GRASSLAND ECOSYSTEM (TERRESTRIAL ECOSYSTEM)
v Grasslands (also called Greenswards) are areas where the vegetation is dominated by grasses and other herbaceous (non-woody) plants.
v Grasslands occupy about 24% of the earth’s surface.
v Grasslands occur in regions too dry for forests and too moist for deserts
v The annual rainfall ranges between 25- 75 cm, Usually seasonal
v The principal grasslands include:
Ø Prairies (Canada, USA),Pampas (South America),Steppes (Europe & Asia) Veldts (Africa)
v The highest abundance & greatest diversity of large mammals are found in these ecosystems.
v The dominant animal species include
v Wild horses, asses & antelope of Eurasia,
v Herds of Bison of America; and
v The antelope & other large herbivores of Africa.
Structure and functions of Grassland Ecosystems
I. Biotic components
1) Producer Organisms
v In grassland, producers are mainly grasses; though, a few herbs & shrubs also contribute to primary production of biomass.
v Some of the most common species of grasses are:
v Brachiaria sp., Cynodon sp., Desmodium sp., Digitaria sp.
v In a grassland, consumers are of three main types;
a) Primary Consumers
v The primary consumers are herbivores feeding directly on grasses. These are grazing animals such as
v Cows, Buffaloes, Sheep, Goats, Deer, Rabbits etc.
v Besides them, numerous species of insects, termites, etc are also present.
b) Secondary Consumers
v These are carnivores that feed on primary consumers (Herbivores)
v These include;-Frogs, Snakes, Lizards, Birds, Foxes, Jackals etc.
c) Tertiary Consumers
v These include hawks etc. which feed on secondary consumers.
v These include wide variety of saprotrophic micro- organism like: Bacteria; Fungi; Actinomycetes
v They attract the dead or decayed bodies of organisms & thus decomposition takes place.
v Therefore, nutrients are released for reuse by producers.
II. Abiotic components
v These include basic inorganic & organic compounds present in the soil & aerial environment.
v The essential elements like C, H, N, O, P, S etc. are supplied by water, nitrogen, nitrates, sulphates, phosphates present in soil & atmosphere.