Pollution-induced community tolerance

Pollution-Induced Community Tolerance (PICT) is an approach to measuring the response of pollution–induced selective pressures on a community. It is an eco-toxicological tool that approaches community to pollution from a holistic stand point. Community Tolerance can increase in one of three ways: physical adaptations or phenotypic plasticity, selection of favorable genotypes, and the replacement of sensitive species by tolerant species in a community.

PICT differs from the Population Tolerance Approach to Community Tolerance in that it can be easily applied to any ecosystem and it is not critical to use a representative test organism, as with the Population Tolerance Approach.

Community tolerance can be used as indicator for determining if a toxicant has a disturbance on an exposed community for multiple types of organisms. Tolerance of a toxicant can increase by three ways; physiological adaptation also known as the phenotypic plasticity of an individual, tolerant genotypes selected within a population over time, and the replacement of species with more tolerant ones within a community. Physiological adaptation, or phenotypic plasticity, is the ability of an individual organism to change its phenotype in response to changes in the environment. This can occur with huge variance between the type of organism and the type of the disturbance they experience. Natural selection that occurs over several generations causes an entire population to exhibit specific selection of genotypes. Overtime, tolerant genotypes can be selected over non tolerant ones and can cause a shift in a population’s genome. Natural selection can also cause a replacement of less tolerant species with more tolerant species. All of these aspects can alter a communities’ structure drastically and if a toxicant can be identified as the culprit, action can take place to prevent that toxicant from further accumulating . PICT can be used for linkage between cause and effect of the toxicants due to the structure of a community that has survived the event also known as toxicant-induced succession (TIS). Toxicant-Induced succession would be the development of more tolerant generations once a chemical was introduced into the environment.

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