Ana səhifə

S national Park Service U. S. Department of the Interior Sequoia and Kings Canyon National Parks Management Directive No. 038 Preventing Introduction and Spread of Invasive Non-Native Plants August 18, 2004 contents

Yüklə 0.51 Mb.
ölçüsü0.51 Mb.
  1   2   3   4   5   6   7


National Park Service

U.S. Department of the Interior
Sequoia and Kings Canyon National Parks

Management Directive No. 038

Preventing Introduction and Spread of Invasive Non-Native Plants

August 18, 2004












This policy establishes guidelines to prevent the introduction and spread of non-native plant species within Sequoia and Kings Canyon National Parks and Devils Postpile National Monument. It covers all activities performed by government employees, park concessioners, permittees, contractors, and partners.

NPS policies on preventing the introduction and spread of non-native plants include the following:

  • Non-native species will not be allowed to displace native species if displacement can be prevented (NPS Management Policies 2001, 4.4.4).

  • New non-native species will not be introduced into parks, except in specific rare situations (NPS Management Policies 2001,

  • Livestock will be fed pelletized feed or hay that is free of weed seeds (NPS Management Policies 2001,

  • Activities may not be categorically excluded from NEPA if they contribute to the introduction, continued existence, or spread of federally listed noxious weeds (DO-12 Handbook 3.5N, Federal Noxious Weed Control Act).

  • Activities may not be categorically excluded from NEPA if they contribute to the introduction, continued existence, or spread of non-native invasive species or actions that may promote the introduction, growth, or expansion of the range of non-native invasive species (DO-12 Handbook 3.5O, Executive Order 13112).

By far the most efficient and cost-effective way to keep invasive non-native plants from displacing native species is to (1) prevent the entry of non-native plants into the parks, and (2) prevent the spread of existing non-native plant populations within the parks. Once new populations of non-native plants establish they may multiply rapidly. As a consequence, removal can be extremely difficult and costly. The importance of a strong prevention program as a vital component in the management of invasive non-native plants cannot be overstated.

Seeds of non-native plants travel wherever and whenever soil is moved from one location to another. Seeds can lodge in the treads of car tires, bicycle tires, or shoe soles. Soil, sand, or gravel imported for construction or other activities can contain non-native plant seeds. Many non-natives, for example puncture vine (Tribulus terrestris), have spiny or hook-like seed coats and can arrive in the park stuck to the fur of pets, wildlife, and pack stock or on people’s clothing, shoelaces, and camping gear. Plants installed around park residences for landscaping can spread to surrounding natural areas. Seeds can blow in from the gardens of neighboring private landowners or can wash downstream in rivers. Hay, used to feed livestock, or straw, used in revegetation projects, can contain non-native plant seeds from the field where the hay was grown.

This policy covers the following activities that have the highest probability of contributing to the introduction and spread of non-native plants:

  • Landscaping and planting of vegetation, including maintenance of cultural landscapes

  • Construction, restoration, and fire activities, including import of equipment, import of materials, and soil disturbance.

  • Import of livestock and feed

  • Movement of people and equipment from frontcountry sites, such as heliports, pack stations, and trailheads, into pristine backcountry sites.


Invasive non-native plants can spread across landscapes and quickly become difficult or impossible to control. Invasive plants can out-compete native vegetation, diminishing native plant diversity and endangering rare plant and animal species. Invasive plants can reduce wildlife habitat and forage and cause illness, injury, and sometimes death in wildlife and livestock. Areas invaded by non-native plants frequently have greater rates of soil erosion and stream sedimentation because invasive plant monocultures tend to be poorer at holding topsoil in place than native plant communities. Invasive plants can alter soil nutrient and moisture levels; these changed growing conditions may displace natives and favor further non-native plant invasions. Invasive plants can increase fire frequency and change the burning season. These altered fire regimes may favor further non-native plant invasion. Invasive plants can cause the deterioration and loss of wetland meadows. Finally, many invasive plants are spiny and can turn a formerly pleasant recreational experience into a painful encounter for visitors.

An example of a non-native species that has greatly diminished the quality of natural ecosystems is yellow star thistle (Centaurea solstitialis). Yellow star thistle has already formed monocultures over millions of acres of public land in the West, reducing the value of the land as natural preserves and for recreation and wildlife. Yellow star thistle has not yet established in these parks, although it is approaching park boundaries.
One of the primary purposes of Sequoia and Kings Canyon National Parks and Devils Postpile National Monument is to protect, restore and maintain the parks’ diverse natural resources against external threats to those resources. The parks are committed to preserving our diverse native flora against the threat of invasive plants by using Integrated Pest Management (IPM). Integrated Pest Management is a method of combining tools (physical/mechanical, chemical, cultural/fire, and biological) for controlling existing infestations Integrated Pest Management systems also place a strong emphasis on preventing import and spread of new non-native plants, early detection and control of small new infestations, and restoring rapid vegetative cover in recent disturbances. Division of Natural Resources crews actively control existing infestations. Prevention of new invasions requires the cooperative efforts of residents and park staff in all divisions, as well as concessioners, visitors, owners of private inholdings, permittees, and neighboring communities. Preventing the import and spread of invasive plants is the most efficient and cost-effective way to protect park resources against the threat of invasive plants.
The biodiversity of these parks has three components: ecosystem, species, and genetic diversity; all must be protected according to NPS Management Policies. Genetic diversity refers to the variation of genes within species. This covers genetic variation between distinct populations of the same species. The genetic variation of a local plant population is often significantly different from that of a population of the same species in a coastal environment, for example. National parks are among the few places in this country that have not, to a large extent, been subject to the introduction of non-local genetic stock; that is, the plants here are evolving in place. As a consequence, national parks that remain relatively “unsullied” by anthropogenic alterations and perturbations are invaluable to evolutionary biologists studying natural selection against a background of natural processes. The introduction of non-local genetic strains of local native species, and their subsequent hybridization with local stock, would confound this “native genetic trace” for future investigators. Therefore, a conservative approach of preserving these parks’ local genes in as pristine a state as possible is warranted.

  1   2   3   4   5   6   7

Verilənlər bazası müəlliflik hüququ ilə müdafiə olunur © 2016
rəhbərliyinə müraciət