Weed management policy

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1.4 Definitions

1.4.1 What is a weed?

A fundamental decision for this policy is clearly defining 'what is a weed?'. Auckland City's management of parks, roadsides and other public open space is determined by a number of statutes, including the Local Government Act, Reserves Act, Biosecurity Act, Resource Management Act, Health and Safety in Employment Act, and policies, plans, by-laws and rules that are derived from this legislation. A definition of a weed in this context must be inclusive of these requirements.

The Biosecurity Act is the predominant legislation governing the control of weeds in New Zealand. It refers to plant pests (weeds) as:

"organisms that are capable of causing at some time a serious adverse and unintended effect on people and/or the natural environment."

The Reserves Act applies to the management of parks and reserves and in meeting its requirements weed control is important. However, this is implied only and no definition of weeds is contained in the Act. It is clear that native plants cannot be considered weeds when growing in their natural habitats and the Reserves Act implies protection for them. Dr Nigel Clunie, a weed ecologist/management consultant, has prepared a weed management strategy for the Auckland Conservancy of the Department of Conservation (DoC) and has defined weeds in the context of DoC's management of land under the Reserves Act and other legislation (Conservation and Wildlife Acts). Clunie (1995) defines weeds as plants:

"that impinge on humans and their endeavours and environment in a harmful way"

and he refers to a definition of environmental weeds by Timmins and Williams (1987) that states:

"An introduced plant which can cause permanent or long term damage to the biota, structure or ecological processes of ecological communities."

The Auckland City Western Area Sports Parks Maintenance Contract (July 1996) defines weeds as:

"any plant not protected in the District Plan which in the Engineer's (Parks Officer) opinion is undesirable or growing in the wrong place."

This definition provides no clear outcomes for weed control and it is recommended that the definition of weeds for the purpose of weed management in Auckland City be more consistent with the Biosecurity and Reserves Acts and be as follows:

Plants which are capable of causing at some time serious adverse and unintended effects on people and/or the natural and physical environment.

This definition is broad enough to cover the different management issues in parks and street environments and the effects of weeds on the natural environment, ancestral values of Maori, peoples' health and safety, City infrastructure, and economic activity.

1.4.2 Environment

The Resource Management Act 1991 defines environment to include:

ecosystems and their constituent parts, including people and communities; and
all natural and physical resources; and
amenity values; and
the social, economic, aesthetic, and cultural conditions which affect the matters stated in paragraphs (a) to (c) of this definition or which are affected by those matters.

However this report is required to separate out a number of these issues and address them individually; for example the costs of vegetation management and its effects on asset value, biodiversity, and human health. For the sake of clarity then, and to ensure that no important factors are overlooked, the term environment is used here to include only natural ecosystems and resources such as water, soil, flora and fauna, etc. It excludes the built environment, human health and safety, economic and cultural considerations, amenity values and aesthetics.

1.4.3 Environmentally damaging weeds

This term is used to described weeds that occur in natural areas of bush in parks and on rural roadsides, wetlands, and coastal ecosystems, and the growth of which causes damage to the natural biodiversity of that particular environment.

Reviewed - October 2006