ABSTRACT
CONTENTS Introduction ............................................................................................................................................ 467 Terminology and Definitions ................................................................................................................. 468 Conceptual Models ................................................................................................................................ 469 Examples of Indicators .......................................................................................................................... 471
Water and Sediment Quality Indicators....................................................................................... 471 Single-Species (Population-Level) Indicators.............................................................................. 472 Community Indicators.................................................................................................................. 472 Ecosystem Indicators.................................................................................................................... 473
Discussion .............................................................................................................................................. 475 Conclusions ............................................................................................................................................ 478 Acknowledgments.................................................................................................................................. 478 References .............................................................................................................................................. 478
Why do we need indicators of ecosystem integrity for estuaries, what are they, and how would one or more of these indicators inform and contribute to management of these diverse, complex systems? The importance of estuaries was expressed nicely by Welsh (1984, p. xiii): “Estuaries … are one of the most heavily utilized and most productive zones in our planet. Their integrative processes … weave a web of complexity far out of proportion to their occupation of less than 1% of the planet’s surface.” Citizens groups, environmental managers, and elected officials want to know the status of estuarine ecosystems, locally, regionally, nationally, and globally. Especially where there have been large public investments in pollution controls and other preventive and restorative measures, people want to know if their money has been well spent (Jordan and Vaas, 2000). Thus, there is a clear need for indicators that will provide comprehensive answers to these questions at appropriate intervals. Murawski (2000, p. 655) recommended “simple, robust indices of ecosystem state that gauge … production, diversity, and variability,” and emphasized that indicators should have the capacity to predict the results of management. Although Murawski was writing in the context of fisheries and fisheries management, these principles apply more broadly to the integrity of ecosystems in general.
