Conservation and restoration of New Zealand Island ecosystems

Towns, David R.; Ballantine, W.J.

doi:10.1016/0169-5347(93)90009-e

Cited by 68 publications

(36 citation statements)

References 3 publications

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“…This strategy has saved entire species from extinction by meeting the first critical step of allowing endangered populations to recover demographically (e.g. cheetah, Acinonyx jubatus [4]; Chatham Island black robin, Petroica traversi [5,6]; Mexican wolf, Canis lupus baileyi [7]; takahe, Porphyrio hochstetteri [8]). A number of risks, however, are inherent in the translocation and isolation of limited numbers of individuals to represent species.…”

Section: Introductionmentioning

confidence: 99%

Genetic consequences of a century of protection: serial founder events and survival of the little spotted kiwi (Apteryx owenii)

et al. 2013

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We present the outcome of a century of post-bottleneck isolation of a long-lived species, the little spotted kiwi (Apteryx owenii, LSK) and demonstrate that profound genetic consequences can result from protecting few individuals in isolation. LSK were saved from extinction by translocation of five birds from South Island, New Zealand to Kapiti Island 100 years ago. The Kapiti population now numbers some 1200 birds and provides founders for new populations. We used 15 microsatellite loci to compare genetic variation among Kapiti LSK and the populations of Red Mercury, Tiritiri Matangi and Long Islands that were founded with birds from Kapiti. Two LSK native to D'Urville Island were also placed on Long Island. We found extremely low genetic variation and signatures of acute and recent genetic bottleneck effects in all four populations, indicating that LSK have survived multiple genetic bottlenecks. The Long Island population appears to have arisen from a single mating pair from Kapiti, suggesting there is no genetic contribution from D'Urville birds among extant LSK. The N e /N C ratio of Kapiti Island LSK (0.03) is exceptionally low for terrestrial vertebrates and suggests that genetic diversity might still be eroding in this population, despite its large census size.

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Section: Introductionmentioning

confidence: 99%

Genetic consequences of a century of protection: serial founder events and survival of the little spotted kiwi (Apteryx owenii)

et al. 2013

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“…In their race against biodiversity erosion, conservation managers are often faced with dilemmas and the resulting choices often translate into a need to give priority to fighting simple direct causes of species loss, leaving little space for interacting processes. In the context of biological invasions, a major cause of population extinctions, this often amounts to controlling invading predators to protect local animal communities (Diamond & Veitch 1981;Towns & Ballantine 1993;Courchamp et al 2003). Yet, processes that are less obvious than direct predation can operate even in very simple systems such as insular ecosystems (Glen & Dickman 2005), which makes risky the necessary removal of exotic predators.…”

Section: Introductionmentioning

confidence: 99%

Rats dying for mice: Modelling the competitor release effect

Caut¹,

et al. 2007

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Introduced vertebrate predators are one of the most important threats to endemic species throughout a range of ecosystems, in particular on islands in biodiversity hot spots. Consequently, the reduction of predator numbers is considered a key conservation action in the management of many native vertebrates vulnerable to predators. It is now established that control attempts may affect non-target species through trophic interactions, but little is known concerning their consequences on competitive relationships. We study a mathematical model mimicking the effects of controlling introduced species in the presence of their competitors.We used two competing rodents to illustrate our study: black rats, Rattus rattus, and mice, Mus musculus. Analyses of the model show that control of only one introduced species logically results in the dramatic increase of the overlooked competitor. We present empirical data that confirm our theoretical predictions. Less intuitively, this process, which we term 'the competitor release effect', may also occur when both introduced competitors are simultaneously controlled. In our setting, controlling both predators can promote their coexistence. This occurs as soon as the inferior competitor benefits from the differential effect of the simultaneous control of both competitors, that is, when the indirect positive effect of control (the removal of their competitors) exceeds its direct negative effect (their own removal). Both control levels and target specificity have a direct influence on the extent of this process: counter-intuitively, the stronger and more specific the control, the greater the effect. The theoretical validation of the competitor release effect has important implications in conservation, especially for control management.

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“…But there have not been significantly more groundnesting species driven to extinction in the period since these predators were introduced (E 3 ). One possible explanation is that predators significantly reduce the populations of ground-nesting species but many vulnerable species have escaped absolute extinction by persisting in small numbers in protected areas, such as offshore islands [75].…”

Section: Discussionmentioning

confidence: 99%

Reconstructing past species assemblages reveals the changing patterns and drivers of extinction through time

et al. 2012

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Predicting future species extinctions from patterns of past extinctions or current threat status relies on the assumption that the taxonomic and biological selectivity of extinction is consistent through time. If the driving forces of extinction change through time, this assumption may be unrealistic. Testing the consistency of extinction patterns between the past and the present has been difficult, because the phylogenetically explicit methods used to model present-day extinction risk typically cannot be applied to the data from the fossil record. However, the detailed historical and fossil records of the New Zealand avifauna provide a unique opportunity to reconstruct a complete, large faunal assemblage for different periods in the past. Using the first complete phylogeny of all known native New Zealand bird species, both extant and extinct, we show how the taxonomic and phylogenetic selectivity of extinction, and biological correlates of extinction, change from the pre-human period through Polynesian and European occupation, to the present. These changes can be explained both by changes in primary threatening processes, and by the operation of extinction filter effects. The variable patterns of extinction through time may confound attempts to identify risk factors that apply across time periods, and to infer future species declines from past extinction patterns and current threat status.

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Conservation and restoration of New Zealand Island ecosystems

Cited by 68 publications

References 3 publications

Genetic consequences of a century of protection: serial founder events and survival of the little spotted kiwi (Apteryx owenii)

Genetic consequences of a century of protection: serial founder events and survival of the little spotted kiwi (Apteryx owenii)

Rats dying for mice: Modelling the competitor release effect

Reconstructing past species assemblages reveals the changing patterns and drivers of extinction through time

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