Optimal Assault On NZ's Environmental Pests

Media Statement
2 May 2005

Research will enable optimal assault on New Zealand's environmental pests

Three research projects that seek to gain a broader understanding of the distribution of and interactions between pests that threaten New Zealand's endangered flora and fauna will receive investment of $2.5M p.a. from the Foundation for Research, Science and Technology.

The successful project bids put forward by Landcare Research move radically away from looking at single pests, such as rats and stoats, in isolation. Instead, researchers seek to gain an ecosystem-level understanding of the consequences of pest control and develop models for predicting the number and type of pests in New Zealand's diverse ecosystems. This will allow better targeting of pest control by conservation managers.

The first project, called "Multiple pest dynamics", seeks to understand how different mammalian pests interact. For example, does reducing stoat numbers to protect birds simply allow a boom in rat numbers, which then go on to prey on birds?

The project will study interactions of possums, ship rats and stoats with large-scale pest removal in both mixed forest and dryland environments.

"Our research will identify when, where and what combination of pest species need to be controlled for greatest conservation benefit," says Landcare Research Science Manager, Biosecurity and Pest Management, Dr Phil Cowan. The second project will further optimise pest control efforts by developing cutting-edge modelling techniques.

Dr Cowan says a map of population density will be invaluable for pest control work but mapping population density is not a well-developed art, especially for difficult to see, mobile, nocturnal species such as rats, possums and stoats. "Producing spot estimates of local population density has challenged wildlife statisticians for nearly 70 years. We think we have a solution that we want to develop further."

In addition to population density, the research team will develop tools for obtaining critical data on pest movements, and show how these findings can be integrated with spatial information on vulnerable species to predict the optimum placement of pest control effort.

The third project, which is subject to final negotiation, focuses on weeds, recognising the significant and increasing threat they pose to New Zealand's natural and primary production ecosystems. "Beating weeds will use a combination of modelling and improved weed control methods to enable weed management to combat the serious environmental impacts of existing and new weed invaders," Dr Cowan says.

ENDS

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