Kemp J.,Science and Technical Group |
O'Donnell C.F.J.,Science and Technical Group
New Zealand Journal of Zoology | Year: 2013
In New Zealand, the toxin sodium fluoroacetate (compound 1080) is used to reduce numbers of introduced brushtail possums (Trichosurus vulpecula) to enhance forest condition and reduce bovine tuberculosis (Tb) infection in livestock. However, there is concern that the use of toxins may cause mortality in non-target species. We investigated the effect of possum control using aerially applied cereal baits containing 1080 on 36 radio-tagged South Island fernbirds (Bowdleria punctata punctata) in winter 2010. During monitoring, five fernbirds dropped their transmitters, one was killed by a predator and three died of 1080 poisoning (a mortality rate from 1080 poisoning of 9.4%, 95% CI = 2.4-22.6%). This study suggests that acute impacts of aerial 1080 operations on fernbird numbers are small and the observed impact could be outweighed by improved productivity and survival resulting from the reduction of impacts caused by introduced mammalian predators that die from 1080 poisoning. © 2013 The Royal Society of New Zealand.
Anderson L.,Victoria University of Wellington |
Cree A.,University of Otago |
Towns D.,Science and Technical Group |
Nelson N.,Victoria University of Wellington
General and Comparative Endocrinology | Year: 2014
Baseline and stress response glucocorticoid (GC) secretion can be modulated by individuals to support activities and physiological functions connected with reproduction (migration, mating, oviposition and/or parturition, care of young). Corticosterone (CORT) is the primary GC in reptiles and, in accordance with other vertebrates, an adrenocortical stress response is observed. Modulation of CORT secretion occurs in several reptile species, such that elevated baseline CORT concentration and/or a dampened CORT response are common during reproductive life-history events. We investigated CORT secretion after 24. h capture-restraint in the oviparous tuatara ( Sphenodon punctatus), the last living rhynchocephalian, and tested whether gravid females have a dampened CORT response compared with non-gravid females. We also included males as a comparison. We confirmed that gravid females have significantly higher baseline plasma CORT concentrations than non-gravid females, suggesting increased CORT secretion during nesting. Furthermore, we found that gravid females exhibit a dampened CORT response compared to non-gravid females and males. Our results demonstrate that female reproductive condition influences CORT secretion in tuatara, and suggest that gravid females modulate CORT secretion during nesting to maintain homeostasis, effectively increasing chances of reproductive success and promoting overall fitness. © 2014 Elsevier Inc.
Cromarty P.L.,Science and Technical Group |
Alderson S.L.,Business Services Group
Notornis | Year: 2013
In New Zealand, translocation of native species is increasingly being proposed and carried out by community groups as well as the Department of Conservation (DOC).Usually a formal translocation proposal needs to be prepared and approved.Trends in the number and type of proposals approved during 2002-2010 are discussed.Over 300 translocation proposals were approved in this period.Many proposals consisted of more than one transfer.In 2002, proposals from community groups and joint proposals with DOC made up 16% of the approved proposals.In 2005 this had increased to 58%, but it dropped down to 38% in 2007 and in 2010 it had again increased to 71%.Proposals to move birds made up the largest proportion of applications (74%), followed by reptiles (15%), plants (6%) and invertebrates (5%).Kiwi (Apteryx spp.), robin (Petroica spp.), North Island kokako (Callaeas wilsoni) and seabird species (including Procellariformes, Spheniscidae and Laridae) were the most commonly translocated species.In response to the increased number of applications from community groups to carry out translocations, DOC has revised and improved the process for carrying out native species translocation projects.© The Ornithological Society of New Zealand, Inc.
Dowding J.E.,DM Consultants |
O'Connor S.M.,Science and Technical Group
Notornis | Year: 2013
The shore plover (Thinornis novaeseelandiae) is a highly threatened shorebird endemic to New Zealand.It is particularly susceptible to introduced mammalian predators, and has a very small total population and a very limited range.This paper lists the translocations that have formed the core of the shore plover recovery programme over the past 22 years, and summarises the outcomes.In the early 1990s, a captive population was established in mainland New Zealand using birds reared from eggs transferred from the last self-sustaining wild population on the Chatham Islands.Since 1994, captive-bred birds have been released on 5 offshore islands around the New Zealand mainland in attempts to found new populations.There have also been transfers of wild-bred birds from South East I to Mangere I in the Chatham Is.Between 1994 and April 2012, 404 juvenile and 28 adult shore plover have been released at a total of 6 sites.Birds bred at 4 of the 6 sites, and breeding populations established at 3 of them.However, recent mammalian predator incursions at 1 (and probably 2) of those, and habitat limitation at the 3rd, mean that the translocated populations are all currently small (6 pairs or less), and their long-term future is uncertain.Other challenges faced during the programme include avian predation of released birds, high rates of dispersal, and outbreaks of avian pox.In spite of recent setbacks, the risk of extinction for the species has gradually been reduced.Since 1990, a self-sustaining captive population has been set up, the number of breeding pairs has increased, and the number of breeding populations in the wild has risen from 2 to 4 (although 1 is currently facing extirpation).Features of the shore plover programme that have contributed to these outcomes are outlined.Aspects of shore plover ecology revealed by the translocations are noted.While progress has been made, existing populations will need to grow, and further populations will need to be established before the shore plover's threat ranking improves.© The Ornithological Society of New Zealand, Inc.
Holzapfel S.A.,Science and Technical Group |
Dodgson J.,71 C Waiwera Street |
Rohan M.,Auckland University of Technology
Plant Ecology | Year: 2015
The conservation and translocation of threatened holoparasitic flowering plants provide added challenges due to their complete host dependency and often large knowledge gaps of their autecology. Here, we present the first successful, quantified field trial to establish from seed populations of dactylanthus (Dactylanthus taylorii, Mystropetalaceae), a threatened New Zealand endemic root-holoparasitic angiosperm. Establishment was monitored at four sites at Waipapa, Pureora Forest Park. The impact of two different sowing methods (broad- and central-sown), canopy state (as a proxy for soil moisture levels) and three dominant host species were tested. Establishment of dactylanthus was confirmed in 22 out of 24 plots 10 years after sowing, with earliest emergence after 4 years. Average and maximum inflorescence numbers per plot were similar to those of protected wild populations. The only open-canopy site performed worse in comparison with a closed-canopy site sharing the same dominant host species; differences in root availability and survival of the desiccation-sensitive seeds were regarded as the most likely explanations. Host species dominance had a significant impact on inflorescence numbers, indicating host preference in the species despite a wide host range. In contrast to longer-established wild populations, most of which are male-biased, female inflorescences strongly outnumbered males, considered as evidence of environmental sex determination and sex-switching of individuals. Findings from this study have increased our knowledge of the biology of dactylanthus, confirmed translocation as an effective tool in the conservation of the species and should be applicable for the protection of threatened parasitic plants species elsewhere in the world. © 2015 The Author(s)
Towns D.R.,Science and Technical Group |
Towns D.R.,Auckland University of Technology |
West C.J.,Science and Technical Group |
Broome K.G.,Science and Technical Group
Wildlife Research | Year: 2013
Context Invasive mammals have been removed from at least 100 offshore islands around New Zealand, covering a total area of around 45000ha. Aims To review the outcomes of eradications, the statutory and social environment in which the eradications were conducted, and the lessons provided for future work. Methods Native species to benefit from the eradications were identified, as were the reasons for the eradications and the agencies responsible. Examples are provided using case studies. Key results Three loosely linked work streams were revealed: research into efficient baits and baiting methods, threatened species-led projects nested within priorities for species recovery and supported by legislation, and community-led projects instigated by restoration societies. At least 180 populations of 14 species of invasive mammals were removed. Numerous species of native plants, invertebrates and more than 70 species of terrestrial vertebrates are recovering or are likely to recover as a result of the eradications. Partnerships have been formed with Māori and innovative projects developed with community groups. Conclusions Eradications of invasive mammals are aggressive conservation actions that can have wide benefits for biodiversity but can also be controversial, technically demanding and expensive. Implications Eradications are multi-scale problems. If they are to gain public acceptance, evidence is needed in support. This evidence can include understanding the detrimental effects of invasive species, the likely responses of native biodiversity, and the benefits ensuing from their recovery. However, the way this evidence is gained and communicated will also require deep understanding of nuances in regional political and cultural environments. © 2013 CSIRO.
Taylor G.,Science and Technical Group |
Cockburn S.,Science and Technical Group |
Palmer D.,Chatham Island Area Office |
Liddy P.,Chatham Island Area Office
New Zealand Journal of Ecology | Year: 2012
We developed a new automated recorder, powered by a 12-volt battery, to monitor activity patterns of wild animals marked with passive integrated transponders (PIT tags). The recorder was used to monitor Chatham Island taiko (Pterodroma magentae), a critically endangered seabird species with remote and dispersed breeding burrows. We collected information on annual return rates of individuals and pairs, dates of return and departure for the courtship and egg-laying periods, duration and dates of incubation shifts and also chick feeding visits. Taiko return to their burrows in September and October each year to mate. Return dates are independent of moon phase. Females can spend as little as one day ashore during the month-long courtship period. The pre-laying exodus averages 55 and 51 days for females and males respectively. The three main incubation shifts average 14-15 days each but some shifts can be as long as 19 days. Adults feed their chicks 32-35 times over a 3-month period, with males feeding their chicks more often than females. We discuss problems encountered during the development and feld testing of the new PIT tag recorders, but also the benefits of these devices over conventional monitoring techniques for cavity-nesting birds. © New Zealand Ecological Society.
Robertson H.A.,Science and Technical Group |
Funnell E.P.,Science and Technical Group
Wetlands Ecology and Management | Year: 2012
Coastal lagoons are at risk internationally due to impacts associated with human-induced land use change. The resilience of aquatic macrophytes in these systems is threatened by altered hydrological regimes, elevated nutrient loading, and increased dominance of nuisance species. We describe the aquatic plant dynamics of the Waituna Lagoon Ramsar Site, a 1,350 ha lagoon frequently opened to the sea for flood mitigation which is characterised by fluctuating water levels and salinity. The shallow lagoon supports a macrophyte community dominated by Ruppia megacarpa and R. polycarpa. Repeated survey of 48 sites across the lagoon during late summer in 2009, 2010 and 2011 were applied to describe aquatic plant composition and abundance. This period coincided with three opening events (winter 2008; winter 2009; spring 2010) when the lagoon switched from a predominantly fresh-brackish system to being influenced by tidal exchange and lower water levels. The lagoon experienced a period of 43 days open to the sea in 2008-2009, 67 days in 2009-2010 and 181 days in 2010-2011, during which macrophytes were subject to saline conditions in excess of 10 ppt. We observed a decline in the occurrence of Ruppia from 2009 (69 % sites) to 2011 (23 % sites). The shift in productivity was associated with the duration of the open phase and the period plants were subject to saline conditions >20 ppt and low water levels. The resilience of the system is also at risk from increased algal-dominance due to the intensification of agricultural land use occurring in the Waituna Lagoon catchment. While lagoon opening events cause extreme changes in water depth and salinity that can limit macrophyte growth, they also provide a mechanism to reduce the effects of eutrophication. Understanding these trade-offs is pivotal in management decisions regarding the likely impact of opening events on the ecological character of coastal lagoons. © 2012 Springer Science+Business Media B.V.
Howell C.J.,Science and Technical Group
Invasive Plant Science and Management | Year: 2012
Data on 111 environmental weed eradication programs carried out by the New Zealand Department of Conservation (DOC) have been collected and summarized. A total of 21 programs were discontinued, and 90 are ongoing. Within the ongoing programs, four have been successful in that no plants remain at any known infestations. All four of the successful eradications had a total area across all infestations of less than 1 ha (2.5 ac); however, many similar-sized programs were not successful. Correctly assessing the extent of infestations appears to be a major problem for discontinued programs. Some of the ongoing programs are progressing toward eradication, but this is taking much longer than initially anticipated. The strongest determinant of progress toward eradication was found to be the identity of the DOC administrative area, for reasons that are only speculative. The number and area of initial infestations had no effect on progress toward eradication. However, the rate at which new infestations were located was negatively correlated with progress. Across many programs, progress was restricted by inconsistent infestation visitation. After running for a decade, DOC's weed eradication strategy has yet to provide significant dividends. Environmental weed eradication is clearly more difficult than has previously been acknowledged in New Zealand. © 2012 Weed Science Society of America.
Anderson L.E.,Victoria University of Wellington |
Cree A.,University of Otago |
Towns D.R.,Science and Technical Group |
Nelson N.J.,Victoria University of Wellington
Conservation Physiology | Year: 2015
Translocations are an important conservation tool used to restore at-risk species to their historical range. Unavoidable procedures during translocations, such as habitat disturbance, capture, handling, processing, captivity, transport and release to a novel environment, have the potential to be stressful for most species. In this study, we examined acute and chronic stress (through the measurement of the glucocorticoid corticosterone) in a rare reptile (the tuatara, Sphenodon punctatus). We found that: (i) the acute corticosterone response remains elevated during the initial translocation process but is not amplified by cumulative stressors; and (ii) the long-term dynamics of corticosterone secretion are similar in translocated and source populations. Taken together, our results show that translocated tuatara are generally resistant to cumulative acute stressors and show no hormonal sign of chronic stress. Translocation efforts in tuatara afford the potential to reduce extinction risk and restore natural ecosystems. © The Author 2015.