Management Methods: Physical Methods

review, Resources, & References

Key Points

1. PHYSICAL METHODS EMPLOY SIMPLE TOOLS

Most of the physical methods used today are based on simple techniques established for early agricultural practices and employ tools and equipment that are typically easy to acquire and simple to use.

2. PHYSICAL METHODS SUPPRESS AND PROMOTE PLANT POPULATIONS

Physical methods can affect plant species directly by physically damaging or injuring plants, and indirectly by altering conditions so that they are less favorable for plant survival and growth. While the effects of physical injury and stress may be lethal to some plants, many plants have characteristics that allow them to persist in the plant community.

3. MANY FACTORS INFLUENCE A PLANT’S RESPONSE TO PHYSICAL METHODS

Plant traits, mechanisms for survival and other factors determine the availability and vulnerability of carbohydrate reserves and viable growing points and propagules required for plants to withstand or recover from physical stress and injury. These traits, mechanisms, and factors include: life history strategy, life cycle stage, growth form, growth status, reproductive mechanisms, adaptations to disturbance, and ecological interactions before and after injury.

4. PRINCIPLES FOR USING PHYSICAL METHODS

Selecting and applying physical methods that achieve management outcomes while promoting and maintaining desired vegetation requires a thorough understanding of how invasive and desirable plant populations within a particular ecosystem will respond to the type of injury and stress a particular physical method inflicts.

5. PHYSICAL METHODS EMPLOY A WIDE RANGE OF TACTICS

Many physical methods are available to manage invasive plants, each requiring different application tactics. In general, controlling invasive plant populations successfully with physical methods depends on selecting a method that is compatible with the target species and the management area, then applying the method at the optimal time and intensity to achieve desired outcomes.

6. SELECTIVE AND NONSELECTIVE PHYSICAL METHODS

Selective physical methods can be quite labor intensive, but typically have low environmental impact and are therefore appropriate for small, localized infestations or infestations that occur in ecologically or socially sensitive areas. Nonselective physical methods can be applied more easily over larger areas, but may have more significant nontarget effects.

7. TIMING CAN IMPROVE EFFECTIVENESS AND MINIMIZE IMPACTS

Because the susceptibility of a plant varies according to its growth stage and seasonal status, timing is important in applying a physical method.

8. TACTICS CAN CONTROL INTENSITY

Tactics for controlling intensity of physical methods—such as manipulating the duration, frequency, location, and depth of treatment—vary among the range of physical methods. Understanding how a method impacts the affected species and environment is necessary to effectively manipulate the intensity of a physical method.

9. MONITORING PROVIDES INFORMATION ABOUT EFFECTIVENESS AND IMPACTS

Monitoring activities should determine whether the physical methods are being applied as planned, are having desired effects on target plants and other ecosystem components, and are meeting invasive plant management objectives. When using physical methods, it is especially important to monitor for regrowth, reestablishment, and dispersal of invasive plants and propagules.

10. PHYSICAL METHODS ARE TYPICALLY INTEGRATED WITH OTHER METHODS

Used alone, physical methods are sometimes too labor intensive and expensive to justify the level of invasive plant control achieved, particularly when applied to well-established or large-scale infestations. Therefore, physical methods are typically applied to complement other methods as part of an integrated strategy to manage invasive plants.

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