Suchergebnisse

Of the extant species of land mammals, 124 (2.6%) can be classed as 'successful invaders', whereas 1038 (21.6%) are classed as threatened, according to the 2006 IUCN Red List. Relatively high proportions of successful invaders are found among Artiodactyla, Carnivora, Lagomorpha and Perissodactyla. Compared with other organisms, mammals seem relatively likely to become established when introduced outside their natural range. Studies of determinants of invasion success indicate that the number of individuals released, the size of the natural range of the introduced species, and the temperateness of climate in the new range can all increase the probability of establishment of introduced mammals. Negative impacts of invasive mammals on native biodiversity include direct effects such as predation, browsing and competition, but can extend to disruption of patterns of nutrient flow, and trophic cascades. Eradication of several species of invasive mammals from increasingly large areas is now possible. In this context, it is important to better understand ecological interactions between such mammals (and between them and other species) to avoid unwanted consequences such as mesopredator or competitor release, after the removal of particular species. Finally, it is increasingly apparent that research is needed on the behaviour of dispersing and invading individuals, to improve the early detection of new mammal invasions or reinvasions.

Brushtail possums (Trichosurus vulpecula) were live-trapped for two years prior to and following depopulation in two ~6-ha areas of native forest in New Zealand. The populations had recovered to 55% of the original density at one site and 40% of the original density at the other site, two years after the depopulation. The post-removal populations responded to reduced density with a higher proportion of females breeding, higher survival rate of young, and less seasonal fluctuation in body condition. The initial recolonisation was probably mainly due to surrounding animals shifting their ranges into the depopulated area, rather than long-range dispersal, which resulted in an even sex ratio in the recovering populations. The greater proportion of adult males in the post-removal populations is likely to increase sexual contact rates for females. This would enhance the dissemination of a viral-vectored biological control agent through the population, when used as part of an integrated control program.

Rats continue to invade rat-free islands around the world, and it remains difficult to successfully intercept them before they establish populations. Successful biosecurity methods should intercept rats rapidly, before they can establish a population. Current island biosecurity practice employs techniques used for high-density rat eradication, assuming that they will be equally effective on low-density invaders. However, such approaches are often untested. Adult male Norway rats (Rattus norvegicus) were individually released onto forested rat-free islands in New Zealand to test methods of detecting and eliminating a single invader. Only half the rats released were caught within a two-week timeframe, although the mean time to interception was just under 14 days. Permanent island biosecurity surveillance systems performed better than contingency responses. Success rates were higher on islands where complete coverage could be obtained, although surveillance systems using multiple devices eventually detected most invading rats. For some rats a change of methods was necessary. Single invading rats left a rat-free island despite the presence of excessive natural food resources. With surveillance systems comprising an array of tested island biosecurity devices, and where necessary a contingency response using alternative methods, it should be possible to maintain islands as rat-free even when they have a high reinvasion rate.

The rate of biological invasions has increased dramatically over recent centuries. Alien invasive vertebrates have significant adverse effects on biodiversity, and island fauna are especially susceptible. Human-induced environmental change is likely to exacerbate these negative impacts of alien invasive species. However, invasion biology has advanced considerably over the last two decades, with improvement in understanding of the processes of establishment and spread. New developments in spatial modelling have elucidated the way in which behavioural processes at the individual level can drive population-level patterns such as spread. Combined with new genetic insights into the process of invasion, these advances may assist in the development of novel, better-targeted management strategies that provide new options in how to deal with the threat posed by invasive species. Decisions about whether to and how we should intervene are questions for all sectors of society, but research on the social and cultural impacts of invasive species is largely lacking. There are many opportunities for enhancing the social dimensions of invasive species research, and integrated assessments of the social, economic and environmental impacts of species provide one potential avenue. As part of this, there is also a need to increase stakeholder participation in the decision-making process regarding alien invasive species. These more holistic approaches are essential if we are to reduce the impact of alien invasive species to within acceptable limits in the face of rapid environmental change.

This paper presents the results of our seventh annual horizon scan, in which we aimed to identify issues that could have substantial effects on global biological diversity in the future, but are not currently widely well known or understood within the conservation community. Fifteen issues were identified by a team that included researchers, practitioners, professional horizon scanners, and journalists. The topics include use of managed bees as transporters of biological control agents, artificial superintelligence, electric pulse trawling, testosterone in the aquatic environment, building artificial oceanic islands, and the incorporation of ecological civilization principles into government policies in China.

This paper presents the results of our seventh annual horizon scan, in which we aimed to identify issues that could have substantial effects on global biological diversity in the future, but are not currently widely well known or understood within the conservation community. Fifteen issues were identified by a team that included researchers, practitioners, professional horizon scanners, and journalists. The topics include use of managed bees as transporters of biological control agents, artificial superintelligence, electric pulse trawling, testosterone in the aquatic environment, building artificial oceanic islands, and the incorporation of ecological civilization principles into government policies in China. This is the seventh annual horizon scan. A team of 24 horizon scanners, researchers, practitioners, and journalists identified 15 issues following widespread consultation and a Delphi-like process to select the most suitable.The issues were wide ranging but included artificial superintelligence, changing costs of energy storage and consumptive models, and ecological civilization policies in China.

This paper presents the results of our seventh annual horizon scan, in which we aimed to identify issues that could have substantial effects on global biological diversity in the future, but are not currently widely well known or understood within the conservation community. Fifteen issues were identified by a team that included researchers, practitioners, professional horizon scanners, and journalists. The topics include use of managed bees as transporters of biological control agents, artificial superintelligence, electric pulse trawling, testosterone in the aquatic environment, building artificial oceanic islands, and the incorporation of ecological civilization principles into government policies in China

This paper presents the results of our seventh annual horizon scan, in which we aimed to identify issues that could have substantial effects on global biological diversity in the future, but are not currently widely well known or understood within the conservation community. Fifteen issues were identified by a team that included researchers, practitioners, professional horizon scanners, and journalists. The topics include use of managed bees as transporters of biological control agents, artificial superintelligence, electric pulse trawling, testosterone in the aquatic environment, building artificial oceanic islands, and the incorporation of ecological civilization principles into government policies in China.