Carrying capacity (K).

 

Unit – 5 Management and Planning of Habitat

Carrying capacity (K).

 

“carrying capacity is the maximum number of individuals of a given species that an area's resources can sustain indefinitely without significantly depleting or degrading those resources.”

 

The carrying capacity for any given area is not fixed. It can be altered by improved technology, but mostly it is changed for the worse by pressures which accompany a population increase. As the environment is degraded, carrying capacity actually shrinks, leaving the environment no longer able to support even the number of people who could formerly have lived in the area on a sustainable basis. No population can live beyond the environment's carrying capacity for very long.

 

“Carrying capacity is a numbers of animals supported by some unit of area.

In population ecology terms, it is "the density of organisms (i. e., the number per unit area) at which the net reproductive rate (R ) equals unity and the intrinsic rate of increase (r) is zero"

 

Estimation of carrying capacity:

 

Carrying Capacity (K) = the largest population that can be maintained for an indefinite period of time in a particular environment

Carrying capacity changes with changes in the environment, either natural or artificial Droughts, pollution, excess rainfall, etc.

ECONOMIC CARRYING CAPACITY

Economic carrying capacity is defined by management goals for population productivity, animal quality and habitat conditions but is determined by a habitat’s variable and limited ability to sustain achievement of these goals. Economic carrying capacities defined by management goals for population productivity and for population control are termed maximum harvest density and minimum impact density.

Maximum harvest density -

The concept is usually applicable to ungulates. It is the number of animals that a habitat will support while producing a maximum sustained harvestable surplus. In terms of the sigmoid model, the population is at or somewhat above the inflection point. The population must be maintained at this level of abundance by harvest. Therefore no lack of welfare factors prohibit the growth of a population

Impact on wildlife populations & its habitat

At maximum harvest density, population quality will be very good though not probably the very best possible. 2. Populations at MHD characteristically exhibit a young age structure and high rate of turnover 3. Habitat condition will also be good though not without signs of use and perhaps retrogressed vegetation

Minimum impact density

Minimum impact density as a goal for wildlife management aims to reduce the impact of wild animals on those of desirable target species. It may be desirable to maintain a population at MID of carrying capacity if - The population is considered to be a pest species, one not to be eliminated but to be controlled - The predator population depresses the production of livestock or desirable wildlife species

 

 

 

Carrying capacity (K in the Verhulst Pearl logistic population growth equation) may be estimated empirically with regression techniques described by Watt (1968) and Poole (1974). These regression techniques require that population densities be recorded for various stages of population growth. The technique is based on observed population densities, thus it does not provide the ability to predict future changes in carrying capacity. For that latter reason, and others discussed in 101 ESM 3, population estimation is not a viable technique for impact assessment purposes. Another technique for estimating carrying capacity is the traditional resource inventory. With this technique, carrying capacity is estimated.

based on how well the habitat will meet the known physiological and behavioral needs of a species. Ecologists working with ungulates have historical ly based carrying capacity estimates on caloric and nutritional values of foods provided by the habitat.

Examples of the data and calculations required are described by Moen (1973) and Mautz (1978). Others , including avian ecologists, have considered structural aspects of the habitat as important determinants of carrying capacity (Elton and Mi l ler 1953). Carrying capacity estimates based on the resource inventory   approach will nearly always be estimates of "potential , Il because the limiting effects of other species (competitors and predators) are difficult to explicitly include in the calculations.