The Response of Ecosystems to Exploitation

Abstract

In the previous chapters we have seen that an ecosystem is built of a number of components, each component being linked to at least one other by a transfer of energy or nutrients. In modelling the ecosystem we were concerned with the equilibrium or steady state, a state that exists when the output from every compartment exactly balances the input. This is an idealized situation, since in nature the random influences, such as weather, will be continually modifying this equilibrium. However, more drastic disturbances may result from the management practices to which the ecosystem is subjected. Some link in the system may be broken, and one wishes to know what effect this will have on the whole ecosystem and in particular on one or two of the species in the ecosystem. Such a broken link may result from the removal of the top carnivore since this animal may be dangerous not only to the other animal species but also to man himself. How do the populations of herbivores respond in this new situation? A lirik may not be completely broken. It is possible to exploit a population heavily without exterminating it completely. What are the characteristics of such a population so that we can recognize the symptoms and carry out prophylactic treatment before the species is added to The Red Book of animals threatened with extinction?

The erratum of this chapter is available at http://dx.doi.org/10.1007/978-1-4899-3410-9_12