FOREST ECOSYSTEM (TERRESTRIAL ECOSYSTEM)
v A forest is an area with a high density of trees.
v World’s total land area is 13,076 million hectares - (Source: FAO; 1989)
v Of which total forests account for about 31% of the world’s land area.
v In India, the forest cover is roughly 19% of the total land area.
v The forest ecosystems are of great concern from the environmental point of view.
v It provides numerous environmental services like;
Ø Nutrient cycling,
Ø Maintaining biodiversity
Ø Providing wildlife habitat
Ø Affecting rainfall patterns
Ø Regulating stream flow
Ø Storing water
Ø Reducing flooding
Ø Preventing soil erosion
Ø Reclaiming degraded land & many more….
v Apart from environmental values, forest ecosystems have some traditional values as well.
v Examples are:
Ø Fire Wood & Timber.
Ø Herbs & drugs.
Structure and Function of Forest Ecosystem
I. Biotic components
v The various biotic components, representatives from the three functional groups, of a forest ecosystem are:
1) Producer Organisms
v In a forest, the producers are mainly trees.
v Trees are of different kinds depending upon the type of forest developed in that climate.
v Apart from trees, climbers, epiphytes, shrubs and ground vegetation.
v Dominant species of trees in major types of forest ecosystems are:
v Tectona grandis, Acer, Betula, Picea, Pine, Cedrus.
v In a forest, consumers are of three main types;
a) Primary Consumers
v These are Herbivores which feed directly on producers.
v Ants, Beetles, Bugs, spiders etc. feeding on tree leaves.
v Larger animals such as Elephants, Deer, giraffe etc. grazing on shoots and/or fruits of trees.
b) Secondary Consumers
v These are carnivores and feed on primary consumers.
Eg: Birds, Lizards, Frogs, Snakes and Foxes.
c) Tertiary Consumers
v These are secondary carnivores and feed on secondary consumers
v These include top carnivores like Lion, Tiger.
v These include wide variety of saprotrophic micro- organism like;
v Bacteria (Bacillus Sp., Clostridium sp., pseudomonas.
v Fungi (Aspergillus sp., Ganoderma sp., Fusarium.
v Actinomycetes (Streptomyces).
v They attract the dead or decayed bodies of organisms & thus decomposition takes place.
v Therefore, nutrients are released for reuse.
II. Abiotic components
v These include basic inorganic & organic compounds present in the soil & atmosphere.
v In addition dead organic debris is also found littered in forests.