Types of ecosystem

1. Forest Ecosystem (Terrestrial Ecosystem)

A forest is an area with a high density of trees. World’s total land area is 13,076 million
hectares, of which total forests account for about 31% of the world’s land area.

In India, the forest cover is roughly 19% of the total land area. The forest ecosystems are
of great concern from the environmental point of view. It provides numerous
environmental services.

Biotic components:
The various biotic components, representatives from the three functional
groups, of a forest ecosystem are:
1. Producer Organisms:
In a forest, the producers are mainly trees. Trees are of different kinds depending upon
the type of forest developed in that climate.

2. Consumers:

In a forest, consumers are of three main types:

(a) Primary Consumers:
These are Herbivores which feed directly on producers. Examples: Ants, Beetles, Bugs,
spiders etc. feeding on tree leaves. Larger animals such as Elephants, Deer, Giraffe etc.
grazing on shoots and/or fruits of trees.

(b) Secondary Consumers:

These are carnivores and feed on primary consumers. Examples: Birds, Lizards, Frogs,
Snakes and Foxes.

(c) Tertiary Consumers:

These are secondary carnivores and feed on secondary consumers. These include top
carnivores like Lion, Tiger.
3. Decomposers:
These include wide variety of saprotrophic microorganism like; Bacteria , Fungi . They
attack the dead or decayed bodies of organisms and thus decomposition takes place.
Therefore, nutrients are released for reuse.

A-biotic components:
These include basic inorganic and organic compounds present in the soil and
atmosphere. In addition dead organic debris is also found littered in forests.

2.Grassland ecosystem
Grassland Ecosystem is an area where the vegetation is dominated by grasses and
other herbaceous (non-woody) plants. It is also called transitional landscape because
grassland ecosystems are dominated by the grass with few or no trees in the area
where there is not enough for a forest and too much of a forest.
Components of Grassland Ecosystem
The components of the Grassland Ecosystem are discussed below:

1. Abiotic Components: These are non-living thing components consist of carbon,

hydrogen, sulphur, nitrogen and phosphorous etc.
2. Biotic Components: These are living components and its sub-components are
discussed below-
(I) Producers: The primary producers of food are the grasses . If herbs and shrubs are
present, they also contribute to the primary production of food.

(II) Consumers: The consumers in a grassland ecosystem are of three levels.

(a) Primary consumers: These feed directly from the grasses (grazing) and include
herbivores such as Cows, Buffaloes, Goats, Rabbits, Mouse etc. and also insects,
termites, centipede, millipedes etc.
(b) Secondary consumers: These consumers are the carnivorous animals such as
snakes, lizard, jackal, foxes, frogs etc. which feed on the primary consumers.
(c) Tertiary consumers: Hawk, Eagles and vultures constitute the tertiary consumer in
the grassland ecosystem which preys upon the secondary and primary consumer.
(III) Decomposers: The organic matter of the grassland is decomposed by the
microbes like fungi, aerobic and anaerobic soil bacteria etc. They release the
minerals back into the soil thus making the soil fertile.
 3.DESERT ECOSYSTEM
Introduction
A desert is a landscape or region that receives almost no rainfall. It occupies
about 17% of the earth’s surface. Deserts are characterized by hot days &
cold nights. The deserts of the world are mainly located in the South- western
United States, Mexico, North America, Asia (Thar, Gobi, Tibet) & west Asia.
Deserts are characterized by scanty flora & fauna. Soils of deserts often have
abundant nutrients but little or no organic matter.
Structure and Functions of Desert Ecosystems
I. Biotic components
1) Producer Organisms
❖
In a desert, producers are mainly shrubs/bushes; some grasses & a few trees.
❖
Dominant plant species include: Succulents (water - retaining plants adapted
to arid climate or soil conditions) & hardy grasses.
❖
Besides some lower plants such as lichens & xerophytic mosses are also
present.
2) Consumer Organisms
These include animals such as insects, reptiles which are capable of living in hot
conditions
❖
Besides some nocturnal rodents, birds & some mammalians like camel etc.
are also found.
3) Decomposers
Due to poor vegetation with very low amount of dead organic matter,
decomposers are poor in desert ecosystem.
❖
The common decomposers are some bacteria & fungi, most of which are
thermophillic.
II. Abiotic components
Due to high temperature & very low rainfall, the organic substances are poorly
present in the soil.
 4.Aquatic ecosystem
Introduction
❖
Aquatic ecosystems deal with biotic community present in water bodies.
❖
In terrestrial ecosystem, carbon dioxide & oxygen are present in gaseous form
whereas in aquatic ecosystem, these are available in dissolved state.
❖
Depending upon the quality and nature of water, the aquatic ecosystem are
categorized into:
❖
Freshwater Ecosystem and
❖
Marine Ecosystem.

Freshwater Ecosystems
❖
Freshwater ecosystems cover 0.8% of the Earth's surface and contain 0.009%
of its total water.
❖
Freshwater ecosystems contain 41% of the world's known fish species.
❖
Aquatic ecosystems perform many important environmental functions. For
example:
➢
They recycle nutrients, purify water, recharge ground water and provide
habitats for wildlife.
➢
Aquatic ecosystems are also used for human recreation, and are very
important to the tourism industry, especially in coastal region.
Lakes & pond Ecosystem
❖
A pond is a place where living organisms not only live but interact with biotic
& abiotic components.
 ❖
Lakes are usually big standing freshwater bodies.
I. Biotic components
1) Producer Organisms
❖
It includes submerged, free floating and amphibious macrophytes and minute
floating and suspended lower phytoplanktons .
2) Consumer Organisms
 a) Primary consumers:These are zooplanktons and benthos.
b) Secondary consumers: These are carnivores like insects and fishes feeding on
herbivores
c) Tertiary consumers: These are the large fishes feeding on small fishes.
3) Decomposers Micro – organisms like bacteria, fungi etc.
II. Abiotic component
❖
These are the inorganic as well as organic substances present in the bottom
soil or dissolved in water. In addition, to the minerals, some dead organic
matter is also present.

Marine or Ocean Ecosystem

❖
Marine ecosystems are among the Earth's aquatic ecosystems. They include:
Oceans, Estuaries and Lagoons, Mangroves and Coral reefs, the Deep sea and
the Sea floor.
❖
These are the reservoirs of water covering approximately 71% of the Earth's
surface (an area of some 361 million square kilometers).
❖
These ecosystems are different from freshwater ecosystem mainly because of
its salty water.
❖
The salt concentration in an open sea is usually 3.5% (35 parts per thousand).
Dominant ions are sodium & chloride.
❖
Average temperature of Marine ecosystem is 2-3 degree centigrade, devoid
of light.

l. Biotic components
1) Producers
It includes phytoplanktons, large seaweeds and mangrove vegetation.
2) Consumers
a) Primary consumers: These are herbivores and feed directly on producers.
b) Secondary consumers: These are carnivorous fishes.
c) Tertiary consumers: These are top carnivorous fishes.
3) Decomposers These are micro – organisms like bacteria, fungi.
II. Abiotic components
❖
, variable dissolved oxygen content, light & temperature make a unique
physiochemical conditions in marine water.