- The desert ecosystem stands as one of the Earth’s crucial ecosystems, covering approximately 17% of the planet’s surface.
- These ecosystems exist on nearly every continent, thriving in areas characterized by minimal annual rainfall and either extreme heat or cold conditions.
- Deserts manifest as expansive, barren landscapes, covered in dry sands. They are categorized into two types: Hot Deserts and Cold Deserts.
- The desert ecosystem is defined by the intricate interactions among species, their surroundings, and various non-living influences shaping the habitat.
- In this arid environment, plants experience a brief life cycle, rapidly growing, germinating, and perishing within a matter of days.
- Adapted for survival, desert plants feature green, succulent stems with a protective waxy coating, enabling them to engage in photosynthesis.
- The scarcity of rainfall in mid-latitudes is often linked to stable high-pressure zones, contributing to the desert’s arid conditions.
- In temperate regions, deserts commonly form in “rain shadows,” where towering mountains obstruct rainfall from reaching the areas adjacent to seas.
DESERT ECOSYSTEMS
The Australian Deserts:
- The Australian deserts comprise highly arid eco-regions in the interior of Australia.
- These areas have sparse populations, with an average population density of less than one person per square kilometer.
- Among deserts globally, Australian deserts have the lowest human population.
The Afrotropic Deserts:
- Extending across Sub-Saharan Africa and reaching the southern regions of the Arabian Peninsula, Afrotropic deserts face considerable human impact, particularly in Madagascar and the Horn of Africa.
The Indo-Malay Region:
- Encompassing hot lowlands like the Indus Valley and Thar, the Indo-Malay region holds the distinction of having the highest human imprint on desert ecosystems globally.
- Also known as the Oriental realm, it reflects significant human influence.
The Neotropic Deserts:
- Covering South America, Central America, the Caribbean islands, and southern North America, Neotropic deserts occupy an estimated 684 million square miles.
- Despite their vast expanse, only 6% of this land is protected.
The Nearctic Deserts:
- Extending over 1.04 million square miles in North America, Nearctic deserts, such as those in Phoenix, experience relatively high population density due to the expansion of urban development in the United States.
The Palearctic Domain:
- This domain boasts the largest collection of deserts globally, covering a staggering 9.9 million square miles, constituting about 63% of all deserts on Earth.
- The deserts within the Palearctic Domain, including the Sahara in Africa, are known for extreme dryness and inaccessibility.
- The Sahara alone occupies nearly 10% of the African continent, featuring diverse landscapes ranging from folded mountains to enclosed basins in the Central region.
TYPES OF DESERTS
Hot Desert – Sahara:
- The Sahara, spanning an immense 8.54 million square kilometers, stands as the largest and hottest desert globally.
- Situated approximately 1,000 meters above sea level in tropical regions, it extends across numerous North African countries, including Algeria, Tunisia, Egypt, Mali, Chad, Niger, Western Sahara, Sudan, Mauritania, Libya, and Morocco.
- Encompassing around 8,600,000 square kilometers, the Sahara experiences an extremely hot and arid climate, receiving minimal precipitation throughout the year.
- Daytime temperatures soar to 45°C to 50°C, heating exposed rocks and sand, while nights can be bitterly cold, occasionally dropping below 0°C.
Cold Desert – Ladakh:
- Ladakh, recognized as India’s cold desert, is situated at high altitudes in the temperate regions of the Great Himalayas in eastern Jammu and Kashmir and the western Himalayas in Himachal Pradesh, North India.
- With elevations ranging from 3,000 meters near Kargil to 8,000 meters in the Karakoram, Ladakh experiences an exceptionally chilly and dry climate due to its high altitude.
- Summer temperatures barely rise above 0°C during the day and drop below –30°C at night.
- The region is marked by the presence of the Gangotri glacier, along with several other glaciers and rivers running through Ladakh.
CLIMATE
Temperature:
- Desert nights exhibit cold temperatures due to the lack of moisture in the air to retain the heat accumulated during the day’s high temperatures.
- The desert biome poses challenges for habitation, given the drastic temperature fluctuations and extremely low water levels.
- With little atmospheric moisture to shield the sun’s rays, daytime temperatures in deserts can be severe.
- The sun’s energy is absorbed by the ground, heating the surrounding air.
- Conversely, when the sun sets, the heated ground and air radiate the collected heat back to the atmosphere, leading to a rapid temperature drop.
- Nighttime temperatures may fall below 0 degrees Celsius.
Precipitation:
- Precipitation patterns vary between hot, dry deserts, and cold deserts.
- Both experience an average annual rainfall of around 15 centimeters.
- Cold deserts, however, receive considerable snowfall, approximately 15-26 cm on average, with higher rainfall in the spring.
Seasons:
- Desert ecosystems encompass a diverse range of seasonal climates.
- Summer temperatures can range from 30 to 49 degrees Celsius, accompanied by minimal precipitation and a prevailing evaporation surplus.
- Winter temperatures typically range from 10 to 20 degrees Celsius, with increased precipitation during the summer season.
- These seasonal variations contribute to the unique and challenging conditions of desert environments.
Soil in Desert Ecosystems
- In any ecosystem, the composition of soil plays a crucial role in determining the types of vegetation that can thrive in the region.
- Desert soils, however, present a challenging environment for plant growth as they lack essential organic matter such as nitrogen and phosphorus, crucial nutrients for plants.
- The soil in desert habitats is characterized by dry, rocky, and sandy conditions, making it unsuitable for the growth of large trees.
Flora in Desert Ecosystems
- Despite facing minimal rainfall and experiencing high daily temperature fluctuations, desert ecosystems host a surprising diversity of plant life.
- Adapted to the challenging conditions, plants in these biomes include cacti, small shrubs, succulents, and grasses.
- Some notable examples of desert flora include Brittle Bush, Desert Ironwood, Chain Fruit Cholla, Joshua Tree, Palo Verde, Jumping Cholla, Ocotillo, Pancake Prickly Pear Cactus, Soaptree Yucca, and Mojave Aster.
Fauna in Desert Ecosystems
- Desert animals have evolved to survive in arid conditions, showcasing unique adaptations.
- Examples of desert fauna include rabbits, wild cats, mountain lions, bobcats, and various species of snakes such as rattlesnakes, coral snakes, and king snakes.
- Lizards, including horned lizards, banded geckos, and tree lizards, are also common in deserts.
- Birds such as the roadrunner, vulture, and golden eagle are prevalent, while mammals like coyotes, javelina, desert tortoise, desert kangaroo rat, and the Sonoran pronghorn antelope contribute to the rich biodiversity of the desert ecosystem.
- Additionally, creatures like the thorny devil, desert bighorn sheep, armadillo lizard, and Sonoran toad further highlight the diversity and adaptability of life in desert environments.
Adaptations in Desert Plants
Desert plants exhibit remarkable adaptations to thrive in the challenging environmental conditions of arid regions:
- Water Storage: Many desert plants store water in their stems and leaves to withstand periods of drought.
- Waxy Coats: Some plants have developed waxy coatings on their leaves, reducing water loss through evaporation.
- Leaf Shedding: Shedding leaves during dry periods helps minimize water loss and ensures survival.
- Long Taproots: Certain plants boast long taproots that reach water tables, allowing them to access water deep underground.
- Dormancy: Some plants go dormant during dry spells, conserving energy until the return of favorable conditions.
Examples include the cactus, with its ability to store water and live for centuries, and the Mugma Tree, whose upward-growing leaves act as rain funnels, directing water to its base.
Adaptations in Desert Animals
Animals in the desert have evolved unique adaptations to cope with extreme conditions:
- Water Conservation: Desert animals, like camels, store water in their humps, enabling them to survive for days without food or drink.
- Insulation: Thick fur and underwool help animals like camels stay warm during cold desert nights.
- Nostril Sealing: Camels can seal their nostrils to prevent sand from entering, protecting their respiratory system.
- Protective Features: Foxes, adapted to desert life, have burrowing and nocturnal habits to avoid daytime heat. Large ears aid in dissipating excess body heat.
- Heat Reflection: Some animals, like those with sandy fur, use their coats for heat reflection and camouflage.
Desert animals employ additional strategies such as panting to regulate body temperature, seasonal migration, and extended periods of dormancy, triggered by moisture and temperature changes. These adaptations collectively contribute to their survival in harsh desert environments.
SIGNIFICANCE
The desert ecosystem, despite its harsh conditions, sustains a rich variety of plant and animal species. The intricate web of relationships among these organisms plays a crucial role in maintaining ecological balance.
Biodiversity Support:
- Diverse Plant and Animal Species: The desert is home to a surprisingly diverse range of plant and animal species, each uniquely adapted to survive in arid conditions.
- Interconnected Relationships: The inhabitants of the desert ecosystem establish intricate relationships with each other, contributing to the overall stability and resilience of the ecosystem.
Microbial Life:
- Bacterial Communities: The sand in the desert habitat harbors various bacterial communities. These microorganisms play a vital role in nutrient cycling and contribute to the overall health of the ecosystem.
- Carbon Sequestration: Some desert bacteria have the remarkable ability to store carbon dioxide, acting as a natural carbon sink. This process aids in mitigating the impact of greenhouse gases on the atmosphere.
Mineral Resources:
- Natural Resource Reservoir: Deserts often house valuable mineral resources, including natural gas. These resources contribute to the economic significance of these environments.
- Geological Diversity: The desert landscape contains a variety of geological features, showcasing unique landforms and oases. This geological diversity not only adds to the scientific interest but also attracts tourists, boosting the tourism industry.
Tourism Impact:
- Landforms and Oasis Attractions: Deserts exhibit captivating landforms, such as dunes and canyons, along with oasis environments. These features draw the attention of tourists, providing them with unique and awe-inspiring experiences.
- Economic Boost: The tourism industry in desert regions benefits from the fascination with the diverse landscapes, contributing to the local economy and promoting awareness about the significance of desert ecosystems.
FAQs – Desert Ecosystem
1. What percentage of the Earth’s surface does the desert ecosystem cover?
A: The desert ecosystem covers approximately 17% of the Earth’s surface, making it one of the planet’s crucial ecosystems.
2. In which continents can desert ecosystems be found?
A: Desert ecosystems are found on nearly every continent, adapting to areas with minimal annual rainfall and extreme temperature conditions.
3. How does the desert ecosystem differ from other ecosystems in terms of biodiversity?
A: The desert ecosystem exhibits lower biodiversity compared to other ecosystems due to its arid conditions. However, it still supports a diverse range of uniquely adapted plant and animal species.
4. What are the two main types of deserts, and how do they differ?
A: Deserts are categorized into Hot Deserts and Cold Deserts. Hot deserts, exemplified by the Sahara, experience extremely high temperatures, while cold deserts, like Ladakh, face exceptionally chilly climates.
5. How do deserts form in “rain shadows”?
A: Deserts often form in “rain shadows” in temperate regions, where towering mountains block rainfall from reaching areas adjacent to seas. This lack of rainfall contributes to the arid conditions of deserts.
6. What are the main biogeographic domains of the desert ecosystem?
A: The desert ecosystem is divided into six biogeographic domains, including the Australian Deserts, Afrotropic Deserts, Indo-Malay Region, Neotropic Deserts, Nearctic Deserts, and the Palearctic Domain.
In case you still have your doubts, contact us on 9811333901.
For UPSC Prelims Resources, Click here
For Daily Updates and Study Material:
Join our Telegram Channel – Edukemy for IAS
- 1. Learn through Videos – here
- 2. Be Exam Ready by Practicing Daily MCQs – here
- 3. Daily Newsletter – Get all your Current Affairs Covered – here
- 4. Mains Answer Writing Practice – here
