What is ecosystem health?
We define ecosystem health in terms of measurable characteristics (Rapport et al., 1998, Dennison and Abal, 1999). Healthy freshwater and estuarine/marine ecosystems have the following attributes:
Freshwater | Estuarine/Marine |
- Vigour (the activity or rate of processes, e.g. slow/steady primary production)
- Organisation (healthy ecosystems have a complex structure, e.g. high biodiversity, complex food webs)
- Resilience (a system's capacity to maintain structure and function in the presence of stress; healthy ecosystems can recover after a disturbance, e.g. following a flood event)
| - Key processes operate to maintain stable and sustainable ecosystems (e.g. there is an absence of blue-green algal blooms)
- Zones of human impacts do not expand or deteriorate (e.g. a reduction in the spatial extent of sewage nitrogen)
- Critical habitats remain intact (e.g. seagrass meadows)
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Species and habitats associated with healthy ecosystems in South East Queensland
(1) Mary River Cod, (2) Healthy riparian cover, (3) Healthy seagrass beds with diverse fauna and (4) A healthy turtle.
Examples of animals and occurrences that typify poor ecosystem health in South East Queensland
(5) Gambusia, an alien (introduced) fish, (6) Poor riparian cover, (7) Unhealthy seagrass beds with Lyngbya majuscula and (8) Turtle infected with fibropapilloma.
Photos courtesy of: (1) Gunther Schmida (2 + 8) Environmental Protection Agency (3,4 +7) Chris Roelfsema, Marine Botany, UQ (5) DPI fisheries (6) Healthy Waterways Library
References:
Dennison, W.C. and Abal, E.G. (1999). Moreton Bay Study: a scientific basis for the Healthy Waterways Campaign. SEQRWQMS, Brisbane.
Rapport, D.J., Costanza, R. and McMichael, A.J. (1998). Assessing ecosystem health. Trends in Ecology and Evolution 13:397-402.