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Is your local creek healthy? The insect population might have the answer. James Cook University aquatic biologist Niall Connolly, who specialises in stream ecology and biomonitoring, has found invertebrates have plenty to say about the health of waterways in the Wet Tropics.
"Invertebrates can tell us a lot about the levels of nutrients in a waterway, as well as sedimentation and concentrations of dissolved oxygen concentrations," he said.
As part of a team of 12 researchers from James Cook and Griffith Universities' Catchment to Reef study, Mr Connolly has been studying larger invertebrates, such as dragonflies and may flies, along streams in the Russell and Mulgrave catchments.
"All streams in the lowland areas have been impacted to some degree, but community work to maintain and improve the condition of the Little Mulgrave and Behana Creek has paid dividends," he said.
"Both those streams are sustaining high biodiversity alongside productive agriculture. That's given us an opportunity to set up a paired study comparing intact and impacted streams within the same area."
"At 10 to 15 sites along each stream we sampled water quality and collected fish, insect larvae and other creek life," Mr Connolly said. "We also studied and examined the condition of the banks and the overall health of the stream at each site."
"We've been able to get a detailed picture of each stream as it flows through different land-use areas," he said. "By comparing those quite healthy streams with others that are not in such good condition, we've been looking for a range of indicators of stream health.
"My particular focus is on invertebrates: looking at what range of bugs you can expect to find in a healthy stream, and what an absence of some species, or an abundance of others, might indicate about stream health."
Mr Connolly found that invertebrate biodiversity dropped by up to 25% at sites where streamside vegetation had been cleared and replaced by para- grass or Singapore daisy.
"At the same time some invertebrate species had increased in abundance, because of an increase in nutrients and algal growth associated with warmer water and more light."
"Water testing can be expensive and time-consuming," Mr Connolly said. "For landholders and community groups, knowing which invertebrates are indicators for particular conditions in their area can be a quick and cost- effective way of determining whether further testing might be needed."
Mr Connolly will present the findings at the Catchments to Coast conference at the Cairns Convention Centre at 5.50pm on Thursday 13 July.
Catchments to Coast, an international conference of more than 540 marine and wetlands researchers, will continue until Friday.
Editor's Note: Original news release can be found here. ' |
