370 resultados para INVASIONS


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Reprint of the 1900 edition published by E. Leroux, Paris.

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Appendix: A. The fragment of this work preserved in the Book of Leinster. B. Chronology and genealogy of the kings of Munster and of Ireland, during the period of Scandinavian invasions. C. Maelseachlainn's description of the battle of Clontarf, from the Brussels ms. D. Genealogy of the Scandinavian chieftains named as leaders of the invasions of Ireland.

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1. Some of the most damaging invasive plants are dispersed by frugivores and this is an area of emerging importance in weed management. It highlights the need for practical information on how frugivores affect weed population dynamics and spread, how frugivore populations are affected by weeds and what management recommendations are available. 2. Fruit traits influence frugivore choice. Fruit size, the presence of an inedible peel, defensive chemistry, crop size and phenology may all be useful traits for consideration in screening and eradication programmes. By considering the effect of these traits on the probability, quality and quantity of seed dispersal, it may be possible to rank invasive species by their desirability to frugivores. Fruit traits can also be manipulated with biocontrol agents. 3. Functional groups of frugivores can be assembled according to broad species groupings, and further refined according to size, gape size, pre- and post-ingestion processing techniques and movement patterns, to predict dispersal and establishment patterns for plant introductions. 4. Landscape fragmentation can increase frugivore dispersal of invasives, as many invasive plants and dispersers readily use disturbed matrix environments and fragment edges. Dispersal to particular landscape features, such as perches and edges, can be manipulated to function as seed sinks if control measures are concentrated in these areas. 5.Where invasive plants comprise part of the diet of native frugivores, there may be a conservation conflict between control of the invasive and maintaining populations of the native frugivore, especially where other threats such as habitat destruction have reduced populations of native fruit species. 6. Synthesis and applications. Development of functional groups of frugivore-dispersed invasive plants and dispersers will enable us to develop predictions for novel dispersal interactions at both population and community scales. Increasingly sophisticated mechanistic seed dispersal models combined with spatially explicit simulations show much promise for providing weed managers with the information they need to develop strategies for surveying, eradicating and managing plant invasions. Possible conservation conflicts mean that understanding the nature of the invasive plant-frugivore interaction is essential for determining appropriate management.

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We present a framework for explaining variation in predator invasion success and predator impacts on native prey that integrates information about predator–prey naïveté, predator and prey behavioral responses to each other, consumptive and non-consumptive effects of predators on prey, and interacting effects of multiple species interactions. We begin with the ‘naïve prey’ hypothesis that posits that naïve, native prey that lack evolutionary history with non-native predators suffer heavy predation because they exhibit ineffective antipredator responses to novel predators. Not all naïve prey, however, show ineffective antipredator responses to novel predators. To explain variation in prey response to novel predators, we focus on the interaction between prey use of general versus specific cues and responses, and the functional similarity of non-native and native predators. Effective antipredator responses reduce predation rates (reduce consumptive effects of predators, CEs), but often also carry costs that result in non-consumptive effects (NCEs) of predators. We contrast expected CEs versus NCEs for non-native versus native predators, and discuss how differences in the relative magnitudes of CEs and NCEs might influence invasion dynamics. Going beyond the effects of naïve prey, we discuss how the ‘naïve prey’, ‘enemy release’ and ‘evolution of increased competitive ability’ (EICA) hypotheses are inter-related, and how the importance of all three might be mediated by prey and predator naïveté. These ideas hinge on the notion that non-native predators enjoy a ‘novelty advantage’ associated with the naïveté of native prey and top predators. However, non-native predators could instead suffer from a novelty disadvantage because they are also naïve to their new prey and potential predators. We hypothesize that patterns of community similarity and evolution might explain the variation in novelty advantage that can underlie variation in invasion outcomes. Finally, we discuss management implications of our framework, including suggestions for managing invasive predators, predator reintroductions and biological control.

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Short-hydroperiod Everglades wetlands have been disproportionately affected by reductions in freshwater inflows, land conversion and biotic invasions. Severe hydroperiod reductions in these habitats, including the Rocky Glades, coupled with proximity to canals that act as sources of invasions, may limit their ability to support high levels of aquatic production. We examined whether karst solution holes function as dry-down refuges for fishes, providing a source of marsh colonists upon reflooding, by tracking fish abundance, nonnative composition, and survival in solution holes throughout the dry season. We paired field surveys with an in situ nonnative predation experiment that tested the effects of predation by the recent invader, African jewelfish (Hemichromis letourneuxi) on native fishes. Over the 3 years surveyed, a large number of the solution holes dried before the onset of the wet season, while those retaining water had low survivorship and were dominated by nonnatives. In the experiment, mortality of eastern mosquitofish (Gambusia holbrooki) in the presence of African jewelfish was greater than that associated with deteriorating water quality. Under current water management, findings suggest that solution holes are largely sinks for native fishes, given the high frequency of drydown, extensive period of fish residence, and predation by nonnative fishes.

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Thesis (Master's)--University of Washington, 2016-06

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Anglers are a recognized vector for invasive fauna, with both intentional and accidental introductions reported worldwide. * The purpose of this study was to investigate the Iberian freshwater angler's habits and perceptions related to biological invasions, using an international and bilingual survey in Spain and Portugal. * The results showed that anglers from both countries cover great distances to fish, and that they commonly visit several places and fish during consecutive days, representing a major risk for invasions. Yet, anglers' activity patterns throughout the year are not constant: the summer months involve more intense activity and, hence, entail higher risk. * In both countries, the preferred fish species were invasive, and their introductions were reported more often than native species, with motivations being country-dependent. * The use of live bait was not frequent, but sometimes invasive species were used and the release of unused bait in the water was reported very frequently. * Most anglers recognize that introductions have environmental impacts and that anglers have an active role in intentional introductions. However, only a minority is aware of the angler's role in accidental transportation of invasive species. * These findings on anglers' behaviour patterns and perceptions may be used to model invasion risks and also improve monitoring and awareness programmes led by government agencies.

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1. Anglers are a recognized vector for invasive fauna, with both intentional and accidental introductions reported worldwide. 2. The purpose of this study 2. The purpose of this study was to investigate the Iberian freshwater angler’s habits and perceptions related to biological invasions, using an international and bilingual survey in Spain and Portugal. 3. The results showed that anglers from both countries cover great distances to fish, and that they commonly visit several places and fish during consecutive days, representing a major risk for invasions. Yet, anglers’ activity patterns throughout the year are not constant: the summer months involve more intense activity and, hence, entail higher risk. 4. In both countries, the preferred fish species were invasive, and their introductions were reported more often than native species, with motivations being country-dependent. 5. The use of live bait was not frequent, but sometimes invasive species were used and the release of unused bait in the water was reported very frequently. 6. Most anglers recognize that introductions have environmental impacts and that anglers have an active role in intentional introductions. However, only a minority is aware of the angler’s role in accidental transportation of invasive species. 7. These findings on anglers’ behaviour patterns and perceptions may be used to model invasion risks and also improve monitoring and awareness programmes led by government agencies.

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Controlling the definition of what was essentially a subjugated culture, the colonisers reserve the power to distinguish authentic aspects of the living traditions of the colonised. If the colonised argue political demands by reference to their culture, the colonisers are quick to adjudicate what is genuine in such claims. (Fannon, 1967) Since colonial invasions, Australia’s Indigenous people have weathered rapid change. While the origins of Australia’s Indigenous peoples continues to be an archaeological interest for many, how Indigenous cultures have survived, transformed and retained a sense of ‘difference’ is fundamental to understanding the diversity of Aboriginal and Torres Strait Islander cultures within this continent as both contemporaneous and historical. It is important that teachers, students and researchers within Indigenous studies remind themselves that much of the literature on Aboriginal and Torres Strait Islanders can be ideologically traced back to the emergence of ‘knowledge’ about native peoples in the context of European imperialism and expansion from the fifteenth century. Care must therefore be taken in not conveying ‘scientific’ rational knowledge as perhaps the hidden agenda or notion of assumptions of European ‘superiority’ and non-European inferiority. The recognition by the High Court of Australia (1992) abandoned the legal myth of terra nullius which based the dispossession of Indigenous land on the basis of it being considered an empty land. It could also be argued that this decision recognised that distinct customs and traditions continue to exist within the social and cultural ‘knowledge’ of Indigenous peoples of Australia. General issues and concerns relating to research design, methodology and articulation within QUT are not just confined to this university and the research project presented as a case study but are important in dealing with how Aboriginal and Torres Strait Islander students and academics participate or are employed within the university. We feel that the design and methodology of research that either covertly or overtly focuses on Indigenous Australians can no longer presume that all research will naturally follow protocols that are culturally appropriate as this appropriateness is usually defined by the institution. By no means do we feel that research should be debilitated as a result of raising these issues, but that collaborative approaches within the ‘process’ of research will address Aboriginal and Torres Strait Islander people and communities as much as the intended outcomes of research itself.

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Rapid advancements in the field of genetic science have engendered considerable debate, speculation, misinformation and legislative action worldwide. While programs such as the Human Genome Project bring the prospect of seemingly miraculous medical advancements within imminent reach, they also create the potential for significant invasions of traditional areas of privacy and human dignity through laying the potential foundation for new forms of discrimination in insurance, employment and immigration regulation. The insurance industry, which has of course, traditionally been premised on discrimination as part of its underwriting process, is proving to be the frontline of this regulatory battle with extensive legislation, guidelines and debate marking its progress.

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Complex surveillance problems are common in biosecurity, such as prioritizing detection among multiple invasive species, specifying risk over a heterogeneous landscape, combining multiple sources of surveillance data, designing for specified power to detect, resource management, and collateral effects on the environment. Moreover, when designing for multiple target species, inherent biological differences among species result in different ecological models underpinning the individual surveillance systems for each. Species are likely to have different habitat requirements, different introduction mechanisms and locations, require different methods of detection, have different levels of detectability, and vary in rates of movement and spread. Often there is a further challenge of a lack of knowledge, literature, or data, for any number of the above problems. Even so, governments and industry need to proceed with surveillance programs which aim to detect incursions in order to meet environmental, social and political requirements. We present an approach taken to meet these challenges in one comprehensive and statistically powerful surveillance design for non-indigenous terrestrial vertebrates on Barrow Island, a high conservation nature reserve off the Western Australian coast. Here, the possibility of incursions is increased due to construction and expanding industry on the island. The design, which includes mammals, amphibians and reptiles, provides a complete surveillance program for most potential terrestrial vertebrate invaders. Individual surveillance systems were developed for various potential invaders, and then integrated into an overall surveillance system which meets the above challenges using a statistical model and expert elicitation. We discuss the ecological basis for the design, the flexibility of the surveillance scheme, how it meets the above challenges, design limitations, and how it can be updated as data are collected as a basis for adaptive management.

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Background Invasive species pose a significant threat to global economies, agriculture and biodiversity. Despite progress towards understanding the ecological factors associated with plant invasions, limited genomic resources have made it difficult to elucidate the evolutionary and genetic factors responsible for invasiveness. This study presents the first expressed sequence tag (EST) collection for Senecio madagascariensis, a globally invasive plant species. Methods We used pyrosequencing of one normalized and two subtractive libraries, derived from one native and one invasive population, to generate an EST collection. ESTs were assembled into contigs, annotated by BLAST comparison with the NCBI non-redundant protein database and assigned gene ontology (GO) terms from the Plant GO Slim ontologies. Key Results Assembly of the 221 746 sequence reads resulted in 12 442 contigs. Over 50 % (6183) of 12 442 contigs showed significant homology to proteins in the NCBI database, representing approx. 4800 independent transcripts. The molecular transducer GO term was significantly over-represented in the native (South African) subtractive library compared with the invasive (Australian) library. Based on NCBI BLAST hits and literature searches, 40 % of the molecular transducer genes identified in the South African subtractive library are likely to be involved in response to biotic stimuli, such as fungal, bacterial and viral pathogens. Conclusions This EST collection is the first representation of the S. madagascariensis transcriptome and provides an important resource for the discovery of candidate genes associated with plant invasiveness. The over-representation of molecular transducer genes associated with defence responses in the native subtractive library provides preliminary support for aspects of the enemy release and evolution of increased competitive ability hypotheses in this successful invasive. This study highlights the contribution of next-generation sequencing to better understanding the molecular mechanisms underlying ecological hypotheses that are important in successful plant invasions.