Chapter 15 - Undesirable Plants and Animals 15.0 Undesirable Plants and Animals 15.1 Introduction Undesirable plants and animals invade and damage natural resources and their spread can result in adverse effects on other resources and people. Plant pests adversely affect both indigenous and production land ecosystems. Plant pests invade indigenous ecosystems often harming native habitats and altering whole landscapes. The uncontrolled spread of plant pests can seriously undermine the production base of land used for productive purposes. Animal pests likewise have an adverse effect by competing with livestock for pastoral habitat, contributing to soil erosion and destroying indigenous fauna and flora. While it is impractical to eradicate all undesirable plants and animals, their adverse effects can be mitigated through control measures and land management practices. 15.2 Issue Undesirable plants and animals invading or damaging land and water ecosystems. The Marlborough Sounds has a wide variety of ecological communities and species present. A large variety of sensitive indigenous species, and productive exotic species occur within these ecosystems. Undesirable plants and animals can damage the characteristics which give value to ecosystems, or directly affect the survival or health of important species. For example, exotic species invade indigenous forests, possums browse indigenous trees, pigs forage for native snails and spartina blocks estuarine areas. These examples all relate to the maintenance of indigenous ecosystems. Undesirable plants and animals also affect primary production ecosystems. For example, possums spread diseases in cattle and deer herds, gorse and broom invade forest lands, and unpalatable species invade pastures. 15.3 Objectives and Policies Objective 1 The protection of land and water ecosystems from the adverse effects of plant and animal pests. Policy 1.1 Prepare and maintain Regional Pest Management Strategies in accordance with the provisions of the Biosecurity Act 1993. Policy 1.2 Provide for agreed methods of pest control by enabling the implementation of National and Regional Pest Management Strategies. 15 - 1