981 resultados para INTRODUCED SPECIES


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Intertidal invertebrates are under pressure from both direct and indirect threats, the most serious being from over-exploitation, habitat loss and alteration, decline in water quality, introduced species and pathogens, and global warming. This article explores the current protective mechanisms in place that provide some protection to intertidal invertebrates in Victoria and looks at a case study of Western Port, Victoria. The results of the case study indicated a general consensus that intertidal invertebrates are not adequately protected in Victoria. The recommended actions to ensure adequate protection in the future are an amendment to current legislation, increased education and greater law enforcement, and further implementation of the concept of integrated coastal zone management.

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The aim of this study was to examine the values and attitudes held by Australasian wildlife managers as they relate to wildlife management issues, and to gain some insight into possible future directions and priorities for Australasian wildlife management. During December 2002 – February 2003, 138 questionnaires were completed by members of the Australasian Wildlife Management Society (AWMS) and registrants of the 2002 AWMS annual conference. Threatened species management, threatened communities/habitats, and management of introduced species were the issues rated as needing the highest priority for the Australasian Wildlife Management Society. Issues such as animal rights, genetically modified organisms and timber harvesting on public lands were the lowest-rating issues. Respondents expressed a strong belief in managing and controlling wildlife to achieve wildlife management objectives, a strong belief that wildlife should be protected and that wildlife managers should minimise the pain and suffering of individual animals, and a belief that resources should be directed towards conserving wildlife populations rather than protecting individual animals from non-threatened populations. While respondents held a strong belief that it is important to consult the community when developing wildlife management policies and programs, there was little support for a comanagerial approach where the community has a significant role to play in decision-making processes.

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The urban landscape encompasses a broad spectrum of variable environments ranging from remnant patches to highly modified streetscapes. Despite the expansion of urban environments, few studies have examined the influence of urbanization on faunal diversity, particularly in the Southern Hemisphere. In this study, four broad habitat types were recognized in the urban environment, representing a continuum of modification ranging from parks with remnant vegetation to streetscapes dominated by native vegetation and those dominated by exotic vegetation to recently developed streetscapes. Bird censuses were conducted at 36 sites throughout urban Melbourne, with nine sites surveyed in each habitat type. The four habitat types supported significantly different bird communities based on species richness, abundance and composition suggesting that bird assemblages of urban environments are non-uniform. Parks and native streetscapes generally supported fewer introduced species than exotic and recently developed streetscapes. Overall abundance and richness of species were lower in the exotic and recently developed streetscapes than in parks and native streetscapes. Significant differences were also observed in foraging guilds within the four habitat types, with parks having the most foraging guilds and recently developed streetscapes having the fewest. The transition from native to exotic streetscapes saw the progressive loss of insectivorous and nectarivorous species reflecting a reliance by these species on structurally diverse and/or native vegetation for both shelter and food resources. The implementation of effective strategies and incentives which encourage the planting of structurally diverse native vegetation in streetscapes and gardens should be paramount if avian biodiversity is to be retained and enhanced in urban environments. It is also critical to encourage the maintenance of the existing remnant vegetation in the urban environment.

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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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The aim of this study was to examine the values and attitudes held by Australasian wildlife managers as they relate to wildlife management issues, and to gain some insight into possible future directions and priorities for Australasian wildlife management. During December 2002 – February 2003, 138 questionnaires were completed by members of the Australasian Wildlife Management Society (AWMS) and registrants of the 2002 AWMS annual conference. Threatened species management, threatened communities/habitats, and management of introduced species were the issues rated as needing the highest priority for the Australasian Wildlife Management Society. Issues such as animal rights, genetically modified organisms and timber harvesting on public lands were the lowest-rating issues. Respondents expressed a strong belief in managing and controlling wildlife to achieve wildlife management objectives, a strong belief that wildlife should be protected and that wildlife managers should minimise the pain and suffering of individual animals, and a belief that resources should be directed towards conserving wildlife populations rather than protecting individual animals from non-threatened populations. While respondents held a strong belief that it is important to consult the community when developing wildlife management policies and programs, there was little support for a comanagerial approach where the community has a significant role to play in decision-making processes.

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There are many questions that need to be examined regarding the effect of urbanisation on bird communities. Surprisingly little research has focused on the urban environment, and its potential to contribute to the sustainability of biodiversity. During the Autumn of 2002 we conducted a study examining the effect of urbanisation on bird community structure and composition in the urban streetscape and park environment. In this study we compared the bird communities of urban woodland parks, streets dominated by established native trees, streets dominated by established exotic trees and new developments with limited established vegetation. Results from this study suggested that the composition of bird communities is highly variable and dependent on the type of site (ie: park or streetscape) and the type of vegetation present (native versus exotic). The most significant trend was the loss of native bird species in the transition from park to non-park habitats, and the loss of native bird species in exotic streetscapes when compared to native streetscapes. Introduced bird species showed an interesting relationship with more species being found in the new developments and the streetscapes with exotic vegetation. This relationship is further highlighted when the density of exotic species is examined. The proportion of the bird density attributed for by introduced birds differed significantly between the different habitat treatments. New developments and exotic streetscapes had significantly higher proportions of the bird density composed of introduced species when compared to parks and sites with native streetscapes. This talk will discuss the effect of urbanisation on avifaunal composition in Melbourne and suggest possible management recommendations.

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Powerline corridor management in Australia has traditionally focused on the complete removal of vegetation using short rotation times due to the perceived fire hazard associated with corridor vegetation. This study assessed vegetation recovery in a powerline corridor, following management, at three sites spanning corridor and forest habitat. Forest and corridor vegetation communities differed significantly between sites and over time. As vegetation recovered, the corridor community became a mix of plants common in the surrounding forest and open areas, changing within the 3-year study from a grass–fern to shrub–sedge community encroached by midstorey species. The current short rotations between management events unnecessarily maintain the corridor in a cycle of degradation, remove resources for native species and may allow introduced grasses and saplings to proliferate in the corridor. Maintaining a shrub layer would help avoid loss of species richness, encourage native species and limit colonisation opportunities of introduced species. Spot spraying emergent saplings and problem plants and mosaic slashing, would keep fire risk low and maintain biodiversity without increasing biomass to dangerous levels.

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Powerline corridors through forested ecosystems have been criticised due their potential to fragment the landscape and facilitate the intrusion of undesirable species into natural areas. This study investigates the effects of vegetation management (slashing), on: (1) timing of small mammal recolonisation; (2) vegetation characteristics that drive small mammal responses; and (3) the point where corridor resources are sufficient to provide functional habitat for native species. Small mammal trapping was undertaken within Bunyip State Park, Australia, across three sites, once a month from January 2001 to May 2002 and every 2 months thereafter until January 2004. Changes in vegetation around each trap station were assessed annually in the forest and bi-annually in the corridor. Principal components analysis on the vegetation structural complexity values produced factors for use in species abundance models. Native small mammal species recolonised the corridor 1.5–3.5 years after management and the corridor supported a breeding population of small mammals around 2.5 years post-management. Males however, generally recolonised the corridor first, resulting in a sex-biased population in these areas. Species corridor habitat models for five native and one introduced species suggested cover and shelter were more important in determining corridor use than plant species per se. Powerline corridors have the potential to create a mixture of different successional stages, enhancing habitat availability for many species. However, the intensity of current management needs to be reduced and an integrated approach to management needs to be undertaken if powerline corridors are to continuously provide habitat for native small mammal species.

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Abstract. In applying a quantitative approach to the reproduction of Trygonoptera imitata, the present study contributes to understanding the wide diversity in the reproductive biology of the family Urolophidae and provides insights to help determine phylogenetic relationships. This localised species is taken as bycatch in several inshore fisheries and potentially impacted by a range of other anthropogenic pressures, including introduced species, particularly in shallow-water pupping areas.T. imitata can be characterised as a species of comparatively lowmatrotrophic histotrophy with an extended period of relatively large eggs in utero (5–8 months) followed by rapid growth of the embryos (4–6 months). The reproductive cycle is annual with parturition occurring during late-February–April, followed immediately by ovulation. Mean size-at-birth is ~225mm total length and there is a ~1000% gain in mean wet mass from egg (15 g) to full-term embryo in utero (150 g), the lowest reported for any viviparous batoid. Litter size increases with maternal length, reaching a maximum of seven, and sex ratio of embryos is 1 : 1. Maximum length and estimates of the maturity–ogive parameters l50 and l95 are similar for females and males.

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This thesis assessed the diet of foxes within the ALCOA lease area of Anglesea to determine which native and introduced species foxes were eating. Results showed that Swamp Wallaby was regularly eaten but many other mammals, birds, insects and reptiles were also consumed. The response of native mammals to seasonal fox removal was also determined.

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Habitat destruction and fragmentation, interactions with introduced species or the relocation of animals to form new populations for conservation purposes may result in a multiplication of population bottlenecks. Examples are the translocations of koalas to French Island and its derivative Kangaroo Island population, with both populations established as insurance policies against koala extinction. In terms of population size, these conservation programs were success stories. However, the genetic story could be different. We conducted a genetic investigation of French and Kangaroo Island koalas by using 15 microsatellite markers, 11 of which are described here for the first time. The results confirm very low genetic diversity. French Island koalas have 3.8 alleles per locus and Kangaroo Island koalas 2.4. The present study found a 19% incidence of testicular abnormality in kangaroo Island animals. Internal relatedness, an individual inbreeding coefficient, was not significantly different in koalas with testicular abnormalities from that in other males, suggesting the condition is not related to recent inbreeding. It could instead result from an unfortunate selection of founder individuals carrying alleles for testicular abnormalities, followed by a subsequent increase in these alleles’ frequencies through genetic drift and small population-related inefficiency of selection. Given the low diversity and possible high prevalence of deleterious alleles, the genetic viability of the population remains uncertain, despite its exponential growth so far. This stands as a warning to other introductions for conservation reasons.

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Mitochondrial DNA (mtDNA) can be a powerful genetic marker for tracing origins and history of invasive populations. Here, we use mtDNA to address questions relevant to the understanding of invasion pathways of common starlings (Sturnus vulgaris) into Western Australia (WA) and discuss the utility of this marker to provide information useful to invasive species management. Mitochondrial sequence data indicate two geographically restricted genetic groups within Australia. Evidence of dispersal from genetically distinct sources outside the sampled range of starlings in Australia suggests increased vigilance by management agencies may be required to prevent further incursions from widely separated localities. Overall, genetic diversity in Australia was lower than in samples from the native range. Within Australia, genetic diversity was lowest in the most recently colonized area in the west, indicating that demographic bottlenecks have occurred in this area. Evidence of restricted dispersal between localities on the edge of the range expansion (ERE) in WA and other Australian sampling localities suggests that localized control within the ERE may be effective in preventing further range expansion. Signatures of spatial and demographic expansion are present in mismatch analyses from sampling localities located at the ERE, but neutrality indices did not support this finding, suggesting that the former may be more sensitive to recent expansion. Additionally, mismatch analyses support the presence of admixture, which is likely to have occurred pre-introduction. We compare our findings with those from a microsatellite study of the same samples and discuss how the mtDNA analyses used here offer valuable and unique insights into the invasion history of introduced species.

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Climate change has already been linked to significant impacts on Earth's ocean ecosystems including shifts in species geographic ranges, changes in population abundance, shits in timing of seasonal events, and establishment of introduced species (Walter et al. 2002, Parmesan and Yohe 2003). Global climate modelling for the Australian region has identified south-eastern Australia as the area that will be subject to the greatest impacts from climatic change (Lough 2009). The major changes predicted include warming of air and water, changes to wind patterns, changes to the strength and southerly extent of dominant oceanic currents flowing down the east and west coasts of Australia, changes to rainfall and run-off (distribution, timing and intensity), increasing ocean acidification, increasing exposure to UV light and sea level rise (Lough and Hobday 2011). Victorian species may be at greater risk than species in other areas of Australia, because Victorian marine waters are in a zone of predicted high climate change (Johnson et al. 2011, Wernberg et al. 2011).

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Exotic animal and plant species introduced into the Australian continent often imparted catastrophic effects on the indigenous fauna and flora. Proponents of biological control introduced the South American Cane Toad (Bufo marinus) into the sugar cane fields of Queensland in 1935. The Cane Toad is one of the most toxic bufonids and when seized by naive Australian predators, the toxin usually kills the attacker. One group of Australian squamate reptiles that are very susceptible to Cane Toad toxins is varanid lizards. Prior to Cane Toad invasion of our study area, the Adelaide River floodplain of the Northern Territory of Australia, annual mortality of adult male radio-tagged yellow-spotted Goannas (Varanus panoptes) was very low. After the arrival of toads in October 2005, all radio-tracked goannas were found dead in August 2006, most likely attempting to feed on the toads. Our results suggest that invasive Cane Toads place naive adult male Yellow-spotted Goannas at risk of possibly >90% mortality. This increase in mortality could reduce the genetic diversity and hamper long-term survival of these large carnivorous lizards.

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Invasive rodent species have established on 80% of the world's islands causing significant damage to island environments. Insular ecosystems support proportionally more biodiversity than comparative mainland areas, highlighting them as critical for global biodiversity conservation. Few techniques currently exist to adequately detect, with high confidence, species that are trap-adverse such as the black rat, Rattus rattus, in high conservation priority areas where multiple non-target species persist. This study investigates the effectiveness of camera trapping for monitoring invasive rodents in high conservation areas, and the influence of habitat features and density of colonial-nesting seabirds on rodent relative activity levels to provide insights into their potential impacts. A total of 276 camera sites were established and left in situ for 8 days. Identified species were recorded in discrete 15 min intervals, referred to as 'events'. In total, 19 804 events were recorded. From these, 31 species were identified comprising 25 native species and six introduced. Two introduced rodent species were detected: the black rat (90% of sites), and house mouse Mus musculus (56% of sites). Rodent activity of both black rats and house mice were positively associated with the structural density of habitats. Density of seabird burrows was not strongly associated with relative activity levels of rodents, yet rodents were still present in these areas. Camera trapping enabled a large number of rodents to be detected with confidence in site-specific absences and high resolution to quantify relative activity levels. This method enables detection of multiple species simultaneously with low impact (for both target and non-target individuals); an ideal strategy for monitoring trap-adverse invasive rodents in high conservation areas.