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United States Department of Agriculture

Agricultural Research Service

Research Project: Reducing the Impact of Invasive Weeds in Northern Great Plains Rangelands Through Biological Control and Community Restoration

Location: Pest Management Research Unit

Project Number: 5436-22000-017-00
Project Type: Appropriated

Start Date: Feb 01, 2011
End Date: Jan 31, 2016

Objective:
Objective 1: Determine proper taxonomic identification and/or knowledge of evolutionary relationships of key emerging invasive plant species, including perennial pepperweed (Lepidium latifolium), Russian olive (Elaeagnus angustifolia), dyer’s woad (Isatis tinctoria), Dalmatian toadflax (Linaria spp.), common tansy (Tanacetum vulgare), oxeye daisy (Leucanthemum vulgare) and their potential biological control agents. (Gaskin and Delaney) Objective 2: Investigate reproductive strategies of key emerging invasive plant species, including perennial pepperweed (Lepidium latifolium) and hawkweeds (Hieracium spp.), and use this information in decision tools for selecting potential biological control agents. Objective 3: Develop insect and pathogen biological control agents, and synergies of these agents, for invasive plants of the Northern Great Plains, including saltcedar (Tamarix spp.), whitetop or hoary cress (Lepidium draba), leafy spurge (Euphorbia esula), and hawkweeds (Hieracium spp.). Objective 4: Investigation of the pathogenicity to native forbs and grasses of Fusarium spp. isolates associated with Tamarix biomass. Objective 5: Determine the effects of biological control on restoration efforts of rangeland and public land and develop restoration protocols that complement future biological control efforts.

Approach:
Exotic invasive weeds cause about $35 billion annually in economic losses in addition to environmental impacts ranging from displacement of species of conservation concern to altered ecosystem functions. Biologically-based control methods can provide cost-effective, sustainable means of limiting the adverse impacts of invasive plants over extensive rangeland and natural areas, but improvements in methodology are warranted. We propose that by better understanding invasive plant taxonomy, evolutionary relationships, origins, population structure and reproductive biology, we can identify more effective and lower risk insect and pathogen biological weed control agents. Additionally, understanding ecological interactions between insect and pathogen agents will let us employ their synergistic action. Biological control of weeds is a step towards returning to desired landscapes, with significantly reduced densities of noxious weeds and increased cover of native or other desired species. Establishing desired species cover in previously infested areas may require the application of successful restoration programs. We will examine the ecological and evolutionary processes that maintain desired communities, and then use this knowledge to improve rates of success in restoration. Additionally, successful biological control can leave a legacy of increased inoculum of soilborne pathogens, and we will investigate if this inhibits restoration efforts. This more holistic view of invasive weed management, starting with a better understanding of the basic biology of the invasion, including ecological and evolutionary studies of the biological control and restoration processes, will enhance our ability to replace invaded areas with ecologically sound and economically useful landscapes.

Last Modified: 4/17/2014
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