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Keyword: spotted knapweed

Linking native and invader traits explains native spider population responses to plant invasion

Publications Posted on: July 15, 2016
Theoretically, the functional traits of native species should determine how natives respond to invader-driven changes. To explore this idea, we simulated a large-scale plant invasion using dead spotted knapweed (Centaurea stoebe) stems to determine if native spiders' web-building behaviors could explain differences in spider population responses to structural changes arising from C. stoebe invasion.

Evaluation of establishment of Cyphocleonus achates and its potential impact on spotted knapweed

Publications Posted on: December 14, 2015
Environmental characteristics of a site may greatly influence the establishment and impact of biological control agents on the target weed. A biological control agent that is highly successful in one region may be virtually ineffective in another (Gurr and Wratten 2000).

Effects of herbicide treatment on invasive knapweed and other grassland plants

Science Spotlights Posted on: August 21, 2015
Invasive plants such as spotted knapweed (Centaurea maculosa) have overrun vast areas of the United States to the detriment of native plants and wildlife. Managers increasingly use broadleaf herbicides to suppress plant invaders, assuming that suppression will relieve the impacts of invasion. Rocky Mountain Research Station scientists evaluated the effects of a common herbicide treatment on grassland plants in western Montana to determine if and when suppression of spotted knapweed may relieve impacts of this notorious invader.

Invasiveness and impact of 48 exotic plant species in native grasslands

Science Spotlights Posted on: July 17, 2015
We quantified and ranked invasiveness and impact for 48 exotic plant species based on surveys over 20,000 km2 of grasslands in western Montana. These data provide a valuable tool for managers to determine the relative impacts of invaders for prioritizing exotic plants for control in the bluebunch wheatgrass habitat type.

Invasive plant erodes bird song diversity via food chain effects

Science Spotlights Posted on: May 20, 2015
Invasive plant impacts on native plants can ripple through native food webs from plants to insects all the way to birds. We observed that the invasion of spotted knapweed into grasslands of western Montana affects not only breeding success of songbirds but also the way song is passed between generations. 

Weak vs. strong invaders of natural plant communities: Assessing invasibility and impact

Publications Posted on: April 21, 2015
In response to the profound threat of exotic species to natural systems, much attention has been focused on the biotic resistance hypothesis, which predicts that diverse communities should better resist invasions. While studies of natural communities generally refute this hypothesis, reporting positive relationships between native species diversity and invasibility, some local-scale studies have instead obtained negative relationships.

Effects of biological control agents and exotic plant invasion on deer mouse populations

Publications Posted on: April 21, 2015
Exotic insects are commonly introduced as biological control agents to reduce densities of invasive exotic plants. Although current biocontrol programs for weeds take precautions to minimize ecological risks, little attention is paid to the potential nontarget effects of introduced food subsidies on native consumers. Previous research demonstrated that two gall flies (Urophora affinis and U.

Invasive plant erodes local song diversity in a migratory passerine

Publications Posted on: October 01, 2014
Exotic plant invasions threaten ecosystems globally, but we still know little about the specific consequences for animals. Invasive plants can alter the quality of breeding habitat for songbirds, thereby impacting important demographic traits such as dispersal, philopatry, and age structure. These demographic effects may in turn alter song-learning conditions to affect song structure and diversity.

Spotted knapweed: Effects of climate change on the invasiveness and biological control

Publications Posted on: October 01, 2013
Exotic weeds have invaded vast stretches of forest and rangeland, yet as highlighted by the previous review by Runyon and others in this issue, little is known about the factors driving the success of these invaders or how factors such as climate change may alter outcomes. Spotted knapweed (Centaurea stoebe) is one of the worst weeds in the Western U.S., infesting over seven million acres.

Invasive Species Science Update (No. 6)

Publications Posted on: April 18, 2013
The sixth issue of the Rocky Mountain Research Station's (RMRS) Invasive Species Science Update is now complete. Published approximately once per year, this newsletter keeps managers and other users up-to-date with recently completed and ongoing research by RMRS scientists, and covers breaking news related to invasive species issues.