Managing invasive plants on sub-Antarctic Macquarie Island

2017 ◽  
Vol 39 (6) ◽  
pp. 537 ◽  
Author(s):  
Brian M. Sindel ◽  
Paul E. Kristiansen ◽  
Susan C. Wilson ◽  
Justine D. Shaw ◽  
Laura K. Williams
Keyword(s):  
Invasive Plant ◽  
Native Plants ◽  
Soil Seed Bank ◽  
Cold Climate ◽  
Grass Species ◽  
Ecosystem Structure ◽  
Weed Species ◽  
Stellaria Media ◽  
Weed Invasion ◽  
Macquarie Island

The Antarctic region is one of the most inhospitable frontiers on earth for weed invasion. On Australia’s world heritage sub-Antarctic Macquarie Island only three species of invasive weeds are well established (Poa annua L., Stellaria media (L.) Vill. and Cerastium fontanum Baumg.), although isolated occurrences of other species have been found and removed. These weed species are believed to have initially been introduced through human activity, a threat which is likely to increase, although strict biosecurity is in place. All three weeds are palatable and may have been suppressed to some extent by pest herbivore (rabbit) grazing. Given the high conservation value of Macquarie Island and threats to ecosystem structure and function from weed proliferation following rabbit eradication, well targeted invasive plant control management strategies are vital. We propose that a successful restoration program for Australia’s most southerly rangeland ecosystem should integrate both control of non-native plants as well as non-native herbivores. Of the non-native plants, S. media may most easily be managed, if not eradicated, because of its more limited distribution. Little, however, is known about the soil seed bank or population dynamics after rabbit eradication, nor the effect of herbicides and non-chemical control methods in cold conditions. A current research project on this non-grass species is helping to fill these knowledge gaps, complementing and building on data collected in an earlier project on the ecology and control of the more widespread invasive grass, P. annua. With an interest in off-target herbicide impacts, our work also includes a study of the movement and fate of herbicides in the cold climate Macquarie Island soils. Research in such a remote, cold, wet and windy place presents a range of logistical challenges. Nevertheless, outcomes are informing the development of effective, low-impact control or eradication options for sub-Antarctic weeds.

scholarly journals Weed flora and weed management of field peas in Finland

2008 ◽  
Vol 14 (2) ◽  
pp. 189 ◽  
Author(s):  
J. SALONEN ◽  
T. HYVÖNEN ◽  
H. JALLI
Keyword(s):  
Weed Management ◽  
Chenopodium Album ◽  
Good Control ◽  
Organic Production ◽  
Grass Species ◽  
Weed Species ◽  
Stellaria Media ◽  
Cropping Practices ◽  
Weed Flora ◽  
Crop Stand

The composition of the weed flora of dry pea (Pisum sativum L.) fields and cropping practices were investigated in southwestern Finland. Surveys were done in 2002–2003 in 119 conventionally cropped fields and 64 fields under organic cropping. Herbicides were applied to 92% of conventionally cropped fields where they provided relatively good control but were costly. Weeds were controlled mechanically only in five fields under organic production. A total of 76 weed species were recorded, of which 29 exceeded the 10% frequency level of occurrence. The average number of weed species per field was 10 under conventional cropping and 18 under organic cropping. The most frequent weed species in both cropping practices were Chenopodium album, Stellaria media and Viola arvensis. Elymus repens was the most frequent grass species. The difference in species composition under conventional and organic cropping was detected with Redundancy Analysis. Under conventional cropping, features of crop stand and weed control explained 38.7% and 37.6% of the variation respectively. Under organic cropping the age of crop stand and field location (y co-ordinate) respectively explained best the variation. Weeds could be efficiently managed with herbicides under conventional cropping, but they represented a significant problem for organic production. Mixed cultivation of pea with cereals is recommended, particularly for organic cropping, as it favours crop competition against weeds.;

scholarly journals Weeds in spring cereal fields in Finland - a third survey

2001 ◽  
Vol 10 (4) ◽  
pp. 347-364 ◽  
Author(s):  
J. SALONEN ◽  
T. HYVÖNEN ◽  
H. JALLI
Keyword(s):  
Average Density ◽  
Grass Species ◽  
Species Number ◽  
Total Biomass ◽  
Weed Species ◽  
Stellaria Media ◽  
Organic Farms ◽  
Weed Biomass ◽  
Cereal Fields ◽  
Crop Stand

A survey of weeds in spring cereal fields was conducted in 16 regions of southern and central Finland in 1997-1999. Data were collected from conventional and organic farms, both of which applied their normal cropping practices. A total of 690 fields were investigated by counting and weighing the weed species from ten sample quadrats 0.1 m2 in size in late July - early August. Altogether 160 weed species were found, of which 134 were broad-leaved and 26 grass species. The total number of weed species ranged from 41 to 84 between regions. In organically farmed fields, the average species number was 24 and in conventionally farmed fields 16. The most frequent weed species were Viola arvensis 84%, Stellaria media 76% and Galeopsis spp. 70%. Only 18 species exceeded the frequency level of 33%. The average density of weeds was 136 m-2 (median= 91) in sprayed conventional fields, 420 m-2 (374) in unsprayed conventional fields and 469 m-2 (395) in organic fields. The average air-dry above-ground biomass of weeds was 163 kg ha-1 (median=63), 605 kg ha-1 (413) and 678 kg ha-1 (567), respectively. Weed biomass accounted for 3% of the total biomass of the crop stand in sprayed conventional fields and for 17% in organic fields. Elymus repens, the most frequent grass species, produced the highest proportion of weed biomass.

scholarly journals Composition of weed flora in spring cereals in Finland - a fourth survey

2008 ◽  
Vol 20 (3) ◽  
pp. 245 ◽  
Author(s):  
J. SALONEN ◽  
T. HYVÖNEN ◽  
H. JALLI
Keyword(s):  
Crop Production ◽  
Average Density ◽  
Grass Species ◽  
Species Number ◽  
Weed Species ◽  
Stellaria Media ◽  
Weed Flora ◽  
Elymus Repens ◽  
Spring Cereals ◽  
Galium Spurium

The weed flora in conventionally and organically grown spring cereals was investigated in southern and central Finland during 2007–2009. The survey was conducted in 16 regions, 283 farms and 595 fields (72 organically cropped and 523 conventionally cropped fields, of which 503 were treated with herbicides). The occurrence of weeds was assessed in late July–early August. Altogether 148 weed species were identified, of which 128 were broad-leaved and 20 grass species. In organically cropped fields, the average species number per field was 21 and the most frequent species were Chenopodium album 96%, Stellaria media 94%, Viola arvensis 94% and Elymus repens 89%. In conventionally cropped fields, the average species number was 12 and the most frequent weed species were Viola arvensis 83%, Stellaria media 65%, Galeopsis spp. 59% and Galium spurium 59%. The average density of weeds was 160 m-2 (median = 112) in sprayed conventional fields and 519 m-2 (468) in organic fields. The average air-dry biomass of weeds was 167 kg ha-1 (median = 82) and 775 kg ha-1 (563), respectively. Elymus repens, the most frequent and abundant grass species, produced the highest proportion (about 30%) of the total weed biomass in both cropping systems. The frequency of Galium spurium in conventional cropping and Fumaria officinalis in organic cropping had increased substantially since the previous survey in 1997–1999. The average size of the weed seedbank in the 5 cm surface layer was about 1 700 seeds m-2, the most predominant seeds being of C. album. Although the weed flora in Finnish spring cereal fields consists of numerous species, only a fraction of them severely threaten crop production in terms of their frequency and abundance. Weeds in conventional cropping were effectively controlled with available herbicides whereas weed management in organic cropping calls for urgent measures such as direct mechanical weed control in crop stands, which was not practised at all in survey fields.;

scholarly journals Weed flora in organically grown spring cereals in Finland

2001 ◽  
Vol 10 (3) ◽  
pp. 231-242 ◽  
Author(s):  
J. SALONEN ◽  
T. HYVÖNEN ◽  
H. JALLI
Keyword(s):  
Chenopodium Album ◽  
Control Measures ◽  
Grass Species ◽  
Total Biomass ◽  
Weed Species ◽  
Stellaria Media ◽  
Weed Flora ◽  
Elymus Repens ◽  
Spring Cereals ◽  
Organically Grown

The weed flora in organically grown spring cereals was investigated in southern and central Finland in 1997-1999 with the primary purpose of determining the species composition and the level of weed infestation. Altogether 165 fields were surveyed in the middle of the growing season. A total of 126 weed species were found, of which 42 exceeded the frequency level of 10%. The most frequent weed species were Chenopodium album, Stellaria media, Galeopsis spp. and Viola arvensis. Elymus repens was the most frequent grass species. The average density of weeds was 469 plants m-2 (median 395), and the air-dry biomass was 678 kg ha-1 (median 567) which accounted for 17% of the total biomass of the crop stand. Infestation by Chenopodium album and the perennial species Elymus repens, Cirsium arvense and Sonchus arvensis is of major concern. Weed control strategies should include direct control measures to overcome weed problems related to the conversion period from conventional to organic growing.

Predicting weed invasion in Canada under climate change: Evaluating evolutionary potential

2012 ◽  
Vol 92 (6) ◽  
pp. 1013-1020 ◽  
Author(s):  
David R. Clements ◽  
Antonio DiTommaso
Keyword(s):  
Climate Change ◽  
Range Expansion ◽  
Invasive Plant ◽  
Perennial Grass ◽  
High Growth ◽  
The United States ◽  
Japanese Knotweed ◽  
Weed Species ◽  
Evolutionary Potential ◽  
Weed Invasion

Clements, D. R. and DiTommaso, A. 2012. Predicting weed invasion in Canada under climate change: Evaluating evolutionary potential. Can. J. Plant Sci. 92: 1013–1020. Many weed species have already advanced northward from the United States into Canada, and their number threatens to increase with warming trends under climate change. For many weed species, this range expansion can be attributed to evolutionary adaptation by northern populations occurring in areas experiencing warmer climates and longer growing seasons in recent decades. In this paper, we examine the potential for invasive plant species to be selected for one or more of 10 character traits: (1) high growth rate, (2) wide climatic or environmental tolerance, (3) short generation time, (4) prolific or consistent reproduction, (5) small seed size, (6) effective dispersal, (7) uniparental reproduction capacity, (8) no specialized germination requirements, (9) high competitive ability, and (10) effective defenses against natural enemies. If any one of these traits is selected for in an invasive species, it would provide the affected species with the potential for a more expansive invasion range than anticipated by models that assume a static genotype. Four weed species of interest exhibiting potential northward range expansion within North America were evaluated: an obligatory outcrossing annual dicot, Himalayan balsam (Impatiens glandilifera Royle), a mostly selfing annual dicot, velvetleaf (Abutilon theophrasti Medic.), a perennial dicot that reproduces via rhizomes but forms fertile hybrids, Japanese knotweed [Fallopia japonica (Houtt.) Ronse Decr.], and a primarily selfing perennial grass, johnsongrass [Sorghum halapense (L.) Pers.]. Evidence for potential evolutionary responses to climate change was observed among particular traits for each of the four species, despite population genetic differences. The population genetics of invasive plants are difficult to model, as is climate change itself, but consideration of weed evolution to whatever degree possible should lead to improved predictive power of such models.

SIMULATION OF INTEGRATED CONTROL STRATEGIES FOR OROBANCHE SPP. BASED ON A LIFE CYCLE MODEL

2001 ◽  
Vol 37 (1) ◽  
pp. 37-51 ◽  
Author(s):  
E. KEBREAB ◽  
A. J. MURDOCH
Keyword(s):  
Seed Bank ◽  
Control Strategies ◽  
Soil Seed Bank ◽  
Integrated Control ◽  
Integrated Approach ◽  
Cultural Control ◽  
Computer Simulation Model ◽  
Weed Species ◽  
Hand Weeding ◽  
High Level

A computer simulation model was developed to investigate strategies for control of the parasitic weed species of Orobanche. The model makes use of data from published literature and predicts infestation levels in a dynamic and deterministic way. It is predicted that sustainable control of the parasite can only be achieved by reducing the soil seed bank to levels of 1000–2000 seeds m−2 and maintaining it at that level in subsequent years. When cultural control methods such as hand weeding, trap/catch cropping, delayed planting, resistant cultivars and solarization were considered individually, a relatively high level of effectiveness was required to contain the soil seed bank. An integrated approach with a selection of appropriate cultural methods is therefore recommended for further testing and validation in the field. The simulations demonstrate the importance of preventing new seeds entering the soil seed bank and that although reducing the soil seed bank may not increase yield for the first few years, it will ultimately increase production.

scholarly journals Distribution of Blue Bull (Boselaphus tragocamelus) and its Conservation Threats in Bardia National Park, Nepal

2020 ◽  
Vol 2 (1) ◽  
pp. 50-60
Author(s):  
Pramila Koirala ◽  
Bijaya Neupane ◽  
Thakur Silwal ◽  
Bijaya Dhami ◽  
Siddhartha Regmi ◽  
...  
Keyword(s):  
National Park ◽  
Habitat Management ◽  
Invasive Plant ◽  
Flash Flood ◽  
Local Level ◽  
Buffer Zone ◽  
Grass Species ◽  
Zone Field ◽  
Conservation Threats ◽  
And Control

Blue bull is Asia’s largest antelope, a species of least concern in IUCN Red data list of 2020. In Nepal, it is vulnerable and is often considered as a problem animal for its crop raiding habit. Although, its population is restricted in India and Nepal, there are insufficient studies conducted on the distribution and threats of the species at local level. This study aimed to assess the distribution of blue bull and its conservation threats in Bardia National Park and its buffer zone. Field survey was carried out to identify the potential area with the information provided by park staff and buffer zone people and by the transect method in the selected habitat to determine the distribution of blue bull population. Additionally, six focus group discussions (1 in each of thefive sites and 1 with park staff) and a half-day workshop (involving 25 participants representing each site and park office) were organized to assess the existing threats to the species. Data were analyzed descriptively using MS Excel, while the distribution map was prepared using Arc GIS. Also, 8 major identified threats were ranked using relative threat ranking procedure and classified into four severity classes. We found that the population of blue bull was dispersed from core area of Bardia National Park towards the buffer zone area. Open grazing, invasive species, predation by tiger and flash flood were the major threats to the blue bull as perceived by the local people. Habitat management activities including control of grazing, removal of invasive plant species, plantation of palatable grass species, increase in other prey species of tiger and control of flood in blue bull’s habitats are recommended to protect the species and thus sustain their threatened population.

scholarly journals Relation between Soil Weed Seedbank and Weed Management Practises and Diversity in Farms in Kisii Central Sub County, Nyanza

2020 ◽  
Vol 10 ◽  
pp. 1-14
Author(s):  
Charles N. Nyamwamu ◽  
Rebecca Karanja ◽  
Peter Mwangi
Keyword(s):  
Seed Bank ◽  
Weed Management ◽  
Management Practices ◽  
Soil Seed Bank ◽  
Shannon Index ◽  
Weed Seed ◽  
Weed Species ◽  
Western Kenya ◽  
Weed Diversity ◽  
Hand Weeding

This study sought to determine the relation between soil weed seed bank and weed management practices and diversity in farms in Kisii Central Sub County, Western Kenya. Eight administrative sub-locations were randomly selected. Ten farms were selected at equal distance along transect laid across each sub-location. Weed soil seed bank was assessed from soil samples collected from each of the farms; a sub-sample was taken from a composite sample of ten soil cores of 5cm diameter and 15cm deep and placed in germination trays in a greenhouse. Weed diversity in soil weed seedbank was calculated using the Shannon index (H’). Twelve weed species from 12 genera of nine families were recorded. Diversity of the weed species in soil weed seed bank was (H'=1.48). Weed management practises significantly affected weed species soil weed seedbank reserves. Use of inefficient and ineffective hand-weeding techniques resulted in high weed species diversity and abundance.

scholarly journals Weeds Interference in Pequi Plants

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
D.A. MARTINS ◽  
A. JAKELAITIS ◽  
A.C. COSTA ◽  
G.M.A. ALMEIDA ◽  
R.O. SILVA FILHO
Keyword(s):  
Additional Treatment ◽  
Grass Species ◽  
Photochemical Quenching ◽  
Forage Grass ◽  
Effective Quantum Yield ◽  
Weed Species ◽  
Juvenile Period ◽  
Ps Ii ◽  
Physiological Variables ◽  
Fruit Species

ABSTRACT: Pequi plants are native fruit species of the Cerrado and is at risk of extinction due to the destruction of native vegetation and the extraction of their fruits. Because this species has a long juvenile period, it becomes susceptible to the interference of weeds, mainly forage grass. This research aimed to evaluate the effects of forage grass species coexisting with small seedlings. The treatments, arranged in a factorial scheme, consisted of three weed species(Melinis minutiflora, Paspalum notatumandUrochloa decumbens)coexisting in four densities (1, 2, 3, and 4 plants per pot) with pequi plants. As an additional treatment a pequi plant was cultivated free of coexistence. The physiological variables photosynthetic rate (A), stomatal conductance (gs), transpiration rate (E) Ci/Ca relation, the effective quantum yield of PS II, transport rate of electrons and non-photochemical quenching, and growth variables: height (PH), Leaf area (LA) and dry matter (DM) were affected by weed coexistence.U. decumbenspromoted greater intensity interference with pequi plants. The degree of interference was greater with increasing density of weeds, with linear decreasing behavior for the variables A, gs, E, PH, LA, MD, stem diameter and number of leaves of pequi plants.

scholarly journals Seed shattering phenology at soybean harvest of economically important weeds in multiple regions of the United States. Part 2: grass species

Weed Science ◽  
2020 ◽  
pp. 1-19
Author(s):  
Lauren M. Schwartz-Lazaro ◽  
Lovreet S. Shergill ◽  
Jeffery A. Evans ◽  
Muthukumar V. Bagavathiannan ◽  
Shawn C. Beam ◽  
...  
Keyword(s):  
The United States ◽  
Grass Species ◽  
Annual Grass ◽  
Weed Seed ◽  
Weed Species ◽  
Seed Shattering ◽  
Physiological Maturity ◽  
Rate Of Progression ◽  
Multiple Regions ◽  
Grass Weed

Abstract Seed shatter is an important weediness trait on which the efficacy of harvest weed seed control (HWSC) depends. The level of seed shatter in a species is likely influenced by agroecological and environmental factors. In 2016 and 2017, we assessed seed shatter of eight economically important grass weed species in soybean [Glycine max (L.) Merr.] from crop physiological maturity to four weeks after maturity at multiple sites spread across eleven states in the southern, northern, and mid-Atlantic U.S. From soybean maturity to four weeks after maturity, cumulative percent seed shatter was lowest in the southern U.S. regions and increased as the states moved further north. At soybean maturity, the percent of seed shatter ranged from 1 to 70%. That range had shifted to 5 to 100% (mean: 42%) by 25 days after soybean maturity. There were considerable differences in seed shatter onset and rate of progression between sites and years in some species that could impact their susceptibility to HWSC. Our results suggest that many summer annual grass species are likely not ideal candidates for HWSC, although HWSC could substantially reduce their seed output at during certain years.

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