Conference 2003

Conference 2003
Greening the City:
Bringing Biodiversity Back
into the Urban Environment


Do Weeds Benefit Native Wildlife in Urban Areas?

Margaret Stanley (Landcare Research, Auckland)

Conflicts can arise where weed control targets an alien plant that provides a resource for one or more native species, particularly where the weed is beneficial to a charismatic vertebrate.

The use of weeds as sources of food and habitat by native wildlife is becoming common in many countries, due to clearance of native vegetation and/or its replacement by invasive weeds.

There have been public concerns in New Zealand, particularly in urban areas, that weed control could leave native fauna without essential resources. However, in most cases, alien plants are not essential resources, and use of weeds by native species is the result of availability or preference rather than dependence.

Research has also demonstrated the inferior quality of resources provided by invasive weeds in comparison to native plants. Weed exploitation by native species may have a number of 'ripple' effects on ecosystems:

  • Increase the spread of weeds in natural areas through fruit consumption and seed dispersal;
  • Native species may no longer fulfil their function as pollinators and dispersers of native plant species;
  • Extra resources could result in unnaturally high population numbers which could in turn result in detrimental economic and ecological consequences.

If, however, there is a risk that weed control could have a negative impact on a threatened or ecologically important species using the weed, management strategies could be put in place to ensure that alternative resources are available when the weed is controlled. Emphasis must be placed on retaining overall biodiversity in urban areas, rather than focusing on the conservation of single vertebrate species.

Conference sponsored by:

British Council NZ
The Community Trust
Landcare Research

Follow this link to view other organisations supportive of the conference

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Last updated: October 12, 2003