Hydrogen molecule s in the fat combine with inhaled oxygen to form water. During a shortage of food or water, camels draw upon this fat for nutrition and moisture.
Dromedary camels, native to the Arabian and Sahara deserts, can lose up to 30 percent of their body weight without harm. People and the Desert About 1 billion people live in deserts. Many of these people rely on centuries-old customs to make their lives as comfortable as possible Civilization s throughout the Middle East and Maghreb have adapted their clothing to the hot, dry conditions of the Sahara and Arabian deserts.
Clothing is versatile and based on robes made of rectangles of fabric. Long-sleeved, full-length, and often white, these robes shield all but the head and hands from the wind, sand, heat, and cold. White reflects sunlight, and the loose fit allows cooling air to flow across the skin.
These robes of loose cloth can be adjusted folded for length, sleeves, and pockets, depending on the wearer and the climate. A thobe is a full-length, long-sleeved white robe. An abaya is a sleeveless cloak that protects the wearer from dust and heat.
A djebba is a short, square pullover shirt worn by men. A kaffiyeh is a rectangular piece of cloth folded loosely around the head to protect the wearer from sun exposure, dust, and sand.
It can be folded and unfolded to cover the mouth, nose, and eyes. Kaffiyehs are secured around the head with a cord called an agal.
A turban is similar to a kaffiyeh, but wrapped around the head instead of being secured with an agal. Turbans are also much longer—up to six meters 20 feet! Desert dwellers have also adapted their shelters for the unique climate.
The ancient Anasazi peoples of the southwestern United States and northern Mexico constructed huge apartment complexes in the rocky cliff s of the Sonoran Desert.
These cliff dwellings, sometimes dozens of meters off the ground, were constructed with thick, earthen walls that provided insulation. Although temperatures outside varied greatly from day to night, temperatures inside did not. Tiny, high windows let in only a little light and helped keep out dust and sand.
The need to find food and water has led many desert civilizations to become nomadic. Nomadic cultures are those that do not have permanent settlements. In the deserts of the Middle East and Asia, nomadic tent communities continue to flourish.
Tent walls are made of thick, sturdy cloth that can keep out sand and dust, but also allow cool breezes to blow through. Tents can be rolled up and transported on pack animal s usually horses, donkeys, or camels. Nomad s move frequently so their flocks of sheep and goats will have water and grazing land. Besides animals like camels and goats, a variety of desert vegetation is found in oases and along the shores of rivers and lakes.
Figs, olives, and oranges thrive in desert oases and have been harvested for centuries. Some desert areas rely on resource s brought from more fertile areas—food trucked in from distant farmlands or, more frequently, water piped from wetter regions.
Large areas of desert soil are irrigate d by water pumped from underground sources or brought by canal from distant rivers or lakes. The booming Inland Empire of southeastern California is made up of deserts the Mojave and the Sonoran that rely on water for agriculture, industry, and residential development. Canal s and aqueduct s supply the Inland Empire with water from the Colorado River, to the east, and the Sierra Nevada snowmelt to the north.
A variety of crops can thrive in these irrigated oases. Sugar cane is a very water-intensive crop mostly harvested in tropical regions. However, sugar cane is also harvested in the deserts of Pakistan and Australia. Water for irrigation is transported from hundreds of kilometers away, or drilled from hundreds of meters underground. Oases in desert climates have been popular spots for tourists for centuries.
The Dead Sea has had flourishing spas since the time of King David. Air transportation and the development of air conditioning have made the sunny climate of deserts even more accessible and attractive to people from colder regions.
Desert parks, such as Death Valley National Park, California, attract thousands of visitors every year. But in cities, structures like buildings, roads, and parking lots hold on to daytime heat long after the sun sets. This is called the urban heat island effect. It is less pronounced in desert cities than cities built in heavily forested areas. New York was built on wetland habitat, and Atlanta was built in a wooded area. They may be only slightly warmer than the surrounding desert.
Deserts can hold economically valuable resources that drive civilizations and economies. The most notable desert resource in the world is the massive oil reserve s in the Arabian Desert of the Middle East. More than half of the proven oil reserves in the world lie beneath the sands of the Arabian Desert, mostly in Saudi Arabia.
The oil industry draws companies, migrant workers, engineers, geologist s, and biologist s to the Middle East. Desertification Desertification is the process of productive cropland turning into non-productive, desert-like environments.
Desertification usually happens in semi-arid areas that border deserts. Human activities are a primary cause of desertification. These activities include overgrazing of livestock , deforestation , overcultivation of farmland, and poor irrigation practices. Overgrazing and deforestation remove plants that anchor the soil. As a result, wind and water erode the nutrient -rich topsoil.
Hooves from grazing livestock compact the soil, preventing it from absorbing water and fertilizer s. Agricultural production is devastate d, and the economy of a region suffers. The deserts of Patagonia , the largest in South America, are expanding due to desertification. Patagonia is a major agricultural region where non-native species such as cattle and sheep graze on grassland. Sheep and cattle have reduced the native vegetation in Patagonia, causing loss of valuable topsoil.
More than 30 percent of the grasslands of Argentina, Chile, and Bolivia are faced with desertification. People often overuse natural resources to survive and profit in the short term, while neglecting long-term sustainability.
Madagascar, for instance, is a tropical island in the Indian Ocean. Seeking greater economic opportunities, farmers in Madagascar engaged in slash-and-burn agriculture. This method relies on cutting and burning forests to create fields for crops. Unfortunately, at the time farmers were investing in slash-and-burn agriculture, Madagascar experienced long-term droughts.
With little vegetation to anchor it, the thin topsoil quickly eroded. Rapid population growth also can lead to overuse of resources, killing plant life and depleting nutrients from the soil. Since the s, Lake Chad has shrunk to half its size. Desertification has severely reduced the wetland habitats surrounding the lake, as well as its fishery and grazing lands.
Desertification is not new. Millions of people had to leave their farms and seek a living in other parts of the country. Desertification is an increasing problem. Every year, about 6 million square kilometers 2. The Sahara Desert crept kilometers 39 miles south between and South Africa is losing million metric tons short tons of topsoil each year. Many countries are working to reduce the rates of desertification.
Trees and other vegetation are being planted to break the force of the wind and to hold the soil. Windbreak s made of trees have been planted throughout the Sahel , the southern border region of the Sahara Desert. These windbreaks anchor the soil and prevent sand from invading populated areas. They anchor the drifting sand with a gridlike network of straw fences.
Straw is poked partway into the sand, forming a pattern of small squares along the contours of the dunes. The resulting fences break the force of the wind at ground level, stopping dune movement by confining the sand within the squares of the grid.
New technologies are also being developed to combat desertification. Nanoclay keeps the sand moist, clumping it together and preventing it from blowing away. Deserts Get Hotter Rising temperatures can have huge effects on fragile desert ecosystems.
Global warming is the most current instance of climate change. Human activities such as burning fossil fuel s contribute to global warming. In deserts, temperatures are rising even faster than the global average. This warming has effects beyond simply making hot deserts hotter. For example, increasing temperatures lead to the loss of nitrogen , an important nutrient, from the soil.
Heat prevents microbe s from converting nutrients to nitrate s, which are necessary for almost all living things. Other antelope species exist in small numbers, though many previously-endemic species are no longer present in the region. In the past the critically threatened addax would probably have occurred in this ecoregion, but this species is likely to be extirpated.
Small numbers of scimitar-horned oryx may have also occurred in the past. The bulk of the rest of the animal diversity of this region is made up of bird species, though small mammals and arthropods can be found in parts of the region. It is the national animal of Algeria. This region is both largely unprotected and undisturbed. The low human population density means that pressures on natural resources and habitats themselves are small and unthreatening; with a population smaller than 1 million people over such a large area, there are no systematic threats from settlements and infrastructure in this area.
But the general insecurity of the regions forced the colleagues to abandon the project in [ 4 ]. The extreme degradation of herb and tree pastures in the Air Mts.
Figure 8 explains the general situation. It shows the two granite ring structures of Agalak and Aroyan and the upper part of the Wadi Anou Mekkerene, one of the greatest of the Air Mts. And it also depicts the altitudinal change in the Air Mts.
Within 4 or 5 years, a rotation system, which functioned on the closure of pastures for several years, aimed to assure the regeneration of grasses, herbs and trees. At the same time, a sustainable exploitation system of the pastures should impede a new degeneration by overgrazing or other forms of over-exploitation. It is situated in the Aroyan-granite ring structure, which could easily be closed in for 4 years.
This area showed the typical transitions from the contracted desert vegetation to the mountain savannas of the Sahelian type. Apparently, trees could profit from the good rainy season and from the reduced concurrence of herbs, which suffered from the preceding drought. In , a first two-days-opening was organised for fruit collection and grass cutting. Within 4 years, the development of tree and grass pastures was as astonishing high, and also people from other villages had planned to initiate comparable systems.
After the controlled opening in , a second pasture was closed for regeneration. For the long run, the village council discussed the models of an interdiction of pastures but with controlled collection of grass and fruits or controlled pasture.
In the mountain savannas, the protection and controlled collection of medicinal herbs was an attractive point too. Anyway, a permanent following up of vegetation development was planned for the future.
The Guide-project evidenced the chances of local and accepted regeneration initiatives and it could have been a model for other regions. Unfortunately, as for the Gourma project, the rebellion and the successive insecurity put a premature end to this success. The creation of extended reserve areas or national parks have been generated by the ideas of an auto-regeneration through excluding further human exploitation or through the protection of emblematic animals as key stone organisms.
These are the greatest protection areas in the Sahara and in Africa as a whole and were supposed bridge the areas of endangered key stone animals [ 15 , 16 , ]. Moreover, there was already a survey on the chances to establish a system of monetary exploitation of ecosystem services [ ].
However, these initiatives often disturbed the traditional pasture systems, and due to the insufficient involvement of the local populations, it led to various problems and frictions. Anyhow, the sense of these protections and reserve areas was not really communicated to and accepted by the concerned populations.
Thus in the s, with the beginning of the rebellions in Mali, Niger and Chad, these projects were no longer accepted by and the state could no longer maintain them. This is the continental flagship of the protection-regeneration projects and follows still the philosophy of expanding ecosystems and the combat against them see Figure 1.
The project was created by the African Union in [ 17 , ] as a km belt from Senegal to Djibouti. Fifteen kilometres wide, it should work as protection against wind and erosion. Afforestation should provide nutrients to the soil and also ameliorate pasture by foliage and shadow too.
Finally, the tradition of agroforestry parks see above was taken as a model see also [ ]. Anyway, as for the other smaller or greater projects, this initiative came to an intermediate?
But the research in the various institutes of the partner states continues in the hope to reactivate and readjust this flagship. However, it already serves for the governmental propaganda. The presidency of Niger claimed to have plated millions of trees in order to reduce soil erosion and to fix dunes [ ]. Several projects and activities concentrate on the regeneration and amelioration of degraded soils in order to restore the soil cover and to assure food production [ , ].
They are mostly organised on personal or village level and so they are participative. These activities have to be seen on the background of a general extensification of agriculture, parallel to the intensification, e. Most Sahelian farmers are still subsistence-oriented. This means that they mainly crop to nurture their families rather than to produce market products. Several examples illustrate these activities see Figure Regeneration and food security measurements in Niger.
B Reduced weeding in S-Niger. C Intensive irrigation for vegetable production at Niamey, Niger. It is based on dug in holes, 10—40 cm in diameter and 10—25 cm in deep in a distance of about 1 m. These holes can store rain and run off and thus support the regeneration of spontaneous vegetation.
They may be filled with leaves or compost in order to attract the termites. The dug in holes must be renovated each year.
In the Haoussa region around Maradi in Niger, average farm size has reached meanwhile about 2 ha. For the simple reason of survival, intensification of cropping is mandatory. However, a number of obstacles exist that hinder the application of innovations. Among these are traditions, low educational level, low investment capacity and the need for risk management. The latter aspect means that farmers are risk averse and are not — in contrast to the normal economical theory— yield or income maximisers.
First of all, the family members need to survive. So the question is: how does innovation needs to be alike to be acceptable for farmers.
The answer is manyfold: the innovation needs to be simple, affordable, relying on local resources, risk reducing, functioning under multiple weather scenarios and it cannot contradict local customs.
One is the re-establishment of ligneous vegetation, and the other is increasing the crop biomass production. At the first glance, these are contradictory objectives.
Is this really so? In order to answer this question, we will discuss different options in the following. Heavy convective storms are a regular phenomenon in the Sahel. They lead to erosion on open surfaces at the beginning of the rainy season and homogenisation of soil surface properties through redistribution of particulate matter [ , ]. The saltating sand grains damage the young seedlings and can lead to crop loss at an early vegetative state.
Therefore, it is reasonable to think of windbreaks as a solution to the problem. A lot of research has been done in this respect [ , ]. However, we hardly see any adoption of this technology by farmers. What are the problems? It begins with legal problems. Planting a tree means to express a claim on property.
This is delicate in societies were the land is distributed according to local traditions. Second, planting trees in a hedgerow means an investment that is hardly affordable for a single farmer. A third argument for rejection is the workload for making the trees survive after planting and for pruning in order to reduce competition with the neighbouring crop later.
And the competition for land, water, light and nutrients is the fourth argument to set this technology aside. In conclusion, hedgerows are a typical innovation typical for scientists and based on on-station results, thus neglecting the constraints of the rural populations. Are there more simple and adoptable solutions? One is, i. It uses the regeneration of ligneous species by re-sprouting from rootstocks. Already Wezel et al. This is achieved through the reduction of the negative wind erosion effects and the increase of the organic matter stock that is the major provider of the major limiting nutrient phosphorus.
As side effect, fire wood is provided. In contrast to hedgerow planting, with this technology, the only input to be provided is low: i. The disadvantage is that it is only possible in non-mechanised agriculture. And, the woody species composition is hardly foreseeable.
Studies in the Maradi area in Niger have shown that in densely populated areas, all still existing woody species are under use and that their distribution is depending on the distance to settlements Figure A survey on tree vegetation in the Faidherbia -park zones around a village in southern Niger.
Survey and assembly by Herrmann Close to settlements, old Faidherbia albida trees dominated are protected, since they deliver high quality animal fodder and do not compete during the rainy season with the crop due to the leaf cover developing in the off-season. Farther away from the settlements, Piliostigma reticulata and Combretum glutinosum dominate are mainly used as fire wood resources. Also crops differ with distance to the settlements, cash crops like cowpea grown more closely to the settlements on the more fertile sites.
Reasons are protection against theft and higher expected yields due to nutrient concentration closer to the settlements. Another variable explaining crop diversity is soil conditions, Sorghum preferentially being cropped on the more loamy sites. If one wants to reduce wind and water erosion effects on cropping, the simple technique of partial weeding is an option Figure 21B. Under Sahelian conditions, sowing and weeding are the most time-consuming agricultural actions.
Labour shortage during these periods limits agricultural performance, since crop surfaces fall out of the scheme. Partial weeding, i. The herbs and grasses left standing then act as a semi-natural erosion barrier. In addition, this vegetation component stores nutrients that were otherwise leached. In this way, the weeds can be used as an intermittent nutrient reservoir that can be managed, and nutrients are provided to the crop when needed by a timely second weeding.
The Sahel is the genetic center for the major staple crop pearl millet that is mainly planted on the sandy sites. Many different land races exist that have been developed by local communities by mass selection over generations. These local communities have a quite determined idea about what a variety must provide with regard to pest and drought resistance, taste, and yield, just to name a few aspects. Therefore, the future agricultural research needs to be more participatory and include the farmers perspective already at the state of objective definition.
Then, higher biomass yielding varieties can be developed. Under the Sahelian conditions, dry sowing before the rainy season is an option if fields are too far from the settlements, if the rainy season starts very later or for women, when they are not able to sow at the time due to the obligation to help her husbands on their fields first. However, dry sowing imposes the risk of seed loss through predation or early droughts.
In order to assure a timely establishment of the pearl millet crop, the seedball technology was developed [ ]. It uses local resources like sand, loam, seeds and a little bit of fertiliser NPK or wood ash to form small balls of about 2 cm diameter. The only constraint is the labour required for seedball production.
However, this can be accomplished during the dry season when opportunity costs are low. The sandy soils of the northern Sahel are characterised by a low chemical fertility, phosphoruns and nitrogen being the main limiting nutrients for cereal crops. The soils are so poor that even the smallest amounts of nutrient addition can boost the yield.
Based on this knowledge, micro-dosing as fertiliser strategy has been developed [ , ]. Micro-dosing means a placed fertilisation in contrast to broadcast application into the sowing pocket at sowing or early in the season, where the nutrients are needed most. Only 2 kg of phosporus are able to double the yield on the poorest sites. Micro-dosing at sowing supports the early establishment of the plant.
Once the crop is established and crop loss ha not to be expected, further fertilisation can be done without the risk of investment loss. However, for the poorest farmers in remote areas, even market access to fertiliser is limited.
They can rely on wood ash as local fertiliser, since cooking is done with firewood. Wood ash provides soluble phosphours, potassium, calcium and other micro-nutrients. It can be considered as a complex fertiliser, since it stems from plants. Consequently, it provides most nutrients needed by plants. For legumes, this local fertiliser is applied shortly before flowering.
OGA is fermented human urine that is used as liquid fertiliser. It is an autochthonous innovation developed by the farmer organisation Fuma Gaskiya in the Maradi area of Niger taking Asian practices as example. It mainly contains nitrogen and potassium as fertilising compounds and has shown to consistently increase pearl millet biomass and grain yield.
It is a resource that is locally available for free. It is placed application makes it efficient in annihilating the nitrogen constraint of crop production. Combined with wood ash application as source for soluble phosphorus , two local resources can be used to fight the notorious soil deficiency with respect to these nutrients. In addition, it is reported by farmers that the smell of OGA is effective to chase off harmful insects.
The head miner became a major during the Sahelian droughts of the s. Pesticide control is out of reach for subsistence farmers. In consequence, a biological control mechanism using the parasitoid wasp Habrobracon hebetor was developed. The parasitoid can potentially be produced locally. However, there is still no agro-enterprise that has taken up this innovation. Perhaps, production is too sophisticated and potential price levels or too high for application by subsistence farmers.
Food security shall be enlarged by intensified and irrigated vegetable production. It constitutes by now a widely accepted activity, wherever the bases are given Figure 21C.
It ranges from the vegetable and fruit production in the vicinity of towns or to intensive onion production for export [ 83 , ]. It can be run on as personal activity or as a collective one.
Thus, these small-scale projects proved chances on the personal of village level to earn its own living and to build sustainable base for villages. They fulfil the demand for participativity and local decision on the projects.
Moreover, they are less endangered by the overall insecurity and they may develop their systems by own experiences, and guaranteeing thus a long performance, independently from external pressures. After all there is an augmentation in the plant cover. But there is still degradation of ecosystems parallel to that recovery in some regions [ 7 , 12 ]. Finally, the green future of the Sahelian areas needs a landscape approach where the different stakeholders jointly act in a way it takes into account that the multiple angles of natural and socio-economic environment.
Short-term action by decision makers who want to see short-term results and who are driven by the dogma of novelty — in particular in science — will not lead to a sound outcome. In contrast, the basics need to be understood, more participatory action is needed, and long-term development concepts need to be supported.
No sophisticated approaches are needed, but the insight that subsistence oriented agriculture needs innovations that are simple, affordable and based on local resources. In a long-term, a re-integration of crop and livestock production is inevitable to partly close the nutrient cycle.
The decade long experience of our colleagues from university of Abdou Moumouni university of Niamey [ , ] came to the general conclusion on regeneration possibilities of degraded landscapes see Figure Damage and degradation of Acacia-albida -parks and Combretaceae-savannas in the Southeast of Niger stages 1 and 2 diminished the resources for the local population in such a dimension that an intervention was necessary. The classical stonewalls on the slopes alone provoked runnels climbing up the slope and aggravated the situation stage 3.
Thus, it was necessary to intervene at all points and for a long period in order to stop further linear erosion and to allow the auto-regeneration of vegetation and soil stage 4. Especially on silty-clayey grounds, it will take time to collect sufficient organic material on the surface to allow an implantation of grasses and herbs as further stages of succession. The northeastern United States is covered in deciduous forest, and tourists flock to the area every autumn to experience the orange, yellow, and red leaves blanketing the region.
Evergreen forests have trees with leaves that stay green all year long. One of the places evergreen forests can be found is on the opposite side of the North American continent —in the Pacific Northwest , which includes the Canadian province of British Columbia and the U. The Pacific Northwest is full of evergreen trees like fir. Sometimes forests are classified by the type of leaves on their trees. Trees in broad-leaved forests have wide, flat leaves.
Tropical rain forests are a type of broad-leaved forest. Coniferous forests have trees with cones and needles instead of leaves. Coniferous forests have the tallest coast redwood , largest giant sequoia , and oldest bristlecone pine trees in the world.
Many forests are mixed, meaning they have both broadleaf and coniferous trees. The eucalyptus forests of Australia are mixed forests, for instance. The evergreen eucalyptus trees are mixed with deciduous trees like beech. Grasslands are, as their name suggests, flat and open areas where grasses are the dominant type of vegetation.
Grasslands can be found on every continent except Antarctica. Climate plays a role in the type of grassland you get. In cool, mild climates, like northwest Europe, grasslands are dominated by tough vegetation, such as oats , that thrives all year. Some of these grasses are so tough and hardy that they are considered weeds. In warmer climates, seasonal vegetation survives better.
Temperate grasslands exist where there are seasonal variations in temperature over the course of the year: hot summers and cold winters. Different grasses thrive in different temperatures here.
Temperate grasslands exist from the prairies of North America to the veld, or rural grassland, of South Africa. Tropical grasslands are called savannas. They do well in weather that is warm year-round and usually pretty dry. The most famous savannas are in Africa. Serengeti National Park, in Tanzania, has three distinct types of savanna grassland: long grass , intermediate grass, and short grass.
This part of the Serengeti is known as the Serengeti Plains , and it supports wildlife from aardvarks to zebras. Grasslands are important for milk and dairy production ; dairy cows are happiest, and most productive, in areas in which they can munch on grass all day. Tundra is an area where tree growth is difficult because of cold temperatures and short seasons.
Vegetation in tundra is limited to a few shrubs, grasses, and mosses. The ground is often too cold for plants to set down roots, and without plants, few animal species can survive. There are two types of tundra: alpine tundra and arctic tundra. Alpine tundra is separated from a forest vegetation region by the tree line , the area beyond which conditions are too harsh or cold for tree growth. The weather in alpine tundras is cold, snowy, and windy. Animals like mountain goat s live in this vegetation region.
Arctic tundra occurs in the far-northern hemisphere of the Earth. It has a bare landscape and is frozen for much of the year. Here, the tundra can include permafrost , or soil that is permanently frozen. Russia and Canada have huge areas of arctic tundra.
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