Introduced weeds pollinated by introduced bees: Cause or effect?

2003 ◽  
Vol 3 (4) ◽  
pp. 204-212 ◽  
Author(s):  
M.E. HANLEY ◽  
D. GOULSON
Keyword(s):  
Introduced Weeds

scholarly journals Dairy farm systems to aid persistence

2011 ◽  
Vol 15 ◽  
pp. 199-209
Author(s):  
K.A. Macdonald ◽  
C. Matthew ◽  
C.B. Glassey ◽  
N. Mclean
Keyword(s):  
Insect Pests ◽  
Decision Rules ◽  
Dairy Farm ◽  
First Year ◽  
Stocking Rate ◽  
Pasture Management ◽  
Nitrogen Fertiliser ◽  
Feed Supplements ◽  
First Year Of Life ◽  
Introduced Weeds

This manuscript reviews fundamental pasture management principles relevant to pasture persistence. We first note some points of context, within which the debate on pasture persistence is occurring: the release of new pasture cultivars, the debate about climate change, and the effects of newly introduced weeds and pests. We then examine trends in farm practice. The critical management period (of most concern to farmers) has shifted from winter/autumn to summer. It is essential that farmers have and use sets of decision rules to govern when and how hard to graze, when to supplement and when to remove cows from pasture to allow pastures to be grazed appropriately to aid pasture persistence. Adaptations available to improve pasture persistence include: the use of nitrogen fertiliser to increase feed supply going into the summer, the use of crops or other feed supplements, stocking rate and on-off grazing to ensure the pastures are appropriately grazed in the summer. New pastures must be treated with care in their first year of life to ensure survival. The response of farmers to these variables to aid persistence of pastures is discussed. Keywords: climate, insect pests, pasture growth model, pasture renewal, weeds

THE BIOLOGY OF CANADIAN WEEDS.: 89. Carduus nutans L. and Carduus acanthoides L.

1988 ◽  
Vol 68 (4) ◽  
pp. 1053-1068 ◽  
Author(s):  
A. M. DESROCHERS ◽  
J. F. BAIN ◽  
S. I. WARWICK
Keyword(s):  
Biological Control ◽  
Seed Production ◽  
Germination Rate ◽  
Effective Means ◽  
Western Canada ◽  
Control Methods ◽  
Carduus Acanthoides ◽  
Carduus Nutans ◽  
Introduced Weeds

Carduus nutans L. and C. acanthoides L. are introduced weeds, primarily of roadsides, fields and pasturelands. Both species occur in eastern and western Canada with C. nutans more common than C. acanthoides in western Canada. High seed production and germination rate on open soil contribute to the success of the species as weeds, as do the spiny leaves and stems which deter grazing by animals. Mowing or the application of hormone-like herbicides are both effective means of control. Biological control methods have also been used for both species, but have been most successful in the control of C. nutans.Key words: Musk thistle, nodding thistle, plumeless thistle, Carduus spp.

AN ECONOMIC EVALUATION OF CONTROL METHODS FOR DIFFUSE AND SPOTTED KNAPWEED IN WESTERN CANADA

1979 ◽  
Vol 59 (2) ◽  
pp. 375-382 ◽  
Author(s):  
P. HARRIS ◽  
R. CRANSTON
Keyword(s):  
Biological Control ◽  
British Columbia ◽  
Economic Evaluation ◽  
Cost Effective ◽  
The Other ◽  
Western Canada ◽  
Spotted Knapweed ◽  
Control Methods ◽  
Effective Solution ◽  
Introduced Weeds

Diffuse and spotted knapweed are introduced weeds that threaten to spread throughout the uncultivated drylands of Western Canada. By 1972 approximately 30 000 ha, mostly in British Columbia, were infested, with forage reductions of up to 88%. Presently the infestation may be increasing by 10% a year and it is estimated that 8.4–10.7 million ha are susceptible to invasion by one or the other species in Western Canada. This would be disastrous to both ranching and wildlife in the region. The economics of various options for control are discussed. Biological control, which is likely to require the introduction of six agents and cost a total of $1.8 million, is the most cost-effective solution. However, until it can be fully implemented (10–20 yr) new infestations can be spot-treated with picloram. It is also economic to convert dense stands to tame pasture after killing the knapweed with picloram at 0.5 kg/ha although the knapweed is likely to begin reinvasion after 4 yr.

Plant Protection Issues. I. A Commentary on New Weeds in the United States

1991 ◽  
Vol 5 (1) ◽  
pp. 232-237 ◽  
Author(s):  
Randy G. Westbrooks
Keyword(s):  
United States ◽  
Plant Protection ◽  
Management Strategies ◽  
The United States ◽  
Widespread Species ◽  
Legislative Authority ◽  
Chemical Pollutants ◽  
National Initiative ◽  
Foreign Commerce ◽  
Introduced Weeds

New or recently introduced weeds are biological pollutants in our natural and agricultural ecosystems. Unlike chemical pollutants, new weeds left unchecked often proliferate and pose problems that may not become apparent until eradication is too expensive or impractical. Management strategies for weeds should include: 1. prevention (from entering foreign commerce); 2. exclusion (detection of weed contaminants in imported products at ports of entry); 3. detection, containment, and eradication of incipient infestations; and 4. perpetual control (of widespread species that cannot otherwise be addressed). Appropriate legislative authority, modern weed technology, funding, and a renewed commitment to the concept of prevention are needed to prevent the introduction of new weeds. A national initiative to prevent the establishment of new weeds would be beneficial by saving on future losses and perpetual control costs. Actions taken now will prevent the continued introduction and spread of new weeds in the United States.

Does the introduced bumblebee, Bombus terrestris (Apidae), prefer flowers of introduced or native plants in Australia?

2005 ◽  
Vol 53 (1) ◽  
pp. 29 ◽  
Author(s):  
Andrew B. Hingston
Keyword(s):  
Native Species ◽  
Native Plants ◽  
Bombus Terrestris ◽  
Ecological Impacts ◽  
Food Sources ◽  
Greenhouse Crops ◽  
Introduced Plants ◽  
Feral Population ◽  
Introduced Weeds ◽  
Australian Native Plants

Proponents of importation of the European bumblebee, Bombus terrestris (L.), into Australia for pollination of commercial greenhouse crops argue that this species will have little impact on Australian native ecosystems because it prefers to forage on flowers of introduced species of plants rather than Australian native plants. However, data presented as evidence of preference for introduced plants have been equivocal. This study compared the attractiveness of introduced and Australian native plants to free-foraging B. terrestris in a garden at the interface between an urban area and native vegetation in the Australian island of Tasmania, where a feral population of B. terrestris had been established for over 10 years. No evidence was found to support the proposal that B. terrestris forages on flowers of introduced plants in preference to those of Australian native plants. The numbers of B. terrestris seen foraging per 1000 flowers did not differ significantly between introduced plants and Australian native plants, and the preferred food sources of B. terrestris included flowers of both introduced and Australian native species. Because B. terrestris forages frequently on many species of both introduced and native plants, assessments of its ecological impacts must include the effects of altered pollination on recruitment rates in both introduced weeds and native plants, and reduced quantities of nectar and pollen of native plants on recruitment rates of dependent fauna.

THE BIOLOGY OF CANADIAN WEEDS.: 63. Sonchus asper (L.) Hill and S. oleraceus L.

1984 ◽  
Vol 64 (3) ◽  
pp. 731-744 ◽  
Author(s):  
IAN HUTCHINSON ◽  
JOSEPH COLOSI ◽  
RALPH A. LEWIN
Keyword(s):  
Population Dynamics ◽  
Rapid Development ◽  
Emergence Period ◽  
Sonchus Asper ◽  
Sonchus Oleraceus ◽  
Canadian Provinces ◽  
Disturbed Habitats ◽  
Agricultural Regions ◽  
Introduced Weeds ◽  
Methods Of Control

Spiny annual sow-thistle (Sonchus asper (L.) Hill) and annual sow-thistle (S. oleraceus L.) are introduced weeds which occur in the agricultural regions of all Canadian provinces, but are most abundant in disturbed habitats in southern Quebec, Ontario, and British Columbia. They occur on a wide variety of substrates and are common weeds of waste places and gardens. Their intermittent and prolonged emergence period, rapid development to maturity, and production of large quantities of highly-dispersive seeds make them difficult to control. Details of the morphology of the annual sow-thistles, their reproductive biology (including previously unpublished material on population dynamics and seed production), their response to parasites, and methods of control are presented.Key words: Biology of Canadian weeds, Sonchus oleraceus, Sonchus asper

scholarly journals Not all weeds are created equal: A database approach uncovers differences in the sexual system of native and introduced weeds

2017 ◽  
Vol 7 (8) ◽  
pp. 2636-2642 ◽  
Author(s):  
Megan L. Van Etten ◽  
Jeffrey K. Conner ◽  
Shu-Mei Chang ◽  
Regina S. Baucom
Keyword(s):  
Sexual System ◽  
Introduced Weeds

THE BIOLOGY OF CANADIAN WEEDS.: 28. Verbascum Thapsus L. and V. Blattaria L.

1978 ◽  
Vol 58 (2) ◽  
pp. 401-413 ◽  
Author(s):  
KATHERINE L. GROSS ◽  
PATRICIA A. WERNER
Keyword(s):  
British Columbia ◽  
Plant Species ◽  
Original Research ◽  
Maritime Provinces ◽  
Southern Ontario ◽  
Verbascum Thapsus ◽  
Abandoned Fields ◽  
Introduced Weeds ◽  
Common Mullein

Verbascum thapsus L., common mullein, and V. blattaria L., moth mullein, are introduced weeds of pasture, abandoned fields, and roadsides occurring in widely-spaced, but dense patches in Southern Ontario, Quebec, the Maritime Provinces, British Columbia and throughout the U.S.A. Original research and information from other studies are incorporated into a summary of the biology of these two fugitive plant species.

Soil Seed Bank Changes after Forest Clearing and Agricultural Use in Alaska

Weed Science ◽  
1984 ◽  
Vol 32 (3) ◽  
pp. 343-347 ◽  
Author(s):  
Jeffery S. Conn ◽  
Catherine L. Cochrane ◽  
John A. Delapp
Keyword(s):  
Seed Bank ◽  
Native Species ◽  
Soil Seed Bank ◽  
Chenopodium Album ◽  
Soil Samples ◽  
Forest Species ◽  
Common Lambsquarters ◽  
Forest Clearing ◽  
Agricultural Use ◽  
Introduced Weeds

Soil samples representing a time series from forest before clearing to land in cultivation for 20 yr were taken near Delta Junction, AK, to determine the changes that occur in the soil seed bank following clearing and agricultural use. The total number of seed was initially low in the forested sites but increased after 3 to 5 yr in cultivation due to seed production by native colonizers and by introduced weeds such as common lambsquarters (Chenopodium albumL. ♯3CHEAL). Viability of seed of several mature forest species was low. There was a shift from a seed bank dominated by native species in the forest and newly cleared sites to a seed bank dominated by introduced colonizers in the older fields. Although seed of introduced species increased in importance over time, native species, especially native colonizers, continued to be an important component of the seed bank throughout the 20-yr period represented.

Historic changes in an urban watershed determined by pollen and geochemical analyses of lake sediment

1982 ◽  
Vol 19 (11) ◽  
pp. 2114-2125 ◽  
Author(s):  
Rolf W. Mathewes ◽  
John M. D'Auria
Keyword(s):  
Soil Erosion ◽  
Sediment Accumulation ◽  
Urban Watershed ◽  
Human Disturbances ◽  
Aluminum Iron ◽  
Cesium 137 ◽  
Geochemical Analyses ◽  
Coniferous Tree Species ◽  
Ornamental Trees ◽  
Introduced Weeds

A 60 cm long sediment core from Deer Lake, Burnaby, British Columbia was analyzed palynologically and geochemically in order to trace the effects of human disturbances since settlement. A settlement horizon was identified at 42.5 cm (ca. 1892) by pollen analysis. Declines in the percentages of coniferous tree species are mirrored by rapid increases in red alder and fern spores, and also by the presence of indicators of human influence, including introduced weeds, ornamental trees and herbs, and corn pollen.Geochemical analyses revealed marked increases in sedimentary aluminum, iron, potassium, titanium, and strontium soon after settlement, coinciding with declines in carbon, nitrogen, and sulfur. A corresponding shift from a highly organic gyttja to a silt- and clay-rich sediment also confirms the increased input up to the present day of inorganic sediment derived from soil erosion in the Deer Lake catchment.A peak in copper at 19 cm was attributed to the deliberate introduction of copper sulfate around 1957, and increasing lead concentrations are correlated with post-1947 traffic increases. Peak radioactivity of the fission product cesium-137 is recorded at 17 cm, probably corresponding to the maximum in above-ground bomb testing of 1963. Sediment accumulation rates were relatively constant from settlement until 1963 (0.3–0.4 cm year−1), increasing to 1.06 cm year−1 since then. An increased pollen influx since 1963 suggests a recent increase in runoff and soil erosion.

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