C.4. Desert Ecosystem

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C.4. Desert Ecosystem

A desert is a dry, barren landscape where minimal rainfall creates harsh conditions for the survival of most plant and animal life. Deserts typically develop in areas receiving less than 25 cm of rainfall annually, though they can also occur in hot regions where rainfall is more abundant but highly irregularly distributed throughout the year.

Desert Ecosystem

In mid-latitude regions, deserts often form due to the presence of stable high-pressure systems that limit rainfall. Additionally, many temperate deserts are located in rain shadow zones—areas where tall mountain ranges block moist air coming from the sea, preventing precipitation from reaching the land on the other side.
The climate of these biomes is modified by altitude and latitude. At high, at a greater distance from the equator, the deserts are cold and hot near the equator and tropics.
As the large volume of water passes through the irrigation system, salts may be left behind that will gradually accumulate over the years until they become limiting, unless, means of avoiding this difficulty are devised.

Adaptations	These plants conserve water by the following method: They are mostly shrubs. Leaves are absent or reduced in size. Leaves and stems are succulent and water-storing. In some plants, even the stem contains chlorophyll for photosynthesis. The root system is well developed and spread over a large area. The annuals wherever present germinates, bloom and reproduce only during the short rainy season, and not in summer and winter. The animals are physiologically and behaviorally adapted to desert conditions: They are fast runners. They are nocturnal in habit to avoid the sun’s heat during day time. They conserve water by excreting concentrated urine. Animals and birds usually have long legs to keep the body away from the hot ground. Lizards are mostly insectivorous and can live without drinking water for several days. Herbivorous animals get sufficient water from the seeds which they eat. Mammals as a group are poorly adapted to deserts.
Indian Desert: Thar Desert (Hot)	The climate of this region is characterized by excessive drought, the rainfall being scanty and, irregular. The winter rains of northern India rarely penetrate into the region. The proper desert plants may be divided into two main groups Depending directly upon rain. Those depending on the presence of subterranean water. 1. The first group consists of two types: (i) The ephemera’s (ii) The rain perennials The ephemera’s are delicate annuals, apparently free from any xerophilous adaptations, having slender stems and root systems and often large Flowers. They appear almost immediately after rain, develop flowers and fruits in an incredibly short time, and die as soon as the surface layer of the soil dries up. The rain perennials are visible above the ground only during the rainy season but have a perennial underground stem. 2.The second group Depending on the presence of subterranean water by far the largest number of indigenous plants are capable of absorbing water from deep below the surface of the ground by means of a well-developed root system, the main part of which generally consists of a slender, woody taproot of extraordinary length. Generally, various other xerophilous adaptations are resorted to such as reduced leaves, thick hairy growth, succulence, coatings of wax, thick cuticle protected stomata, etc. all having for their object of reduction of transpiration.
Fauna	It is home to some of India’s most magnificent grasslands and sanctuary for a charismatic bird, the Great Indian Bustard. Among the mammal fauna, the blackbuck, wild ass, chinkara, caracal, Sandgrouse, and desert fox inhabit the open plains, grasslands, and saline depressions. The nesting ground of Flamingoes and the only known population of Asiatic wild Ass lies in the remote part of Great Rarm, Gujarat. It is the migration flyway used by cranes and flamingos. Some endemic flora species of the Thar Desert include Calligonum Polygonoides, Prosopis cineraria, Tecomella undulate, Cenchrus biflorus, and Sueda fruticosa, etc.
Cold Desert/ Temperate Desert	The cold desert of India includes areas of Ladakh, Leh, and Kargil of Kashmir and Spiti valley of Himachal Pradesh, and some parts of northern Uttaranchal and Sikkim. Lies in the rain shadow of Himalayas. Oak, pine, deodar, birch, and rhododendron are the important trees and bushes found there. Major animals include yaks, dwarf cows, and goats. Severe arid conditions: Dry Atmosphere Mean annual rainfall less than 400mm. » Soil type- Sandy to sandy loam. » Soil pH – neutral to slight alkaline. » Soil nutrient – Poor organic matter content, low water retention capacity.
Bio-Diversity	Cold desert is the home of highly adaptive, rare endangered fauna, such as Asiatic Ibex, Tibetan Argali, Ladakh Uriyal, Bharal, Tibetan Antelope (chiru), Tibetan Gazelle, Wild Yak, Snow Leopard, Brown Bear, Tibetan Wolf, Wild Dog, and Tibetan Wild Ass (‘Kiang’ a close relative of the Indian wild ass), Woolly hare, Black Necked Crane, etc. India as a signatory to United Nations Convention to Combat Desertification (UNCCD).