Anthropogenic stressors

Natural disturbance patterns can be very important when evaluating the likelihood of recovery from anthropogenic stressors. Ecosystems that have been subjected to repeated natural disturbances may be more vulnerable to anthropogenic stressors (e.g., overfishing). Alternatively, if an ecosystem has become adapted to a disturbance pattern, it may be affected when the disturbance is removed (fire-maintained grasslands). The lack of natural analogues makes it difficult to predict recovery from novel anthropogenic stressors such as exposure to synthetic chemicals. 

Walker, H.A., Latimer, J.S., and Dettmann, E.H. (2000) Assessing the effects of natural and anthropogenic stressors in the Potomac estuary implications for long-term monitoring. Environ. Monit. Assess. 63, 237-251. 

Perhaps the most recent development is the awareness that effects and risks must be seen on a regional scale. Multiple natural and anthropogenic stressors occur to a variety of connected habitats. In order to understand the patterns in the environment that result from the introduction of chemicals, we must take a larger scale approach. 

Van Son TC, Thiel M (2007) Anthropogenic stressors and their effects on the behavior of aquatic crustaceans. In Duffy JE, Thiel M (eds) Evolutionary ecology of social and sexual systems Crustaceans as model organisms. Oxford University Press, New York, pp 413-441... 

Environmental stress is just one of many potential causes for reduction of standing variation within a population and genetic diversity measures based on RAPD-PCR are unlikely to be able to distinguish between naturally occuring and anthropogenic stressors. In addition, a reduction of genetic diversity is not necessarily the only selective response to anthropogenic stressors. 

Nonethele.sensitive measure of population health in at least four different species to detect significant differences in genetic diversity between sites affected by common anthropogenic stressors and very similar but unaffected reference sites. As such, RAPD-PCR based measures of a population s genetic diversity have the potential to be the basis of a valuable alternative or augmentation to conventional assessments of environmental insults. 

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