“Natural” or “Healthy” Ecosystems: Are U.S. National Parks Providing Them?

Abstract

Ecosystem ecologists are now generally agreed on the desirability of having areas of natural biota minimally disturbed by technological societies to serve as reference points for understanding the structure and function of ecological systems. Systems of course exist along a continuum from little or no human disturbance to complete anthropogenic alteration (cf. McDonnell et al. Chapter 15 this volume). An in-depth understanding of how they respond to different intensities of human perturbation what constitutes ecosystem sustainability and how profoundly altered systems can be restored is facilitated by a knowledge of structure and function along the entire continuum.