James' work epitomises the valuable insights creativity provides in science. Managers often rely on simplistic environmental parameters and indices for their decisions. James' work reminds us that by looking at higher order functions we can more directly assess the resources that we truly value and thereby gain a greater systemic understanding with real-world benefits.
Benthic Science Student Prize for Thinking outside the square: Creativity in Science in recognition of a presentation which exemplifies good science inspired, conducted, or presented with exceptional creativity.
Scavenging pressure: a measurable ecosystem service correlated with estuarine health
Webley, James * and Connolly, Rod
Australian Rivers Institute – Coasts and Estuaries, Griffith University, Gold Coast, QLD 9726
Ecosystem management strategies should aim to preserve the following characteristics of healthy ecosystems: resistance, organisation and vigour. Monitoring these characteristics is logistically difficult as they apply to the whole ecosystem. Therefore, a suite of easily measured abiotic indicators is often used as a surrogate of ecosystem health. The health of estuaries in southeast Queensland is measured using a long-term Ecosystem Health Index (EHI) generated from a suite of surrogate indicators.
Scavenging of carrion is an important biotic ecosystem process and a component of vigour. Scavenging tends to recycle nutrition within higher trophic groups, rather than allowing nutrients to fall to the decomposers. The scavenging rate is likely to be higher in healthy estuaries because of the intense competition and large abundance and diversity of organisms present. We predicted that the scavenging rate would be greater in estuaries with a “healthier” EHI. Contrary to our hypothesis, the scavenging rate was lower in estuaries with “healthier” EHI scores (r2 = 0.70, P < 0.005).
The EHI is essentially an index of water quality. Although water quality is important, it is only one driver of estuarine health. There are other drivers, such as fishing and invasive species, which may not directly relate to water quality. Fishing pressure may explain the reduction in scavenging rate within “healthier” rivers. Measuring water quality is wise but, because we do not completely understand estuarine health, we need to gauge management actions against our best measure of estuarine health. We can improve our measurement of estuarine health by including direct measures of higher order ecosystem processes.
