Managing Invasive Plants: Concepts, Principles, and Practices link

U.S. Fish & Wildlife Service
America's National Wildlife Refuge System

MANAGING INVASIVE PLANTS: Concepts, Principles, and Practices

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Planning

Photo of planning flowchart overlaid on a coastal landscape (left); people at a table in the process of planning (right).
Photo credits: D Pitkin/USFWS (left background image); USFWS (right)

Introduction

Approaching invasive plant problems through a strategic process can help achieve management goals and objectives. Commonly, a plan is developed that guides management in direction and time. While stand-alone plans for invasive species management are not required by the National Wildlife Refuge System, planning for invasive species management may be required for certain planning documents, and in some cases, creating a separate stand-alone plan may be advantageous.

Developing a plan for managing invasive plants can be highly beneficial. A plan can serve as a reference while management progresses and can support decision making and problem solving needed to achieve desired vegetation conditions. Having a plan in place also ensures consistency in management efforts as personnel change, helps engage stakeholders and citizens, and is useful as supporting material for writing grants and soliciting partnerships.

In this module, you will become familiar with

  • federal directives on invasive species
  • elements and activities of invasive plant management
  • planning frameworks used in invasive plant management
  • general components of a plan for managing invasive plants
  • considerations for Refuge System planning for managing invasive plants
  • value of partnerships among land managers, scientists, stakeholders, and volunteers
  • incorporating volunteer services into invasive plant management

Planning Considerations

Diagram composed of invasive plant management terms.

Invasive plant management planning is built upon a framework that takes into account a myriad of considerations—from operating under policies and laws, to working with adjacent landowners, to selecting control methods that are effective in a particular environment. Planning can be an ongoing process that is adjusted or refined by assessing new information until invasive plant management objectives are achieved, and ultimately, desired vegetation conditions are realized.

Federal Directives

Executive Order 13112

National Invasive Species Management Plan

In 1999, Executive Order 13112 established the National Invasive Species Council, which was directed to develop the National Invasive Species Management Plan:

“The purpose of the Plan is to provide a blueprint for Federal action (in coordination with State, local, and private programs and international cooperation) to prevent the introduction of invasive species, provide for their control, and minimize their economic, environmental, and human health impacts.”

Under this Plan, the US Fish and Wildlife Service (USFWS) is responsible for implementing the directives on the public lands and waters it manages.

The Plan identifies nine areas of action and associated timelines for implementation:

  • leadership and coordination
  • prevention
  • early detection and rapid response
  • control and management
  • restoration
  • international cooperation
  • research
  • information management
  • education and public awareness

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Invasive Species Definition

The definition of invasive species for federal agencies, including the USFWS, follows Executive Order 13112. For the purpose of the learning modules, invasive plants are considered invasive species.

“Invasive species - an alien species whose introduction does or is likely to cause economic or environmental harm or harm to human health.”

“Alien species - with respect to a particular ecosystem, any species, including its seeds, eggs, spores, or other biological material capable of propagating that species, that is not native to that ecosystem.”

Department of Interior Integrated Pest Management Policy

Integrated Pest Management (IPM) planning, a framework that guides pest management (including invasive species), is required for the USFWS National Wildlife Refuge System by the Federal Insecticide Fungicide and Rodenticide Act (FIFRA, 7 U.S.C. 136r-1), Department of the Interior IPM policy (517 DM 1), and as expressed in the Director’s Memo (2004). In addition, plans for managing invasive plants may be subject to the National Environmental Policy Act (NEPA), and may require the development of an appropriate NEPA document (e.g., Environmental Action Statement [Categorical Exclusion], Section 7 Consultation, Environmental Assessment, Environmental Impact Statement).

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Elements and Activities of Invasive Plant Management

Planning for invasive plant management requires fundamental knowledge and key information to adequately assess and address the problems in the context of land management goals. This knowledge and information is derived from common elements and activities of invasive plant management, and is essential for management planning.

Elements and Activites of Invasive Plant Management

Management directives and societal considerations

  • identify land management goals (e.g., resource protection/conservation, production, etc., identified in a refuge’s Comprehensive Conservation Plan)
  • adhere to laws and policies
  • collaborate and communicate with scientists, stakeholders, citizens

Inventory/survey and mapping

  • assess the status of invasive plant populations (e.g., location, distribution, abundance)
  • identify areas free of invasive plants
  • detect new invasive plant species/populations

Risk assessment

  • assess the relative risk of invasive plant species/populations (i.e., prioritizing and ranking) and control methods

Management methods

  • select appropriate methods (physical, chemical, biocontrol, prescribed burning, prescribed grazing) for eradication, suppression, containment, or restoration

Monitoring

  • assess trends of invasive plant populations to determine the effectiveness of management methods (e.g., control treatments), or species’ invasiveness
  • detect new invasive plant species/populations

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Frameworks for Planning

For more than a decade, there has been a slow but obvious shift toward an ecological approach to managing plant invasions in wildland ecosystems, and away from simply removing unwanted plants. To achieve desired vegetation conditions, land managers and scientists are referring to the ecological principles and processes operating within plant communities (e.g., species interactions) to the larger scale of ecosystems (e.g., effects of natural disturbances). Knowledge of ecological principles and processes can be incorporated into management in many ways, from evaluating soil properties and plant life history strategies, to directing desired changes in plant communities according to successional theory (Krueger-Mangold et al. 2006, Sheley et al. 2006).

Another aspect of the broader ecological approach emphasizes examining the underlying causes of plant invasion. This perspective recommends analyzing socioeconomic factors such as land use activities that contribute to plant invasions (Hobbs and Humphries 1995).

Integrated Pest Management

The philosophy and technology of IPM, which has a long history in agriculture, is being applied to invasive plant problems on lands managed by the USFWS. The IPM approach emphasizes integrating methods to increase the effectiveness of invasive plant control and minimize risks.

“IPM is a sustainable approach to managing pests by combining biological, cultural, physical, and chemical tools in a way that minimizes economic, health, and environmental risks.” (FIFRA, 7 U.S.C. 136r-1)

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Components of an IPM Framework

  • identify current and potential pest species, their biology, and conditions conducive to the pest(s) (air, water, food, shelter, temperature, and light)
  • understand the physical and biological factors that affect the number and distribution of pests and their natural enemies
  • conserve natural enemies
  • prevent, avoid, and monitor potential pest species
  • establish “Action Thresholds” (such as a certain number of pests per acre) at which point an approved management strategy will be implemented
  • review available tools and best management practices for the management of the identified pest(s)
  • select the most effective, low risk pest management strategies in accordance with applicable laws, regulations, and policies
  • build consensus with stakeholders/occupants, decision-makers, and technical experts (ongoing throughout the process)
  • document decisions and maintain records
  • obtain approval, define responsibilities, and implement selected best management strategies
  • evaluate results of management strategies; determine if objectives have been achieved; modify strategy if necessary
Adaptive Management

Adaptive Management is another framework that is used by the USFWS and can be incorporated into an invasive plant management program. This framework, which was first applied to natural resource management in the late 1970s, supports complex decision making by generating new knowledge about natural resource systems through experimental management.

The information that follows is from Adaptive Management: The US Department of the Interior Technical Guide (Williams et al. 2007)

An Adaptive Management framework

  • is useful when there is substantial uncertainty regarding the most appropriate strategy of managing natural resources
  • is not a trial and error process but rather links management objectives with learning about the systems, and adjusts management based on the learning
  • incorporates testable models that can range from simple qualitative and conceptual, to quantitative and highly detailed
  • incorporates monitoring, which is fundamental for testing models and for measuring progress toward management objectives
  • requires institutional leadership and stakeholder agreement, commitment, and support for monitoring and assessment for the project’s duration

Adaptive Management Operational Steps

Diagram of the Adaptive Management process.
Diagram of the Adaptive Management process. From Adaptive Management: The US Department of the Interior Technical Guide (Williams et al. 2007).

Set-up phase

  1. Stakeholder involvement
    Ensure stakeholder commitment to adaptively manage the enterprise for its duration
  2.  

  3. Objectives
    Identify clear, measurable, and agreed-upon management objectives to guide decision making and evaluate management effectiveness over time
  4.  

  5. Management actions
    Identify a set of potential management actions for decision making
  6.  

  7. Models
    Identify models that characterize different ideas (hypotheses) about how the system works
  8.  

  9. Monitoring plans
    Design and implement a monitoring plan to track resource status and other key resource attributes

Iterative phase

  1. Decision making
    Select management actions based on management objectives, resource conditions, and enhanced understanding
  2.  

  3. Follow-up monitoring
    Use monitoring to track system responses to management actions
  4.  

  5. Assessment
    Improve understanding of resource dynamics by comparing predicted vs. observed change in resource status
  6.  

  7. Iteration
    Cycle back to Step 6 and, less frequently, to Step 1