A question that has plagued New Zealand botanists for many years is the occurrence of the divaricate growth form in several different plant families, and what selection pressure could have led to such parallel evolution. One prominent theory is that the divaricate habit is an adaptation to climatic extremes. This study aims to test if the 'self-shading' growth form of divaricates protects their internal leaves from photoinhibition under physiological drought and high irradiance. By being able to forego the costs of maintaining photoprotective mechanisms, they should have greater carbon gain than their non-divaricate congeners under these conditions. To test if divaricates are protected from the detrimental effects of photoinhibition, the water potentials, pigment and vitamin E concentrations, and photosynthetic rates of two divaricates species in their natural habitat were measured. Additionally, these parameters were recorded for the same divaricate species and their non-divaricate congeners under glasshouse conditions. In the field there were clear differences in several key parameters between divaricates under different levels of irradiance and water availability, and in most cases there was clear evidence of photoinbition. In the glasshouse, the maximum photosynthetic rates were significantly higher in divaricate leaves than in non-divaricate leaves, but there were no clear differences in the avoidance of photoinhibition between divaricates and non-divaricates. Interestingly, more pronounced responses to the different treatments were observed between genera than between the growth forms in the field and glasshouse experiments. The presence of photoinhibition and photoprotective mechanisms in divaricate leaves does not support the theory that the divaricate habit evolved as a physiological response to extreme climate conditions. The absence of a strong difference in the amount of photoinhibition between divariacte and non-divaricate congeners mean that high irradiance and drought stress are unlikely to have been a key factor in the evolution of the divaricate habit. That the within genus physiologies are more similar than within the growth forms would indicate that the divaricate habit possibly evolved after the evolution of the physiological responses of the genera.

In the New Zealand context, considerable academic and government attention has been given to the socioeconomic and ethnic disparities in health, and how they have evolved over time. Despite evidence of clear regional health patterning within New Zealand, there has been very little research monitoring how the geographical trends in health have evolved over time. The period 1980 to 2001 is very important in New Zealand's contemporary history, as it was a time of rapid social and economic change. For this reason, researchers are motivated to examine the extent to which health differentials evolved during the same period. The reduction of health inequalities are at the top of the Government's health agenda, it is therefore important not only to monitor the success, or otherwise, of a reduction in social inequalities, but also, geographic inequalities. This thesis examines the extent of geographic inequalities in mortality in contemporary New Zealand, and whether or not mortality has become geographically polarised between 1981 and 2000. This thesis builds on research carried out in New Zealand, and seeks to delve deeper into the specifics of the geographic variation of mortality. Importantly, it fills several knowledge gaps during this period, which include: the geographic inequality of cause-specific mortality, the difference in regional cause-specific mortality between males and females, and the inequalities of mortality at a finer geographic resolution. A significant debate revolves around the relative contribution of compositional and contextual explanations for the geographic variation of health outcomes. The research undertaken in this thesis examines the contribution of population change and deprivation to the geographic inequalities of mortality. Numerous key findings were identified in this research, four of which are as follows: In 2000, significant geographic inequalities in cause-specific mortality existed within New Zealand; between 1981 and 2000 the geographic mortality gap remained relatively stable; and when the geographic areas are sorted by deprivation, the results indicate that there has been a widening of the mortality gap. Analysis of the relationship between population change and mortality provide cautious support for the finding that mortality rates are higher in areas that have experienced population decline and conversely, that mortality rates are lower in areas where there has been a growth in population. The high and stable levels of geographic inequality should be of great concern to policy makers as the results of this research indicate that policies addressing health inequalities in New Zealand are not sufficiently potent.

Fossil beetle based palaeoclimatic and palaeoenvironmental reconstructions are presented from the Westport region, West Coast, South Island, New Zealand for the last glacial cycle. They include the longest continuous fossil beetle record from New Zealand, covering 16,000 years over the OIS 3/OIS 2 transition. Early last glacial (OIS 4) and mid- Holocene (OIS 1) reconstructions are also presented. The assumptions underlying fossil beetle research in New Zealand are tested indicating beetles are suitable proxies for reconstructing palaeotemperature and palaeoprecipitation. This thesis provides the first quantitative estimates of temperature and precipitation from the Westport region for the last glacial. Reconstructed temperatures indicate stadial cooling was seasonal. Maximum cooling was ca. 5℃ in winter and ca. 2-3℃ in summer. Winter cooling is consistent with previous quantitative estimates from New Zealand. Mean annual precipitation decreased a maximum 35-40% during stadials. Temperatures and precipitation varied during OIS 3/2 indicating multiple possible drivers for glaciation. A glacial advance ca. 34-28ka BP correlates with ca. 5℃ winter cooling and ca. 40% less precipitation, which supports temperature driven glaciation whereas a glacial advance ca. 24-22ka BP correlates with ca. 3℃ winter cooling and precipitation similar to present, which supports precipitation forced glaciation. Palaeoenvironmental reconstructions of stadial vegetation from the Westport region indicate lowland Nothofagus fusca-type forest during OIS 4 and a forest-grassland mosaic during OIS 3/2. These records contrast with pollen-based reconstructions of a treeless landscape in Westport during stadials but are consistent with quantitative estimates of stadial cooling. A shift of reproductive strategy in arboreal vegetation may explain the lack of tree pollen in stadial pollen records. This is significant for our understanding of glacial palaeoecology and palaeoclimatology as pollen records may not accurately represent stadial vegetation.

This study was intended to provide information on certain aspects of the population ecology of H. pacificus. A population on Quail Island in Lyttelton Harbour was chosen for intensive study over a period of one year. Some information on the population was already available. derived from a preliminary study in 1970 (McIvor, 1970a). The following aspects were investigated; population density, natality and mortality, age structures and sex ratios, annual and seasonal growth, daily and seasonal activity, reproduction (detailed investigation of testicular activity), home range and movements and diet. Much of the population information was obtained from recapture of marked individuals. This study helps to fill some of the major gaps in our knowledge of the biology of the nocturnal gecko. Hoplodactylus pacificus.

Topography growth and sediment fluxes in active subduction margin settings are poorly understood. Geological record is often scarce or hardly accessible as a result of intensive deformation. The Hawke Bay forearc basin of the Hikurangi margin in New Zealand is well suited for studying morphstructural evolution. It is well preserved, partly emerged and affected by active tectonic deformation during Pleistocene stage for which we have well dated series and well-known climate and eustasy. The multidisciplinary approach, integrating offshore and onshore seismic interpretations, well and core data, geological mapping and sedimentological sections, results in the establishment of a detailed stratigraphic scheme for the last 1.1 Ma forearc basin fill. The stratigraphy shows a complex stack of 11 eustasy-driven depositional sequences of 20, 40 and 100 ka periodicity. These sequences are preserved in sub-basins that are bounded by active thrust structures. Each sequence is characterized by important changes of the paleoenvironment that evolves between the two extremes of the glacial maximum and the interglacial optimum. Thus, the Hawke Bay forearc domain shows segmentation in sub-basins separated by tectonic ridges during sea level lows that become submerged during sea level highs. Over 100 ka timescale, deformation along active structures together with isostasy are responsible of a progressive migration of sequence depocenters towards the arc within the sub-basins. Calculation of sediment volumes preserved for each of the 11 sequences allows the estimation of the sediment fluxes that transit throughout the forearc domain during the last 1.1 Ma. Fluxes vary from c. 3 to c. 6 Mt.a⁻¹. These long-term variations with 100 ka to 1 Ma timescale ranges are attributed to changes in the forearc domain tectonic configuration (strain rates and active structure distribution). They reflect the ability of sub-basin to retain sediments. Short-term variations of fluxes (<100 ka) observed within the last 150 ka are correlated to drastic Pleistocene climate changes that modified erosion rates in the drainage area. This implies a high sensitiveness and reactivity of the upstream area to environmental changes in terms of erosion and sediment transport. Such behaviour of the drainage basin is also illustrated by the important increase of sediment fluxes since the European settlement during the 18th century and the following deforestation.

The New River Estuary is a large mesotidal estuary connected to Foveaux Strait by way of an inlet, and has two principle rivers (the Oreti and the Waihopai) flowing into it. The purposes of this study have been to describe the sediment distribution within the estuary; investigate the sediment source-sink relationships.; to calculate whether on a net basis sediment is being deposited in or eroded from the New River Estuary, and to investigate some of the influences on the sediment dynamics of this estuary. Textural analysis of the sediment indicated that there are three sedimentary environments within the estuary, and each is distinguishable due to the relative mix of fine sand. It was shown that Foveaux Strait is a dominant source of medium-fine sand. The Oreti River and the channels of the main estuary body are also important sources of these sediments. Medium-fine sand is transferred into the estuary and very fine sand is transferred out of the estuary and onto the continental shelf. Aerial photographs indicated that estuarine morphology was stable over a 31 year period (from 1947 to 1978). However a network of scour rods indicated that the intertidal sediment surface was spatially and temporally dynamic. It was calculated that on a net basis sediment was deposited in the estuary over a five month period. An important influence on the sedimentation of the New River Estuary has been the reduction of the tidal com partment by 25%, due to the reclamation of 12.2 km2.

Growth retardation in King salmon Oncorhynchus tshawytscha (Walbaum) is a common and significant problem affecting marine farming operations in New Zealand. While the basic marine culture requirements for the King salmon species are well understood, the etiology of seawater adaptation and growth retardation remains understudied. Consequently, this study was established to investigate the physiological state and causative factors of growth retardation in collaboration with a leading New Zealand aquaculture company, New Zealand King Salmon Ltd (NZKS). Hypoosmoregulatory indicators are not currently used by marine farmers in New Zealand due to the belief that King salmon are more adaptable to seawater than their more highly cultured counterparts, Coho and Atlantic, and can be transferred to seawater anytime after a critical weight is achieved. This study sought to investigate changes in hypoosmoregulatory ability and its relation to water temperatures commonly used in the hatchery environment. This was determined by changes in the activity of the predominating seawater-adapting gill enzyme Na+/K+-ATPase, as an indirect measure of its abundance during smoltification. Changes in plasma ion profiles and the ability to regulate ions after abrupt transfer were also measured and compared with enzymatic activity throughout the austral springtime smoltification period in commercial strains of under-yearling King salmon. It was found that King salmon do undergo a distinct austral spring-time temporal increase in hypoosmoregulatory processes. This was characterised by a 2-fold increase Na+/K+-ATPase activity which was concomitant with reduced plasma Na+ in freshwater and following a seawater challenge in fish between fork lengths of 140-160 mm. Despite no consistent reduction in Na±/K+-ATPase activity during desmoltification, it was shown that the percent of ATP dependent activity specific to Na+/K+-ATPase diminished over time. Increased residual ATP dependent activity is hypothesised to be a result of apical H+-VATPase activity as a compensatory mechanism to rapidly normalise plasma Na+ during desmoltification concomitant with elevated basolateral Na+/K+-ATPase. Water temperature has been linked with the advancement and shortening of the smoltification period in several species. Gill Na+/K+-ATPase activity and hypoosmoregulatory ability in King salmon were negatively affected by increasing water temperatures above 12°C in contrast to a constant 12°C. The level of growth retardation was dependent on the time of transfer to seawater and was found to increase during a period of reducing hypoosmoregulatory ability. The transfer of growth retarded King salmon back to freshwater resulted in a complete reversal of the growth retarded state, comparable to that observed in Coho and Atlantic salmon. Growth retarded fish were able to readapt back to freshwater with higher survival and growth rates compared to the transfer of normal growing sub-adult King salmon, strongly demonstrating that growth retarded fish are more adapted to freshwater. Osmoregulatory physiology, and endocrinology during the transfer of growth retarded and normal growing fish were investigated. Overall, these results have fundamental implications for the aquaculture of King salmon that are able to be applied by industry to improve current husbandry practices.

Craspedia (Compositae: Gnaphalieae) is a genus of 23 species found only in Australia and New Zealand. New Zealand species of Craspedia have confusing and continuous character variation, with boundaries between species often indistinct and relationships difficult to elucidate. Taxonomic treatments in the genus so far have been regionally based, with the result that species between New Zealand and Australia have not been adequately compared. Phylogenetic analyses of ITS, ETS and psbA-trnH non-coding spacers show that New Zealand Craspedia is a monophyletic group nested within Australian Craspedia. This is consistent with a jump-dispersal event from Australia to New Zealand across the Tasman Sea. The New Zealand lineage is identified as sister to one of two Australian lineages, which consists of mainly subalpine and alpine species found on the main divide of south eastern Australia and in Tasmania. An estimate of when New Zealand Craspedia diverged, using ITS substitution rates from other mainland/island disjunctions in Compositae, gave an approximate date of between 650,000 and 325,000 years ago. This is consistent with the New Zealand fossil pollen record, and with other molecular studies, in suggesting that the Pleistocene, a period of mountain building and climate change, has been an important factor in the evolution of the New Zealand herbaceous flora. The two Australian lineages have not previously been recognised based on morphology and it is suggested they represent two independent species radiations into the Australian alpine zone. Although the New Zealand clade is only partly resolved, the phylogenetic analyses of ITS and ETS indicate that some relationships are incongruent with those previously suggested by morphology and current species boundaries.

Agricultural intensification on the Canterbury Plains in New Zealand has lead to the degradation of natural streams and rivers through lowering of water quality and significant reduction of surface flows from the use of ground and surface water resources. However, this same agricultural expansion has led to the development of a network of permanently flowing open water races to supply stock water to farms across the Canterbury Plains. Stock water races form an extensive network, with approximately 6,500 km of races. Initially I surveyed 62 water races and compared habitat characteristics, water quality, benthic invertebrate and fish communities with nearby natural streams. Races are characterised physically by straight, narrow and shallow channels, and small, uniform substrate. Water races are more turbid than natural streams, and can have high summer temperatures. The benthic macroinvertebrate communities of water races contained a range of taxa, including some not found in natural streams, but communities were less diverse than communities in natural streams, and tended to be dominated by a limited set of generalist taxa. A longitudinal study of three water races showed gradients in physical characteristics of races, including a downstream decrease in channel width, water depth, current velocity and substrate size. However, few strong longitudinal changes to community structure were found, as the generalist taxa commonly occurring in water races were able to tolerate conditions throughout the race network. To test if macroinvertebrate communities were limited by the homogeneous habitat of water races, I conducted a substrate manipulation experiment, where large cobbles and small boulders were added to reaches in five water races. Despite an increase in substrate and current heterogeneity, there were few significant changes to the macroinvertebrate communities over the four months of the manipulation. This outcome does not eliminate low habitat heterogeneity as a limiting factor for water race communities. Rather, the benthic invertebrate community throughout the water race network is a product of the homogeneous habitat, which limits the availability of colonists of taxa that would benefit from increased habitat diversity. A survey of the fish assemblages of water races found races had a depauperate fish community. Only two species were commonly found in water races, and the average species richness of races was 1.5. By contrast natural streams had a higher diversity of fish species (mean 4 three species), and contained representatives of a greater number of species that are typical of streams and rivers on the Canterbury Plains. My research has shown that stock water races provide an important source of aquatic biodiversity on the plains, both in addition to natural streams and in their own right. However, the biodiversity value of stock water races could be improved with enhancement of in-stream habitat.

The potential of kauri (Agathis australis) for paleoclimate research is well established. Multiple treering chronologies have been derived from living and sub-fossil material and growth-climate relationships have been identified. Work has progressed to the stage where raw ring-width data and chronologies covering the last half of the second millennium can confidently be placed in the public domain, to facilitate multiproxy paleoclimate studies. This paper outlines progress in deriving kauri tree-ring chronologies, summarises data availability and quality, and explores the scope for developing composite chronologies. Statistical quality control of the available data was undertaken, following application of an "optimum" standardisation technique. Variations in sample depth with time and between sites result in a complex evolving pattern of chronology quality across sites. Analysis of inter-site statistical relationships identified a pervasive regionalscale signal in kauri with some minor secondary patterns. In light of the strong common signal, a kauri master chronology was built by pooling tree-ring series. Analysis of the quality of this chronology indicates that high-quality master chronologies can be derived for A.D. 1597-1996 from as few as 25 trees from seven sites.