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    A study of labour saving techniques on North Island sheep farms : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science at Massey University, New Zealand
    (Massey University, 1969) Milne, A. C.
    This thesis reports the results of a farm survey conducted to find and evaluate labour saving techniques on North Island sheep farms. The motivation for this study was the hypothesis that many sheep farmers were at least partly restricted in their farming activities because of the availability and price of farm labour. There are three major barriers to the profitable utilis­ation of labour on North Island sheep farms;- farm size, the nature of the production process, and the location of sheep farming areas. The size of the majority of sheep farms is small enough that additional permanent labour is a major input. In many cases, adding one man may mean doubling the permanent labour force. The stock husbandry required for many operations requires a degree of familiarity and expertise on the part of farm labour. How­ever the nature of sheep farm production produces characteristic peak demands for labour only at certain times of the year. The location of sheep farming regions and farms may make casual and contract labour difficult to obtain. People working as employees may find rural life too insecure or lacking in social and educational amenities to stay long. [From Introduction]
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    An evaluation of sulphur topdressing strategies in Eastland pastures : a thesis presented in partial fulfilment for the requirements for the degree of Master of Agricultural Science in Soil Science at Massey University
    (Massey University, 1982) Nguyen, Minh-Long
    Two sampling surveys for soil and herbage, one in autumn and the second in the following spring, were carried out to assess the pasture sulphur status in the Eastland area of the North Island. A preliminary glasshouse experiment using ryegrass as an indicator plant was also conducted to determine which soil test method best estimated the plant available sulphur pool in the soils covered by the survey. In comparison with calcium chloride extractable sulphur, soil sulphur extracted with calcium phosphate solution was shown to relate well to the yield response of ryegrass. Thus a calcium phosphate extractant was used as the criterion of soil sulphur status in the survey. In most of the soils surveyed, the levels of phosphate-extractable sulphur tended to decrease with depth down to 30 cm and were not constant throughout the year. Levels were lower in spring than in autumn, possibly due to the leaching loss of sulphate and the slow mineralisation rate of soil organic sulphur during winter. The decrease in soil sulphate levels during winter was observed even at sites with low annual rainfall (900 - 1000 mm) and in soils with anion retention capacities as high as 70% as measured by the phosphate retention test. Although the levels of Olsen extractable soil phosphorus also tended to decrease over winter, this decrease in available phosphorus was not nearly as great as for sulphate, suggesting that sulphate, being the more weakly adsorbed anion, had been leached more readily. Soil sulphur levels in autumn also reflected the sulphur fertiliser history more markedly than those in spring, thus providing further evidence of sulphate leaching during winter. The results obtained from the herbage survey were consistent with those derived from the glasshouse study and soil survey in showing that the sulphur status of pasture herbage, whether expressed in terms of total sulphur, sulphate or N:S ratios was generally lower in spring than in autumn. The lower sulphur status of soil and herbage in spring suggests that if sulphur deficiencies do occur in the Eastland pastures, they may be most apparent in early spring. To confirm the suspected spring sulphur deficiency observed in the survey, five field trials were laid down in the spring of the following year on soils belonging to three New Zealand soil groups: a yellow-grey earth, an intergrade between yellow-grey and yellow-brown earths and a yellow-brown pumice soil. Significant yield responses to spring application of sulphur were recorded at three out of the five sites. These sulphur-responsive sites included both those where there had been no recent application of sulphate-containing fertiliser and also those which had received regular autumn applications of sulphate at rates of 25 to 33 kg S hā¹ annum̄¹. Spring application of sulphur-free nitrogen fertiliser greatly increased dry matter yield but did not appear to aggravate the effect of sulphur deficiency on pasture growth at the sulphur-deficient sites, as evidenced by the fact that yield responses to sulphur application in the presence of nitrogen fertiliser were of similar or lower magnitude than those obtained with sulphur in the absence of nitrogen fertiliser. However, spring application of sulphur-free nitrogen led to very wide N:S ratios (18:1 to 23:1) in mixed herbage at two sulphur-deficient sites. In such situations, there may be a decrease in the nutritive value of the extra feed produced by a tactical application of nitrogen fertiliser.
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    Pollination ecology of New Zealand orchids : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Ecology at Massey University
    (Massey University, 2002) Lehnebach, Carlos A
    The New Zealand orchid flora comprises twenty-five genera and at least 100 species occurring throughout the country. Although the number of endemic species is high (69%) only four genera are endemic to New Zealand. The main physical threats to orchid survival in New Zealand are habitat destruction, modification and fragmentation. The effect of the disruption of interactions with their pollinators has never been considered. This study concentrates on this mutualistic interaction, by assessing the breeding system, pollination syndromes and pollinator-dependence of four widespread terrestrial (Gastrodia cunninghamii, Thelymitra longifolia, Pterostylis alobula and P. patens) and four widespread epiphytic orchids (Earina autumnalis, E. aestivalis, E. mucronata and Winika cunninghamii) occurring in the southern portion of the North Island. In order to determine the breeding system and the presence of self-incompatibility, hand-pollination treatments were conducted in all eight orchid species during the flowering seasons of 2001 and 2002. Pollen grains and ovules numbers, pollen:ovule ratio and presence of floral scent glands were assessed. In those nectariferous species (E. autumnalis, E. aestivalis, E. mucronata and W. cunninghamii), the nectar standing crop was determined using the anthrone colorimetric assay for total carbohydrates. The activity of pollinator was observed both in the field and in captivity. Insects observed foraging in these orchids were identified and ranked according to their likely pollination effectiveness. Finally, measurements of pollination success and pollinia removal and deposition were used to assess whether fruit-set is pollen limited in these species and explore the effect contrasting rewarding strategies (nectar v/s deception) has on the pollination success of these orchids. Pollination treatments in three terrestrial (T. longifolia, P. alobula and P. patens) and two epiphytic (E. autumnalis and E. mucronata) orchids confirmed the absence of genetic incompatibility. Despite these five orchids being self-compatible, their reproduction relies on contrasting reproductive strategies. T. longifolia is predominantly self-pollinated, whereas Pterostylis and Earina species are incapable of autonomous selfing and completely dependent on pollinators. The epiphytic species E. aestivalis and W. cunninghamii are partially self-incompatible and also completely dependent on pollinators. Agamospermy is likely to occur in G. cunninghamii but not involved in seed-production in any of the remaining seven orchids. Both terrestrial and epiphytic species showed a positive reaction to neutral red except E. autumnalis. This indicated the presence of scent glands, mainly located around the column, lip and sepal tips. Pollen:ovule ratios calculated for these species ranged from 20:1 in E. mucronata and E. aestivalis to 320: 1 in P. alobula. Of the four terrestrial orchids studied, insect visitation was observed only in P. alobula. This orchid is pollinated by male fungus gnats of the genus Zygomyia (Diptera: Mycetophilidae). Pollination by sexual deception is likely to occur in species of this genus. Numerous insects were recorded visiting the nectariferous epiphytic orchids (3 orders, 13 families). Insects considered as "probable pollinator" were Eristalis tenax (Diptera: Syrphidae) for Earina autumnalis, Dilophus nigrostigmus (Diptera: Bibionidae) for E. mucronata, and Melangyna novaezealandiae (Diptera: Syrphidae), Calliphora quadrimaculata (Diptera: Calliphoridae), the Ichneumonid wasp Aucklandella sp. (Hymenoptera: Ichneumonidae), Hylaeus sp. (Hymenoptera: Colletidae) and an unidentified weevil (Coleoptera: Curculionidae) for E. aestivalis. In W. cunninghamii the species Apis mellifera and the native syrphid flies Helophilus antipodus and M. novaezealandiae were considered as "probable pollinators". Levels of natural fruit-set were similarly low in rewarding and non-rewarding species fluctuating from 4.3% (P. alobula) to 40% (P. patens). Fruiting in these orchids is pollen limited, as supplementary hand-pollinations increased fruit set above 40% in all species except P. patens. The degree of pollen limitation varied from 0.32 (P. patens) and 0.94 (P. alobula and E. mucronata). Pollen limitation in these orchids may be caused by the simplicity of their flowers, the poor efficiency of their pollinators in depositing pollinia and the use of species-specific pollination systems (e.g. Pterostylis). The survival capability and conservation requirements of these orchids are discussed in the light of the specific reproductive requirements revealed by this study.
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    The effect of conservation management on Little Blue Penguins (Eudyptula minor) on North Island, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Conservation Biology at Massey University, Auckland, New Zealand
    (Massey University, 2009) Lowe, Mark Ian
    This study aimed to fill a gap in research, particularly on the size of breeding populations of Little Blue Penguins in the North Auckland area, while also providing recommendations for the conservation management of Little Blue Penguins. Three sites North of Auckland were used for the majority of this study; Tawharanui North, Tawharanui South and Goat Island The abundance and nest density of Little Blue Penguins was estimated for the three sites north of Auckland. All three sites had a very low nest density: 0.0096 nests/100m2 at Goat Island, 0.0064 nests/100m2 at Tawharanui North and 0.0048 nests/100m2 at Tawharanui South. Abundance showed a similar trend, with Goat Island having the highest average number of birds coming ashore over the year (2.25 birds per night), followed by Tawharanui North (1.81 birds per night) and finally Tawharanui South (1.19 birds per night). Habitat surveys were conducted at the three sites and differences in habitat structure were found between all three. Tawharanui North was predominantly sand and flax and Tawharanui South was predominantly pebbles and scrub, while Goat Island displayed mostly sand with no vegetation. The results suggested that grass and boulders make up the Little Blue Penguins‘ preferred nesting habitat and it was predicted that sites containing more of this habitat type would have higher nest densities and abundance, although small sample sizes prevented this from being validated statistically. The nest success was calculated, again for the three sites, using the Mayfield method. The key results showed that the incubation period was associated with the lowest success rate of any of the nesting stages observed. Success rates for the incubation stage at the three sites fell between 0.11 and 0.66, success rates for the guard stage fell between 0.74 and 1.00, and success rates for the post-guard stage fell between 0.62 and 1.00. Findings also revealed that nest success was greater at the two Tawharanui sites (where similar rates of nest success were observed) than at the Goat Island site The number of carcasses recovered was recorded as follows: Goat Island, 0.67 birds/km; Tawharanui North, 0.63 birds/km; and Tawharanui South, 0.43 birds/km. There was no statistically significant difference between the rates of carcass recovery and the study site, nor was there a statistically significant difference between the rates of carcass recovery and the season. The rates of carcass recovery were also determined to be lower than historically found for these sites. As an aside to the rest of this study the acute stress response of Little Blue Penguins to pit tag and metal flipper band application was assessed through measuring corticosterone levels in the blood of the birds. The results showed that implantation of a pit tag produced a significantly greater acute stress response than banding with the traditional metal flipper bands. This study makes recommendations regarding the study and conservation of Little Blue Penguins. These recommendations are found throughout this thesis; however, key recommendations are repeated here for convenience.  Re-assess density and abundance measures for the Tawharanui and Goat Island sites in 5 to 10 years time  Research what makes a particular habitat type more preferable than another for Little Blue Penguins  Place nesting boxes around the Tawharanui coast to increase suitable nesting habitat  Carry out ongoing carcass recovery observations and necropsies on penguin populations in Auckland to better understand the causes of mortality  Engage in further study regarding both the acute and chronic stress levels induced by different identification techniques  Engage in further study into possible alternatives to both pit tags and metal bands for penguin identification  Protect Little Blue Penguins from predators on the mainland where possible