See posted comments (2) Post a Comment Great Man-made River Project, Al Kufra

Libyan Arab Jamahiriya

In the 1950s, oil exploration in Libyan Arab Jamahiriya turned up another resource beneath the scorching sands: the Nubian Sandstone Aquifer System. Radiocarbon analysis showed that some of the water in the aquifer system was 40 000 years old. Tapping the aquifers was chosen as the most cost-effective option for meeting the country's water needs. In 1993, Phase I of the Great Man-made River (GMMR) Project brought water from eastern well-fields at Sarir and Tazerbo to Benghazi (not shown). In 1996, Phase II brought water from well-fields at Jebel Hassouna to Tripoli (not shown). Phase III is still under construction. The project's largest reservoir, known as the Grand Omar Mukhtar, is located at Suluq (2006 image, yellow arrows). When fully operational, the GMMR will pump 3.6 million cubic metres of the Nubian Aquifer water per day. Water from the aquifer is used to support extensive centre-pivot irrigation agriculture at Al Kufra (see 1972 and 2001 images above). At current extraction rates the Nubian Sandstone Aquifer System is not likely to be depleted for a thousand years. Nevertheless, it is shared among four African nations: Libyan Arab Jamahiriya, Chad, Sudan, and Egypt. The concern of environmentalists is that eventually people will drain the aquifer faster than nature can renew it. The International Atomic Energy Agency is trying to bring the four countries together to plan rational shared use of the water. View detailed information

See posted comments (0) Post a Comment São Tomé

Sao Tome and Principe

São Tomé is the capital city of the island that shares its name. Located in the island's Agua Grande district, the population of São Tomé increased from a mere 8 431 in 1940 to 51 886 in 2001. The satellite image shows how settlements, especially along roads, have expanded inland from the city. While much of the island still retained its natural vegetation in 2007, vegetation loss is obvious near the capital city and surrounding settlements, where forests have been converted to croplands. Substantial oil reserves have recently been discovered off the island of São Tomé, which will most likely fuel increased development. View detailed information

See posted comments (0) Post a Comment Anjouan Island

Comoros

Comoros’ population quadrupled between 1950 and 2000. On Anjouan Island, where population density is 446 people per square kilometre, agricultural land is in short supply and many areas of steep terrain not suitable for agriculture have nevertheless been cultivated. Traditional agriculture leaves many trees in the fields, which help control soil erosion. However, pressure for food production is leading to more open field agriculture and some monoculture farming on the island of Anjouan. These more intense methods of agriculture encourage soil erosion. The top image above shows Anjouan’s fragmented forest. The reddish yellow areas on the simulated 3-D images show agricultural lands on Anjouan’s slopes. As a whole, Comoros lost about 60 per cent of its forest cover between 1950 and 1985. View detailed information

See posted comments (1) Post a Comment Coral Reefs of Mauritius

Mauritius

Over the past 50 years, the population of Mauritius has nearly doubled, to 1.2 million. It currently has the highest population density of any African country, 652 people per km2. Mauritius has also seen a dramatic growth in its economy, which has increased demands on its environment. Coral reefs almost surround Mauritius. Coral reefs are complex ecosystems, rich in biodiversity yet only able to survive in very clear, warm and nutrient-poor ocean waters. In these satellite images, coral reefs (yellow arrows) form a fringe along the island's shores and create shallow lagoons that are extremely important to the fishing and tourist industries. The island's population density as well as agricultural runoff, untreated sewage, changes in freshwater runoff, tourist activity, and global warming all threaten the health of the reefs. View detail information

See posted comments (0) Post a Comment Balanta Rice Farming

Guinea-Bissau

Rice is a major crop and staple food in Guinea-Bissau. The production of paddy, or "wetland," rice started in the late 17th and early 18th centuries, when the Balanta (the country's largest ethnic group) started organising men and women for agricultural production. Rice paddies have replaced many of the mangroves along the Gêba and Mansôa Rivers to the north of the capital, Bissau (2007 image). These rice paddies are built by cutting a path through the mangroves and piling up mud to form a dike that will keep back the tide. The mangroves, cut off from the ocean, quickly die. The ground is then burned to clear remaining undergrowth. After the paddies are constructed, their walls trap rain water, in which rice will grow. The 2007 image (above right) shows several dark green belts of mangrove forests adjacent to the Gêba and Mansôa Rivers. Intensive rice farming is indicated by the light-grey areas bordering these mangroves. This pattern is observed around Bissau, as well as the smaller towns of Cufar, Mansôa, Bissassema de Cima, and Nã Balanta. The 2005 high-resolution image (above left) shows the intensity of rice cultivation in an area near Cufar (from yellow box, above right). Inundated rice paddies (whitish rectangles) and rice fields (light- to dark-green rectangles) surround the meandering river. Only isolated patches of mangroves (deep-green) remain along much of the river. View detailed information

See posted comments (1) Post a Comment Swaziland Sugar Plantations

Swaziland

Sugar cane production has become Swaziland's biggest industry as large-scale producers have been joined by hundreds of small-scale farmers. Much of this growth can be attributed to government promotion of sugar cane farming. While this growth has come at the expense of natural flora and fauna, it has brought significant benefits for the eastern province of Lubombo. Sugar cane plantations are found primarily in northeastern Swaziland where temperatures are optimal. However, this region is also characterized by erratic rainfall with periods of drought; precipitation provides only 25 per cent of the water sugar cane crops need. To meet the sugar cane industry's remaining water requirements, several dams have been constructed along major rivers, including the Sand River and Mnjoli Dams. These satellite images, from 1979 and 2006, show the dams and how the area devoted to sugar cane plantations has increased over time. Sugar cane exports bring in roughly US$1 500 million annually to Swaziland. Lubombo Province, in particular, relies heavily on income from sugar cane as well as social services that the industry provides, including medical care, education, housing, and access to clean water. Yet fluctuating sugar prices have prompted the Swazi government to promote the production of other crops. Such a transition, however, is far easier for small-scale farmers than for large-scale producers with extensive plantations. View detailed information

See posted comments (0) Post a Comment Souss-Massa Valley

Morocco

The Souss-Massa Valley is located in southwestern Morocco. Rainfall in the valley is only about 200 mm per year, which is not enough to support most types of agriculture. In 1968, Morocco's King initiated a plan to irrigate one million hectares. In 1972, the Youssef Ben Tachfine Dam (photo below) was built on the Massa River, creating a reservoir that supported a substantial growth in agriculture in the valley and allowed development of a modern agricultural area of 18 000 hectares, primarily dedicated to vegetable and citrus cultivation. Irrigated agriculture in the valley also uses groundwater; however, groundwater withdrawal has exceeded the natural rate of recharge. Since the 1970s groundwater resources have declined, forcing farmers to drill much deeper wells to reach water. In the 1970s, greenhouse agriculture was introduced to the area. It requires 80 per cent less water per kg of crop than unprotected agriculture. The 1988 satellite image shows a few greenhouses (light blue squares) scattered throughout the valley. The 2003 image shows the expansion that has occurred in greenhouse agriculture, with greenhouses (white squares) covering a substantial portion of the valley's agricultural land. The Souss-Massa Valley is Morocco's leading region for greenhouse agriculture, covering 14 530 hectares in 2004. Vegetables are the primary crops, with tomatoes covering more than half the greenhouse area. View detailed information

See posted comments (0) Post a Comment Jebel Marra Foothills

Sudan

The Jebel Marra Massif is a region of high, jagged peaks and fertile valleys in western Sudan. The southern foothills of the Jebel Marra receive an average of 600 to 800 mm of precipitation annually, just above the minimum needed to support rain-fed agriculture. Crops include sorghum, millet, groundnuts, and cowpeas that are raised along watercourses and adjacent areas. Pastoralists seasonally graze their cattle on the natural vegetation in the region; the number of grazing herds has increased in recent decades as droughts have made water and pasture scarce further north. Population growth , especially in the latter half of the 20th century, coupled with an influx of refugees from drought and conflict in Northern Darfur have put increasing pressure on this fragile ecosystem. Human activities have greatly altered the natural open-savannah woodlands. The 1972 image shows substantial tree cover across much of the lower left half of the image. The 2006 image shows the degree to which vegetation has been reduced, particularly in the less hilly areas and away from croplands concentrated along the watercourses. The loss of trees and shrubs in this fragile environment is leading to land degradation and reduced capacity to support the area's ever-increasing population. View detailed information

See posted comments (0) Post a Comment Amatole Mistbelt Forests

South Africa

While forests are not believed to have ever covered a large part of South Africa, logging, clearing for agriculture, and forest plantations have much reduced their original extent. Indigenous forests now cover only 0.33 per cent of South Africa's land area. South Africa's Amatole Mistbelt Forests are part of the southernmost areas of Afromontane forest in Africa. They contain some small remaining patches of indigenous forest. These forests fall within the Maputaland-Pondoland-Albany biodiversity hotspot and are home to variety of unique plant and animal species, including several endemic species such as the endangered giant golden mole (Chrysospalax trevelyani). They are also important resources for local people who rely on them for wood and non-wood products. Some of the characteristic tree species are yellowwood (Podocarpus falcatus), (see photo), red currant (Rhus chirindensis), and black ironwood (Olea capensis). South Africa's Department of Water Affairs and Forestry defined the areas of Isidenge and Pirie as "irreplaceable" patches of indigenous forest. While nearly half of the forests in the Amatole Mistbelt Forests are under state management, less than 1.5 per cent are under strict protection. Comparison of these 1972 and 2001 images shows some new areas of tree cover, (yellow arrows); however, these are primarily plantation forests of pine and eucalyptus, which threaten to alter the hydrology and reduce the biodiversity of these ecosystems. View detailed information

See posted comments (0) Post a Comment Pico de Fogo

Cape Verde

On 2 April 1995, residents on Fogo Island reported a red glow atop Pico de Fogo volcano. It was the beginning of volcanic eruptions that would continue for seven-and-a-half weeks, sending lava across the floor of Chas das Calderiras (Plain of Craters) that eventually covered 4.3 km2 of farmland, destroyed the village of Boca de Fonte, and forced the evacuation of approximately 1 300 residents. Despite the danger, people live in the caldera and raise coffee, wine grapes, fruits, and other crops in the fertile volcanic soils (red arrows). The 1995 eruption on the southwest slope sent lava flowing to the northwest across the main road through the caldera (yellow arrows). Studies are ongoing as to the stability of Pico de Fogo. View detailed information

See posted comments (0) Post a Comment Kafue Wetlands

Zambia

In southern Zambia, the Kafue River crosses a broad floodplain roughly 255 km long. Before the Itezhi-tezhi Dam was built on the river in 1978, flooding beginning in December would cover much of the plain well into the dry season. Although the dam was built to allow the release of sufficient water to cause seasonal flooding, this mimicking of the natural floods has in general not been practised. The Kafue Flats floodplain provides important habitat for rare and endemic species, including the Kafue lechwe (antelope) and wattled crane, and supports local livelihoods, especially cattle-raising and fishing. Limited seasonal flooding following the construction of the dam has been linked to a decline in fish production and in the Kafue lechwe population. The number of lechwe fell from around 90 000 before the dam was built to around 37 000 in 1998. In 2004, a partnership between World Wildlife Fund, the Zambian Ministry of Energy and Water Development, and the Zambian Electricity Supply Company put new rules in place for water releases from the dam to mimic natural flooding patterns more successfully. The 1970s image shows Kafue Flats in the dry season, with water levels retreating. The Kafue Gorge Dam can be seen in the lower right corner of the image (yellow arrow). Itezhi-tezhi Dam was built a few years later to provide more storage capacity for electricity generation at the Kafue Gorge Dam. The 2007 image shows the Kafue Flats during wet season floods, helped for the first time by the release of adequate water from the Itezhi-tezhi Dam. View detailed information

See posted comments (1) Post a Comment Bou Craa

Western Sahara

The Bou Craa phosphate mine is located 100 km inland from the capital city of El Aaiun. The Bou Craa area's phosphate resources were discovered by the Spanish in 1947; phosphate deposits are near the surface and are very pure. Phosphate mining, however, did not begin until the 1960s. Since 1974, the Bou Craa mining operation has been growing steadily. In 2000, the mine covered more than 1 225 hectares. In 2001, its output was approximately 1.5 million metric tonnes of phosphate. Morocco controls the area of Western Sahara where the mine is located and jointly operates the mine with Spanish interests. While the mine amounts to only two or three per cent of Morocco's phosphate production, the reserves are valuable because of the uranium that can be extracted from them. The phosphate-containing rock is transported from the Bou Craa mine to the port at El Aaiun via a 100-km-long conveyor belt, which can move 2 000 metric tonnes of rock per hour. The conveyor belt is visible as a straight line from the upper left corner toward the centre of the 1987 and 2007 images above. Below these images are two long, horizontal images, captured in 1972/1973 and 2000. The conveyor belt is visible in the 2000 image running from the mine to the coast. Note the fringe of drifting sand spreading downward from the belt's path (yellow arrows). View detailed information

See posted comments (0) Post a Comment Sidi Toui National Park

Tunisia

The semi-arid Sahelian grassland and scrub of southern Tunisia has been profoundly altered by human activities during the last century. Located on the northern fringe of the Sahara Desert, this ecosystem is susceptible to erosion and desertification brought on by droughts, overgrazing, and agriculture. In 1993, Sidi Toui National Park was established. Within the bounds of this protected area, natural vegetation began to return. The 1987 image shows the barren condition of the region before the park was created. In the 2006, image the outline of the park, which is protected from the effects of grazing cattle, contrasts markedly with the surrounding landscape. Protection substantially increased the vegetation density and species diversity, particularly of the grasses. The Scimitar-horned oryx (Oryx dammah) and five other species of gazelles and antelope native to this area had been brought to near extinction by lack of habitat and overhunting throughout the 20th century. Classified as critically endangered in 1996, a small population of Scimitar-horned oryx was introduced into Sidi Toui Park in 1999. If the population inside the park thrives, it may enable future reintroductions of Scimitar-horned oryx elsewhere, Sidi Toui also provides habitat for several native species of antelope, as well as a variety of bird species. View detail information

See posted comments (0) Post a Comment Nangbeto Reservoir

Togo

A feasibility study in the 1960s identified the Nangbéto region as the best location for hydroelectric power development in Togo. The site - 160 km upstream from the coast – is the only place where a dam of sufficient volume to regulate the flow of the Mono River was possible. As demand for electricity grew, the decision was made in the 1980s to proceed with the Nangbéto Hydroelectric Dam. Satellite images from 1986 and 2001 show the region before and after the dam's construction. The completed dam created a reservoir with a surface area of approximately 180 km2 and a volume of 1 465 million m3. In addition to generating electricity for domestic and commercial use, the dam also provides water for agricultural irrigation and is a source of commercial fishing and tourism. However, these benefits have been offset by environmental costs. Construction of the dam, creation of the reservoir, and installation of transmission lines resulted in the loss of nearly 150 km2 of savannahs and gallery forests that provided habitat for rare local fauna. The reservoir submerged 1 285 households and 5 500 hectares of agricultural land. Loss of the natural vegetation in the region has altered the climate enough to have had a negative impact on nearly 350 hectares of banana plantations. The creation of the reservoir has also increased the population of two species of aquatic snails that serve as intermediate hosts of the parasite that causes the disease bilharzia. View detailed information

See posted comments (0) Post a Comment Fynbos

South Africa

The Cape Floristic Region is a Mediterranean-type ecosystem unique to the southwest tip of Africa. It has the greatest concentration of plant species in the world outside of tropical ecosystems, with 6 210 of its 9 000 species occurring nowhere else in the world. Although the region is relatively small, its plant biodiversity is the richest per unit area on Earth, prompting its designation as a biodiversity hotspot. The characteristic and most widespread type of vegetation in the Cape Floristic Region is fynbos, an Afrikaans word that translates as "fine bush." Covering some 46 000 square kilometres, fynbos is a shrubland comprising hard-leafed, evergreen, fire-adapted shrubs. Fynbos covers half of the surface area and accounts for 80 per cent of the plant varieties of the Cape Floristic Region. The 1978 image shows large, relatively intact areas of native fynbos vegetation. Over subsequent decades, however, large tracts of fynbos have been cleared for agriculture or lost to urban expansion around Cape Town. The 2007 image shows how roads, urban development, and agriculture have overtaken much of the area. Fynbos areas are also threatened by invasive alien species, particularly wattle and acacia species from Australia, as well as pine plantations. Many fynbos species have gone extinct, and more than 1 000 are endangered. Their conservation is a priority, and reserves have been established in many areas. View detailed information

See posted comments (0) Post a Comment Juba River Flooding

Somalia

Late in the fall of 2006, the Horn of Africa received heavy rains generally believed to have been the consequence of an El Niño weather pattern over the Pacific Ocean. By late November and early December, flooding had displaced roughly half a million people, destroyed crops and villages, and caused outbreaks of disease. The severity of the floods made relief efforts extremely difficult. By December these floods were the worst Somalia had seen in ten years. In March 2007, predictions of above-normal spring rains in the upper reaches of the Juba River watershed threatened to cause more flooding. On the left page, September 2006 and December 2006 images show a portion of the Juba River before and after the rains came, respectively. Flooded areas appear as dark-green to black. Small portions of these images (yellow rectangles) are shown on the right in greater detail. In spite of profound negative impacts of the flooding in the Juba River region, two consecutive seasons of heavy precipitation may have benefited cereal grain production and improved pastoral conditions in the region, substantially reducing the need for humanitarian assistance. View detailed information

See posted comments (0) Post a Comment Rutile Mining in Moyamba District

Sierra Leone

Sierra Leone is mineral rich; titanium minerals such as rutile and ilmenite are its principle mineral exports. Before war erupted in 1991, mining represented 90 per cent of Sierra Leone's registered exports and roughly 20 per cent of its GDP—rutile accounted for well over half of that. The Moyamba District, which borders the Atlantic Ocean in the west and Bonthe to the south, is the most active rutile mining area in the country. Although mining companies left during the war, they returned when the war ended in 2002. Rutile is mined by creating large artificial lakes which are then dredged, leaving behind large water-filled pits up to 600 m long. In Sierra Leone, these activities have left vast areas of land deforested and degraded. It is estimated that between 80 000 and 120 000 hectares of land have been mined out in different parts of the country with minimal efforts at restoration. In the 1974 image, one small mining operation is visible (centre); however, much of the Moyamba District was still covered with relatively intact forests at that time. By 2003, mining activities had replaced large portions of forest with water-filled pits. These mining sites have extremely poor health and sanitary conditions; the pits teem with mosquitoes and bacteria that are linked to a high incidence of malaria, cholera, and diarrhoea. View detailed information

See posted comments (0) Post a Comment Freetown

Sierra Leone

Freetown, Sierra Leone's capital city, shares a peninsula with the Western Area Forest Reserve'a small remnant of the Guinean Forests that historically stretched from Guinea to Cameroon. The century-old reserve covers a chain of forested hills that are home to approximately 300 species of birds and a small population of chimpanzees. Intense population growth began in Freetown in the 1970s. However, a buffer of forested land remained between the Reserve and the edge of the city. By the mid-1980s, however, the growing city had expanded into the buffer zone and much closer to Reserve borders (1986 image). Between 1991 and 2002, as many as one million people fled to Freetown as a result of war in Sierra Leone. Many of these refugees moved into the hills of the Reserve, where they relied on its resources to survive. Deforestation and land degradation of these valuable protected lands was the result. By 2003, the border of the Reserve had been breached in many places (2003 image), with urban populations encroaching from several directions. The Reserve is now recognized as vital, not only to the biodiversity and natural systems it supports, but to the people of Freetown as well. The forest is crucial for recharging Freetown's reservoirs, which are already struggling to meet the city's water needs. View detail information

See posted comments (0) Post a Comment Mahe Island

Seychelles

The east coast of Seychelles’ Mahe Island has undergone major environmental change during the last 30 years, primarily due to land reclamation projects. In 1973, land was reclaimed to create a site for the Seychelles International Airport, and in 1986, for a new port facility. Two further phases of reclamation were completed in the early 2000s, parts of which can be seen in the 2007 image above (yellow arrows). These reclamation projects have impacted both marine and coastal environments. Several new wetland areas have been created, some of them colonized by mangroves, which provide valuable bird habitat and nursery areas for marine species. However, sedimentation from reclamation projects has killed some of the coral along Mahe's eastern coast as well. View detailed information

See posted comments (0) Post a Comment Leboudou Doue

Senegal

In the black and white image, the darker areas of the land enclosed by this great loop on the Senegal River show the extent of the riverine forest in 1966. The 2006 image shows that very little of that forest remains. Similar deforestation has occurred in the fertile floodplains along hundreds of kilometres of the Senegal River. Only a small fraction of these riverine woodlands remain (see photo panel below). Much of the forest was cleared by local people to make way for subsistence agriculture. The most common riverine tree species, Acacia nilotica, is also the preferred source of wood for fuel and construction, and for charcoal production. Production of charcoal for sale as far away as Dakar and Saint Louis has further increased the pressure on what remains of these woodlands. Acacia nilotica woodlands that covered 39 000 hectares along the Senegal River in 1966 had been reduced to 9 000 hectares by 1992—a reduction of 77 per cent. These pressures were compounded by two developments in the late 1980s. In 1988, the Manantali Dam was built upstream in Mali. The dam controls roughly half of the Senegal River's discharge. While controlled releases of water from the dam can recreate natural flooding, below-normal flood levels may be contributing to loss of Acacia nilotica stands. The area's population has also grown dramatically over the past several decades, including the influx of some 120 000 Mauritanian refugees and Senegalese expatriates following an ethnic conflict in 1989. View detailed information

See posted comments (0) Post a Comment Dakar

Senegal

Like many West African cities, Senegal's capital city of Dakar has grown dramatically over the past several decades. Growth is expected to continue. While birth rates have begun to decline, natural growth still accounts for much of Dakar's expansion. In addition, Dakar experienced a large rural-to-urban migration beginning in the 1960s, when Senegal suffered from declining precipitation and periods of extreme drought. By 2005, Senegal's urban population exceeded its rural population. By 2030, two-thirds of the country's population is expected to be urban. Roughly half of Senegal's urban population lives in the greater Dakar metropolitan area. Urban population growth has turned the Cap Vert Peninsula into a sprawling metropolis, where settlements reach ever-further inland and onto the prime farmland that has historically supported the city. Pikine, initially begun as a resettlement of urban slum dwellers 15 km east of Dakar, has grown to over one million people. Its location in the fertile Niayes region displaced large areas of urban and peri-urban agriculture that once provided livelihoods for a substantial portion of the population. In the aerial photo mosaic from 1942, Dakar is concentrated at the southern tip of the peninsula, with only the airport and a few scattered roads and settlements to the north. The 2006/2007 image shows only a portion of the greater Dakar area, which currently stretches another 14 km to the city of Rufisque (not shown). View detailed information

See posted comments (0) Post a Comment Tahoua Province

Niger

A band across the southern third of Niger receives enough rain (250-750 mm) to sustain most of the country's rain-fed agriculture and pastoralism. This stretch of semi-arid Sahel is also where most of Niger's rapidly growing population lives. However, the Sahelian climate is quite variable and in this ecologically frail region this poses serious problems for traditional livelihoods. In recent decades, Niger's climate and its demographic problems have negatively impacted its agricultural land by forcing agriculture onto land that had been historically used for livestock— land receiving less than 350 mm of rain per year. This intense pressure on fragile lands led to acute environmental degradation (1975 image). More recently, a combination of various projects and farmer initiatives has led to significant revitalization of the land in large part by the planting and protection of trees. Farmers no longer clear tree saplings from their fields before planting crops. Instead they protect and nurture the trees, carefully plowing around them when sowing millet, sorghum, peanuts, and beans. A recent study revealed 10 to 20 times the number of trees across three of Niger's southern provinces than there were in the 1970s (2005 image). This transformation of the land has reduced drought vulnerability and will help people diversify their livelihoods so as not to rely solely on rain-fed crops. View detailed information

See posted comments (0) Post a Comment Baban Rafi Forest

Niger

Along the southern border of Niger in the Department of Maradi, population has increased by roughly 400 per cent over the past 40 years. The area under agriculture in the department as a whole grew by 26 per cent between 1975 and 1996. In the south of the district, this expansion of population and agriculture has meant the loss of a large portion of the Baban Rafi Forest to agriculture. The remaining woodlands are being degraded by overexploitation for fuelwood and non-wood forest products. Baban Rafi Forest is the most significant area of woodland in the Maradi Department. Located at the southern extreme of the Sahel, it has areas of both savannah and Sahelian vegetation. In the savannah areas, the balance of trees, grasses, and shrubs varies. The wooded areas are dominated by just four species of trees—Guiera senegalensis, Combretum micranthum, Combretum nigricans, and Acacia macrostachya—likely as a result of selective exploitation and some combination of drought and disease. These satellite images show the loss of a significant fraction of the natural landscape (darker green areas) of Baban Rafi Forest to agriculture between 1976 and 2007. The intensity of demand for agricultural land has also led to near continuous use of farmland in the area, with shortened or no fallow period for it to recover fertility. The high resolution image below shows in more detail the area within the yellow box of the 2007 image. The lighter areas are where the woodland savannah vegetation has been cleared for farming. Continuing population growth will put further demands on this already dramatically changed landscape. View detailed information

See posted comments (0) Post a Comment Kavango Region

Namibia, Angola

The Kavango Region, located in Namibia's relatively wet northeastern corner, is part of the eight per cent of the country that receives about 500 mm of rain per year—the minimum considered necessary for non-irrigated agriculture. However, because this rainfall is irregular and evaporation rates are high, it is often inadequate for successful farming. Many of the soils in this area, with low nutrients or high salinity, are also marginal for farming. Nevertheless, roughly 55 per cent of the region is used for subsistence agriculture with pearl millet being the predominant crop. Savannah woodlands are the natural vegetation in the sandy soils surrounding Rundu, near the Okavango River. Many of the woodlands along the river were cleared for agriculture long ago. More recently, government-dug wells have enabled settlement and farming further from the river, leading to further deforestation, particularly in the dry river beds (omurambas), where the soils are better for farming. The Namibian government considers this area an important focus of economic activity and supports many water and agricultural projects. Along with rapid development, the population of Rundu is growing at a staggering pace—911 per cent between 1981 and 1991. These images, from 1973 and 2007, show the dramatic increase in the land area cleared for agriculture (light yellow patches) around Rundu and elsewhere along the river. View detailed information

See posted comments (0) Post a Comment Diawling National Park

Senegal, Mauritania

Prior to construction of Diama Dam across the Senegal River, land surrounding the Senegal Estuary was flooded with fresh water from late July to late September each year. During the dry season, these delta wetlands would become saltier than the ocean, as their waters were reduced by evaporation. This yearly cycle was disrupted by the construction of the Diama Dam in 1986 (yellow arrow). Both the Diama Dam, and the Manantali Dam constructed upstream in Mali, were intended to regulate the flow of the Senegal River, generate hydroelectric power, and facilitate development of irrigated agriculture. However, irrigation in the delta has been less successful and less productive than planned; lacking proper drainage systems, the land is becoming waterlogged and saline after just a few years under irrigation. Drought had already begun to impact the wetlands before construction of the dams in the 1980s (1979 image). Following their construction in the 1980s, fish stocks decreased and wetland vegetation was decimated. In the early 1990s, a restoration project began using controlled flooding of the delta by managed water releases. It has revived the wetlands and restored much of the lost flora and fauna to the area. The 2006 image shows the restored wetlands in and around Diawling National Park. View detailed information

See posted comments (0) Post a Comment Morondava

Madagascar

The large circular fields of irrigated sugarcane near Morondava in western Madagascar are an anomalous sight in this area more known for its baobab trees. While the average temperature in the area is ideal for sugarcane cultivation, a long dry season (April to November) makes irrigation necessary. These three images show the region before irrigation (1973), after irrigation was introduced (2000), and after further expanded irrigation (2006). Managed by a foreign company, most sugar cane grown in the area is exported. Ironically, sugar must be imported for the local market. Roughly 22 000 metric tonnes of sugar were produced here in 2006. Baobabs, (see photo panel below) sometimes called "upside down trees" can live for up to 5 000 years. While there is only one baobab species on the African continent, Madagascar is home to seven different species. The volume of water needed for irrigating sugar cane fields may threaten the survival of these ancient trees if sugar cane farming extends into baobab areas—particularly the "allée des Baobabs" (Baobabs Boulevard, yellow arrows). Baobabs are also under threat by local community rice farming. Since August 2007 the "allée des Baobabs" has been temporarily classified as a protected area, the result of consultation between local communities, local authorities, and government authorities. View detailed information