Flood or drought, the unique ecology of Innamincka Regional Reserve survives


Updated

September 08, 2018 13:19:09

When it rains, the Innamincka Regional Reserve is a hive of activity, with tourists flocking to see the water source and animals nesting and living with abundant sources of food and water.

But when the good times end, and the water subsides, the many animals that call this region home have adapted in a unique way to survive even the harshest droughts.

The Reserve is in South Australia’s far north-east corner, 1,000 kilometres from both Adelaide and Brisbane.

Julian Reid is an ecologist with the Australian National University and has been researching the Reserve for almost 40 years.

Dr Reid said many animal species lived along the creek full-time, but others only visited during periods of floods — including pelicans.

“Lake Goyder, which is the biggest of the Coongie Lakes, has a series of islands along the northern margin,” Dr Reid said.

“Under the very big flood conditions, I’ve seen a colony of up to about 50,000 Australian pelicans breeding there.

“The pelicans have flown in from all over the coastline of Australia to form this massive breeding colony and, of course, they’re feeding on fish.”

Dr Reid said it was not yet known how pelicans became aware of the significant flood event so far from the coast.

How do fish survive a drought?

The Coongie Lakes are a series of fresh water lakes that sit along the northern edge of Cooper Creek, about 100 kilometres north of the Innamincka township.

Dr Reid said these fish had evolved to allow them to survive, even through the harshest of droughts.

There are a few permanent water holes in the Coongie Lakes and Cooper Creek system.

“The deepest is Cullyamurra waterhole on the Cooper Creek, just upstream of Innamincka,” Dr Reid said.

“Even though the birds can fly out when things start to dry out, the aquatic animals, like the turtles, the fish, they have to retreat back to those few permanent waterholes.

“Those few deep, permanent water holes are absolutely critical to the persistence of all that aquatic richness.”

Dr Reid said the waterholes protect the species during drought and allowed them to have population explosions during the next flood event.

Unique and colourful bird species

During periods of abundance, many parrot and finch species can be found at the Innamincka Regional Reserve, including some that are unique to the region.

“There is a distinct sub-species of red-rumped parrot — a pale coloured form — that occurs in that Innamincka region,” Dr Reid said.

“Because they have evolved into this distinctively paler population, then they must have gotten in there some time ago — long before humans — and adapted.

“They have a limited ability to fly around, they don’t rocket around the country like those water birds.”

Dr Reid said the permanent waterholes allowed the red-rumped parrot to survive in the region during drought times.

Other bird species, including fairy wrens and tree martins also live in the region.

Tree martins nest in small hollows in river red gum and coolabah trees.

Dr Reid said only the “wisest” sedentary birds would be able to survive the drought periods and take advantage of sporadic localised thunderstorms.

Moisture from their prey

Being north of the dog fence, the Innamincka Regional Reserve is home to dingoes, one of Australia’s only native predators.

But Dr Reid said even they would feel the pinch during periods of extended drought.

“They’d like to drink regularly — most days if they can,” he said.

“Being a highly structurally societal animal, the prized territories would be those permanent waterholes.

Much like introduced animals like cats, Dr Reid said the dingo likely could get enough moisture from its prey to sustain it through drought.

“And they have all sorts of behavioural mechanisms like sheltering in their den, keeping out of the sun during the day and restricting their activities to night,” he said.

The impact of pastoralism

Pastoralism has been ongoing in the Innamincka Regional Reserve for more than 130 years.

In fact, the Reserve is open to several industries, including pastoralism and mining.

However, despite that, Dr Reid said we still don’t know if the native animals had been affected by industry.

“There have been very few large enough studies done to examine critically the impacts of pastoralism,” Dr Reid said.

However, he said compared with other farming practices, pastoralism had a much smaller effect on the natural environment.

“Any farming which involves the clearance of landscapes, the destruction of all the native vegetation, the impacts of that are well documented and they are very severe,” he said.

“The impacts of pastoralism are far less severe because the native vegetation is not cleared.

“A good land manager can recognise when [cattle are] starting to affect the perennial vegetation and that’s when the cattle should be sold off or sent down south.”

Topics:

animals,

animals-and-nature,

ecology,

regional,

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port-augusta-5700,

port-pirie-5540,

adelaide-5000,

brisbane-4000,

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First posted

September 08, 2018 13:10:58



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