Terrestrial ecosystems can be divided into following main types:
- Temperate deciduous forest
- Coniferous alpine and boreal forests
- Tropical rain forests
- Grassland ecosystem
- Desert ecosystem
- Tundra ecosystem
TEMPERATE DECIDUOUS FORESTS
1, Location: Temperate moist conditions are present in Neelam valley and Shogran in Pakistan. These forests originally covered India, Southeast Asia. eastern. North America, Europe, China, Australia, Japan, North and South America.
2 Adaptation for conservation of water: The –rainfall is not constant slightly farther away from the equator. So there are distinct wet and dry season in these area. 8o they have distinct summer and winter season. The trees cannot get enough water from the soil during dry season. Therefore, they cannot compensate the loss of water by evaporation from their leaves. Thus these plants show certain adaptation for the dry season. They shed their leaves during_ dry season.
- Rain fall: The average rainfall is between 750 — 1500 mm.
- Temperature: Moderate temperature ranges from 4° C -30° C.
- Plants: Some dominant plants are Taxus baccata. Pinus wallichiana, Berberis lyceum. Many herbs and shrubs also present. Some grasses, ferns and other herbaceous plants make up field layer. At the bottom or floor level many mosses liverworts and lichens covered with litter layer are present.
- Animals: Some very common animals are Macaca mulatto (rhesus monkey), Solenorotos tibitanus (black bear). Felis bengalensis (leopard cat). deer, and wolves.
- Microorganism: Various types of microorganism are also present These microorganisms convert the litter into organic matter such as bacteria, fungi and earthworms.8. Soli condition: The soil of temperate deciduous forest is grayish brown in colour. It is very fertile and rich in organic matter. It has maximum water holding capacity.
CONIFEROUS ALPINE AND BOREAL FORESTS
- Location: These forests are present in upper Kaghan, Dir and Chiles, Malam Jaba in Swat valley in Pakistan. They are present in Eurasia (Europe + Asia) and North America, Canada just south of the tundra. Northern coniferous forests are also called Taiga.
- Climate: Conditions in taiga are harsher than the temperate deciduous forest The winters are long and cold. So the growing season is shorter. The warm weather is a short period. Thus the trees do not grow luxuriously and there is no regrowing of these trees. Therefore, evergreen coniferous trees grow in this forest, These plants have small waxy needles, The wax forms a coating on small surface area of the needles. Thus it reduces the loss of water by evaporation during cold months. These leaves remain on the trees throughout the year.
- Types of coniferous forest: There are two types of coniferous forests:
- Alpine coniferous forest: Alpine forests are located at high altitude.
- Boreal coniferous forest: They are located at high latitude.
- Snow cover and temperature: There is a constant cover of snow in these forests. They have long severe winter. Temperatures may be below freezing point, up to 10°C.
- Plants: Plants like Pinus wallichiana, Pinus roxburgii, Abies pindrow, Picea smithiana Cederous deodara are present.
- Animals:These forest face harsh climate. So there is low diversity of life. Large mammals are bison, wolf, black bear: deer, Marco polo sheep. The small animals small Kashmir flying squirrel, snowshoe hare, wolverine and crossbills.
THE GRASS LAND ECOSYSTEM
The ecosystem with grassy lands and with annual rain fall from 250 to 750 mm (10 — 30 inches) is called grass land ecosystem.
- Location: Grassland ecosystem are found in Gilgit, Kashmir, Waziristan. lower Chitral and North Kallat. Large grasslands are present in the center of Eurasian continents.
- Types of grass lands: There are two types of grass lands:
(a) Prairies: The grass’ land without woody trees is called prairies. Grasslands present in temperate climates are also called Prairies. These grasslands do not have woody plants. So they are known as Prairies. For example Prairies of North America, Pampas of Argentina.
(b) Savanna: The grassland with scattered woody trees Is called savanna. These are the grassland of tropic climates. They have woody
trees. So these grasslands are called Savanna, •
Rain .fall: Annual rainfall is about 250 to 750 mm (.10 — 30 inches). Thus grassland occurs in regions where mean annual rainfall is midway between forest and a desert. The grassland usually faces severe droughts. They have a continuous cover of grass. Generally, trees are present only along the rivers, Water and fire are the important factors in the competition between grasses and trees.
Plant life: The dominant species are graminoids i.e. grasses, and grasses like plants.
Layering: Layering is the characteristic feature of the grassland.
- Tall grasses (Andropogon, Panicum) form the first layer
- Mid high grasses (Stipa, Sporobolus, Oryzopsis) form the second layer
- Third *layer is formed by short grasses and forbs and warfare species (Poa, Bromus) with mosses and lichens.
- Soil conditions: There is low precipitation (raining) in grass lands, So the soil moisture is limited due to high evaporation. Upper soil layer is normally moist. But deeper layers are constantly dry. The soil of grassland is basically impermeable. It has excessive salinity.
- Animal life: Dominant species are herbivores, Invertebrates including
insects are very numerous. Grasshoppers become so numerous that they can compete with other herbivores for plant foliage. The predators are reptiles, amphibians and mammals, such as lizards, toads and turtles. They prey on insects. Foxes and wolves are very common.
- Decomposers: The most common decomposers 3 many bacteria, actinomycetes and fungi like molds, yeasts, mushrooms and bracket fungi. Large animals like zebras, wild horses, bisons are important.
Productivity: In temperate grassland the rate of primary production is about 700 — 1500 g/m annually. In sub-humid tropical grassland it is more than 4000 g/m. In annual grassland, large grazing animals consume relatively small amount of (5 — 10%) of the total herbage produced. Invertebrates, rodents and birds may consume equal amount or a little more.
The ecosystem with less than 30cm (10 inch) annual rain is called desert.The more common deserts are characterized by widely, spaced vegetation and large area of bare grounds.
1 Location: The desert ecosystem present in western Punjab (Mianwali and Bukhar) is known as Thal. In southern Punjab, areas like Fort Abbass, Bahawal Nagar, Yazman Bahawal Pur (Cholistan), Khan Fur and Rahimyar khan also has deserts. In Sindh this desert ecosystem is called Thar. These biomes are found in every continent. These are present often around 20° to 300 north and south latitude. Deserts are also found in the rain shadows of major mountain ranges. Desert includes a variety of environment. The extreme form of deserts is Sahara or Chile. There is no raining in these deserts. So there is no vegetation at all in these deserts.
- Rain fall: Less than 25 to 50 cm (10-20 inches) or not at all.
- Plant life: The plants are planted by hand. So the plants are often evenly spaced. The perennial plants are bushes or cacti. These plants have large shallow root systems.
Plants are covered with the waterproof waxy coating. This coating prevents evaporation of precious water. Water is stored in thick stem of cacti and other succulent parts of plant. There is variety of ways to conserve water in desert plants. Cacti and Euphorbia have fleshy stems.for storage of water. Water is stored during the period of drought.
- Animals: The animals are also specially adapted to survive on little water. The animals live in cool under ground burrows. ,These burrows give them relief from the sun and heat. Therefore, most deserts are without animal life during day time. The desert cools down at night. Thus the horned lizards. snakes and other reptiles come out for feeding. Mammals such as kangaroo. rat, and birds such as burrowing owl also come out at night for feeding.
The treeless region on the high attitude or latitude is called tundra. There are two types of tundra:
(a) Arctic tundra: The tundra present on the high latitude is called arctic tundra. It is the last biome comes before reaching the polar ice-caps Arctic tundra is a vast treeless region bordering the Arctic Ocean. It is used to describe types of vegetation in treeless high latitudes. It is present between taiga and polar ice caps. Arctic tundra is present in Northern North America, Northern Europe and Siberia (with high latitude).
(b) Alpine tundra: The tundra. present at high altitude is called alpine tundra. It is present at high altitude across the mountain above timberline If is present on the mountain of Karakoram and Koh Hindu Kush in Pakistan.
- Plants: The ground is carpeted with small perennial flowers and dwarf willows. These •are only a few centimeters tall. Often large lichen called reindeer moss is also present.
- Animals: The standing pools provide habitat to mosquito. The mosquitoes and other insects are food of numerous birds (ducks and geese). Most of these birds migrate to a long distance. They make their nest there. Finally they produce theft young during the brief summer period. The tundra vegetation supports lemmings. These lemmings are eaten by wolves, snowy owls arctic foxes and grizzly bears.