Follow the TREND

24 10 2011

A little clichéd, I know, but that’s what it says on the T-shirt.

It’s been an interesting week. Not only did I return to some much-needed field work (even if it was diving in the muck of Adelaide’s Outer Harbour with 40-cm visability), but it was also the week when the TREND project became ‘official’ with the launching of its website and its public début at the Earth Station festival in Belair National Park over the weekend.

I can see the thought bubbles already – what the hell is ‘TREND‘ (apart from the obvious)?

Admittedly a somewhat contrived acronym, TREND stands for TRends in ENvironmental monitoring and Decision making – a multi-million dollar project financed mainly by the state government of South Australia and the Terrestrial Ecosystem Research Network (TERN – I know, another bloody acronym that is weirdly similar to TREND; oh how we Aussies love our acronyms and initialisms!). Here’s the official summary:

“TREND provides a system of data collection across native ecosystems, primary production regions and marine environments. By assessing the impacts of various potential climatic and environmental shifts, TREND will provide an early warning system for changes in South Australia’s diverse environments and a lasting legacy of long-term monitoring, informed policy and proactive response to environmental change.

The TREND program focuses on transects of bushland, farmland and marine environments in South Australia, which follow specific environmental gradients. These overlapping transects range from the relatively high rainfall region of the southern Mt Lofty Ranges to the hotter and drier northern Flinders Ranges, some sites across the Eyre Peninsula, and marine sites within the Spencer Gulf and the Gulf of St Vincent (see transect map). Within the transects, species are being monitored in terms of their distribution, structure, life-cycle, overall health, appearance and genetic variation.”

Ok, still too generic? Well, I can mostly speak from the ‘marine transects‘ side of TREND (and yes, that’s me in the photo), which we’ve been setting up for about a year now. Together with Dr. Jason Tanner of SARDI, we’ve been establishing settlement and translocation plots at various sites along Gulf St Vincent to examine the effects of rising temperature and salinity on the sessile invertebrate fauna associated with solid substrata.

In this case, jetty pylons are a wonderful experimental set-up because we have identical, replicate vertical structures on which we can examine how invertebrates colonise under different temperature and salinity regimes, and how well local invertebrate communities are adapted to local conditions using translocation experiments.

The reason that South Australian gulfs (St Vincent and Spencer) are so ideally poised for this sort of thing is the amazing  environmental gradients that develop there each summer, such that we can use a ‘space-for-time’ approach to predict the effects of climate change (i.e., assuming sites in the south will eventually come to resemble sites in the north as things warm up). These gulfs are known as inverse estuaries because they have a temperature and salinity gradient opposite to typical estuaries with freshwater inflow. The temperature and salt budgets within the gulfs are instead dominated by evaporation, such that temperatures can vary by as much as 15 deg C along their north-south gradients in late summer and early winter, and salinities range from > 48 practical salinity units (psu) near the head to ~35-38 psu near the mouth (about a distance of 300 km in Spencer Gulf and 140 km in Gulf St Vincent).

Basically, TREND is a landscape-scale experiment of almost untold control over a concentrated environmental gradient that exists practically nowhere else on the planet. And we’re pretty excited about the prospects.

So far on the marine side we have done all the clearance quadrats at 3 different depths for 5 sites in Gulf St Vincent, and we’re just starting the translocation trials. We’ve also deployed salinity and temperature loggers at all sites. We haven’t yet really analysed any of the collected specimen or the photo-point data, but we should start seeing results emerge this autumn.

It’s a big ask, but a lot of fun (and work) setting up (in fact, we’re heading out for a dive at Rapid Bay tomorrow). I have high hopes for our ability to develop some pretty cool predictive models for what the gulfs might look like in terms of basic community shifts over the next 50 to 100 years.

Oh, and let’s not forget the terrestrial side of things – I’m sure we’ll have some equally cool results from those transects soon too. Stay tuned, and follow progress on the TREND website.

CJA Bradshaw



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