A little creek smothered in bulrushes harbours a rare native fish that is consuming much of Phillip Fowler's time.
The conservationist became engrossed in Lang's Creek about 12 years ago, while helping Landcare friends plant trees there. Mr Fowler brought Rockview, a 120-hectare property in 2008, which includes 1.2 kilometres of the creek's head waters.
North-east of Yass, the spring-fed creek flows into Blakney Creek and the Lachlan River, and NSW Fisheries are trying to stock creeks in the area with the endangered pygmy perch, which were found more than a decade ago in small pools during the drought.
Fisheries researcher Luke Pearce says the nine-centimetre perch was once so common throughout the Murray catchment a 1970s fishing book recommended it as live bait for trout.
Now it is found in only three places in NSW, including Blakney Creek, where it is fast losing ground to noxious redfin. In 2007, pygmy perch were in a 25-kilometre section of the creek, in 2009 this was reduced to 15 kilometres, in 2013, 12 kilometres.
"It just astounds me that some people still believe the redfin is a native fish," Mr Pearce said. He said the introduced predator had been found in a section of Lang's Creek.
Further east on the Lachlan River, fat-lamb producer and Landcare stalwart Vince Heffernan says some landholders would not know or care whether fish were in their creeks.
"Those creeks are the last pockets of the vast Murray Darling Basin that are in exceptionally good condition. They have a huge number of aquatic plants in them. In one pond you might find 20 different species of aquatic plants, and that's what gives cover to things like the southern pygmy perch," he said.
Mr Heffernan says a new, merged Landcare group was prioritising the plight of the pygmy perch. In rare places it appeared, other species like turtles, crayfish and waterbirds not seen elsewhere were likely to be living as well.
"It is not about one fish, it is the health of an entire freshwater riparian ecosystem, really," he said.
Mr Fowler believes the absence of trout, carp and redfin has allowed the perch to thrive in his section of Lang's Creek, but is worried about redfin. The Commonwealth Department of Environment biodiversity fund allocated $24,000 to Mr Fowler in 2012 to protect and enhance his patch of the creek.
"If you leave the bush [un-grazed] it will re-revegetate itself," Mr Fowler says. "It has been doing it for at least 100,000 years, and is much better than us re-vegetating.
"Same with the creek, if you take away the grazing animals and erosion, it will do it itself, and that is what is happening," he said. Over time he hopes to cover the bare, eroded patches on the banks, which he reckons have so much acid their pH equivalent would be close to battery acid.
Cassinia and silver wattle are taking hold on the rock-hard banks. Bare gullies have been softened over recent years with dumps of hay to improve the soil.
Mr Fowler's toughest battle is with blackberries, which he has burned and slashed. He will not use chemical spray. "This is 100 per cent organic landcare," he says. Where blackberries have been cut back, pioneer trees like the wattle begin to grow.
"In the long run, the economic benefits will be exponential, just like the biodiversity benefits. We are having little or no creek erosion. For seven years we have been managing the land, the main threat is erosion, sedimentation and pollution," Mr Fowler said.