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montana invasive weed modeling project nature conservancy


Evaluating the Costs and Benefits of Alternative Weed Management Strategies for Three Montana Landscapes

Invasive plant species management at the landscape scale in the Western U.S. is generally based on fine-scale experience and arbitrary decisions (“rules of thumb”) with limited understanding of long-term outcomes across broad areas or over long periods.  Range managers are often faced with dilemmas in applying limited resources to the control of invasive plants across a complex landscape, and few tools are available to guide real-world decision making across large landscapes.  Due to uncertainty about invasive plant management across large areas and over long periods, research and demonstrations have generally focused on the refining control techniques at fine scales (e.g. small patches of weeds or experimental plots), rather than prioritization across thousands of acres.  In order to develop the best strategies to maintain landscape values and prevent the spread of invaders, quantitative tools are needed to compare the effectiveness of various management strategies at different spatial scales and over several decades.
Computer models have been used to evaluate alternative management strategies of invasive species, while accounting for uncertainties related to actual landscapes, weed ecology, and management strategies.  We used a spatially explicit simulation model to model the spread of leafy spurge and spotted knapweed and the effects of management actions in three Montana landscapes – the Centennial Valley (CV), Rocky Mountain Front (RMF), and Montana Glaciated Plains (MGP).  We compared several management strategies under a variety of budget constraints to evaluate the long-term advantages of different approaches, identify appropriate resource allocation levels, and assess costs and benefits of strategies within an economic analysis framework.


Centennial Valley | Montana Glaciated Plains | Rocky Mountain Front


Montana Weed Control Association January 2011
Rocky Mountain Front Weed Roundtable January 2011
Centennial Valley 2011

Model Instructions

VDDT Software from ESSA
TELSA Software from ESSA 
Guide for running model simulations in TELSA (download pdf)

The Nature Conservancy in Montana
32 South Ewing
Helena, MT  59601

    David Hanna:
    (406) 466-5299
    Nathan Korb:
    (406) 443-2261
    Brad Bauer:
    (406) 443-2267
    Brian Martin:
    (406) 443-6733
ESSA Technologies, Ltd.
600 - 2695 Granville St.
Vancouver, BC  V6H 3H4

Leonardo Frid
(604) 947-6956