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Interspecific interactions of herbivores sharing a host plant may be important in structuring herbivore communities. We investigated host plant-mediated interactions of root (Hylobius transversovittatus) and leaf herbivores (Galerucella calmariensis), released to control purple loosestrife (Lythrum salicaria) in North America, in field and potted plant experiments. In the potted plant experiments, leaf herbivory by G. calmariensis reduced H. transversovittatus larval survival (but not larval development) but did not affect oviposition preference. Root herbivory by H. transversovittatus did not affect either G. calmariensis fitness or oviposition preference. In field cage experiments, we found no evidence of interspecific...
Saltcedars (Tamarix spp., Tamaricaceae) (SC), are exotic, invasive shrubs to medium trees native to the Old World. In riparian ecosystems of the western United States, SC replaces native plant communities, degrades wildlife habitat, reduces biodiversity, alters stream channel morphology, uses large quantities of groundwater, increases wildfire frequency, reduces recreational and agricultural usage, and probably has contributed to the decline of many wildlife and fish species. In recent years, the southwestern willow flycatcher (Empidonax trailii extimus) (sw WIFL) has begun nesting extensively in SC in some of its major breeding areas in Arizona, but not in other areas, since SC has replaced its native willow nest...
Broom snakeweed (Gutierrezia sarothrae [Pursh] Britton & Rusby) increases and dominates rangelands following disturbances, such as overgrazing, fire, and drought. However, if cattle can be forced to graze broom snakeweed, they may be used as a biological tool to control it. Cattle grazed broom snakeweed in May and August 2004–2007. Narrow grazing lanes were fenced to restrict availability of herbaceous forage to force cattle to graze broom snakeweed. They used 50–85% of broom snakeweed biomass. Mature broom snakeweed plant density declined because of prolonged drought, but the decline was greater in grazed lanes. At the end of the study, density of mature plants in grazed lanes was 0.31 plants ?m22, compared...
This presentation aired as part of the Great Basin LCC webinar series on August 28, 2017. Speakers include Matt Germino, U.S. Geological Survey and Great Basin LCC; David Pyke, U.S. Geological Survey; Richard Lee, Bureau of Land Management; Mike Gregg, U.S. Fish and Wildlife Service; Jane Mangold, Montana State University; and Brynne Lazarus, U.S. Geological Survey.Download the presentation slides: http://bit.ly/2wHxN9CDescription: Cheatgrass (Bromus tectorum) and medusahead (Taeniatherum caput-medusae) invasions pose a serious threat to Great Basin ecosystems. Managers and scientists are hopeful that strains of the bacterium Pseudomonas fluorescens that have been selected for their weed-suppressive properties in...
Bromus tectorum is a dominant winter annual weed in cold deserts of western North America. We followed patterns of seed carry-over and abundance of the pathogen Pyrenophora semeniperda over 5 years at B. tectorum-dominated shadscale (Atriplex confertifolia) and sagebrush (Artemisia tridentata) sites in southern Idaho. We hypothesised that more seeds could potentially carry over at the drier shadscale site because of minimal autumn precipitation, but that P. semeniperda, a pathogen that primarily kills dormant seeds, would have more impact at the drier site, where a higher density of dormant seeds would likely be present in the early spring seedbank. Successful first-year seed carry-over was higher in years with...
Biological control of invasive saltcedars (Tamarix spp.) in the western U.S. by exotic tamarisk leaf beetles, Diorhabda spp., first released in 2001 after 15 years of development, has been successful. In Texas, beetles from Crete, Greece were first released in 2004 and are providing control. However, adults alight, feed and oviposit on athel (Tamarix aphylla), an evergreen tree used for shade and as a windbreak in the southwestern U.S. and México, and occasionally feed on native Frankenia spp. plants. The ability of tamarisk beetles to establish on these potential field hosts was investigated in the field. In no-choice tests in bagged branches, beetle species from Crete and Sfax, Tunisia produced 30–45% as many...
There have been relatively few tests of resource-ratio theory in terrestrial systems. Additionally, resources are known to be an important factor determining the success of invasive species. Here I discuss how the study by Newingham and Belnap (pp. 29?40, this issue) tests predictions of resource-ratio theory and how they apply it to questions of invasion by Bromus tectorum in a terrestrial grassland. Published in Plant and Soil, volume 280, issue 1-2, on pages 23 - 27, in 2006.
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These data were compiled for a study that investigated the effects of drought seasonality and plant community composition on two dominant perennial grasses, Achnatherum hymenoides (C3 photosynthesis), and Pleuraphis jamesii (C4 photosynthesis), in a dryland ecosystem. In 2015 USGS Ecologists recorded vegetation and soil moisture data in 36 experimental plots which manipulated precipitation in two plant community types. The experiment consisted of three precipitation treatments: control (ambient precipitation), cool-season drought (-66% ambient precipitation November-April), and warm-season drought (-66% ambient precipitation May-October), applied in two plant communities (perennial grasses with or without a large...
Tags: Achnatherum hymenoides, Botany, C3 photosynthesis, C4 photosynthesis, Canyonlands National Park, All tags...
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The videos of ant (Crematogaster sp.) predation on giant applesnail (Pomacea maculata) egg masses were taken on September 24 of 2018 at the Hudson Woods Unit of the Texas Mid-Coast National Wildlife Refuge Complex (29°09’52” N, 95°30’5” W). Jennifer Wilson (US Fish and Wildlife Service) took the videos using a smart phone.
Broom snakeweed is one of the most widespread range weeds in western North America. Although a native plant, it increases with disturbance such as overgrazing, fire, and drought, and can dominate sites. The objective of this study was to test the hypothesis that defoliation of broom snakeweed alone, and along with associated grasses, would reduce its vigor and increase its mortality in bunchgrass plant communities. The study was conducted at two locations: near Nephi, UT in an invaded crested wheatgrass stand and at Howell, UT in a bluebunch wheatgrass/Wyoming big sagebrush community. Clipping treatments consisted of (1) untreated Control; (2) All Clip—clipping all herbaceous vegetation 2 cm above the soil surface,...
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Conclusions: Four plant species have been tested in the majority of field evaluations, while plants native to the test area and perennial plants are particularly underrepresented. Native plants useful in restoration of rare ecosystems can increase natural enemy abundance and provide ecosystem services as much as widely recommended non-natives. Thresholds/Learnings: Synopsis: The intentional provision of flowering plants and plant communities in managed landscapes to enhance natural enemies is termed habitat management and is a relatively new but growing aspect of conservation biology. The focus of most habitat management research has been on understanding the role of these plant-provided resources on natural enemy...
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FY2017The Integrated Rangeland Fire Management Strategy Actionable Science Plan places a high priority on assessing control measures for invasive annual grasses, which provide fuel for rangeland fire and impede restoration of desirable perennials. Weed-suppressive strains of the bacterium Psuedomonas fluoresens (P.f.) are an emerging but yet untested tool for selectively reducing these annual grasses. P.f. may suppress annuals for approximately 2-5 years, bridging the short-term action of herbicides and long-term resistance provided as native bunchgrasses recover. In 2015-2016, the USGS responded to a request from the Idaho sage grouse action group to establish a series of field-based experiments to assess the efficacy...


    map background search result map search result map Maximizing ecosystem services from conservation biological control: The role of habitat management Evaluation of Weed-Suppressive Bacteria for Control of Exotic Annual Grasses Two videos of acrobat ants (Crematogaster sp.) preying on applesnail (Pomacea maculate) egg masses Precipitation, soil moisture, and vegetation data from 36 experimental plots in southeastern Utah, near Canyonlands National Park (2015 - 2018) Evaluation of Weed-Suppressive Bacteria for Control of Exotic Annual Grasses Precipitation, soil moisture, and vegetation data from 36 experimental plots in southeastern Utah, near Canyonlands National Park (2015 - 2018) Two videos of acrobat ants (Crematogaster sp.) preying on applesnail (Pomacea maculate) egg masses Maximizing ecosystem services from conservation biological control: The role of habitat management