PRODUCTIVITY OF AN ECOSYSTEM

       PRODUCTIVITY OF AN ECOSYSTEM

(i)                 Defination.The amount of food energy produced by a particular trophic level per unit area in a unit time is called productivity. It is also defined as a rate of biomass production.it is highest in the trophical rain forests while in the desert ecosystem.

(ii)               Types.it is of three types :

(a)   Primary productivity .it refers to the productivity at the producer levelit is again of two types:

(1)   Gross primary productivity (P_G). It refers to total photosynthesis or total assimilation i.e the total amount of food formed by the producers per unit area in unit time.

(2)   Net primary productivity (P_N).  It refers to gross production minus losses by the way respiration and decomposition. It is also called apperent photosynthesis or net assimilation.

                       P_N =P_G – R

(b)    Secondary productivity.it refers to productivity at the consumers level. It indicates the rate of assimilation of food energy at the trophic level of consumers .

(c)    Community productivity.it is the rate of net synthesis of organic matter (biomass) by a community per unit time and area.