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Hamilton, New Zealand

Allibone R.,Golder Associates | David B.,Environment Waikato | Hitchmough R.,Science and Research and Development Group Division | Jellyman D.,NIWA - National Institute of Water and Atmospheric Research | And 3 more authors.
New Zealand Journal of Marine and Freshwater Research | Year: 2010

The threat status of 74 freshwater and estuarine fish present in New Zealand was determined. Fifty-one native taxa were ranked of which 67% were considered Threatened or At Risk. A single species was classified as Extinct, the New Zealand grayling, which has not been observed since the 1920s. Four taxa were classified in the highest threat category, Nationally Critical, and a further 10 taxa as Threatened (Nationally Endangered or Nationally Vulnerable). Twenty taxa were ranked in the At Risk group with the majority ranked as Declining. Endemic galaxiids (Galaxiidae) dominated the Threatened and At Risk taxa. The majority (68%) belonged to the Galaxias genus, comprising 81% of recognised taxa in this genus and all five species in the genus Neochanna were also ranked as Threatened or At Risk. In addition to 51 native taxa, a further three fish species were considered colonists and 20 introduced species were classified as naturalised, although two of these are considered rare. The majority of the Threatened species occur in the Canterbury and Otago regions where a suite of rare non-migratory galaxiids exist. Threat mechanisms that were identified as causal in the decline of freshwater fish species were the impact of introduced fish species, declining water quality, effects of water abstraction, loss of habitat via land-use change and land-use activities, and river modifications. Source

Freeman C.,University of Otago | Clark R.D.,Environment Waikato | Van Heezik Y.,University of Otago
Geographical Research | Year: 2011

Effective planning to support and enhance ecological values in sites of conservation interest requires accurate, comprehensive and detailed ecologically based maps and data, not only for the conservation site but for the wider landscape in which such sites are situated. In this paper we present an efficient and low cost method for combining appropriate technologies and available data to produce such maps at a landscape level. This method is described and evaluated using a case study of a land use and habitat map, with an associated geographic information system (GIS). The map was created for the district of Dunedin, New Zealand, an area of approximately 3340km2. This paper demonstrates how the map can be adapted for use by small, locally based conservation organisations that typically do not have the resources to obtain detailed, consistent and comprehensive spatial data for the areas they manage. The example of Orokonui Ecosanctuary is used to illustrate the potential applications of the map including mapping assets and habitats within a site and for exploring the relationship between the Ecosanctuary's internal and external habitats. External habitats can form a vital habitat network for many of the endangered species being reintroduced into the Ecosanctuary as well as a source of threats through potential reinvasion by pests and land use change. Though the mapping method presented in this paper is not necessarily new, it demonstrates the potential for utilising advances in mapping techniques and available data sets to offer a pragmatic support mechanism of practical value for small conservation organisations. © 2010 The Authors. Geographical Research © 2010 Institute of Australian Geographers. Source

Harland D.P.,Agresearch Ltd. | Caldwell J.P.,Environment Waikato | Woods J.L.,Agresearch Ltd. | Walls R.J.,Agresearch Ltd. | Bryson W.G.,Leather and Shoe Research Association of New Zealand
Journal of Structural Biology | Year: 2011

Tomograms of transverse sections of Merino wool fibers obtained from fleeces differing in fiber curvature were reconstructed from image series collected using a 300. kV transmission electron microscope. Trichokeratin intermediate filaments (IFs) from the ortho-, para- and mesocortices were modeled from the tomograms. IFs were predominantly arranged in left-handed concentric helices with the relative angle of IFs increasing progressively from the center to the periphery of orthocortex macrofibrils. The median increase in IF angle between adjacent IFs between the center and periphery was 2.5°. The length of one turn of the helical path of an IF was calculated to be approximately 1μm for an IF tilted at 30° and positioned 100. nm from the macrofibril center. With the exception of one paracortex macrofibril that weakly resembled an orthocortex macrofibril, all para- and mesocortex macrofibrils modeled had a parallel arrangement of the IFs, with a more ordered arrangement found in the mesocortex. Within the limited sample set, there appeared to be no significant relationship between IF angle and fiber curvature. We examined the matrix/IF ratio (in the form of proportion of matrix to one IF, calculated from IF center-to-center distance and IF diameter) for 28 macrofibrils used for modeling. The proportion of matrix was significantly different in the different cortex cell types, with paracortex having the most (0.61), orthocortex having the least (0.42), and mesocortex being intermediate (0.54). Fibers of different crimp type (high, medium or low crimp) were not significantly different from each other with respect to matrix proportion. © 2010 Elsevier Inc. Source

Gaw S.,University of Waikato | Gaw S.,University of Canterbury | Northcott G.,The New Zealand Institute for Plant and Food Research Ltd | Kim N.,Environment Waikato | And 2 more authors.
Environmental Toxicology and Chemistry | Year: 2012

Orchard soils can contain elevated concentrations of 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p′-DDE), 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (p,p′-DDT), and heavy metals as a result of historical agrichemical applications. The bioavailability of p,p′-DDE, p,p′-DDT, As, Cd, Cu, and Pb from five field-aged New Zealand orchards and three grazing soils was assessed by using a 28-d bioassay with Aporrectodea caliginosa and chemical assays. Significant relationships were found between total soil and earthworm tissue concentrations for p,p′-DDE (p<0.001), p,p′-DDT (p<0.001), Cu (p<0.001), and Pb (p<0.01). Two neutral salt solutions, 0.01 M CaCl2 and 1 M NH4NO3, were used as surrogate measures of the bioavailability of heavy metals. Copper was the only heavy metal for which significant correlations were found between neutral-salt-extractable and earthworm tissue concentrations (p<0.001). Up to 28% of the aged DDT residues were released from the soils by Tenax over a 24-h extraction period. Significant relationships (p<0.01) between the Tenax-extractable and earthworm tissue concentrations for p,p′-DDE and p,p′-DDT showed that Tenax provides a good surrogate measure of the bioavailability of these compounds to A. caliginosa. Surprisingly, there was a similarly significant relationship (p<0.001) between the total soil and earthworm tissue concentrations for p,p′-DDE and p,p′-DDT, suggesting that total soil concentrations alone were sufficient to predict uptake by A. caliginosa. These results demonstrate that the aged agrichemical residues in orchard soils, and particularly p,p′-DDE and p,p′-DDT, remain highly bioavailable to A. caliginosa despite decades of weathering and continue to present an environmental risk. © 2012 SETAC. Source

Death R.G.,Massey University | Collier K.J.,Environment Waikato | Collier K.J.,University of Waikato
Freshwater Biology | Year: 2010

1. Management of stream biodiversity is often tightly linked with the restoration and protection of riparian and catchment vegetation. Despite that, there are no established guidelines on how much forest should be retained or replanted in riparian zones and surrounding catchments to maintain or re-establish instream ecological integrity. In this study, we assess relationships between vegetation cover at multiple spatial scales (reach, segment and catchment) and macroinvertebrate metrics that reflect community structure, ecological condition and biodiversity at 138 Waikato, New Zealand, stream sites sampled in 2006.2. Percentage of catchment vegetation in native forest had stronger relationships with measured diversity and condition metrics than segment or reach scale measures of riparian vegetation. Functional feeding group metrics were weakly associated with upstream catchment vegetation cover.3. Of the macroinvertebrate metrics tested, the RIVPAC O/E and an organic pollution tolerance metric based on species presence-absence (Macroinvertebrate Community Index; MCI) had the strongest relationships with percentage native riparian vegetation, followed by the quantitative MCI and measures of the richness and relative abundance of Ephemeroptera, Plecoptera and Trichoptera faunas. The O/E and MCI indicated that catchments with 80-90% in native forest or scrub (low-growing trees) were associated with faunas indicative of "clean" water quality.4. Of the biodiversity indices considered Fisher's α Index of species richness had the strongest relationship with percent native riparian vegetation in the upstream catchment. There are no established thresholds for measuring biodiversity loss in New Zealand streams, but this analysis indicates that on average streams draining catchments with 40-60% upstream native vegetation cover retain 80% of the mean biodiversity present in pristine forest streams.5. This research indicates that riparian management aimed at enhancing macroinvertebrate biodiversity and the ecological condition of streams is likely to be more successful when focused on protecting and/or restoring headwater catchments rather than short stretches of stream. © 2009 Blackwell Publishing Ltd. Source

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