Opening Remarks by Session Chairman
These papers are inevitably concerned with many habitats and organisms. But there are common threads. One general conclusion is that to restore ecosystems we need to understand the steps in the process by which they become degraded. Many of these are mentioned in Part II as well as Part III; they include soil nutrient depletion, the destruction of vegetation by fire and the pollution of aquatic systems. It is not, however, a clear-cut picture. Atmospheric pollution, for example, may supply nitrogen or sulphur as well as cause damage. The interactions are vitally important.