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(Dr. Carmel Pollino) So within Australia we have a diversity
of inland water ecosystems, rivers, so riverine kind of ecosystems.
And even within rivers we have different types of rivers,
we have perennial rivers, so permanent rivers,
and then we have more ephemeral kind of streams,
and so they also support different types of ecosystems.
From there we have wetlands as well, so we have wetlands
that often sit at the bottom of river systems,
but also wetlands that sit through an actual catchment as well.
And we have a range of floodplains and floodplain
ecosystems, and so when you have a river that floods it
supports a whole lot of water dependent
ecosystems along the breadth of its floodplain.
We also have groundwater ecosystems, and they're probably one of our
least studied type of ecosystems, and so they sit -- we obviously can't see
them there in the groundwater, but they're very isolated
systems and support a very unique biodiversity.
And we have many unique ecosystems that are supported
through Australia, and one of them, the largest kind of
iconic ecosystem is Lake Eyre Basin. So it's an inland draining basin,
it's very much one of those iconic basins in
terms of being a boom and a bust.
So when Lake Eyre floods it's a big... it's a big flood event,
you often have a boom in terms of fish productivity,
a boom in terms of the number of waterbirds that
move to the Lake Eyre Basin. And then after that
period of the boom you have a drying, a bust
kind of period is what we call it, and so during
the bust period you have the drying up to kind of remnant creek areas,
and it's those remnant areas that are
really important for supporting your fish,
and it's about supporting those fish through the dryer times,
through the bust times, to be able to get to that next boom.
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So humans have had a dramatic influence on our inland
water ecosystems and that extends back many years.
An example of that is the Brewarrina fish traps
which are believed to be about 40,000 years old,
and what they are is a series of rock culverts through a river
system, and they were used by the Indigenous people to trap fish,
and obviously eat those fish.
Since the early 20th Century
we've seen a large expanse in terms of water
resource development in Australia, and that has been
particularly in the south east part of Australia.
So irrigated agriculture is very important in terms of
it provides us with food, irrigated agriculture in the
Murray-Darling Basin provides a great proportion of our agriculture in terms
of people being able to use the food that comes from that particular basin.
And so the challenge that we have is how do we start sustainably have our
agricultural systems and meet the diversity of values
that we have, particularly in the Murray-Darling Basin.
So ensuring that we have a healthy working river,
a healthy river in terms of its ecologically able to function,
and also be able to support communities,
and irrigation communities that are now reliant
on the water resources within the basin.
So what we've seen in terms of water resource development
through many parts of Australia, and certainly through the south eastern
parts of Australia, is that it's actually the changes in the flooding
cycles that are starting to affect our ecology on those floodplains,
so our floodplains are retracting,
they're getting smaller in terms of their size,
and associated with that you have a change in your
biodiversity and your flora and your fauna.
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It's through restoration activities that we start
to try and improve our wetlands and restore the
impacts that we've seen through irrigation.
And an example of that is looking at the Paika Lake
wetland system, and that's in the Murrumbidgee,
it's down in the Lowbidgee part of the catchment,
so the lower part of the catchment.
And the Paika Lake system was isolated from
the river system for about a hundred years,
and so through development of irrigation infrastructure,
as well as just development of roads, you saw no connection
of water through to the Paika Lake ecosystem.
And so what has happened in the last few years is environmental
flows have started to be delivered to that ecosystem
and it's a restoration activity that's been undertaken,
and what has been observed is a great boom in terms of
you had a lot of birds move into the area, we've seen fish move into the
area, aquatic plants emerge from the soils,
and it's a very nice little case study where we can start
to see how best to restore our ecosystems
after such a long period of dry.
So with the challenges of climate change and water
resource development there's a real need for the science.
And that science to inform how we can protect our
inland waters and our biodiversity within our
inland waters, but also how to also cater for the various
uses of water within our ecosystems, so we can
do that equitably across our users of the water.
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