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Global Distribution of Desertification

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Introduction

The distribution of deserts worldwide depends on the region’s atmosphere and air circulation. For the same reason, most of the desserts are found in North and South latitude lines of 30˚. The climate in these regions is dominated by a large amount of sunlight, little rain, and high evaporation (Cunningham n.d.). The world’s deserts exist in six broader biogeographically fragmented areas. The Afrotropic deserts are present in sub-Saharan Africa, in countries such as Algeria, Chad, and Egypt and so on. The Sahara desert covers 10% of the African continent. The southern part of the Arabian Peninsula includes countries like UAE, Oman, Yemen, and Saudi Arabia. Australia has the Australasian deserts, which are made out of lowland ecological regions marked by intense aridity. The Indo-Malay region consists of two deserts: the Indus Valley and the Thar. The area includes Pakistan, Indian, etc. The Nearctic deserts are located in North America and cover 1.04 million square miles of land. On the other hand, South America has the Neotropic deserts (Desert Locations. (n.d.).

Global Distribution of Desertification

The three ecological areas, which divide the UAE, include the deserts, which form 80% of the country’s city. The deserts especially dominate the western region (the United Arab Emirates, 2008). The deserts in the UAE spread from the Arabian Gulf coast to the vast unpopulated expanse of sand in the Rub’ al Khali or the Empty Quarter and moves on to cover the gravel plains near the Hajar Mountains in the east (Desert Locations. (n.d.). 

Deserts have primary ecological importance. If rainfall decreases in the desert areas, the probability of cross-boundary dust storms will increase. 50-70% of the dust particles originate from deserts of North Africa and 10-25% from deserts in Asia. The desert dust carries phosphorus and silicon, which increases the growth of phytoplankton in the ocean. The desert sand increases the productivity of marine ecosystems and of soils in the tropical region, which lack nutrients, as seen in the Amazon basin, where the sand of the Sahara desert deposits. Desert also provides a doorway to the birds, which do not belong to the desert, to migrate to other areas. Birds crossing the Sahara desert compete with the human population for small oases, which only occupies 2% of the domain (GEO Year Book 2006).

Main Topics

The most important abiotic factor, which influences the desert ecosystem, is rainfall. Mostly deserts are characterized by the fact that it experiences little or no rainfall. The deserts receive a total of less than 300 mm of rainfall per year, where a rainforest gets about 2000 mm. The lack of rain, and ultimately water in a desert makes the vegetation scarce and influences the adaptation of the plants and organisms. Plants such as cacti, which are very common in a desert ecosystem, have adapted to water scarcity by storing water in their stems. The saguaro cacti do not have profound roots, allowing it to soak up rain and dew before it evaporates. Its porous surface expands to hold more water (Cunningham n.d.). Bushes develop small, and few leave, but long roots to adapt to the harsh conditions by conserving water. Some plants are short-lived and grow only when rain is available (Desert: Mission: Biomes. (n.d.). 

Temperature is another crucial factor that has a significant impact on the ecosystem, ultimately affected by another abiotic factor, sunlight. Heat in the deserts reaches its extremes daily because there is no humidity in the desert air to block the sunrays. The solar radiation received by desert areas is twice as much as received by humid regions, and they cool down twice as much at night. The mean annual temperature in North American deserts like Chihuahuan, Sonoran, and Mojave, for example, is 20-25°, whereas it can reach up to 49°. The minimum temperature here can drop to -18° as well. However, temperatures can be so high that rain starts falling and is evaporated while it reaches the ground (The desert biome. (n.d.).

The desert ecosystem is influenced by soil also. The land ranges from being wonderfully textured sand to rocky, coarse-textured sand full of gravels. Hot and deserts have soil that drains water well and has no water on their surface. Due to less weathering, the sand turns out to be coarse. The larger rocks are left behind as sand blows away. Semiarid deserts have soil with low salt concentration since they receive fewer rainfalls. The coastal areas have finely textured sands where leafy plants can grow and consume a large amount of water. Their deep roots can also take in water from the soil (The desert biome. (n.d.).

The biotic factors which make up the desert ecosystem include the many organisms specific to this ecosystem like Scorpions, Kangaroo rats, Camels, Lizards, Dung beetles, etc. and also the plants, namely different Cacti like Organ Pipe Cactus, Barrel Cactus, Willow tree, etc. Like any food chain, the desert food chain begins from the source, which can be a prickly pear cactus. The producer gets its energy from an abiotic factor i.e., the sunlight. The organisms, which feed upon the producer, are the primary consumers, which can be Harris’s antelope squirrel. The squirrel, which feeds upon the fruit of the cactus, derives its energy from it. The primary consumer can then be eaten by the secondary consumer, which can be a diamondback rattlesnake. The secondary consumer can be consumed by the tertiary consumer, which can be the roadrunner. A quaternary consumer called the red-tailed hawk can prey upon the roadrunner (Anderson, J. (n.d.). In this way, these different trophic levels make up the desert ecosystem, as seen in figure 1. 

Desert Ecosystem

 

In deserts, small ecosystems thrive with mammals that develop a sensitive relationship with other organisms. Herbivores help spread seeds in the soil, and other mammals dig out tunnels in it, in turn enriching it and increasing water infiltration. ‘Off-roading,’ which is very popular in UAE deserts, destroys the soil and the vegetation on it by our cars. The most devastating part of human play in destroying habitat is through remaking the habitat, for example, after fires and overgrazing (Smith 2012).

Dubai Desert Conservation Reserve aims to achieve sustainability of deserts in Dubai, and it started a natural seed bank project wherein 6000 indigenous seeds and shrubs were planted. The 70 endangered Oryx, which was released in a protected area, has evolved into a total of 400 Oryx. Where in 2003, only 60 species of birds had been recorded, protected area measurements have increased the count to 126. The organization plans to teach the guides and tourists alike for greater sustainability. The Reserve limits the entry of people and vehicles wherever it can for minimal impacts. It puts strictness on all the activities that strain the environment (Sustainability – Dubai Desert Conservation Reserve. (n.d.). Dubai Municipality, in its press release, stated that it updated its cleaning team and was successful in cleaning 581 tonnes of waste from 17 square kilometer camping areas and distributed leaflets to spread awareness (Robertson 2014).

Conclusion   

Though the desert ecosystem gives us the impression that it may remain unharmed by human activities because of its desolation, the desert continues to be at a threat today. It is our job to conserve wildlife and vegetation, which is teeming with life like any other ecosystem. We should not let the very intricate balance between its organisms get disturbed by our reckless attitude. We must conserve an ecosystem like a desert distributed in different parts of the world and not look of great ecological and economic importance. But the fact that it also serves an environmental role, we should make efforts to protect it for greater sustainability and make good use of it like utilizing the solar power there, without harming it.

References;
  • Cunningham, M. (n.d.). Earth’s Deserts: Definition, Distribution & Location. Retrieved December 10, 2014, from http://education-portal.com/academy/lesson/deserts-definition-and-distribution.html#lesson
  • Desert Locations. (n.d.). Retrieved December 10, 2014, from http://www.defenders.org/desert/locations
  • United Arab Emirates. (2008). Retrieved December 10, 2014, from http://www.fao.org/nr/water/aquastat/countries_regions/untd_arab_em/index.stm
  • Desert Locations. (n.d.). Retrieved December 10, 2014, from http://www.defenders.org/desert/locations
  • GEO Year Book. (2006). Retrieved December 10, 2014, from http://www.unep.org/geo/gdoutlook/005.asp
  • Desert : Mission: Biomes. (n.d.). Retrieved December 10, 2014, from http://earthobservatory.nasa.gov/Experiments/Biome/biodesert.php
  • The desert biome. (n.d.). Retrieved December 10, 2014, from http://www.ucmp.berkeley.edu/exhibits/biomes/deserts.php
  • Anderson, J. (n.d.). Food Chains, Trophic Levels and Energy Flow in an Ecosystem. Retrieved December 10, 2014, from http://education-portal.com/academy/lesson/food-chains-trophic-levels-and-energy-flow-in-an-ecosystem.html#lesson
  • Smith, B. (2012, September 9). ‘Human Activities’ Reduce Desert Environment Diversity. Retrieved December 10, 2014, from http://www.redorbit.com/news/science/1112690144/desert-diversity-human-impact-090912/
  • Sustainability – Dubai Desert Conservation Reserve. (n.d.). Retrieved December 10, 2014, from http://www.ddcr.org/en/conservation/sustainability/
  • Robertson, C. (2014, June 5). Desertification: How UAE lands are under threat. Retrieved December 10, 2014, from http://gulfnews.com/gn-focus/world-environment-day/desertification-how-uae-lands-are-under-threat-1.1343175 

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