India has a forest-covered landmass of 7,12,249 square kilometres, with tropical thorn forest covering 16,491 square kilometres. In India, tropical thorn forests can be found mostly in the northern parts along with some drier areas of the Deccan Plateau. The biotic components (producer, consumers and decomposers) such as cacti, babool, and wild date palm species can be found in these forests. The abiotic factors (climate, temperature, soil, precipitation) such as very little rainfall, low humidity and extreme temperatures characterize the tropical thorn forest ecosystem. This article will explain to you about Tropical Thorn forests which will be helpful in preparing the Environment syllabus for the UPSC Civil service exam.

Distribution of Tropical Thorn Forests

• Tropical Thorn Forests are found in Rajasthan, Punjab, Haryana, and sections of Gujarat and Madhya Pradesh.
• They are also found in the dry parts of the Deccan plateau, where annual rainfall is less than 75 cm.
• Outside India, this forest can be found in much of southwestern North America and southwestern Africa, as well as in lesser regions of Africa, South America, and Australia.

Distribution of Tropical Thorn Forests

Climatic Factors

• The annual rainfall is less than 70cm.
• The humidity is substantially lower than 50%,
• The temperature is extremely warm, possibly between 25 and 30 degrees.

Features of Flora in Tropical Thorn Forests

• Open stunted trees with prickly bushes can be found in areas with less than 70 cm of yearly rainfall.
• The plants get adapted to the hard climate conditions and scorching temperatures. Trees rarely grow to be more than a few feet tall.
• The roots of these woods are lengthy and the thorns are sharp.
• They assist them in obtaining moisture from the depths. Animals are kept at bay by sharp thorns.
• Their height ranges from 6 to 10 meters.
• Rainfall reduces as you move east to west, and trees become little thorny plants and shrubs. They, too, vanish into the sand in the Thar Desert.

Flora

• The vegetation is stunted and dominated by Acacia species that rarely reach 6 metres in height.
• Prosopis, Grewia, Salvadora, Zizyphus, Anogeissus, Gardenia, Capparis, and Carissa are among the other trees and shrubs that make up the forest community.
• Climbers like Tragia, Rivea, Tinospora, Vitis, and Peristrophe provide structural complexity to the trees.
• All are xerophytic species, indicating they can flourish in arid environments. In drier places, thorn forests give way to xerophytic shrubs dominated by cactus-like Euphorbia species.
• Salvadora and Tamarix dominate the plant community closer to the coast, where the soils are more saline, whereas regions with extremely high salinity have no vegetation at all.

Fauna

• Animals are unable to eat most of the trees due to their sharp thorns.
• Wild cats such as the common leopard, caracal, Indian desert cat, jungle cat, and rusty-spotted cat, as well as canids such as grey wolf, golden jackal, desert fox, Indian fox, and striped hyena, live in this ecoregion.
• There are various herbivorous animals in addition to these diversified carnivore species.
• Blue bull (nilgai), Indian gazelle (chinkara), four-horned antelope (chousingha), and blackbuck are among the most common herbivores.
• Smaller carnivores prey on smaller animals including the black-naped hare, Indian desert jird, Indian jerbil, and even porcupines.
• The antelope rat, commonly known as the Indian gerbil, makes burrows in sandy plains and grasslands, replete with chambers for food storage and resting.

Threats to Tropical Thorn Forests

• The original environment of the ecoregion has been transformed to the point where only small, dispersed pieces remain.
• Forests have been largely converted to agriculture over the last century or two.
• Although the protected areas cover around 4% of the huge ecoregion, individual reserves are modest.
• Because the local people hold wild animals, particularly the blackbuck, in high regard, wildlife has been mostly protected from hunting.
• The region, however, is abundant in granite and marble, and mining is harming ecosystems and wildlife habitats.
• From 1992 through 2009, various court decisions in India limited or outright prohibited mining in some environmentally sensitive areas.

Conservational Steps

As a result, some of the prioritised conservation efforts include:

• monitoring and ensuring that mining operations do not resume in environmentally vulnerable regions;
• implementing sustainable forest management techniques, as well as conservation awareness, research, and monitoring; and
• engaging local communities as conservation guardians.

Conclusion

Grazing and fuelwood are the primary uses of the tropical thorn forests. They play an important role in the lives of the locals. Animals can utilize the trees for nourishment. It is employed in the construction industry. Watershed protection is provided by this forest ecosystem. It comprises desert locations with significant economic value as a result of recreational and sporting activity.

FAQs

MCQs

1. Which of the following regions is most likely to have tropical thorn forests?

A) Western Ghats
B) Rajasthan Desert
C) Sunderbans
D) Eastern Himalayas

2. Which of the following plants are commonly found in tropical thorn forests?

A) Mangroves
B) Teak
C) Acacia and Babool
D) Sal

3. Tropical thorn forests are found in areas receiving less than how many centimeters of annual rainfall?

A) 200 cm
B) 100 cm
C) 50 cm
D) 150 cm

4. What is the main adaptation of plants in tropical thorn forests?

A) Large broad leaves
B) Deep root systems and small leaves
C) Presence of aerial roots
D) Growth along riverbanks

5. Which of the following factors primarily influences the distribution of tropical thorn forests?

A) High humidity
B) Seasonal rainfall and dry conditions
C) Coastal proximity
D) Low altitude

GS Mains Questions and Model Answers

Q1: Explain the distribution and ecological significance of Tropical Thorn Forests in India.

Answer: Tropical thorn forests are found in the semi-arid regions of India, particularly in the northwestern and central parts, such as Rajasthan, Gujarat, Punjab, Haryana, Uttar Pradesh, and parts of Madhya Pradesh. These regions receive less than 50 cm of annual rainfall and experience extreme dry conditions. The vegetation in these forests has adapted to survive in such an environment through features like thick bark, spiny leaves, and deep root systems. Key species include acacia, babool, and cacti.

The ecological significance of tropical thorn forests is considerable, especially in preventing desertification in arid and semi-arid areas. The dense root systems of these trees help in stabilizing the soil, preventing erosion, and conserving moisture. Additionally, these forests provide essential ecosystem services, such as habitat for drought-resistant species, grazing land for livestock, and firewood for local communities. The biodiversity found in these forests is crucial for maintaining ecological balance in regions where water is scarce. Conservation of these forests is vital to preventing further desertification and maintaining the livelihoods of people dependent on these resources.

Q2: Discuss the adaptations of vegetation in tropical thorn forests and how these help in survival under dry conditions.

Answer: The vegetation in tropical thorn forests has evolved several key adaptations to cope with extreme aridity and scarce water resources. The trees and shrubs in these forests are typically drought-resistant, with deep root systems that allow them to access underground water even in dry conditions. These deep roots enable the plants to survive long dry spells, and this characteristic is critical for their survival in semi-arid and arid regions.

Another adaptation is the presence of thick bark and reduced leaf surface area, which help minimize water loss through transpiration. The leaves are often small or modified into spines, as seen in acacia and cacti, which reduce the surface area exposed to the sun and thereby conserve water. Some plants also have succulent tissues that store water for prolonged periods. The presence of thorns and spines not only reduces water loss but also protects the plants from grazing by herbivores. These adaptations collectively allow the vegetation to thrive in regions with less than 50 cm of annual rainfall, ensuring their survival despite harsh climatic conditions.

Q3: How do tropical thorn forests contribute to the livelihoods of people living in semi-arid regions?

Answer: Tropical thorn forests are a critical source of livelihood for the populations residing in semi-arid and arid regions of India. The local communities rely on these forests for a variety of resources, including firewood, which is a primary source of energy for cooking and heating. The trees in these forests, such as acacia and babool, provide high-quality timber that is used in construction and fencing, while their leaves, twigs, and pods serve as fodder for livestock. Grazing is another significant activity in these areas, as the thorny bushes and grasslands offer essential grazing grounds for animals, especially during the dry season.

Additionally, tropical thorn forests support biodiversity, which includes medicinal plants that are used by local populations for traditional medicine. They also help in sustaining water availability through the conservation of soil moisture, thus indirectly supporting small-scale agriculture. The forests prevent soil erosion and desertification, thereby maintaining land productivity. Conservation and sustainable management of tropical thorn forests are essential for preserving the ecological balance and ensuring the continued availability of these resources to the people living in these harsh environments.

Previous Year Questions on Tropical Thorn Forests

1. UPSC CSE Prelims 2021:

Question: In which of the following states would you expect to find tropical thorn forests?

A) Kerala
B) Rajasthan
C) Assam
D) Odisha

Answer: (B)

Explanation: Tropical thorn forests are typically found in arid and semi-arid regions, such as Rajasthan, due to the low annual rainfall and dry conditions.

2. UPSC CSE Mains 2020 (GS Paper 1):

Question: "Analyze the role of tropical thorn forests in mitigating the effects of desertification in India. How can these forests be conserved?"

Answer: Tropical thorn forests help mitigate desertification by stabilizing soils, reducing wind erosion, and maintaining vegetation cover in arid regions. Conservation measures should include afforestation programs, sustainable grazing practices, and the protection of these forests from deforestation. Promoting community-based conservation and increasing awareness about their ecological value are also key strategies.