UPSC MainsBOTANY-PAPER-II201320 Marks
Q25.

Describe various phytogeographical zones and their characteristics in India. Give further details of the zone which experiences high temperatures, restricted snowfall and high rainfall, and has adundance of Rhododendrons, Ferns, Orchids and Oaks.

How to Approach

This question requires a comprehensive understanding of Indian phytogeography and detailed knowledge of specific zones. The approach should involve first outlining the major phytogeographical zones of India, briefly describing their characteristics. Then, focus specifically on the zone fitting the description – high temperatures, restricted snowfall, high rainfall, and abundance of Rhododendrons, Ferns, Orchids, and Oaks – detailing its climate, vegetation, and ecological significance. A map-based understanding will be beneficial.

Model Answer

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Introduction

Phytogeography, the study of the distribution of plants, is crucial for understanding the ecological diversity of India. India, due to its varied climatic and topographic conditions, exhibits a remarkable range of vegetation types, categorized into distinct phytogeographical zones. These zones are influenced by factors like rainfall, temperature, soil, and altitude. Understanding these zones is vital for conservation efforts and sustainable resource management. The country can be broadly divided into several zones, each with unique floral and faunal characteristics, reflecting its biogeographical history and present-day ecological processes.

Major Phytogeographical Zones of India

India’s phytogeographical zones can be broadly classified as follows:

  • Western Himalayan Zone: Characterized by coniferous forests, alpine meadows, and scrub vegetation.
  • Eastern Himalayan Zone: Rich in biodiversity, featuring subtropical and temperate forests, and alpine vegetation.
  • Indian Desert Zone: Sparse vegetation adapted to arid conditions, including thorny shrubs and grasses.
  • Gangetic Plains Zone: Dominated by alluvial grasslands and deciduous forests.
  • Central Indian Zone: Characterized by dry deciduous forests and teak forests.
  • Deccan Plateau Zone: Diverse vegetation ranging from dry deciduous forests to thorn forests and scrublands.
  • North-Eastern Zone: Evergreen forests, semi-evergreen forests, and grasslands.
  • Coastal Zone: Mangrove forests, tidal forests, and coastal vegetation.
  • Island Zone: Unique vegetation adapted to island ecosystems.

Detailed Description of the Zone with Specific Characteristics

The phytogeographical zone that experiences high temperatures, restricted snowfall, high rainfall, and an abundance of Rhododendrons, Ferns, Orchids, and Oaks is the Eastern Himalayan Zone, specifically the Eastern Himalayan sub-tropical and temperate forests. This zone extends across states like Sikkim, Darjeeling hills of West Bengal, Arunachal Pradesh, and parts of Assam.

Climate

This zone experiences a warm, humid climate with high rainfall, typically exceeding 2000 mm annually. Summers are warm and wet, while winters are mild with occasional snowfall at higher elevations. The restricted snowfall is due to the lower altitudes compared to the Western Himalayas, and the influence of the monsoon winds.

Vegetation

The vegetation is incredibly diverse, exhibiting a mix of subtropical and temperate forest types. Key characteristics include:

  • Rhododendrons: Abundant species of Rhododendrons, forming vibrant displays during the flowering season.
  • Ferns: A high diversity of ferns, thriving in the moist and shaded understory of the forests.
  • Orchids: Numerous epiphytic and terrestrial orchid species, contributing to the zone’s floral richness.
  • Oaks: Various species of oaks (Quercus), forming a significant component of the forest canopy.
  • Other Trees: Alongside oaks, other dominant trees include maples, birches, laurels, and magnolias.
  • Bamboo: Extensive bamboo forests are also present, particularly at lower elevations.

Ecological Significance

This zone is a biodiversity hotspot, harboring a large number of endemic and endangered species. It plays a crucial role in watershed management, soil conservation, and climate regulation. The forests provide habitat for a variety of wildlife, including the Red Panda, Snow Leopard, and numerous bird species.

Altitudinal Variation

Vegetation changes with altitude. Lower slopes are dominated by subtropical forests, transitioning to temperate forests at higher elevations. Above the tree line, alpine meadows and scrub vegetation are found.

Altitude (m) Vegetation Type Dominant Species
500-1500 Subtropical Forests Sal, Bamboo, Laurel
1500-3000 Temperate Forests Oak, Maple, Birch, Rhododendron
Above 3000 Alpine Meadows & Scrub Rhododendron, Juniper, various herbs

Conclusion

The Eastern Himalayan Zone stands out as a unique phytogeographical region in India, characterized by its high rainfall, moderate temperatures, and exceptional biodiversity. The abundance of Rhododendrons, Ferns, Orchids, and Oaks highlights its distinct ecological features. Conservation efforts are crucial to protect this biodiversity hotspot from threats like deforestation, habitat fragmentation, and climate change, ensuring the long-term sustainability of its unique ecosystems and the services they provide.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Phytogeography
The branch of botany concerned with the geographical distribution of plant species and their influence on the environment.
Endemic Species
Species that are found exclusively in a particular geographic area and nowhere else in the world.

Key Statistics

The Eastern Himalayas are recognized as one of the 34 biodiversity hotspots globally, containing approximately 16,500 plant species (as of 2010, Source: WWF).

Source: WWF

Approximately 30% of plant species in the Eastern Himalayas are endemic (as of 2018, Source: Botanical Survey of India).

Source: Botanical Survey of India

Examples

Khangchendzonga National Park

Located in Sikkim, this national park exemplifies the biodiversity of the Eastern Himalayan Zone, showcasing a wide range of flora including rhododendrons, orchids, and oak forests, alongside unique fauna like the Snow Leopard and Red Panda.

Frequently Asked Questions

What are the major threats to the vegetation of the Eastern Himalayan Zone?

Deforestation due to agriculture and urbanization, unsustainable harvesting of medicinal plants, climate change leading to altered rainfall patterns, and invasive species are major threats to the vegetation of this zone.

Topics Covered

BotanyEcologyGeographyIndian VegetationBiodiversityEcosystems