Gecko numbers under scrutiny
A $20,000 monitoring programme will be set up by the Auckland Regional Council to assess native gecko populations in the Waitakere Ranges and across the greater isthmus.
Council's natural heritage scientist Matt Baber says exact numbers relating to the endemic lizard are not known.
The project will look specifically at the green and forest gecko species and try to explain why there are higher concentrations in some forests than others.
"We found about 27 geckos in three hours on Waiheke Island, which is absolutely unprecedented and it's three times higher than the abundance normally found," Mr Baber says.
"But overall the gecko is threatened and on a gradual decline.
"If we find out how many there we can manage them better. And we have strong evidence that these geckos recover well when you take predators out of their environment," Mr Baber says.
One of the areas to be monitored will be the Ark in the Park wildlife sanctuary in the Waitakere Ranges.
Mr Baber says two of the geckos' main threats – rats and wasps – are a problem out west.
"The ship rat can climb right up into the branches and eat them and wasps can take out a lot of their food sources like stick insects and wetas – they also eat baby geckos."
Mr Baber says geckos can benefit the general health of the forest.
"They have an important function in the eco-system by keeping numbers of invertebrates in check and they also help pollinate some plants as well as carrying seeds.
"They would have had quite a major role in the environment and so it's important to have these populations recovering."
One possible outcome of the monitoring programme and pest control is the return of some almost extinct species of gecko to the ranges.
"New Zealand has one of the most unique and diverse collection of reptiles in the world," Mr Baber says.
"And we have seen rare species like the Pacific gecko start to come back in other parts of country when predators are eradicated."
The regional council programme is expected to cost between $18,000 and $20,000 to set up and between $5000 and $10,000 to keep running each year.