Biotic potential

Biotic potential is the maximum reproductive capacity of a population if resources are unlimited. Full expression of the biotic potential of an organism is restricted by environmental resistance, any condition that inhibits the increase in number of the population. It is generally only reached when environmental conditions are very favorable. A species reaching its biotic potential would exhibit exponential population growth and be said to have a high fertility, that is, how many offspring are produced per mother.

Biotic Potential is a fundamental species characteristic, defined by Chapman (1925) as "the inherent power of organisms to reproduce and survive"^[1]. In 1931, Chapman redescribed it as: "It is a sort of algebraic sum of the number of young produced at each reproduction, number of reproductions over a period of time, sex ratio of the species, and their general ability to survive under given physical conditions."^[2]

Chapman relates to a "vital index":

Vital Index = (number of births/number of deaths)*100

Biotic potential is the highest possible vital index of a species; therefore, when the species has its highest birthrate and lowest mortality rate.

Significance of Biotic Potential

If the potential value of population increase can be determined, the impact of the environment upon the population also can be determined.

• Compute the biotic potential (potential increase) and subtract the actual or observed value of decrease; this difference represents how effective the environment is in preventing the species from attaining its full potential.

Components of Biotic Potential

• Reproductive potential - potential natality: It is the upper limit to biotic potential (in the absence of mortality)
• Survival potential: Because reproductive potential does not account for the number of gametes surviving, survival potential is a necessary component of biotic potential; it is the reciprocal of mortality (in the absence of mortality, biotic potential = reproductive potential)

Chapman identified two components:

• nutritive potential - the ability to acquire and utilize food for growth and energy
• protective potential - potential ability of the organism to protect itself against the dynamic forces of the environment
  • assuring successful fertilization (mating)
  • care of young
  • Graham Moss

References

1. ^ Chapman, R. N., 1925. Animal Ecology with Special Reference to Insects. Burgess Brook Inc.,Minneapolis. 370 pp. See pp.158-161.
2. ^ Chapman, R. N. (1931) Animal Ecology. McGraw-Hill, New York