title: Mechanisms of interference between kahikatea and grey willow in the Waikato

authors: Coleman, Emma J.

subjects: Interference

abstract: Research was undertaken to determine the nature of the coexistence between kahikatea and grey willow in the Waikato Ecological Region. Three main questions were investigated. Is grey willow inhibiting recruitment of kahikatea? If this is occurring, which mechanisms (of interference) are involved? And does anthropogenic disturbance influence this interaction?
The first and third were addressed by measuring kahikatea and grey willow populations for age, stem frequency and diameter at six sites, to assess how populations were structured, to reconstruct the population histories at each site and to determine whether kahikatea is successfully regenerating and what possible factors influence regeneration. Results indicated grey willow was establishing after kahikatea populations at all but the Totara Park site, and that once grey willow had reached the canopy, no further recruitment of kahikatea into the canopy occurred. No kahikatea saplings were present in grey willow densities above two per 10m2 and sapling presence did not always result in canopy emergence. Sites containing the highest sapling frequencies were those most recently exposed to moderate to large-scale disturbance, and those closest to a large seed source, rather than those with long established kahikatea populations. This suggests anthropogenic disturbance of certain scale and frequency can promote the regeneration of both species.
The second question was investigated using a range of methods. Dendrochronology was employed to compare diameter growth rates between the species at each site and found grey willow only performed marginally better than kahikatea and its competitive advantage in reaching the canopy faster is likely exerted via more rapid height growth rates. Experimental methods involved measuring annual height and diameter growth rates of forty introduced and twenty naturally established seedlings in various grey willow canopy treatments and water table heights in Totara Park, Hamilton city. Hemispherical photography and water table measurements were used to quantify seedling microhabitats. The greatest seedling diameter and height growth rates were recorded in the open canopy introduced treatment and the lowest in the closed canopy naturally established treatment irrespective of water table height. The reduction in summer light levels from a grey willow canopy regularly caused apical stem death or reduced growth rates of kahikatea seedlings.
Interference effects from allelopathy were investigated as previous research indicated kahikatea litter is toxic to its own seedlings. A trial was set up using potted grey willow cuttings and Sinapus alba seedlings and regularly sprayed with kahikatea litter extract. Results were inconclusive and the natural concentrations of kahikatea litter found at Totara Park did not appear to affect the growth of either species.
Overall this research suggests grey willow is inhibiting kahikatea regeneration via overtaking kahikatea growth to the canopy, shading out further recruitment, and maintaining dominance through efficient vegetative reproduction. Active management is required to ensure the return to dominance of kahikatea in Waikato swamp forests and highly disturbed sites, close to abundant seed source may provide novel opportunities for restoration.

text: Mechanisms of interference between kahikatea and grey willow in the Waikato Research was undertaken to determine the nature of the coexistence between kahikatea and grey willow in the Waikato Ecological Region. Three main questions were investigated. Is grey willow inhibiting recruitment of kahikatea? If this is occurring, which mechanisms (of interference) are involved? And does anthropogenic disturbance influence this interaction?
The first and third were addressed by measuring kahikatea and grey willow populations for age, stem frequency and diameter at six sites, to assess how populations were structured, to reconstruct the population histories at each site and to determine whether kahikatea is successfully regenerating and what possible factors influence regeneration. Results indicated grey willow was establishing after kahikatea populations at all but the Totara Park site, and that once grey willow had reached the canopy, no further recruitment of kahikatea into the canopy occurred. No kahikatea saplings were present in grey willow densities above two per 10m2 and sapling presence did not always result in canopy emergence. Sites containing the highest sapling frequencies were those most recently exposed to moderate to large-scale disturbance, and those closest to a large seed source, rather than those with long established kahikatea populations. This suggests anthropogenic disturbance of certain scale and frequency can promote the regeneration of both species.
The second question was investigated using a range of methods. Dendrochronology was employed to compare diameter growth rates between the species at each site and found grey willow only performed marginally better than kahikatea and its competitive advantage in reaching the canopy faster is likely exerted via more rapid height growth rates. Experimental methods involved measuring annual height and diameter growth rates of forty introduced and twenty naturally established seedlings in various grey willow canopy treatments and water table heights in Totara Park, Hamilton city. Hemispherical photography and water table measurements were used to quantify seedling microhabitats. The greatest seedling diameter and height growth rates were recorded in the open canopy introduced treatment and the lowest in the closed canopy naturally established treatment irrespective of water table height. The reduction in summer light levels from a grey willow canopy regularly caused apical stem death or reduced growth rates of kahikatea seedlings.
Interference effects from allelopathy were investigated as previous research indicated kahikatea litter is toxic to its own seedlings. A trial was set up using potted grey willow cuttings and Sinapus alba seedlings and regularly sprayed with kahikatea litter extract. Results were inconclusive and the natural concentrations of kahikatea litter found at Totara Park did not appear to affect the growth of either species.
Overall this research suggests grey willow is inhibiting kahikatea regeneration via overtaking kahikatea growth to the canopy, shading out further recruitment, and maintaining dominance through efficient vegetative reproduction. Active management is required to ensure the return to dominance of kahikatea in Waikato swamp forests and highly disturbed sites, close to abundant seed source may provide novel opportunities for restoration.

year: 2010

title: We Reddit in a Forum: The influence of Message Boards on firm stability

authors: Corbet, Shaen

abstract: The use of messaging boards to instigate coordinated manipulation of stock prices is not a novel phenomenon. However, the growing breadth and sophistication of social media, the widespread availability of technological cloaking techniques, and the ready accessibility of leveraged derivatives have all significantly contributed to the growth of the infamous Reddit forum r/wallstreetbets. Using a lexicon of terminology designed to identify explicit and implicit manipulation attempts, this research presents several novel findings. The results indicate significantly positive, pronounced, and persistent abnormal returns in the aftermath of manipulative events, with the results being robust across several testing procedures. These abnormal returns have increased significantly in line with the growth of forum users and the reach of manipulation-related comments. Significant effects on market liquidity and analyst recommendations are further identified across tests. Such continued predatory headwinds are certainly of interest to market-makers, regulators, and policymakers alike, as the irrational exuberance incited by millennial meme stocks and sarcastic GIFs is found to have played a significant role in disrupting market functionality. The desired outcome of some of these five million monthly forum users is to create enough momentum to trigger algorithmic responses to move out-of-the-money options into a profitable state. Our results present evidence that this potential threat to corporate stability is concrete.

text: We Reddit in a Forum: The influence of Message Boards on firm stability The use of messaging boards to instigate coordinated manipulation of stock prices is not a novel phenomenon. However, the growing breadth and sophistication of social media, the widespread availability of technological cloaking techniques, and the ready accessibility of leveraged derivatives have all significantly contributed to the growth of the infamous Reddit forum r/wallstreetbets. Using a lexicon of terminology designed to identify explicit and implicit manipulation attempts, this research presents several novel findings. The results indicate significantly positive, pronounced, and persistent abnormal returns in the aftermath of manipulative events, with the results being robust across several testing procedures. These abnormal returns have increased significantly in line with the growth of forum users and the reach of manipulation-related comments. Significant effects on market liquidity and analyst recommendations are further identified across tests. Such continued predatory headwinds are certainly of interest to market-makers, regulators, and policymakers alike, as the irrational exuberance incited by millennial meme stocks and sarcastic GIFs is found to have played a significant role in disrupting market functionality. The desired outcome of some of these five million monthly forum users is to create enough momentum to trigger algorithmic responses to move out-of-the-money options into a profitable state. Our results present evidence that this potential threat to corporate stability is concrete.

year: 2022

title: Viruses without vaccines, or valuing indigenous research? The tensions of introducing Western research assessment practices into an indigenous university

authors: Bruce Ferguson, Pip

abstract: Over my past twenty-five years of educational practice, I have striven to develop a better understanding of indigenous ways of being and doing (in New Zealand’s case, this involves the values and knowledge of Māori). I have done this by visiting and occasionally staying on marae (Māori gathering-places); by reading relevant literature; by engaging in conversations with knowledgeable scholars and by researching the impact of Western practices on indigenous peoples.

In 2003 I managed a research team for Te Wānanga o Aotearoa, a Māori tertiary institution with branches across the country. Our Tertiary Education Commission had just introduced a variation of the English RAE, called the Performance-Based Research Fund, through which government research funds would henceforth be distributed. In collaboration with Māori colleagues, we chose to enter this process, believing that Māori research would be recognised and funded by our participation.

While this proved to be the case, there were significant examples of values clashes, such as the requirement for people to ‘boast’ of their research achievements in a context where such boasting is anathema; to claim ownership of knowledge where tradition often indicates that knowledge is not the property of individuals; and worst, at one point I found myself accused by my Māori manager of introducing ‘viruses without vaccines’. By this he meant Westernised ideas and practices which appeared to be benevolent but in fact were toxic (the idea derives from white settlers who apparently gave native Americans blankets permeated with a virus, causing thousands to die).

In this paper I will explore tensions of operating cross-culturally, and whether/how we can protect people from unintended toxic consequences of intended benevolent actions.

text: Viruses without vaccines, or valuing indigenous research? The tensions of introducing Western research assessment practices into an indigenous university Over my past twenty-five years of educational practice, I have striven to develop a better understanding of indigenous ways of being and doing (in New Zealand’s case, this involves the values and knowledge of Māori). I have done this by visiting and occasionally staying on marae (Māori gathering-places); by reading relevant literature; by engaging in conversations with knowledgeable scholars and by researching the impact of Western practices on indigenous peoples.

In 2003 I managed a research team for Te Wānanga o Aotearoa, a Māori tertiary institution with branches across the country. Our Tertiary Education Commission had just introduced a variation of the English RAE, called the Performance-Based Research Fund, through which government research funds would henceforth be distributed. In collaboration with Māori colleagues, we chose to enter this process, believing that Māori research would be recognised and funded by our participation.

While this proved to be the case, there were significant examples of values clashes, such as the requirement for people to ‘boast’ of their research achievements in a context where such boasting is anathema; to claim ownership of knowledge where tradition often indicates that knowledge is not the property of individuals; and worst, at one point I found myself accused by my Māori manager of introducing ‘viruses without vaccines’. By this he meant Westernised ideas and practices which appeared to be benevolent but in fact were toxic (the idea derives from white settlers who apparently gave native Americans blankets permeated with a virus, causing thousands to die).

In this paper I will explore tensions of operating cross-culturally, and whether/how we can protect people from unintended toxic consequences of intended benevolent actions.

year: 2012