Environment and Ecology Notes for UPSC Exam
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Environment and Ecology Notes for UPSC Exam
Ecology is, literally, the study of where living organisms live. By contrast, Environmental Science is a broader, interdisciplinary field in which ecologists work with other physical, chemical, and biological studies and seek solutions to environmental problems.
- Terrestrial ecosystems are the ecosystems that occur inland.
- There are many types of terrestrial ecosystems.
- A terrestrial ecosystem can be distinguished from marine and freshwater ecosystems that occur underwater.
Tundra stands for barren land so they are found in very severe environmental conditions.
- Arctic tundra
- Alpine tundra
Arctic tundra extends below the polar ice caps and above the treeline in the northern hemisphere.
Alpine tundra occurs in high mountains.
Flora and fauna:
Typical vegetation of the arctic tundra is cotton grass, sedges, dwarf heath, willows, and birches. Animals of tundra are reindeer, musk ox, arctic hare, caribou, lemmings, and squirrel.
- Most of the animals have a long life and they are protected from chillness by thick cuticle and epidermal hair.
- Mammals are characterized by large body size, small tail, and ear to escape heat loss from the body surface.
- The body is covered with fur for insulation.
- Insects have short life spans which they complete during the favorable periods of the year.
The nature of the soil, climate, and topography are the factors that determine the distribution and abundance of trees in forest vegetation.
- Forest may be evergreen or deciduous
- On the basis of leaves, forests are broad-leafed and needle leafed.
- The forest ecosystem includes a complex assemblage of different biotic communities.
- The forest ecosystem is classified into three categories-coniferous, temperate, and tropical.
- Cold regions with high rainfall, strong seasonal climates with long winters, and short summers are characterized by boreal coniferous forests.
- Light-colored acidic soil of coniferous forest is called podzol. Soils are low in mineral content, organic material and number of invertebrates like earthworms.
- Evergreen plant species like spruce, fir and pine trees and animals such as lynx, wolf, bear, red fox, porcupine etc are seen.
TEMPERATE DECIDUOUS FOREST-
They are characterized by a moderate climate and broad-leaved deciduous trees.
- Soil is podzolic
TEMPERATE EVERGREEN FOREST-
The Mediterranean-type climate is characterized by warm, dry summers and cool, moist winters.
- Plants are adapted to regenerate quickly after being burnt as fire is the most important hazardous factor.
TEMPERATE RAIN FOREST
- Seasonal variation with respect to temperature and rainfall is seen.
- Rainfall is high and fog may be very heavy. It is a more important source of water than rainfall.
- The biotic diversity of temperate rain forests is higher than temperate forests and lower than a of tropical rainforest.
TROPICAL RAIN FOREST
- Occur near the equator.
- They are the most diverse and rich Communities.
- Annual rainfall exceeds 200 cm and is generally distributed throughout the year.
- Soil is red latosols, and they are very thick.
- A high rate of leaching makes soil useless for agricultural purposes.
- Vertical stratification is seen with tall trees which are often covered with vines, creepers, lianas, epiphytes, etc.
- The lowest layer is formed by an understory of trees, shrubs, herbs, like ferns and palms.
TROPICAL SEASONAL FOREST:
- Also known as monsoon forest, it occurs in regions with higher total annual rainfall.
- Found in southeast Asia, South America, northern Australia, western Africa, etc.
SUBTROPICAL RAIN FORESTS:
They are found in regions with high rainfall and less temperature difference between winter and summer.
- Epiphytes are common
- Animals are similar to tropical rainforest
- India has a diverse range of forests.
- Climate, soil type, topography, and elevation are the main factors that determine the type of forest.
- Forests vary according to their nature and composition, the type of climate in which they thrive, and its relationship with the surrounding environment.
- Forests in India are classified into 16 types by champion and Seth.
TROPICAL WET EVERGREEN FOREST
Found along western ghats, Andaman and Nicobar Islands, and along north-eastern regions.
- Characterized by tall, straight, evergreen trees
- The most common trees are jackfruit, betel nut palm, Jamun, mango etc.
- Shrubs cover the layer closer to the ground, followed by short trees, and then are taller.
TROPICAL SEMI-EVERGREEN FOREST
- Location- Andaman and Nicobar Islands, Western Ghats and Eastern Himalayas
- They consist of a mixture of wet evergreen trees and moist deciduous trees.
TROPICAL MOIST DECIDUOUS FOREST
- Location- found throughout India except in western and north-western regions.
- Tall trees with broad branching trunks and roots to hold them firmly to the ground.
- Shorter trees and evergreen shrubs form a lower layer.
- Dominant vegetation- sal and teak, mango, bamboo, and rosewood.
LITTORAL AND SWAMP
- Location- Andaman and Nicobar islands and along delta area of the Ganga and Brahmaputra.
- Their roots consist of soft tissue so that the plants can respire in the water.
TROPICAL DRY DECIDUOUS FOREST
- Found throughout the northern part of the country except in the northeast.
- Also found in Madhya Pradesh, Gujarat, Andhra Pradesh, Karnataka and Tamil Nadu.
TROPICAL THORN FOREST
Found in areas with black soil
Trees do not grow beyond 10 meters.
TROPICAL DRY EVERGREEN FOREST
Location- Tamil Nadu, Andhra Pradesh, and Karnataka coast.
Mainly hard left and trees are evergreen with fragrant flowers, along with a few deciduous trees.
SUB TROPICAL BROAD-LEAVED FOREST
Found in Eastern Himalayas and the Western Ghats, along the Silent Valley.
- Vegetation differs in both areas. In the Silent Valley, poon spar, cinnamon, rhododendron, and fragrant grass are predominant.
- Eastern Himalayas are badly affected by forest fires and shifting cultivation.
SUBTROPICAL DRY EVERGREEN FOREST
They have a prolonged hot and dry season and cold winter.
Location- Shivalik hills and foothills of the Himalayas up to a height of 1000 meters.
MONTANE WET TEMPERATE FOREST
Location- east of Nepal into Arunachal Pradesh, with a minimum rainfall of 2000 mm. Also found in parts of Nilgiri Hills.
- The higher layer consists of conifers, the middle has deciduous trees and the lowest is covered by rhododendron and Champa.
HIMALAYAN MOIST TEMPERATE FOREST
Location- Western Himalayas to Eastern Himalayas.
- Western section-broad leaved oak, brown oak, walnut, rhododendron, etc are found. So vegetation is dense.
HIMALAYAN DRY TEMPERATE FOREST-
Found in Lahaul, Kinnaur, Sikkim, and other parts of the Himalayas.
Mainly coniferous trees and broad-leaved trees like oak, maple, and ash are present.
SUB ALPINE FOREST
Extend from Kashmir to Arunachal Pradesh.
- Due to heavy rainfall and high humidity, the timberline in these parts is higher.
MOIST ALPINE SCRUB
Found along all Himalayas and on higher hills near the Myanmar border.
- Mosses and fern cover the ground in patches.
- It is a low scrub, dense evergreen forest.
DRY ALPINE SCRUB-
Found about 3000 meters to about 4900 meters.
Dwarf plants dominate.
IMPORTANCE OF FOREST-
- Purify air
- Prevent floods and soil erosion
- Provide medicinal properties, fuel, timber, raw materials for industry
- Indirect a role in precipitation.
Deforestation is the permanent destruction of forest in order to make it useful for other purposes like urbanization, industrialization, mining operations etc.
Effects of deforestation-
- Loss of biodiversity,
- Soil erosion and desertification in extreme cases,
- The disturbed water cycle,
- Increased carbon dioxide concentration in the atmosphere.
SHIFTING CULTIVATION/ SLASH AND BURN AGRICULTURE-
- A piece of land is cleared, vegetation is burned and ash is mixed in soil which acts as a fertilizer.
- This land is then used for agricultural purposes for two to three times or sometimes for grazing cattle.
- Then the farmers move to other areas and repeat the process.
Many projects like hydroelectric projects, large dams, and reservoirs, laying of railway lines etc leads to immense deforestation.
RAW MATERIAL REQUIREMENTS
Industries obtain their raw material from plants like drugs, scents, perfumes, resin, gums, waxes, turpentine, latex and rubber, tannins, alkaloids, bee wax etc.
- Wood is also used as raw material for making paper, plywood, furniture, match sticks, etc.
Overgrazing, agriculture, mining, urbanization, flood, fire, etc.
Grasslands are found in places where the rainfall is about 25-75cm per year.
- In India, they are found mainly in the Himalayas. Grasslands in India are mainly steppes and savannas.
- Soil is always exposed, sometimes rocky but mostly sandy.
TYPES OF GRASSLANDS-
There are six types of grasslands based on climatic conditions.
It covers the northern portion of Gujarat, Rajasthan, Western Uttar Pradesh, Delhi, and Punjab.
DRY SUB-HUMID ZONES
Covers the whole of peninsular India.
MOIST SUB-HUMID ZONES
It Covers Ganga alluvial plain in northern India.
Topography is level, low lying, and ill-drained.
HUMID MONTANE REGIONS
Extends to humid montane regions and moist sub-humid areas of Assam, Manipur, West Bengal, Uttar Pradesh, Punjab, Himachal Pradesh, and Jammu and Kashmir.
- India teems with animals of all shapes and sizes from buffaloes to sheep and there are millions of them.
- Livestock wealth plays a crucial role in Indian life. It is a major source of fuel, draught power, nutrition, and raw material for village industries.
- But only about 13 million hectares in the country are classified as permanent grazing lands. On top of it, they exist in a highly degraded state.
- Grassland biomes are important to maintain the population of many domesticated and wild herbivores.
- A place that is difficult to inhabit.
- They can be hot or cold but both conditions are difficult for organisms to inhabit.
- Deserts are formed in regions with less than 25 cm of annual rainfall.
- Deserts in temperate regions often lie in “ rain shadows” i.e where high mountains block off moisture from the seas.
- At higher altitudes and at a greater distance from the equator, deserts are cold and hot near the equator.
- Water is the major limiting factor. So productivity depends on rainfall.
- Perennial plants like creosote bush, cactus, etc are found.
Desert plants are adapted to survive the intense heat and limited water.
- Plants conserve water by following methods:
- They are mostly shrubs
- Leaves are either reduced or absent. eg.cacti, opuntia
- The stem is flattened in some plants to perform the function of photosynthesis.
- The vast root system is capable of reaching great depths.
- Wax coating on leaves prevents water loss through evaporation.
- A specific photosynthetic pathway is present which enables stomata to remain closed during the daytime.
ADAPTATIONS IN ANIMALS
- Animals are fast runners and mostly nocturnals to avoid the sun’s heat during day time.
- Long legs are present which keep the body away from ground heat.
- They excrete almost 4-5 times concentrated urine.
- Lizards are mostly insectivorous and herbivores meet their water demands by feeding on moist seeds.
- Kangaroo rat nevers drinks water and is found in deserts.
- Camel- ships of the desert can travel long distances without drinking water for several days.
Hot desert- Thar desert
- Present around the equator.
- The temperature remains hot throughout the year; nights are cooler than days with temperatures below freezing point.
- The relative humidity is always low.
- Only plants and animals with special adaptations can survive.
Desert plants are divided into the following groups-
- Depending directly upon rain- ephemerals and rain perennials
- Depending on the presence of underground water
- Ephemerals- delicate annuals, free from xerophytic adaptations. They appear immediately after rain, develop flowers and fruits in a short time, and then die when the surface layer of soil dries.
- Rain perennials- visible above ground only in the rainy season, but the perennial underground stem is present.
- Plants that depend on underground water- the largest number of plants have a well-developed tap root system that can absorb water from great depths.
Reduced leaves, wax coating, succulence, the thick cuticle are the common xerophytic adaptations.
Mammals- Blackbuck, wild ass, chinkara, caracal, sandgrouse, and desert fox.
It is the migration flyway used by cranes and flamingos.
COLD DESERT/TEMPERATE DESERT
Cold deserts in India include Ladakh, Leh, and Kargil of Kashmir and Spiti valley of Himachal Pradesh.
- These areas lie in the rain shadows of the Himalayan mountain system.
- Characterized by extremely cold weather
- Soil type- sandy to sandy loam
- Soil pH- neutral to slightly alkaline
- Soil has a low retention capacity
- Heavy snowfall occurs between November and March
- Insignificant monsoon- Mean annual rainfall less than 400mm
- Wind erosion is more common
It is a process of land degradation by which region becomes progressively drier.
- It is the main problem faced by desert adjoining areas like Rajasthan, Gujarat, Punjab and Haryana.
- Human activities are the main cause of deforestation.
- Population pressure
- Increase in cattle production, overgrazing
- Increased agriculture
- Development activities
Some of the major programs currently implemented which are related to land degradation and desertification are-
- Integrated watershed management program
- National afforestation program
- National mission for green India
- Mahatma Gandhi national rural employment guarantee scheme
- Soil conservation in the catchment of river valley project and flood-prone river.
- National watershed development project for Rainfed Areas.
- Desert development program.
- Fodder and feed development scheme.
It is a massive forestry program to meet the demands of local people for fuel, fodder, timber, etc.
- The presence of vegetation prevents soil erosion and modifies the hostile climate.
- State of forest report is published by Forest Survey of India(FSI) on a biennial basis since 1987.
- The Indian State of Forest report 2019 is the 16th report in the series.
- Every two years, the Forest Survey of India (FSI) undertakes an assessment of the country’s forest resources, the results of which are presented as the ‘India State of Forest Report (ISFR)’.
- It is based on the Government of India’s vision of Digital India, FSI’s assessment is largely based on digital data whether it is satellite data, vector boundaries of districts or data processing of field measurements.
- According to the 2019 report, the total forest cover of the country is 712,249 square kilometers (21.67 percent of India’s total geographical area) slightly up from 708,273 sq. km (21.54 percent) in 2017.
- The tree cover of the country is 95,027 sq. km (2.89 percent of the total area) again slightly up from 93,815 sq. km. (2.85 percent) in 2017.
- Total carbon stock in the country's forest: estimated to be 7,124.6 million tonnes.
- In terms of area, Madhya Pradesh has the largest forest cover in the country followed by Arunachal Pradesh, Chhattisgarh, Odisha, and Maharashtra.
- In terms of forest cover as a percentage of their total geographical area, the top five states are Mizoram (85.41 percent), Arunachal Pradesh (79.63 percent), Meghalaya (76.33 percent), Manipur (75.46 percent), and Nagaland (75.31 percent).
- Andaman and Nicobar island has the maximum forest cover area among the Union territories in India. it has an 86.93% forest cover area.
- On Other hand, Lakshadweep has zero percent forest cover area.
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