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Management Methods: Physical Methods
Collecting floating water chestnut plants (Trapa natans), removing saltcedar trees (Tamarix spp.), cutting kudzu vines (Pueraria lobata), girdling black locust trees (Robinia pseudoacacia). Photo credits: USFWS
Introduction
Management methods that use manual or mechanical means to remove, kill, injure, or alter growing conditions for unwanted plants are termed physical methods. Such methods are relatively expensive and labor intensive, and may need to be used repeatedly or in combination with other management methods. However, for socially sensitive sites and sites with high ecological value, highly selective physical methods may be desirable because of their minimal environmental impact.
The physical methods that may be applied to invasive plants in terrestrial and aquatic environments are many and varied. They vary in the type of injury or stress they inflict, their selectivity and potential for nontarget impacts, and the procedures, skills, equipment, labor, and funds they require.
In this module, you will become familiar with
- physical methods that are used for invasive plant management
- impacts of physical methods on invasive plants and the environment
- principles and tactics for managing invasive plants with physical methods
- examples of how physical methods can be integrated into invasive plant management
Ever since people began to prefer certain assemblages of vegetation over others, they have manipulated plants in the environment. Vegetation management in its earliest form used simple physical methods—removing some plants and adding or sustaining others.
Over time, the physical methods and tools used in agriculture—that is, in growing crops and removing unwanted plants—were adapted for other situations, such as gardens, pastures, roadsides, and wildlands.
Physical Methods for Terrestrial Habitats |
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Mowing common reed (Phragmites australis) at Rachel Carson NWR in Maine. Photo credit: USFWS |
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Pulling |
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Hoeing |
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Tilling |
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Mowing |
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Cutting |
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Stabbing |
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Girdling |
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Chaining |
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Mulching |
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Soil solarization |
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Flooding |
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Physical Methods for Aquatic Habitats |
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Mechanical harvester collecting floating water chestnut plants (Trapa natans) in Silvio O. Conte NFWR. Photo credit: USFWS
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Harvesting |
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Diver dredging |
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Benthic barriers |
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Water drawdown |
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Physical methods typically employ simple, readily available tools and equipment. However, the effectiveness, impacts, and expense of physical methods can vary greatly depending on the type of method used and the characteristics of the infestation.
Some physical methods can be quite labor intensive and therefore expensive, but these usually have low environmental impact and are therefore appropriate for small, localized infestations or infestations in ecologically or socially sensitive areas. Physical methods that can be applied more easily over larger areas, may have more significant nontarget effects.