Coast Of South Island Research Articles

Biological control of ragwort in the New Zealand dairy sector: an ex-post economic analysis

ABSTRACTRagwort flea beetle, released in New Zealand in 1983, successfully controls ragwort, except in regions that receive very high rainfall such as the West Coast of South Island. If biocontrol had not been instigated, expenditure on ragwort control across New Zealand dairy farms in 2015 would have been an estimated NZ$64 million (adjusted for inflation and national herd size). Data on the impact of the flea beetle were used to estimate the national benefit from reduced control costs to dairy farms from biocontrol which, in 2015, was NZ$44 million. Ragwort biocontrol in New Zealand was attempted from 1926, and a net present value (NPV) analysis gave a 14:1 benefit:cost ratio, which remained positive in robust sensitivity testing. In New Zealand, the flea beetle was rejected as a biocontrol agent in 1933 on anecdotal evidence of its low impact on ragwort. This poor decision cost the dairy industry NZ$8.6 billion (NPV) from 1945 to 1999.

Taxonomy and conservation of allopatric moth populations: a revisionary study of the Notoreas perornata Walker complex (Lepidoptera: Geometridae: Larentiinae), with special reference to southern New Zealand

The Notoreas perornata Walker complex (Lepidoptera: Geometridae) is reviewed. Species concepts applicable to allopatric populations are discussed, with special reference to criteria of diagnosability. Based on a version of the General Lineage Species Concept, five species are recognised here: N. perornata for populations from Northland (North Island) to Westland and the Marlborough coast (South Island), N. simplex Hudson for northern South Island mountain and Canterbury coastal populations; N. elegans Patrick & Hoare, n. sp., for inland Otago, Southland and Fiordland populations, and the coastal Shag Point (Dunedin) population, N. casanova Patrick & Hoare, n. sp., for Southland coastal populations and N. edwardsi Patrick & Hoare, n. sp., for the population at Mason Bay, Stewart Island. Notoreas regilla (Philpott) is newly synonymised with N. simplex. Uppersides and undersides are illustrated for all taxa, and genitalia for N. elegans. No consistent genitalic distinctions have been found between species. Conservation implications for the Notoreas perornata complex are discussed. Of the entities formerly listed (under tag names) as threatened, N. edwardsi and N. casanova are here accorded species status, with N. edwardsi accorded the highest priority for conservation. Molecular work is desirable to clarify the status, interrelationships and genetic distinctiveness of all populations, especially of the northern populations here retained as N. perornata. The whole system is of great value and importance for the study of incipient speciation, and warrants conservation in toto. We therefore argue for an inclusive approach to conservation of all populations belonging to the complex; suggested priorities (based on current distribution and threats) are listed.

Breeding biology and breeding success of the blue penguin (Eudyptula minor) on the West Coast of New Zealand's South Island

This paper presents the first detailed study of the timing and breeding success of an apparently declining population of blue penguins (Eudyptula minor) on the West Coast, South Island, New Zealand. Nest contents of 138 natural burrows and 19 nest boxes were determined at regular intervals during the 2006 breeding season. Hatching, fledging, and overall breeding success rates were comparatively high at 78.9, 83.9, and 66.2%, respectively, suggesting that the apparent population decline cannot be explained solely by low breeding success. With 1.18 fledglings produced per pair, productivity was lower than on the east coast of the South Island, possibly due to the absence of double clutching. The high incidence of road kills suggests that road traffic may be a major contributing factor to the decline of the blue penguin population in the study area.

Thaumamermis zealandica n sp (Mermithidae: Nematoda) parasitising the intertidal marine amphipod Talorchestia quoyana (Talitridae: Amphipoda) in New Zealand, with a summary of mermithids infecting amphipods.

A new nematode, Thaumamermis zealandica n. sp. (Mermithidae; Nematoda), is described parasitising the intertidal marine amphipod Talorchestia quoyana Milne-Edwards (Talitridae) from the coast of South Island, New Zealand. The new species is characterised by the degree of dimorphism of the spicules, the arrangement of the genital papillae, the shape and length of the vagina and the anteriorly-placed amphids. This is the first known marine host of a member of the family Mermithidae. Published records of mermithid nematodes from amphipods are presented.

Genetic monogamy mirrors social monogamy in the Fiordland crested penguin

Fiordland crested penguins (Eudyptes pachyrhynchus, henceforth tawaki) are restricted to the southwest coast of South Island, New Zealand where they nest in small isolated colonies of <25 pairs. Tawaki are socially monogamous and adults are philopatric: pair‐bonds last some years, both resident adults participate in brooding and feeding of young, and birds regularly return to the same nest site or colony between years. To test whether tawaki are genetically as well as socially monogamous we assessed parentage in 24 families using multilocus minisatellite DNA fingerprinting. The DNA profiles of chicks were directly attributable to the resident male and female. There was no evidence supporting intraspecific brood parasitism or extra‐pair fertilisations, although maternal attribution of one chick was ambiguous. Social monogamy appears to indicate genetic monogamy in this species.

Variations in the alginate content and composition of Durvillaea antarctica and D. willana from southern New Zealand

The brown seaweeds Durvillaea antarctica andD. willana are dominant components of the lowerlittoral and upper sublittoral of exposed rocky shoresin southern New Zealand. Tissue samples of bothspecies, harvested from a site on the south-east coastof South Island over a period of 2 years, wereanalysed for alginate content and composition.Individuals of both species were further separatedinto different blade (lamina and palm) and stipe(cortex and medulla) fractions to assess variationwithin the thallus. On average the alginate contentand frequency of mannuronic acid (Fm) was higherin D. antarctica than in D. willana. Blades contained more alginate than stipes, laminaeand stipes were rich in mannuronic acid whereasholdfasts were rich in guluronic acid. Variations incomposition are considered to reflect the functionaldifferences of the tissue, giving flexibility to bladeand stipe and rigidity to the holdfast. Despitefluctuations in content and composition betweencollection times no seasonal trends in eithercomponent were apparent.

Macrobenthic assemblages of the continental shelf and upper slope off the west coast of South Island, New Zealand

Benthic macrofaunal samples were taken at 30 stations on the continental shelf and upper slope (32–1120 m) off the west coast of South Island, New Zealand, southeastern Tasman Sea (c. 41–43° S, 169–172° E). The area receives a high input (increasing southward) of river‐borne sediment, so fine‐grained sediments characterise the shelf and uppermost slope. Most samples were dominated by polychaetes (mean of 36% of individuals), with bivalves and amphipods usually the next most abundant major taxa (mean of c. 10–11 % of individuals). Polychaetes, molluscs and peracarid crustaceans together accounted for c. 11% of species collected. Four main station groups were identified by multivariate analysis: (1) 4 stations at 32–51 m on silty sand characterised by Sthenelais cf. chathamensis, Nephtys sp., Aglaophamus macroura, Paraprionospio sp., Ampharete kerguelensis, Diplocirrus sp. (all Polychaeta), Austrofusus glans (Gastropoda) and Maorimactra ordinaria (Bivalvia); (2) 12 stations at 87–297 m on sandy mud characterised by Aglaophamus verrilli, Lumbrineris ?brevicirra, Paraprionospio coora, Diplocirrus sp. (all Polychaeta), Poroleda lanceolata (Bivalvia) and Ampehsca chiltoni (Amphipoda); (3) 3 stations at 195–248 m on sand at the northern end of the study area where characterising species were Otionella affinis (free‐living Bryozoa) and Chloeia inermis (Polychaeta); and (4) 10 stations at 477–1120 m on sandy mud where good discriminators were Apseudes diversus (Tanaidacea) and Ophiozonella stellamaris (Ophiuroidea). Mean biomass estimates for the four station groups were 79, 40, 35, and 6 g wet wt m‐2 respectively. Ordination of polychaete genera indicated similarities between shallow (< 500 m water depth) west coast samples and directly comparable samples from the Chatham Rise east of the South Island, whereas deeper (> 500 m) west coast samples were more disparate.

Spatial and temporal variation in the growth rate of elephantfish (Callorhinchus milii)

Growth rate estimates were obtained for elephantfish using length‐frequency and tag‐recapture data from the east coast of South Island during 1966–88. Elephantfish hatch from egg cases at about 10 cm fork length (FL) during May‐July. Females grow faster than males after their first year and growth is fastest in summer. In 1966–68, elephantfish in Pegasus Bay grew faster than in Canterbury Bight, resulting in modal length differences that were maintained for the first 3 years of life. This suggests there are at least two distinct juvenile nurseries. Maximum observed lengths were 76 cm FL for males and 97 cm FL for females. Length‐frequency analyses identified 5–8 male age classes and 8–9 female age classes, but longevity probably exceeds these values. Growth rates of 0+ elephantfish in Pegasus Bay in 1983—84 and Canterbury Bight in 1988 were 33–56% greater than in 1966–68. The faster growth rate meant male age at maturity was 4+ in the 1960s and 2+ to 3+ in the 1980s. If female length at maturity was the same in the 1980s as in the 1960s, then female age at maturity would have been 5+ to 6+ in the 1960s and 4+ to 5+ in the 1980s. The increased growth rates and earlier maturity may have led to an increase in elephantfish stock productivity between the 1960s and 1980s.

Validated ages, growth, and productivity parameters for silver warehou (Seriolella punctata) off the south and east coasts of South Island, New Zealand

Abstract A method is described to determine the age of silver warehou using the zones in sectioned otoliths. The technique was validated by examining the state of otolith margins from fish sampled regularly over 1 year, and by following the progression of length modes in length‐frequency distributions (for age classes 0+ to 3+). Von Bertalanffy growth parameters are estimated for silver warehou off the south‐east coast of South Island, New Zealand. The fish grow rapidly up to the time of first spawning, but the annual growth increment decreases markedly after sexual maturity (about 4–6 years). Growth in length is negligible after about 10 years. Female fish have a significantly faster rate of growth than males. An estimate of 0.25 for instantaneous natural mortality (M) is proposed, but instantaneous total mortality (Z) could not be estimated.

Age and growth of red cod (Pseudophycis bachus) off the south‐east coast of South Island, New Zealand

Abstract A method is described to determine the age of red cod using the bands in sectioned otoliths. The technique was validated by examining the state of otolith margins over a 1‐year period, and by following the progression of length modes in length‐frequency distributions (for age classes 0+ to 3+). Von Bertalanffy growth parameters are estimated for red cod off the south‐east coast of the South Island. Few fish appear to live longer than 4 years. Because of the few age classes in the population at any time, age distributions may be obtained for most of a sample using length modes.

Brittle deformation adjacent to the Awatere strike-slip fault in New Zealand: Faulting patterns, scaling relationships, and displacement partitioning

On the coast of South Island, New Zealand, the active dextral-reverse Awatere fault has 22 m to 1.5, consistent with an elastic-plastic model of fault growth. Younger domino-style oblique-normal faults resulted in oblique extension of the Awatere fault zone, with mean σ 1 oriented ≈30° clockwise from its strike. Transtension may have been caused by divergence between rotating, crustal-scale fault blocks, the result of a mode II fault tip to the east, which caused a local rotation of stress trajectories. The early faults are relict, and their kinematics is a poor index of slip sense on the mature fault. Close to the Awatere fault, dextral-reverse faults are synthetic to that mature structure. Their disposition indicates incremental compression acting ≈45°–50° clockwise to the strike of the Awatere fault. These youngest faults mirror the slip kinematics of the adjacent mature fault. Their attitude is controlled apparently by local kinematics, not by far-field stress orientations.

Catenary relationships of downland soils derived from loess, South Canterbury, New Zealand

Very limited information is available on soil variability within the large soil map units of the loess-mantled downlands of the east coast of South Island, New Zealand. In this study eight profiles were sampled in a catenary transect across a valley to assess the morphological, chemical and particle-size changes both within and between soil profiles for both sunny and shady aspects. Profiles from each landform element had similar sequences of horizons but thickness of horizons varied. Profiles on shoulder slopes had thinnest topsoil and subsoil horizons above underlying fragipans. There was a rapid thickening of topsoils and depth to fragipans immediately below the point of slope inflection between planar midslopes and concave lower slopes. The most striking difference in soil morphology was the overthickened topsoil horizons in footslope sites. This was attributed to effects of cultivation, either directly, through mechanical movement of soil material during cultivation operations, or indirectly, through the promotion of soil erosion. There was no indication of the expected catenary relationship involving translocation of exchangeable bases from upper to lower slopes. Differences in P-retention, KCl-extractable aluminium and clay content were identified in soils with different aspects but were not attributed to climatic differences.

Variations of upwelling and associated nutrient nitrogen dynamics off the north‐west coast of South Island, New Zealand

Abstract The surface distribution and metabolic uptake of nitrate and ammonium were investigated as they related to the movements of water in the upwelling zone off the north‐west coast of South Island, New Zealand. Analyses were also made of chlorophyll a and paniculate nitrogen as indicators of phytoplankton biomass. The movement of water and resulting dispersion from the upwelling focus were shown to differ greatly from day to day; this could confound simple correlations between nutrient nitrate and phytoplankton. A suitable model to investigate metabolic processes due to influx of fertile upwelled water which could avoid this problem can be based upon assays of NO3 and NH4 uptake by the plankton. These assays, done with 15NH4 and I5NO3, could provide an operational index for identifying the zone of nett production due to nutrient upwelling.

Sediment texture of the continental shelf and upper slope off the west coast of South Island, New Zealand

Abstract Surface sediments on the continental shelf and upper slope off the west coast of the South Island, New Zealand, from north of Karamea Bight (40°45'S) to the Whataroa River mouth (43°07'S) consist almost entirely of sands and muds. Inshore (< 50 m depth) sediment is predominantly fine sand to coarse silt. Silt‐clay content increases towards mid‐shelf depths, and areas of mud occur at depths of about 90–140 m. Sediments tend to become coarser again on the outer shelf, and sandy mud or muddy sand covers the outer shelf and upper slope. The west coast shelf experiences a high input of fluvial sediment, probably c. 12–26 × 106 tonnes y‐1 for the study area. Sedimentation rate on the shelf is estimated to average at least 1–2 mm y‐1. Sedimentation is probably appreciably lower than this in the north of the area and higher in the south, and this is reflected in shelf grain‐size parameters and sediment carbonate content. There are north‐to‐south decreases in mean grain size and in the ranges of sorting a...

Nestegis(Oleaceae) pollen in coastal sites in Westland

Abstract Pollen grains of the tree genus Nestegis (Oleaceae) have been identified in interglacial sites along the west coast of the South Island from Westport to Hari Hari, but they are not recorded in any post-glacial site in the South Island. he pollen records provide a means of recognising interglacial sites along the west coast of northern South Island.

Generation of 2–3‐hour oscillations on the east coast of New Zealand

Abstract Observed sea‐surface oscillations with periods of about 2.5 hours in New Zealand east coast harbours have previously been regarded as a response to edge waves on the continental shelf and slope, generated by atmospheric forcing and occasionally by tsunamis (Heath 1976, 1979). Calculations of the longshore wavelengths of the edge waves associated with the bathymetry of the east coast continental shelf and slope, and the Chatham Rise (a rise extending 1000 km perpendicular to the east coast of South Island), suggests that the Chatham Rise also takes part in the generation mechanism by acting as a three‐quarter wavelength aerial to double‐sided edge waves.

Patterns of chlorinated hydrocarbon contamination in New Zealand sub-Antarctic and coastal marine birds

Eggs and tissues of seabirds breeding on the coast of South Island, New Zealand, the Snares Islands and the Auckland Islands in the sub-Antarctic were examined for chlorinated hydrocarbon contamination. Higher levels of both industrial and agricultural compounds in the birds from the New Zealand coastal area reflected local contamination sources. In the sub-Antarctic, DDE residues were several times lower and PCB levels were lower by 1–2 orders of magnitude than in species occupying comparable ecological niches at Amchitka on a comparable latitude in the North Pacific. Concentrations of DDE in an unhatched egg of the New Zealand falcon from the sub-Antarctic were sufficiently high, on the basis of comparison with related species, to be associated with significant shell thinning.

Mouth-brush dimorphism in larvae of Opifex fuscus Hutton (Diptera, Culicidae)

Among larval populations of the mosquito Opifex fuscus Hutton from supralittoral pools on the east coast of South Island, New Zealand, some individuals in the second, third and fourth instars had only simple hairs in their mouth-brushes, others had pectinate bristles. All first-instar larvae had simple hairs, and samples of these from the same pool were reared in the laboratory at 25°C. Of 13 fed on dehydrated blood serum, only two developed pectinate bristles, but of 15 fed on fish food (particle size 0·1–0·6 mm.), all but one did. Of a later sample of 16 reared at room temperature on fish food in the first two instars and then on the blood serum, all developed pectinate bristles in the second instar but had reverted to simple hairs by the fourth. In nature, larvae of O. fuscus observed to be feeding by filtering were predominantly of the simple-hair type and those browsing of the pectinate-bristle type. Environmentally controlled dimorphism may increase the probability that an individual will develop to maturity.