Regeneration of the native sand dune plant Pimelea arenaria in the lower North Island, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Science in Ecology at Massey University, Palmerston North, New Zealand

New Zealand has 300,000 ha of coastal sand dunes in which many native species and introduced plant and animal species are established. One native plant inhabiting dune ecosystems is Pimelea arenaria (Thymeleaceae), the native sand daphne, which is gynodioecious with female and hermaphrodite flower types and listed as nationally declining. The cause of the decline is unknown, but anecdotal evidence suggests recruitment failure is occurring. This thesis looked at four P. arenaria populations in the lower North Island of New Zealand The aims were (1) examine the population structure and establish whether recruitment failure was evident, (2) whether any failure was due to problems with pollination, and (3) whether house mice (Mus musculus) or birds had any impact on P. arenaria by removing fruit. The P. arenaria populations ranged from 0.53-4.05 plants/ha, with female plants comprising the smaller portion of each population, the exact sex ratios varying between the sites. The standing crop of nectar of hermaphrodite flowers is modest and varies from 24 to 56 µg/flower. The pollen:ovule ratio (1987:1), as well as casual observations, suggest that insects are the main pollen vectors. Recruitment failure in P. arenaria occurred with few or no seedlings found at any site, the maximum height above substrate and the surface area of substrate covered suggesting an adult biased population. Profuse flowering occurred (360-510 flowers/m²), leading to viable seed from both female and hermaphrodite plants. Less than 50% of seed germinated from either flower type, regardless of pollination method (natural, hand out-crossed, or autonomously selfed). Female plants observed higher germination success in seeds in both hand out-crossed and natural pollination P. arenaria seed weight remained constant between sexes and treatments, however the pulp weight was variable, with hermaphrodite autonomously selfed fruit having the smallest amount of pulp, but this was not significant (p=0.37). Graded exclosures showed that fruit was removed but this was preventable by bagging the fruit (p<0.001). However, the results from the exclosures were unable to distinguish between mice and birds suggesting that both have similar, possibly cumulative, effects on fruit loss. Within the bagged fruit there were peaks of fruit loss at the start and end of the fruiting season suggesting that selective abortion of ovules is occurring, possibly because of low abundance of pollen sources or pollen vectors Fruit loss occurred, but there was no direct field evidence of predation by mice and birds A feeding trial with mice established that both female and male mice eat and destroy P. arenaria fruit and seed, and at a low dose rate (3 fruit/mouse) the fruit of P. arenaria was not poisonous. Areas for future work are discussed for each section

Variation in a host-epiphyte relationship along a wave exposure gradient

The red alga Polysiphonia lanosa (L ) Tandy is an obligate epiphyte that primarily occurs on the fucoid brown algal basiphyte Ascophyllum nodosum (L) Le Jolis In the present study we examine how epiphytic interactions between P lanosa and A nodosum vary along a wave exposure gradient within the southern Gulf of Maine, USA P lanosa was most dense on protected shores, however because the stature of P lanosa was greater on exposed than on sheltered shores, greater biomass occurred In exposed habitats Epiphytlc P lanosa pnmanly attached to inlured vegetative bssue at exposed sites, while ~ t osc currence was primarily receptacular at sheltered sites A significantly stronger correlation was found between host receptacle abundance and epiphyte abundance at a protected low than an exposed site As a result, the distribution of epiphytes along the host S stlpe vanes at different sites We suggest that changes in the distribution and abundance of P lanosa across this wave exposure gradient are highly influenced by vanations in the distribution and persistence of suitable attachment sites on the host plant Because both the quantity and quality of attachment sites vanes w t h exposure, we hypothesize that d~fferenpt rocesses limit or de t e rm~neP lanosa populations in different locations In protected sites P lanosa may be limited by the presence of adequate substrata (inlured bssue and lateral pits) where successful recruitment may occur By contrast at exposed sites the supply of P lanosa sporelings, rather than quantity of appropnate substrata, may limlt population size

Situating graphs as workplace knowledge

We investigate the use and knowledge of graphs in the context of a large industrial factory. We are particularly interested in the question of "transparency", a question that has been extensively considered in the general literature on tool use, and more recently, by Michael Roth and his colleagues in the context of scientific work. Roth uses the notion of transparency to characterise instances of graph use by highly educated scientists in cases where the context was familiar: the scientists were able to read the situation "through" the graph. This paper explores the limits of the validity of the transparency metaphor. We present two vignettes of actual graph use by a factory worker, and contrast his actions and knowledge with that of a highly-qualified process engineer working on the same production line. We note that in neither case were the graphs transparent. We argue that a fuller account that describes a spectrum of transparency is needed, and we seek to achieve this by adopting some elements of a semiotic approach that enhance a strictly activity-theoretical view

Improving work processes by making the invisible visible

Increasingly, companies are taking part in process improvement programmes, which brings about a growing need for employees to interpret and act on data representations. We have carried out case studies in a range of companies to identify the existence and need of what we call Techno-mathematical Literacies (TmL): functional mathematical knowledge mediated by tools and grounded in the context of specific work situations. Based on data gathered from a large biscuit manufacturing and packaging company, we focus our analysis here on semiotic mediation within activity systems and identify two sets of related TmL: the first concerns rendering some invisible aspects visible through the production of mathematical signs; the second concerns developing meanings for action from an interpretation of these signs. We conclude with some more general observations concerning the role that mathematical signs play in the workplace. The nee

Attributing meanings to representations of data: the case of statistical process control

This article is concerned with the meanings that employees in industry attribute to representations of data and the contingencies of these meanings upon context. Our primary concern is to characterise more precisely how the context of the industrial process is constitutive of the meaning of graphs of data derived from this process. We draw on data from a variety of sources including ethnographic studies of workplaces and reflections on the design of prototype learning activities supplemented by insights obtained from trying out these activities with a range of employees. The core of this article addresses how different groups of employees react to graphs used as part of statistical process control, focussing in particular on the meanings they ascribe to mean, variation, target, specification, trend and scale as depicted in the graphs. Using the notion of boundary crossing we try to characterise a method that helps employees to communicate about graphs and come to data-informed decisions

Techno-mathematical literacies in the workplace: a critical skills gap

There has been a radical shift in the mathematical skills required in modern workplaces. With the ubiquity of IT, employees now require Techno-mathematical Literacies, the mastery of new kinds of mathematical knowledge shaped by the systems that govern their work. The education system does not fully recognise these skills, employees often lack them, and companies struggle to improve them. This project has developed prototype learning resources to train a variety of employees in the mathematical awareness and knowledge that today’s employment require

Characterizing the use of mathematical knowledge in boundary crossing situations at work

The first aim of this paper is to present a characterisation of techno-mathematical literacies needed for effective practice in modern, technology-rich workplaces that are both highly automated and increasingly focused on flexible response to customer needs. The second aim is to introduce an epistemological dimension to activity theory, specifically to the notions of boundary object and boundary crossing. In this paper we draw on ethnographic research in a pensions company and focus on data derived from detailed analysis of the diverse perspectives that exist with respect to one symbolic artefact, the annual pension statement. This statement is designed to facilitate boundary crossing between company and customers. Our study showed that the statement routinely failed in this communicative role, largely due to the invisible factors of the mathematical-financial models underlying the statement that are not made visible to customers, or to the customer enquiry team whose task is to communicate with customers. By focusing on this artefact in boundary-crossing situations, we identify and elaborate the nature of the techno-mathematical knowledge required for effective communication between different communities in one financial services workplace, and suggest the implications of our findings for workplaces more generally

The spatial impact of local infrastructural investment in New Zealand

In this paper we estimate the impact of local authority infrastructure spending in New Zealand using spatial econometric modeling, with the infrastructure spending itself endogenously determined. Utilizing data from the New Zealand Census and Local Authorities Finance data (1991-2008), aggregated to functional labor market areas, we formulate a simultaneous equations growth model of real income, population, land rent and public infrastructure investment. Estimation is conducted using a spatial 3SLS procedure. We find that an increase in local infrastructure spending increases population growth, real income and land values, but is itself endogenous and spatially correlated