Question

Jane the rancher wants to estimate the ecological (or trophic) efficiency of her bison herd in extracting energy in the form of standing biomass from her pasture land. If assimilation efficiency is 50% and production efficiency is 20%, what is the trophic efficiency, assuming consumption efficiency is 100%? Note: Convert the percentages to proportions before making your calculations. Then convert back to percentage when reporting you answer. Do not add the percentage symbol or any units, just report the number. For example, is 0.2, convert to 20%, and respond with 20 as your answer. Submit response

Answer 1

Trophic effiency =10%

Explanation:

*Trophic efficiency= Net production energy (NPE)of bison herd/net production energy of next lower trophic level

*Consumption efficiency= consumed energy /NPE of next lower trophic level

Since consumption efficiency is 100% ,then

*NPE of next lower trophic level= consumed energy

*Assimilation efficiency of bison herd= assimilated energy/consumed energy

Given assimilation efficiency is 50%,that is 1/2

So,

*Consumed energy= 2× assimilated energy

*Production efficiency of bison herd=NPE of bison herd/assimilated energy

Production efficiency is 20%,that is 1/5.

So NPE of bison herd =1/5 × assimilated energy

Putting these values in trophic efficiency formula,

*Trophic efficiency=NPE of bison herd/NPE of next lower trophic level

Trophic efficiency =(1/5×assimilated energy)÷(2×assimilated energy)

*Trophic efficiency= 1/10=10%

(Trophic efficiency can be simply calculated by multiplying assimilation efficiency,production efficiency and consumption efficiency.

Trophic efficiency=20%×50%× 100%

Trophic efficiency=0.2×0.5×1=0.1=10% )