982 resultados para billygoat weed


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One potentially serious impact of environmental weed invasion is an alteration to the fuel characteristics and subsequent fire regimes of an area. Considerable global evidence indicates that environmental weed invasion may produce 'new' fuel types, but there is little documented evidence of the impact of invasive exotic species on fuel characteristics and fire regimes in south-eastern Australia. This study on the impact of invasive exotic grasses in southeastern Australia has revealed major changes to fuel characteristics, particularly fuel loads.

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The Rufous Bristlebird (Dasyornis broadbenti) is a sedentary, ground-dwelling passerine of southern Australia, which is listed as nationally vulnerable, and as near-threatened (lower risk) in Victoria. The species inhabits a variety of vegetation, including shrub thickets in coastal gullies to heathlands on limestone cliffs. This study aimed to assess the size, distribution and habitat use of a population of the subspecies D. b.  broadbenti at Portland in south-western Victoria. Monthly surveys (2002–03) were conducted on foot for 1 h after official sunrise and 1 h before official sunset, and presence of Bristlebirds recorded using vocalisations and sightings. Observations outside of the survey times were also recorded to estimate the size of territories and core area of occupancy. To quantify habitat preferences, vegetation composition and structure were measured in areas where Bristlebirds were present, as well as surrounding areas where they were not detected. The population in the survey areas was estimated at between 70 and 86 individuals in the 170-ha survey area. The estimated size of territories of eight selected pairs of Bristlebirds ranged from 0.5 to 3 ha, with core areas of occupancy ranging from 0.2 to 0.6 ha. During the nesting season (August November) Bristlebirds were detected at greater frequencies in the core area of occupancy within each territory. Significant associations were found between the presence of Bristlebirds and floristic associations dominated by the native environmental weeds Acacia sophorae and Leptospermum laevigatum. Bristlebird presence was significantly positively correlated with increasing vegetation density in the mid-canopy level (80–120 cm) indicating that vegetation structure is a key factor in habitat use.

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This paper discusses, an application of social marketing relating to pro-environmental awareness and social change. The integration of consumer behaviour theory into social marketing has been highlighted in the literature as requiring greater attention. Social marketing campaigns, like all marketing activities, rely on an understanding of stakeholders' attitudes and motivations in regard to the issue of concern, as well as towards the desired modified behaviour or lack of behaviour. The study highlights the marketing paradigms of benchmarking and social marketing in a not for profit governmental environment. Serrated Tussock has been designated as a weed of national significance and therefore the program has national implications (Thorp 2000). Even though issues associated with introduced species are less publicised than other environmental issues on the world stage, the associated environmental problems are no less severe than those caused by production and consumption activities. Weed control is a widespread problem facing individuals, communities and governments at all levels. A triangulatory approach, involving three distinct phases and incorporating both qualitative and quantitative tools, was used for the research design. The qualitative phase involved focus groups and in depth interviews with landholders, focus groups with professionals in the field and a focus group of key stakeholders. The mail survey resulted in a representative sample of 608 usable responses from the infestation area. The research conducted in this study illustrates how the various stages in the social marketing process were achieved and recommendations consistent with social marketing theory were generated.

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Results of fauna and vegetation surveys conducted around Portland Aluminium smelter between 1979 and 2004 found small mammal abundance and diversity had declined and changes in vegetation communities were related to changes in fire patterns, vegetation fragmentation and weed invasion. Small mammal numbers were greater in nearby National Parks.

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The effects of animal species (AS; Angora goats, Merino sheep or goats and sheep mixed grazed together at ratio 1:1) and stocking rate (SR; 7.5, 10 and 12.5 animals/ha) on the availability, botanical composition and sward characteristics of annual temperate pastures under continuous grazing were determined in a replicated experiment from 1981 to 1984. AS and SR had significant effects on pasture availability and composition and many AS SR interactions were detected. The pastures grazed by sheep had significantly reduced content and proportion of subterranean clover and more undesirable grasses compared with those grazed by goats. There were no differences in dry matter availabilities between goat- and sheep-grazed pastures at 7.5/ha, but at 10 and 12.5/ha goat pastures had significantly increased availabilities of green grass, dead and green clover and less weeds compared with sheep pastures. There was a significant AS SR interaction for the density of seedlings in May following pasture germination. Between July and January, the height of pastures was greater under goats than sheep but from January to March pasture height declined more on goat-grazed than on sheep-grazed pastures. There was an AS SR interaction for incidence of bare ground. Increasing the SR increased bare ground in pastures grazed by sheep but no change occurred on pastures grazed by goats. Changes in pasture characteristics due to increased SR were minimised on pastures grazed by goats but the grazing of sheep caused larger and faster changes and the pastures were damaged at the highest SR. Goats did not always select the same herbage material as sheep, changed their selection between seasons and were not less selective than sheep. Angora goats were flexible grazers and continually adapted their grazing behaviour to changing herbage conditions. Goat grazing led to an increase in subterranean clover, an accumulation of dead herbage at the base of the sward, reduced bare ground, taller pastures in spring and a more stable botanical composition. Mixed-grazed pasture characteristics were altered with SR. With careful management Angora goats on sheep farms may be used to manipulate pasture composition, to speed up establishment of subterranean clover, to decrease soil erosion and to reduce weed invasion.

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Weeds are one of the primary threats to biodiversity; however, their impacts on wildlife can vary. This research investigated the habitat value of Gorse Ulex europaeus L. and Hawthorn Crataegus monogyna Jacq. and the impacts of its removal on birds in a bushland park in Victoria. The area search method was used to survey birds in vegetation dominated by these two weeds, in native vegetation and in areas where a weed removal program was undertaken; this included revegetated areas. The highest bird species richness and abundance was found in sites dominated by the weeds. At sites where the weed removal program was in the early stages, a much lower species richness and abundance occurred. The final stage of the weed removal program, where revegetated areas were older than five years, supported high richness and abundance of birds, but not as high as that of sites dominated by the weeds; nor was the composition the same. Thus, even after five years, revegetation may not provide for the bird community that was originally supported by weeds. This is an important weed management consideration in this park, and should be for weed removal projects elsewhere

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Recent phylogenetic analyses of Albugo candida using the mitochondrial cytochrome c oxidase subunit II (cox2) gene, the nuclear ribosomal RNA large subunit (LSU) gene and the nuclear ribosomal RNA internal transcribed spacer (ITS) gene region have revealed significant genetic variation and led to the description of new species in the A. candida complex. This study examined the genetic diversity within Australian collections of A. candida from various Brassicaceae species in a range of geographic locations. Phylogenetic analysis of 31 Australian A. candida collections from 11 hosts using the rDNA ITS region, rDNA LSU region and cox2 mtDNA showed that the majority of Australian A. candida collections were the common form of A. candida. One collection from a common weed host, hairy bitter cress (Cardamine hirsuta), was found to belong to a previously reported but undescribed species, while three collections, also from C. hirsuta, were found to belong to a new undescribed species.

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Efforts to increase the productivity and sustainability of agro-ecosystems have resulted in increased research focused on generating improved microbiological inoculant technologies. Plant growth-promoting rhizobacteria (PGPR) are one area receiving increased attention due to their potential for use as biofertilizers, plant-growth promoters, and biocontrol agents for weed and disease control in farming systems (Siddiqui, 2006).

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This research found that weeds provided valuable habitat for some wildlife, but that current weed management does not adequately account for such interactions. By retaining weed structure during weed management this study showed that wildlife could remain unaffected by considered weed management.

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Riparian ecosystems are among the most degraded systems in the landscape,and there has been substantial investment in their restoration. Consequently, monitoring restoration interventions offers opportunities to further develop the science of riparian restoration, particularly how to move from small-scale implementation to a broader landscape scale. Here, we report on a broad range of riparian revegetation projects in two regions of south-western Victoria, the Corangamite and Glenelg-Hopkins Catchment Management Areas. The objectives of restoration interventions in these regions have been stated quite broadly, for example, to reinstate terrestrial habitat and biodiversity, control erosion and improve water quality. This study reports on tree and shrub composition, structure and recruitment after restoration works compared with remnant vegetation found regionally. Within each catchment, a total of 57 sites from six subcatchments were identified, representing three age-classes: <4, 4–8 and >8–12 years after treatment, as well as untreated (control) sites. Treatments comprised fencing to exclude stock, spraying or slashing to reduce weed cover, followed by planting with tube stock. Across the six subcatchments, 12 reference (remnant) sites were used to provide a benchmark for species richness, structural and recruitment characteristics and to aid interpretation of the effects of the restoration intervention. Vegetation structure was well developed in the treated sites by 4–8 years after treatment. However, structural complexity was higher at remnant sites than at treated or untreated sites due to a higher richness of small shrubs. Tree and shrub recruitment occurred in all remnant sites and at 64% of sites treated >4 years ago. Most seedling recruitment at treatment sites was by Acacia spp. This assessment provides data on species richness, structure and recruitment characteristics following restoration interventions. Data from this study will contribute to longitudinal studies of vegetation processes in riparian landscapes of south-western Victoria.