Ozkundakci D.,University of Waikato |
Ozkundakci D.,Leibniz Institute of Freshwater Ecology and Inland Fisheries |
Hamilton D.P.,University of Waikato |
Kelly D.,Aquatic and Reporting Unit |
And 5 more authors.
Ecological Indicators | Year: 2014
Ecological integrity (EI), a concept referring to the structural and functional components of ecosystems, which is closely related to the integrity and stability of biotic communities, has deteriorated markedly in freshwater ecosystems across the globe. In New Zealand, many deep lakes appear to have been affected to a lesser extent by anthropogenic activities. The objective of this study was to identify and quantify a range of key in-lake indicators that could be used to report EI for deep New Zealand lakes, many of which may be expected to have high EI values. Individual indicators of EI in the lakes were related statistically to selected anthropogenic pressure indicators. Values of EI were only weakly related to the anthropogenic pressure indicators, and catchment and lake morphometric and climate characteristics were strong moderators of the relationship and suggests that monitoring of EI requires careful consideration of natural variability amongst different lake ecosystems. Physico-chemical indicators of EI tended to be more closely related to anthropogenic pressure indicators than biological EI indicators. Monitoring of physico-chemical and biological indicators in a set of reference lakes largely devoid of anthropogenic influences will help to better define elements of EI which include "nativeness", "pristineness", diversity and resilience.© 2013 Elsevier Ltd. All rights reserved.
Aguirre J.D.,Massey University |
Bollard-Breen B.,Auckland University of Technology |
Cameron M.,Research and Evaluation Unit RIMU |
Constantine R.,University of Auckland |
And 19 more authors.
Regional Studies in Marine Science | Year: 2016
The Waitematā Harbour is a drowned river valley in the south-west of the Hauraki Gulf, on the north east of New Zealand's North Island. The central business district for the city of Auckland is situated on the southern shore of the central Waitematā Harbour and is New Zealand's largest and fastest growing city. The Waitematā Harbour hosts a major international port, New Zealand's primary naval base and international cruise terminal, as well as a large and committed community of recreational users. In comparison with the marine ecosystems surrounding many of the world's coastal cities, the Waitematā Harbour and the Hauraki Gulf have experienced a relatively short period of human occupation. Nonetheless, rapid and widespread changes have occurred within these ecosystems. Habitat loss and declines in biodiversity as well as impacts on human activities such as safe swimming and recreational harvesting have motivated several conservation and restoration initiatives. Here, we review the natural and social context of the Waitematā Harbour and Hauraki Gulf, and summarise some of the pressures the region faces. Last, we present three case studies highlighting current participatory initiatives aimed at ensuring more sustainable management of the region's marine ecosystems. The Waitematā Harbour and Hauraki Gulf have provided considerable ecological, social and economic wealth for the people of Auckland; accordingly, conserving these ecosystems and preserving future prosperity should be a collective priority for all sectors of society. © 2016.
Chilvers B.L.,Aquatic and Reporting Unit |
Chilvers B.L.,Massey University |
Baker G.B.,University of Tasmania |
Baker G.B.,Latitude |
And 4 more authors.
Polar Biology | Year: 2015
The Auckland Island shag (Phalacrocorax colensoi) is endemic to New Zealand and restricted to the subantarctic Auckland Islands. The species is classified as “Vulnerable” under the New Zealand threat classification systems. The total breeding population is estimated at <1000 pairs, with Enderby Island considered to be the stronghold for the species. The trend of the population is unknown, and it has been recommended a census of the entire adult population be conducted once a suitable methodology has been developed. The objective of this research was to examine census methods to estimate population size for the Auckland Island shag. Three census methods were trialled on Enderby Island during the 2011/2012 breeding season: (a) boat-based counts; (b) aerial photography using a helicopter and; (c) direct counts from the ground. The aerial photographic survey recorded 1889 pairs of Auckland Island shags breeding on Enderby Island during the 2011/2012 breeding season. In comparison, boat-based and ground count surveys recorded lower population sizes by 27 and 26 %, respectively. This research provides the first comparable methodology and baseline population estimate for the breeding stronghold of this threatened seabird and forms the basis for long-term population monitoring. All methodologies examined here could be used for other cliff-nesting seabird species; however, these results indicate a level of bias may be present for any survey method. © 2015 Springer-Verlag Berlin Heidelberg
Maseyk F.J.F.,The Catalyst Group |
Gerbeaux P.,Aquatic and Reporting Unit
New Zealand Journal of Ecology | Year: 2015
The Resource Management Act 1991 places obligations on local authorities to protect and maintain indigenous biodiversity on land in private tenure. However, how this should be done is not explicitly prescribed. Authorities are guided by a variety of means (e.g. ecological guidance and case law), and implement their responsibilities to varying degrees and with inconsistent success. The protection of indigenous biodiversity on private land is a challenging and contentious issue. This paper reports on two different approaches for the identification and assessment of significant habitats that were recently validated by Court decisions in two regions of contrasting biodiversity loss in New Zealand: Manawatu-Wanganui and the West Coast. The rigorous semi-quantitative desktop methodology used in Horizons Regional Council’s resource management plan included a predictive model to compile a schedule of habitat types in the Manawatu-Wanganui Region, coupled with significance criteria to facilitate regulatory protection of significant habitat. This was the first time in New Zealand a region-wide habitat type approach had been undertaken and was subsequently accepted by the Environment Court. The methodology for identifying significant wetland areas in the West Coast Regional Council’s Land and Water Plan used a more traditional approach, employing schedules of mapped sites selected through applying a set of significance criteria. The Environment Court also endorsed this approach but recognised the need for more rigorous criteria. A caucus of experts was directed to improve the weak set of criteria initially proposed. The revised significance criteria now sit in the plan and have also been adapted for use by other regions (e.g. Canterbury). In both regions, the Environment Court rejected the use of site condition as a prerequisite for determining significance. This was also supported by the High Court in the West Coast case. These court decisions represent landmark case law, which advance the national debate on the application of significance criteria. © New Zealand Ecological Society.
Pham L.,University of Otago |
West D.,Aquatic and Reporting Unit |
Closs G.P.,University of Otago
Ecology of Freshwater Fish | Year: 2013
The rehabilitation of native communities by means of eradicating unwanted fish species using piscicides is an example of employing disturbance to achieve conservation successes. Such projects provide a valuable opportunity to test the efficiency of the tool and the impacts on the receiving aquatic communities, as disturbance occurs at a known time. The piscicide 'rotenone' has been widely used to eradicate invasive or unwanted fish species worldwide. However, there is little information regarding the impact on native fish being reintroduced to a stream after rotenone treatment. The mass depletion of aquatic invertebrates due to rotenone dosing is of particular concern, as food-limitation could negatively impact on fish growth, condition and recruitment, compromising the aims of rehabilitation. For the first time in New Zealand, rotenone was employed to eradicate brown trout (Salmo trutta) from two streams that also supported populations of banded kokopu (Galaxias fasciatus). Impacts on fish and aquatic invertebrates were studied in two treatment and two reference streams in Karori, Wellington. Analysis showed that invertebrate densities declined significantly in the treatment streams in the 2-week to 2-month period after dosing. Following reintroduction after rotenone treatment, banded kokopu condition declined significantly and levels of fish mobility were variable. One year after rotenone dosing, there was recruitment of banded kokopu juveniles in the treatment streams indicating successful reproduction, with no equivalent increase in the reference streams. Results are a positive indication for the use of rotenone as an effective conservation tool to remove unwanted fish species where they threaten native populations. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.