Date: Thursday, October 9, 2014
笔谤辞箩别肠迟:听Eastern Australian Waterbird Survey
Observer: Richard Kingsford
Backpacker central, relieving see breezes and screeching beach stone curlews seemed an age away as we headed west over the Great Dividing Range, heading for Mt Isa. This was Band 10, our most northerly survey band. A rolled map on my knees showed every wetland or river in a 30km wide survey band from the coast to the Northern Territory border. We zig zagged from wetland to wetland, heading across the survey band.
First on the list of survey wetlands was Peter Faust Dam, west of Proserpine, built in 1990 and with about a Sydney Harbour鈥檚 volume of water. It had hundreds of Eurasian Coot and Hardhead and a flock of over a thousand cormorants so bunched they looked like a fish school. This is the way they feed, harvesting fish like some super organism. Then we flew over the Clarke Range of the Great Dividing Range, near Collinsville, today cloaked in a smoke haze, the like of which none of us had seen in thirty years. Almost as soon as we hit it, we were out of it and into the dry country. It was parched this year; the scattered bone dry small farm dams told a grim story, a dependable barometer of the season. Our waterbird surveys similarly track such ups and downs - the booms and busts.
Photo 1. Small farm dams have dried right back, the rare places for livestock and a few waterbirds
The land is dissected by the big rivers: the Bowen and the Burdekin. Rocky beds jutted out of sand and water and melaleucas in the bed of the river were bent backwards by the force of past floods. Here there were white-faced herons, cormorants, egrets and jabirus standing elegantly on the river bank. 鈥淲ho will be the first one to see a croc?鈥, pilot Richard chipped in. In about the last 10 years, we regularly see estuarine crocodiles in the Burdekin River, a pattern reflected across northern Australia after widespread hunting was stopped. Almost when we were out of the 鈥榮weet zone鈥, I spotted a 3m individual floating lazily in the water.
聽from Centre for Ecosystem Science.
Up the Burdekin and over the dam wall of the Burdekin Falls Dam also known as Lake Dalrymple. This expansive body of water of more than 22,000 ha, stretches in every direction, holding nearly four Sydney Harbour鈥檚 worth of water. My old rolled up map doesn鈥檛 show the dam which was built in 1987, four years after our aerial survey began. Its water supplies Townsville and irrigates cotton, sugar among other crops. 聽Large dams like this are not good waterbird habitat: poor diversity and low numbers. Cormorants and pelicans do well on the fish but many of the other waterbirds such as the ducks and wading birds are seldom seen.
Photo 2. Lake Dalrymple or Burdekin Falls Dam dominates the Burdekin River, storing four Sydney Harbour's in volume of water. Pelicans and comorants are in reasonable numbers but few other waterbirds.
We headed west over the rugged White Mountains of the Great Dividing Range. The plane bobbed and lightly bounced along as we head west, similar to the turbulence you get in a jet coming going through the clouds. It鈥檚 constant for us and no place for the queasy. Lunch at Hughenden 鈥 home of Muttaburrasaurus fossil, the seven metre four tonne giant dinosaur.
Photo 3. The rugged White Mountains form a barrier to rivers which either flow west or east of the Great Dividing Range.
Getting back into the plane wasn鈥檛 inviting as the 340C heat had baked the inside over lunch so it felt like a sauna. Our black earphones were hot from the sun. About fifty kilometres west, green irrigated paddocks contrasted the drab brown landscape, alongside the Flinders River, which flows west then north into the Gulf of Carpentaria. These northern rivers are the new frontier for water resource development 鈥 an illusory drive to make the desert bloom. Here on the Flinders, attempts continue to develop irrigation, with the building of large storage to be filled when the floods come. Further west 鈥 cotton fields were prepared but an empty storage illustrated the challenges of water reliability in this unpredictable continent. The consequences of developing these gulf rivers, like those of the Murray-Darling, will be predictable and devastating for the environment and the cattle industry that depend on the floods.聽聽
Photo 4. Irrigation is the reasonably new agricultural enterprise in the Flinders River catchment. Here a dry off river storage shows the challenges of a predictable water supply for irrigated agriculture.
Dry river beds, like crazy paving, thread their way across the terrain, only interrupted by lonely homesteads. Waterbirds are few and far between, occasionally along the few waterholes and bore drains that thread their way across this arid landscape.
Photo 5. Dry sandy river beds criss cross this landscape, running during the wet season when the monsoons bring water to the catchment
The survey day ends in a moderate counting frenzy at Lake Moondara, a dam which supplies water to the residents of Mt Isa, just to the south. Unlike dams on the Great Dividing Range, the shallow water areas and finger-like protrusions of the dam to the west have created an incredibly productive wetland for waterbirds. The water is clear and thick with aquatic plants, creating lots of food for herbivorous waterbirds but also the many invertebrates which are also food for many ducks and fish. This year the wetland was disappointing in terms of waterbirds. I had expected vast numbers, usually in the tens of thousands, given the dryness of surrounding areas. But the lake was less than half full and the numbers of waterbirds which are usually in the tens of thousands, numbered only a few thousand.
Photo 6. Lake Moondara, Mt Isa's water supply is usually a great place for waterbirds but not this year. Low lake levels and a series of dry years have probably contributed.
Map of flight path for Thursday the 9th of October