Introduced Mammals in a New Environment

Atkinson, I. A. E.

doi:10.1007/3-540-30023-6_4

Cited by 20 publications

(19 citation statements)

References 39 publications

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“…Losses of native biodiversity (including the extinction of endemic species) as a consequence of invasion by new mammal species have now been widely documented, especially in isolated ecosystems such as New Zealand (Atkinson 2006) and other oceanic archipelagos. It is clear that invasive mammals are capable of causing radical change to ecosystems that they invade, not only by extinguishing native prey species and altering plant communities, but also by disrupting patterns of nutrient flow.…”

Section: Changes To Ecosystem Processesmentioning

confidence: 99%

The invasion ecology of mammals: a global perspective

2008

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Abstract. 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.

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Section: Changes To Ecosystem Processesmentioning

confidence: 99%

The invasion ecology of mammals: a global perspective

2008

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“…Our species lists came primarily from Long (2003), with additional information obtained from Thomson (1922), Wodzicki (1950), King (2005) and Atkinson (2006) for New Zealand, Hinton and Dunn (1967), Myers (1986), Bentley (1998) andForsyth et al (2004) for Australia andde Vos et al (1956), Fitter (1959), Baker (1990) and Yalden (1999) for Great Britain. We included species that had a release propagule of two or more animals and excluded 10 species for which the release of a viable propagule was uncertain (Appendix 1).…”

Section: Species Datamentioning

confidence: 99%

Determinants of establishment success for introduced exotic mammals

Bomford¹,

Darbyshire²,

Randall³

2009

Wildl. Res.

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We conducted comparisons for exotic mammal species introduced to New Zealand (28 successful, 4 failed), Australia (24, 17) and Britain (15, 16). Modelling of variables associated with establishment success was constrained by small sample sizes and phylogenetic dependence, so our results should be interpreted with caution. Successful species were subject to more release events, had higher climate matches between their overseas geographic range and their country of introduction, had larger overseas geographic range sizes and were more likely to have established an exotic population elsewhere than was the case for failed species. Of the mammals introduced to New Zealand, successful species also had larger areas of suitable habitat than did failed species. Our findings may guide risk assessments for the import of live mammals to reduce the rate new species establish in the wild.

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“…The flora and fauna of New Zealand are especially vulnerable to rats because they have evolved for the last 16 million years in the absence of terrestrial mammals except bats (Atkinson 2006;Worthy et al 2006). In addition, due to many accessible islands with different rat statuses, New Zealand is a particularly appropriate system for studying the short-term effects of invasive rats.…”

Section: Introductionmentioning

confidence: 99%

Invasive rats alter woody seedling composition on seabird-dominated islands in New Zealand

2009

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Invasive rats (Rattus rattus, R. norvegicus, R. exulans) have large impacts on island habitats through both direct and indirect effects on plants. Rats affect vegetation by extirpating burrowing seabirds through consumption of eggs, chicks, and adults. These seabirds serve as ecosystem engineers, affecting plant communities by burying and trampling seeds and seedlings, and by altering microclimate. Rats also directly affect plant communities by consuming seeds and seedlings. We studied the direct and indirect impacts of rats on the seedlings of woody plants on 21 islands in northern New Zealand. We compared seedling densities and richness on islands which differed in status with respect to rats: nine islands where rats never invaded, seven islands where rats were present at the time of our study, and five islands where rats were either eradicated or where populations were likely to be small as a result of repeated eradications and re-invasions. In addition, we compared plots from a subset of the 21 islands with different burrow densities to examine the effects of burrowing seabirds on plants while controlling for other factors that differ between islands. We categorized plant communities by species composition and seedling density in a cluster analysis. We found that burrow densities explained more variation in seedling communities than rat status. In areas with high seabird burrow density seedling densities were low, especially for the smallest seedlings. Species richness and diversity of seedlings, but not seedling density, were most influenced by changes in microclimate induced by seabirds. Islands where rats had been eradicated or that had low rat populations had the lowest diversity and richness of seedlings (and adults), but the highest seedling density. Seedling communities on these islands were dominated by Pseudopanax lessonii and Coprosma macrocarpa. This indicates lasting effects of rats that may prevent islands from returning to pre-invasion states.

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Introduced Mammals in a New Environment

Cited by 20 publications

References 39 publications

The invasion ecology of mammals: a global perspective

The invasion ecology of mammals: a global perspective

Determinants of establishment success for introduced exotic mammals

Invasive rats alter woody seedling composition on seabird-dominated islands in New Zealand

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