February 4, 2025 2:42 am
Terrestrial ecosystems encompass the interactions between organisms and their environment on land, collectively known as terrestrial ecology. These interactions are heavily influenced by variations in topography, including valleys, mountains, and slopes, which cause differences in both material and biotic diversities. Altitudinal and latitudinal variations further influence climatic patterns, impacting the distribution of plant and animal life, resulting in different ecosystem segments within the larger biosphere. The two primary limiting factors for terrestrial ecosystems are moisture and temperature.
3.1 Tundra Ecosystem
- Definition: The term “Tundra” translates to “barren land,” describing an environment characterized by severe climatic conditions.
- Types:
- Arctic Tundra: A continuous belt below the polar ice cap and above the tree line in the Northern Hemisphere. Locations include Canada, Alaska, European Russia, and Siberia. The South Pole has minimal tundra due to ocean coverage.
- Alpine Tundra: Found in high mountain regions at all latitudes, with notable day and night temperature fluctuations.
- Flora and Fauna:
- Vegetation: Cotton grass, sedges, dwarf heath, willows, birches, and lichens.
- Animals: Reindeer, musk ox, arctic hare, caribou, lemmings, and squirrels.
- Adaptations:
- Plants: Thick cuticles and epidermal hair for protection from extreme cold. For example, the arctic willow has a lifespan of 150 to 300 years.
- Mammals: Large bodies, small tails, and small ears to minimize heat loss, along with fur for insulation.
- Insects: Short life cycles that coincide with the brief favorable period each year.
3.2 Forest Ecosystem
Forests are complex biotic communities that establish under optimal conditions of temperature and ground moisture. The soil, climate, and topography determine the distribution and types of trees in a forest.
- Types of Forest Ecosystems:
- Coniferous Forest (Boreal Forest):
- Climate: Cold regions with long winters, short summers, and significant rainfall.
- Flora: Evergreen species such as spruce, fir, and pine trees.
- Fauna: Lynx, wolf, bear, red fox, porcupine, and amphibians like Hyla and Rana.
- Soil: Thin, nutrient-poor, and acidic podzols due to slow weathering and decomposition of conifer needles.
- Productivity: Lower than other forest ecosystems due to harsh conditions and nutrient-deficient soil.
- Temperate Deciduous Forest:
- Climate: Moderate, with trees that shed leaves in the fall, remaining bare in winter and regrowing in spring.
- Precipitation: Uniform throughout the year.
- Soil: Deep and podzolic.
- Temperate Evergreen Forest:
- Climate: Mediterranean, with warm, dry summers and cool, moist winters.
- Flora: Low, broad-leafed evergreen trees adapted to fire, which helps them regenerate.
- Temperate Rain Forest:
- Climate: High rainfall, with heavy fog providing significant water.
- Biodiversity: Higher than other temperate forests but lower than tropical rainforests.
- Tropical Rain Forest:
- Location: Near the equator, characterized by high biodiversity and dense vegetation.
- Climate: High temperature and humidity, with annual rainfall exceeding 200 cm.
- Vegetation: Tall trees, vines, epiphytes, and layered forest structure with minimal sunlight at ground level.
- Soil: Red latosols, thick but nutrient-poor due to rapid nutrient cycling.
- Tropical Seasonal Forest:
- Location: Areas with distinct wet and dry seasons, such as Southeast Asia, South America, and parts of India.
- Flora: Adapted to seasonal rainfall variations.
- Subtropical Rain Forest:
- Location: Areas with high rainfall and minor temperature variations.
- Fauna: Similar to tropical rainforests, with many epiphytes.
- Coniferous Forest (Boreal Forest):
3.3 Indian Forest Types
India’s forests range from tropical rainforests in Kerala to alpine pastures in Ladakh, influenced by climate, soil type, topography, and elevation. The Champion and Seth Classification divides forests into 16 types:
- Tropical Wet Evergreen Forests:
- Location: Western Ghats, Andaman & Nicobar Islands, Northeastern India.
- Flora: Tall, straight trees like jackfruit, betel nut palm, mango, and hollock, with various ferns and orchids.
- Tropical Semi-Evergreen Forests:
- Location: Western Ghats, Andaman Islands, Eastern Himalayas.
- Vegetation: Dense forest with both evergreen and deciduous trees.
- Tropical Moist Deciduous Forests:
- Location: Throughout India, except the northwest.
- Trees: Sal, teak, mango, rosewood, and bamboo.
- Littoral and Swamp Forests:
- Location: Andaman Islands, Ganga and Brahmaputra deltas.
- Adaptations: Soft tissue roots for breathing in waterlogged conditions.
- Tropical Dry Deciduous Forests:
- Location: Northern India, Madhya Pradesh, Gujarat, Tamil Nadu.
- Trees: Sal, various acacias, and short trees.
- Tropical Thorn Forests:
- Location: Black soil areas in North, West, and South India.
- Vegetation: Cactus, spurge, and caper.
- Subtropical Broad-Leaved Forests:
- Location: Eastern Himalayas, Western Ghats.
- Flora: Oak, birch, chestnut, cherry, and diverse bamboo and creepers.
- Subtropical Pine Forests:
- Location: Shivalik Hills, Central Himalayas.
- Trees: Pine, oak, rhododendron.
- Montane Wet Temperate Forests:
- Location: East of Nepal to Arunachal Pradesh, parts of Kerala and Nilgiri Hills.
- Flora: Conifers, deciduous trees, and lush undergrowth.
- Himalayan Moist Temperate Forest:
- Location: Western to Eastern Himalayas.
- Trees: Broad-leaved oak, walnut, rhododendron, and bamboo.
- Himalayan Dry Temperate Forest:
- Location: Lahul, Kinnaur, Sikkim, and parts of the Himalayas.
- Vegetation: Predominantly conifers, with broad-leaved trees like oak and maple.
- Sub-Alpine Forest:
- Location: Kashmir to Arunachal Pradesh, at elevations of 2900-3500 meters.
- Flora: Juniper, rhododendron, and willow.
- Moist Alpine Scrub:
- Location: Higher Himalayan regions and near Myanmar border.
- Vegetation: Low scrub, rhododendron, mosses, and ferns.
- Dry Alpine Scrub:
- Location: Elevations between 3000-4900 meters.
- Vegetation: Dwarf plants like black juniper and honeysuckle.
Importance of Forests:
- Forests help maintain ecological balance, purify air, influence precipitation, prevent soil erosion, and provide resources like medicinal plants, timber, and raw materials.
3.4 Deforestation
- Definition: The large-scale clearing of forests, often for urbanization, agriculture, or resource extraction.
- Causes:
- Shifting Cultivation: Land cleared and burned for farming, then abandoned.
- Development Projects: Construction of dams, roads, and railways.
- Fuel Requirements: Increased demand for firewood.
- Industrial Use: Wood for paper, furniture, and raw materials.
- Other Factors: Overgrazing, mining, urbanization, and natural disasters.
- Effects:
- Reduced biodiversity, lower groundwater levels, altered precipitation patterns, and habitat destruction.
- Disruption of nutrient cycles and increased soil erosion.
3.5 Grassland Ecosystem
- Definition: Ecosystems in regions with 25-75 cm of annual rainfall, often in temperate climates.
- Types:
- Semi-Arid Zone: Northern Gujarat, Rajasthan.
- Dry Sub-Humid Zone: Peninsular India.
- Moist Sub-Humid Zone: Ganga Plains.
- Humid Montane Regions: Himalayas and Northeast India.
- Economic Importance:
- Supports livestock, provides fuel, and is a source of nutrition and raw materials.
- Impact of Grazing:
- Overgrazing leads to soil compaction, reduced infiltration, and disrupted nutrient cycles.
- Role of Fire:
- Essential for controlling shrubs and promoting grass growth.
3.6 Desert Ecosystem
- Definition: Regions with annual rainfall under 25 cm, characterized by extreme conditions.
- Types:
- Hot Deserts: Like the Thar Desert, with scorching temperatures.
- Cold Deserts: Ladakh, Spiti Valley, with freezing winters.
- Adaptations:
- Plants: Succulent stems, reduced leaves, extensive root systems.
- Animals: Nocturnal habits, efficient water conservation, long legs for heat dissipation.
- Indian Desert:
- Habitat for the Great Indian Bustard, blackbuck, and migratory birds.
- Cold Desert:
- Found in Ladakh, with limited vegetation and rare wildlife.
3.7 Desertification
- Definition: The degradation of land into desert-like conditions, often human-induced.
- Causes: Overpopulation, overgrazing, deforestation, and development projects.
- Impact in India: 69.6% of land is dry; 81.45 million hectares are undergoing desertification.
- Control Measures:
- Afforestation, watershed programs, and employment schemes.
3.8 Indian State of Forest Report, 2021
The India State of Forest Report (ISFR) is a biennial publication by the Forest Survey of India (FSI), providing comprehensive assessments of the nation’s forest and tree cover. The most recent edition, ISFR 2021, was released in January 2022. However, the subsequent ISFR, due in 2023, has experienced a significant delay and remains unpublished as of November 2024.
Key Points:
- ISFR 2021 Highlights:
- Total Forest Cover: 713,789 square kilometers, accounting for 21.71% of India’s geographical area.
- Increase Since 2019: An addition of 1,540 square kilometers in forest cover.
- Tree Cover: 2.91% of the geographical area, with a 721 square kilometer increase since 2019.
- Combined Forest and Tree Cover: 24.62% of the country’s geographical area, marking a 0.28% rise at the national level.
- Mangrove Cover: A 0.34% increase compared to the previous assessment.
- Carbon Stock: Estimated at 7,204 million tonnes, reflecting a 79.4 million tonne increase since 2019.
- Forest Fire Prone Areas: 22.27% of forest cover identified as prone to fires.
- Bamboo Resources: A decrease of 10,594 square kilometers in bamboo-bearing areas compared to ISFR 2019.
- Delay of ISFR 2023:
- The ISFR 2023, traditionally released every two years, has been delayed by over a year. This postponement has led to speculation among forestry officials regarding potential declines in forest cover, which might explain the government’s hesitation to publish the report.
- Afforestation Initiatives:
- The Indian government has implemented several afforestation programs to enhance forest cover:
- Green India Mission (GIM): Aims to increase forest cover and improve ecosystem services.
- Nagar Van Yojana: Targets the creation of 600 Nagar Vans and 400 Nagar Vatikas between 2020-21 and 2024-25 to boost urban green cover.
- Compensatory Afforestation Fund Management and Planning Authority (CAMPA): Utilizes funds for afforestation to compensate for forest land diverted for non-forest purposes.
- The Indian government has implemented several afforestation programs to enhance forest cover:
- Concerns Over Data Integrity:
- The delay in releasing ISFR 2023 has raised concerns about the integrity of forest data. Some officials suggest that the postponement may be due to significant declines in forest cover, prompting the government to withhold the report.
The delay in the ISFR 2023 release underscores the need for timely and transparent reporting on India’s forest resources to inform policy decisions and conservation efforts.