title: The ecology of bivalves on Centre Bank, Tauranga Harbour

authors: Hull, Penelope Jane

subjects: Tauranga Harbour

abstract: An investigation into the ecology of bivalve molluscs on Centre Bank, the flood tidal delta of Tauranga Harbour was undertaken over the period December 1994 - March 1996. The primary purpose of which was to gather quantitative data on bivalve diversity, spatial patterns of distribution, abundance, and population size structure of bivalves present on Centre Bank. Experiments were conducted to assess the burrowing behaviour of the bivalve Paphies australis. It was intended that information obtained be such that it could be used as a base for future investigations into changes in the ecology of Centre Bank.
Two broad scale benthic surveys of 27 sites on Centre Bank, conducted 6 months apart resulted in a total of 31 bivalve taxa being identified. Temporal and spatial variation in abundance was prominent for all species. Three species Paphies australis, Tawera spissa and Ruditapes largillierti occurred in far greater abundances than any others. Distribution of bivalves in both surveys was patchy with some species showing strong associations with particular sites.
Small scale abundance patterns of P. australis was examined in detail by systematic sampling of a 50 m x 15 m grid. The grid was monitored at 2- monthly intervals from March 1995 to November 1995. Abundances at sites in the northern half of the grid were found to be very dense (up to 1400 m², mean shell length=55-65 mm), while densities at the southern end were noticeably lower. Through time densities across the grid appeared to decrease evenly in a constant north-west direction. The smothering effect of mobile sand ridges was speculated to be the cause of these density decreases.
Experiments examining the burrowing behaviour of the infaunal bivalve Paphies australis were conducted both in the field and in the laboratory. The ability of P. australis to bury into the sediment if left exposed on the sediment surface was examined in the field. It appeared that P. australis were able to bury relatively quickly with the majority of experimental animals reburying within 40 minutes. Laboratory experiments showed P. australis to be capable of burrowing to the sediment surface after being inundated with sediment to a depth of 10 cm.

text: The ecology of bivalves on Centre Bank, Tauranga Harbour An investigation into the ecology of bivalve molluscs on Centre Bank, the flood tidal delta of Tauranga Harbour was undertaken over the period December 1994 - March 1996. The primary purpose of which was to gather quantitative data on bivalve diversity, spatial patterns of distribution, abundance, and population size structure of bivalves present on Centre Bank. Experiments were conducted to assess the burrowing behaviour of the bivalve Paphies australis. It was intended that information obtained be such that it could be used as a base for future investigations into changes in the ecology of Centre Bank.
Two broad scale benthic surveys of 27 sites on Centre Bank, conducted 6 months apart resulted in a total of 31 bivalve taxa being identified. Temporal and spatial variation in abundance was prominent for all species. Three species Paphies australis, Tawera spissa and Ruditapes largillierti occurred in far greater abundances than any others. Distribution of bivalves in both surveys was patchy with some species showing strong associations with particular sites.
Small scale abundance patterns of P. australis was examined in detail by systematic sampling of a 50 m x 15 m grid. The grid was monitored at 2- monthly intervals from March 1995 to November 1995. Abundances at sites in the northern half of the grid were found to be very dense (up to 1400 m², mean shell length=55-65 mm), while densities at the southern end were noticeably lower. Through time densities across the grid appeared to decrease evenly in a constant north-west direction. The smothering effect of mobile sand ridges was speculated to be the cause of these density decreases.
Experiments examining the burrowing behaviour of the infaunal bivalve Paphies australis were conducted both in the field and in the laboratory. The ability of P. australis to bury into the sediment if left exposed on the sediment surface was examined in the field. It appeared that P. australis were able to bury relatively quickly with the majority of experimental animals reburying within 40 minutes. Laboratory experiments showed P. australis to be capable of burrowing to the sediment surface after being inundated with sediment to a depth of 10 cm.

year: 1996

title: Time-varying risk premia in the term structure of interest rates in New Zealand

authors: Margaritis, Daimitri

subjects: New Zealand

abstract: An empirical analysis of the term structure of interest rates in New Zealand during the post-1985 financial liberalization period is presented. Particular emphasis is placed upon the effect of time-varying risk premia in the term structure equation. The risk premium is assumed to depend on the time-varying conditional variance of the excess holding yield. The results indicate that the expectations theory cannot be rejected at the short end of the term structure provided that account is taken of the volatility clustering in interest rate data. There is also support for the expectations theory in the term structure relationship between long-term and short-term interest rates. The results do not indicate excess over- or under-sensitivity of long rates to current short rates. Initial statistical evidence suggests that excess returns on long-term bonds can be explained by their lagged values and macroeconomic variables. However, this return predictability is removed once the effects of changing real and nominal uncertainty are accounted for in the term structure equation. The latter result suggests that a monetary policy of low and stable inflation can affect the risk characteristics of long-term bonds. The presence of varying real uncertainty in bond returns indicates that the slope of the yield curve may not be a reliable indicator for assessing inflationary pressures in the economy when compared to a situation where the variation in bond returns was solely driven by nominal uncertainty.

text: Time-varying risk premia in the term structure of interest rates in New Zealand An empirical analysis of the term structure of interest rates in New Zealand during the post-1985 financial liberalization period is presented. Particular emphasis is placed upon the effect of time-varying risk premia in the term structure equation. The risk premium is assumed to depend on the time-varying conditional variance of the excess holding yield. The results indicate that the expectations theory cannot be rejected at the short end of the term structure provided that account is taken of the volatility clustering in interest rate data. There is also support for the expectations theory in the term structure relationship between long-term and short-term interest rates. The results do not indicate excess over- or under-sensitivity of long rates to current short rates. Initial statistical evidence suggests that excess returns on long-term bonds can be explained by their lagged values and macroeconomic variables. However, this return predictability is removed once the effects of changing real and nominal uncertainty are accounted for in the term structure equation. The latter result suggests that a monetary policy of low and stable inflation can affect the risk characteristics of long-term bonds. The presence of varying real uncertainty in bond returns indicates that the slope of the yield curve may not be a reliable indicator for assessing inflationary pressures in the economy when compared to a situation where the variation in bond returns was solely driven by nominal uncertainty.

year: 1994

title: E hoki mai nei ki te ūkaipō | Return to your place of nourishment [Gallagher Academy of Performing Arts]

authors: Apiata, Hāwea

abstract: E hoki mai nei ki te ūkaipō | Return to your Place of Nourishment brings together works by four wāhine Māori artists which explore narratives of pakanga|conflict through toi|art. This exhibition aims to create a dialogic space in which the artworks reflect and challenge the current troubled economic and political landscape. In this show, the four artists weave together their unique practices and stories to present a cohesive yet diverse examination of conflicts, with a particular focus on the artists’ own whānau and hapū narratives.

Ultimately, this collection of works interrogates political strategies that have exploited division and discord through carefully curated histories. This collection is also a reclamation of those narratives and histories by descendants who live in the aftermath of their ancestors’ mamae | pain.

text: E hoki mai nei ki te ūkaipō | Return to your place of nourishment [Gallagher Academy of Performing Arts] E hoki mai nei ki te ūkaipō | Return to your Place of Nourishment brings together works by four wāhine Māori artists which explore narratives of pakanga|conflict through toi|art. This exhibition aims to create a dialogic space in which the artworks reflect and challenge the current troubled economic and political landscape. In this show, the four artists weave together their unique practices and stories to present a cohesive yet diverse examination of conflicts, with a particular focus on the artists’ own whānau and hapū narratives.

Ultimately, this collection of works interrogates political strategies that have exploited division and discord through carefully curated histories. This collection is also a reclamation of those narratives and histories by descendants who live in the aftermath of their ancestors’ mamae | pain.

year: 2024