature Reserve in Libya – which stretches only 1000 square kilometers. The development projects that have started in the deserts of Algeria and Tunisia using irrigated water pumped from underground aquifers have led to salinization and soil degradation. This has further destroyed the existing ecosystems. There is an urgent need to create more protected areas as not only will it benefit the wildlife and the habitat but also improve the lives of the local nomadic people by increasing ecotourism and boosting domestic economy.
There has been great pressure on the few remaining populations
of large mammals that have managed adapt to the harsh desert conditions.
Populations of almost all organisms have been on a sharp decline. For example,
the addax is now critically threatened with extinction due to over-hunting. Most
of the other desert-adapted antelopes are also in danger of extinction.
Proposals to improve the Human Impact on the Ecosystem
If things continue to be the way they have been for the past
few decades, the natural ecosystems in the Sahara Desert will be completely
destroyed. There is an urgent need for the establishment of natural reserves by
strong foundations like World Wide Fund (WWF).
It is possible that the Sahara Desert be utilized in a
manner that does not impact the ecosystems. There can be installation of Solar
Projects to accommodate the energy needs of the area’s residents. It is
believed that if only 0.3% of the Saharan Desert was used for a concentrating
solar plant, it would produce enough energy to sustain Europe.
Water treatment plants should be set up that process sea
water (instead of oases) water for drinking and domestic purposes. This will greatly help to save the small
ecosystems surrounding oases to be affected negatively. These measures can only
be reached with the help of strong foundations and developed economies since
the current state of affairs in Africa is far away from allowing people to live
a reasonable standard of living, let alone a drive to support environmental conservation.
The figure above shows Vegetation cover and precipitation patterns of Africa. Patterns of precipitation (expressed as annual means, in units of mm/y) are tightly correlated with patterns of vegetation cover. Northern Africa is dominated by the Sahara, the largest hot desert on the planet today. The transition between the Sahara and the savannas to the south occurs in the Sahel zone (outlined in black). A close up of Sahara is in the image below which shows vegetation cover to the south of Sahara:
Sahara desert is slowly expanding, consuming the more productive ecosystems to the south. This process of desertification —the loss of perennial vegetation and topsoil and the associated decline in
biological productivity—is often cited as one of the main ecological threats
The figure above shows Vegetation cover and precipitation patterns of Africa. Patterns of precipitation (expressed as annual means, in units of mm/y) are tightly correlated with patterns of vegetation cover. Northern Africa is dominated by the Sahara, the largest hot desert on the planet today. The transition between the Sahara and the savannas to the south occurs in the Sahel zone (outlined in black). A close up of Sahara is in the image below which shows vegetation cover to the south of Sahara:
Sahara desert is slowly expanding, consuming the more productive ecosystems to the south. This process of desertification —the loss of perennial vegetation and topsoil and the associated decline in
biological productivity—is often cited as one of the main ecological threats
Reference list
1. "Northern Africa." Wildlife
Conservation, Endangered Species Conservation. N.p., n.d. Web. <http://worldwildlife.org/ecoregions/pa1327>
2. "Sahara Desert Was Once
Lush and Populated." LiveScience.com. N.p., n.d. Web.
<http://www.livescience.com/4180-sahara-desert-lush-populated.html>
1. 3. "Ecosystem." - National Geographic Education. N.p., n.d. Web. <http://education.nationalgeographic.com/education/encyclopedia/ecosystem/?ar_a=1>
4. "Sahara Desert Facts." -
Interesting And Fun Facts About Sahara Desert. N.p., n.d. Web. <http://lifestyle.iloveindia.com/lounge/sahara-desert-facts-3619.html>
5. The Sahara
Desert Apr 08, 2010." The Sahara Desert. N.p., n.d. Web. <http://www.thunderbolts.info/tpod/2010/arch10/100408sahara.htm>
7. "The
Living Africa: The Land." ThinkQuest. Oracle Foundation,
n.d. Web. <http://library.thinkquest.org/16645/the_land/saha_tp.shtml>
8. "World’s Largest Solar Project Planned for Saharan
Desert | Inhabitat - Sustainable Design Innovation, Eco Architecture, Green
Building." In habitat Sustainable
Design Innovation Eco Architecture Green Building Worlds Largest Solar Project
Planned for Saharan Desert Comments. N.p., n.d. Web.
<http://inhabitat.com/worlds-largest-solar-project-sahara-desert/>
9. "Sahara Desert." Sahara
Desert. N.p., n.d. Web.
<http://www.eoearth.org/article/Sahara_desert?topic=49460>
10. "Expansion and Contraction of the Sahara Desert from 1980 to 1990"
Compton J. Tucker, Harold E. Dregne, Wilbur W. Newcomb
11. "Regime Shifts in the Sahara and Sahel: Interactions between Ecological and Climatic Systems in Northern Africa"
Jonathan A. Foley, Michael T. Coe, Marten Scheffer
<http://www.eoearth.org/article/Sahara_desert?topic=49460>
10. "Expansion and Contraction of the Sahara Desert from 1980 to 1990"
Compton J. Tucker, Harold E. Dregne, Wilbur W. Newcomb
11. "Regime Shifts in the Sahara and Sahel: Interactions between Ecological and Climatic Systems in Northern Africa"
Jonathan A. Foley, Michael T. Coe, Marten Scheffer
