Student encourages bugs in his system

University of Otago zoology student Gene van der Zanden counts bugs captured from one of the 54...
University of Otago zoology student Gene van der Zanden counts bugs captured from one of the 54 Dunedin gardens being surveyed as part of an urban biodiversity study. Photo by Peter McIntosh.
University of Otago zoology student Gene van der Zanden is spending his days counting bugs, so it is no surprise he finds it hard to get them out of his mind when he gets home.

"I'm not too far off dreaming about insects," he said.

Mr van der Zanden has been employed as a summer research intern to assist three university staff members who are carrying out a detailed survey of the contents of 54 suburban Dunedin gardens.

He has already helped make 250 bug flush traps from gutter down pipes and plastic cups, installed them them at ground level in the chosen gardens, waited for 10 days, then collected up the unfortunate invertebrates which have walked into the traps and met a watery death.

Now he is painstakingly counting the different types of bugs, a process which can take up to six hours for each garden.

As expected, the most common bugs trapped were spiders, beetles, flies, wasps, moths, snails, centipedes and millipedes, he said.

Traps were set in different parts of the gardens, such as on lawns and beneath trees or bushes, and already trends were emerging.

"I am already seeing the lawn species tend to be spiders and flies and ants, whereas in traps under a covered area there may be more beetles and some weta."

The most unusual specimen collected was a large, furry spider with orange stripes on its back commonly known as an Andersons Bay spider.

Mr van der Zanden, who has a bachelor of science degree majoring in zoology and minoring in psychology, said he had heard about Andersons Bay spiders but had never seen one and was not sure they actually existed until one turned up in a trap.

"They are certainly a lot bigger than most of the spiders in Dunedin gardens, that's for sure."

The "coolest" part of the internship for Hamilton-born Mr van der Zanden was visiting gardens all over Dunedin, he said.

". . . I've travelled through suburbs I've never been to before, from Northeast Valley to Musselburgh to Brockville.

"And the gardens have been so different.

"One was [outside] a pensioner flat in St Kilda and another was the massive garden of an architecturally designed house in Maori Hill which had a river running through it, and gigantic trees.

"In that garden you can't believe you are in the middle of the city."

The garden study is a collaboration between Assoc Prof Claire Freeman (geography), Prof Kath Dickinson (botany) and Dr Yolanda van Heezik (zoology).

The aim was to understand not just what was in people's gardens, but to try to find out how people related to their gardens, Dr van Heezik said.

"The single largest green space in any city is gardens, not reserves and parks.

"So people's gardens are potentially a big biodiversity resource, and a resource which has largely been neglected."

The study began at the start of this year and already, vegetation had been identified and bird songs and skink numbers counted, she said.

Data collection should be finished by April and it would be another year before the study results were collated, she said.

The results would be published and shared with any community groups which wanted them.

Dr van Heezik said she hoped the survey would lead to more understanding about the need to maintain suburban garden space in cities.

"The way new housing subdivisions are designed is not very friendly towards biodiversity.

"Even if section sizes stay the same houses tend to be bigger, and it has been shown in parts of Australia, for example, that the size of people's gardens is getting smaller and smaller."

Even if people did not want a high maintenance garden, they could plant natives, she said.

"You could plant your whole section out in native species and put wood chips underneath and you would be doing native biodiversity a big favour," Dr van Heezik said.



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