Structure and Function of Forest Ecosystem(Terrestrial Ecosystem)

FOREST ECOSYSTEM (TERRESTRIAL ECOSYSTEM)

Introduction

^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    Fruits.

^Ø    Gums.

^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.

2) Consumers

^v   In a forest, consumers are of three main types;

a) Primary Consumers

^v   These are Herbivores which feed directly on producers.

Eg:

^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.

3) Decomposers

^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.