Limiting Factor

Condition and Resources

Condition is Physicochemical features of the environment that may be altered by the activities of living organisms, but not consumed.  The example of conditions are temperature, relative humidity, pH, salinity, current velocity, soil structure and pollutant concentration.

While resource is quantities of something that can reduced by the activities of a living organism during its growth and development. The example of resources  are solar radiation, inorganic materials - CO₂, water, oxygen, mineral nutrients (macro-, micronutrients), food, and space.

There are some effect of condition. They are:
1.      For each species, there is some level/concentration/intensity of a factor at which it does best - its optimum for that factor.
2.      Optimum conditions result in individuals with the highest fitness.
3.      Higher or lower levels of a factor result in reduced fitness or non-survival

The principle of limiting factors can be illustrated by reference to the productivity of phytoplankton in lakes, that is, the community of unicellular algae that live in the water column. In most freshwater lakes algal productivity is limited by the availability of inorganic phosphorus in the form of the ion phosphate. When experimentally fertilized with phosphate, most lake waters will respond by a large increase in productivity. (This will also happen if the lake receives phosphate through sewage inputs or agricultural runoff). In contrast, if the lake water is fertilized with other important nutrients such as nitrate, ammonium, potassium, or inorganic carbon, there will be no increase in productivity, indicating that these are not primary limiting nutrients. However, if the lake water is first well fertilized with phosphate, its productivity will then respond to nitrate addition, indicating that this source of inorganic nitrogen is the secondary limiting factor.