Behavioral relationship of biomass

Biomass: 

The amount of living matter in a unit area or volume of habitat

•Net recruitment (H) It is the excess of addition of biomass from

 reproduction and growth over the losses from mortality and like 

occurring independently of harvest

•Harvest /Use of resource (R)

•Time dimension (t)

•In favorable time H is more than R

•In bad time H is less than R

•H is determined by:

H= h(St, Nt, Xt)

Nt= Support provided by environment or input provided by nature

Xt= Inputs under control of human

Biomass production function of time

•In a stable unmanaged ecosystem the biomass of any species tends

 to increase towards upward

•If due to some reasons the biomass falls it may fall towards zero

•S is the extinction threshold

•Net recruitment (H) is negative for  biomass of less than S

•At S* the maximum sustainable biomass is achieved and net

 recruitment stabilizes at zero

The sustainable yield is the net annual reproduction from a given stock—for every population of a resource, there is an associated average rate of population increase, and that increase represents a sustainable harvest that can be removed every year without affecting the base population.

Sustainable harvest of biological resources:

•S* is the point of sustainable harvest.

At this point R*=H* 

The growth, or sustainable yield, curve for a renewable natural resource indicates the increase in stock over one time period for any given.The Y-axis can measure growth or harvest, that is, flows from or to the existing stock depicted on the X-axis.Any harvest up to the total stock is theoretically possible.A harvest at any point on the sustainable yield curve, such as S, is just equal to the growth in the stock, and hence has no net impact on stocks. Harvests above the sustainable yield curve deplete the resource, and harvests below the curve lead to an increase in the stock, as indicated by the arrows.