A terrestrial ecosystem (TE) is a land-based community of organisms (biotic) and their interactions with the abiotic components in a given area. The type of TE found in a particular place is dependent on the following factors:
- Topography- valleys, mountains, plains and plateaus
- Altitudinal and latitudinal variations
- Quality of soil
- Amount of light
- Amount of precipitation received
- Temperature range
|Allen’s rule: Animals living in colder regions have shorter limbs (smaller body surface) as an adaptation to control the dissipation of heat.|
|TYPES OF TERRESTRIAL ECOSYSTEM|
Tundra means a “barren land”. Tundra ecosystems are treeless regions where environmental conditions are very severe.
|ARCTIC TUNDRA||ALPINE TUNDRA|
|Distribution: It extends as a continuous belt below polar ice cap and above tree line in the northern hemisphere. In the southern hemisphere, it is limited to some parts of Antarctica and Falkland islands||Distribution: It is found at any latitude in a high altitude area.|
|Examples: Alaska, Canada, Russia, Greenland, Iceland, and Scandinavia.||Examples: The Himalayas, the Alps, Tibetan Plateau, The Caucasus Mountains, the American Cordillera etc.|
|Flora: Mosses, lichens, sedges, cotton grass, sedges, dwarf heath, willows, birches||Flora: Mosses, sedges, liverworts, grassy vegetation.|
|Fauna: Arctic foxes, polar bears, caribou, musk-ox.|
|Fauna: Pikas, marmots, mountain goat, reindeer, musk ox, arctic hare, caribous, lemmings and squirrel.|
- A forest ecosystem is a dynamic complex of different kinds of biotic components and their abiotic environment interacting as a functional unit, where trees are a key component of this ecosystem.
- The forest ecosystems have been classified into three major categories: coniferous forest, temperate forest and tropical forest.
- All these forest biomes are generally arranged on a gradient from north to south latitude or from high to lower altitude.
|TYPES OF FOREST ECOSYSTEM:|
|· It is sandwiched between the tundra to the north and the temperate forest to the south.|
Tropical Rain Forest
It is an act of clearing or thinning forest to fulfill varied purpose of humankind. Following are the prominent causes of deforestation:
- Shifting cultivation – It is a practice of clearing a patch of land by burning and left abandoned to recover its fertility.
- Infrastructure expansion: It can be for construction of highways, industries, real estates, communication line, urban outgrowth.
- Forest fire: It can be of natural cause (high atmospheric pressure and low humidity) or man-made cause (deliberate firing by local inhabitants, discarded cigarettes, electric spark and mining).
- Logging: It is a process of cutting and processing trees in order to meet the requirements of fuel, fiber, timber, pulp, latex and rubber etc.
- Large-scale agriculture and overgrazing: Burgeoning population demands for more food (crops and livestock) which in turn encroaches forest land.
|EFFECTS OF DEFORESTATION|
|Disturbance of hydrological cycle|
|Loss of biodiversity|
- Grassland ecosystem is an area where the vegetation is dominated by continuous cover of grasses and herbaceous (non-woody) plants. It accounts between 20 and 40% of world’s land area. The grasslands are found where rainfall is about 25-75 cm per year, not enough to support a forest, but more than that of a true desert.
- Typical grasslands are vegetation formations that are generally found in temperate climates. In India, they are found mainly in the high Himalayas. The rest of India’s grasslands are mainly composed of steppes and savannas.
- Major difference between steppes and savannas is that all the forage in the steppe is provided only during the brief wet season whereas in the savannas forage is largely from grasses that not only grow during the wet season but also from the smaller amount of regrowth in the dry season.
Savanna/Tropical Grassland: “Big Game Country”
E.g: Savanna of Africa, Campos of Brazilian highland, Llanos of Orinoco basin.
Steppe/Temperate Grassland: “Granaries Of The World”
Desert ecosystem is a region of scanty rainfall supporting a community of distinctive plants and animals specially adapted to the harsh environment. Deserts are formed in regions with less than 25 cm of annual rainfall.
|TYPES OF DESERT ECOSYSTEM|
|ADAPTATIONS OF DESERT VEGETATION:|
- Extensive root system to tap underground water
- Thick cuticle or sunken stomata to reduce transpiration
- Leaves- Absent or reduced in size or modified into either thorns, leathery, hard and waxy leaves.
- Large fleshy (succulent) stems and leaves for water storage
- Plants lie dormant for years until rain falls.
|ADAPTATIONS OF DESERT ANIMALS:|
- Nocturnal in habit to avoid the sun’s heat
- Store fat in their humps, thus they can live months without food
- Excrete concentrated urine to conserve water
- Camel “the ship of the desert” can travel several days without water (drink gallons of water at one go)
- Body temperature can change to avoid losing water through sweating. (Remember kharai camel)
|DESERTIFICATION – “The greatest environmental challenge of our time”|
It is the destruction of biological potential of the land in arid, semi-arid and dry sub-humid areas due to various factors, including climatic variations and human activities.
|LAND MANAGEMENT: Deforestation + Overgrazing + Over-cultivation of crops + Developmental activities + Inappropriate irrigation.|
|CLIMATE RELATED: Natural fluctuations in climate + Global warming as a result of human-caused GHGs.|
|LAND DEGRADATION NEUTRALITY|
|THE BONN CHALLENGE|
|INDIAN STATE OF FOREST REPORT, 2019 (16TH REPORT IN THE SERIES)|
- It is a biennial publication of Forest Survey Of India, the first being the report of 1987.
- It is based on the interpretation of LISS III sensor of Resourcesat-2 satellite
- Total forest and tree cover- 24.56% of the geographical area of the country.
- Total forest cover- 21.67%; Total tree cover- 2.89%
- Largest forest cover in India:Madhya Pradesh > Arunachal Pradesh > Chhattisgarh > Odisha
- Forest cover as percentage of total geographical area: Mizoram (85.41%) > Arunachal Pradesh (79.63%) > Meghalaya (76.33%) > Manipur (75.46%) > Nagaland (75.31%).
- States/UTs showing significant gain in forest cover: Karnataka > Andhra Pradesh > Kerala > J&K
- States showing loss in forest cover:Manipur > Arunachal Pradesh > Mizoram.