title: Comparative tolerances of non-indigenous bridled goby and native exquisite goby to salintiy, temperature and sediment

authors: Theobald, Kylie

subjects: non-indigenous

abstract: The Australian bridled goby (Arenigobius bifrenatus) has been in New Zealand since 1996, and has subsequently spread to thirteen estuaries and the coastal Otara Lake. The native exquisite goby (Favonigobius exquisitus) may be displaced or threatened by the bridled goby as they share estuarine habitat. The ecophysiological tolerances and sediment preferences for both goby species were examined to determine the potential for niche overlap and habitat selection. 

The results of acute salinity and temperature tolerance tests supported the hypotheses that bridled gobies are more tolerant than exquisite gobies to extremes of salinity and temperature. The incipient ten day LT50 values were 6.7 C and 11.8 C for bridled and exquisite gobies, respectively, however, both tolerated temperatures up to 35 C. Both species showed some mortality at low salinities, but mortality did not exceed 50% for either species at the lowest salinity tested (2.2 ppt) after 96 h. Bridled gobies displayed a strong preference for fine sediment (less than 63 um), whereas exquisite gobies were less selective, accepting a broad range of sediment grain sizes (63-250 um).

Bridled gobies have successfully established and dispersed in New Zealand, and their ecophysiological adaptations that allowed them to survive harsh conditions in ballast water, their presumed introduction vector, will likely aid their future spread throughout New Zealand. Their increasing abundance is likely to see them encounter and possibly encroach on the habitat of exquisite gobies. Bridled gobies may displace the smaller exquisite gobies from optimal habitats, as exquisite gobies are unlikely to survive competition from and predation by bridled gobies. However, exquisite gobies should be able to relocate to adjacent habitat with coarse sediment that is unsuitable for burrow construction by bridled gobies. Additionally, acclimatisation to local environmental conditions may extend the tolerance limits determined in this thesis, and may allow bridled gobies to spread to upstream zones in estuaries and occupy freshwater.

New Zealand presently has eight recognised gobiid species of which one is endemic, two are native, two are not recorded in mainland waters and three are proposed as non-indigenous. Additionally, several tropical and subtropical gobies exist in the aquarium trade. Similar ecophysiological tests of tolerance and preference may determine the possibility that these species could establish in the wild following accidental release.

text: Comparative tolerances of non-indigenous bridled goby and native exquisite goby to salintiy, temperature and sediment The Australian bridled goby (Arenigobius bifrenatus) has been in New Zealand since 1996, and has subsequently spread to thirteen estuaries and the coastal Otara Lake. The native exquisite goby (Favonigobius exquisitus) may be displaced or threatened by the bridled goby as they share estuarine habitat. The ecophysiological tolerances and sediment preferences for both goby species were examined to determine the potential for niche overlap and habitat selection. 

The results of acute salinity and temperature tolerance tests supported the hypotheses that bridled gobies are more tolerant than exquisite gobies to extremes of salinity and temperature. The incipient ten day LT50 values were 6.7 C and 11.8 C for bridled and exquisite gobies, respectively, however, both tolerated temperatures up to 35 C. Both species showed some mortality at low salinities, but mortality did not exceed 50% for either species at the lowest salinity tested (2.2 ppt) after 96 h. Bridled gobies displayed a strong preference for fine sediment (less than 63 um), whereas exquisite gobies were less selective, accepting a broad range of sediment grain sizes (63-250 um).

Bridled gobies have successfully established and dispersed in New Zealand, and their ecophysiological adaptations that allowed them to survive harsh conditions in ballast water, their presumed introduction vector, will likely aid their future spread throughout New Zealand. Their increasing abundance is likely to see them encounter and possibly encroach on the habitat of exquisite gobies. Bridled gobies may displace the smaller exquisite gobies from optimal habitats, as exquisite gobies are unlikely to survive competition from and predation by bridled gobies. However, exquisite gobies should be able to relocate to adjacent habitat with coarse sediment that is unsuitable for burrow construction by bridled gobies. Additionally, acclimatisation to local environmental conditions may extend the tolerance limits determined in this thesis, and may allow bridled gobies to spread to upstream zones in estuaries and occupy freshwater.

New Zealand presently has eight recognised gobiid species of which one is endemic, two are native, two are not recorded in mainland waters and three are proposed as non-indigenous. Additionally, several tropical and subtropical gobies exist in the aquarium trade. Similar ecophysiological tests of tolerance and preference may determine the possibility that these species could establish in the wild following accidental release.

year: 2007

title: Plots, plants and paradoxes: contemporary domestic gardens in Aotearoa/New Zealand

authors: Longhurst, Robyn

subjects: domestic gardens

abstract: Currently, gardens, gardening and horticulture—plots and plants—are receiving increasing attention from geographers and others interested in spatial disciplines because they provide a useful lens for understanding the complex politics surrounding social and cultural life. In this paper I aim to add to this literature by examining contemporary domestic gardens as paradoxical spaces. The paper begins by outlining some of the reasons for choosing to examine contemporary domestic gardens. Following this is a brief review of a range of geographical literature on gardens, gardening and horticulture. The paper then presents data collected on domestic gardens and gardening practices in Hamilton and Auckland, Aotearoa/New Zealand to illustrate that domestic gardens are paradoxical spaces where the binaries nature and culture, private and public, individuality and sociality, leisure and work, and colonial and postcolonial are destabilized. The paper concludes that although domestic gardens are paradoxical spaces, this does not necessarily mean that they pose a threat or danger because of their ambiguity, or that they are sites of radical politics. Rather domestic gardens are spaces where it is possible to reinforce hegemonic geographies and/or create alternative ones.
Les jardins, le jardinage et l'horticulture—les parcelles et les plantes—bénéficient présentement d'une attention accrue de la part de géographes et de ceux qui s'intéressent aux disciplines spatiales, car celles-ci fournissent une lentille utile pour saisir les questions politiques complexes entourant la vie sociale et culturelle. Par cet article, je souhaite apporter une contribution à la littérature de ce domaine en considérant les jardins domestiques contemporains comme des espaces paradoxaux. D'entrée de jeu, cet article présente brièvement les raisons pour lesquelles les jardins domestiques contemporains ont fait l'objet d'une étude et passe en revue la littérature géographique sur les jardins, le jardinage et l'horticulture. Par la suite, cet article présente les données recueillies sur les jardins privés et les pratiques de jardinage à Hamilton et à Auckland, en Aotearoa/Nouvelle Zélande dans le but de montrer que les jardins domestiques sont des espaces paradoxaux dans lesquels les couples nature et culture, privé et public, individualité et socialité, loisir et travail, et colonial et postcolonial sont ébranlés. En terminant, bien que les jardins privés soient des espaces paradoxaux, cela ne signifie pas pour autant qu'ils constituent une menace ou un danger en raison de leur ambiguïté, ou qu'ils représentent des lieux de politiques extrémistes. Les jardins domestiques, en fait, sont des espaces o[ugrave] il est envisageable de consolider des géographies hégémoniques et/ou de d'en concevoir d'autres.
Actualmente los jardines, jardinería y horticultura—parcelas y plantas—reciben cada vez mas atención de los geógrafos y otros interesados en las disciplinas espaciales, ya que ofrecen una manera útil de entender la compleja política de la vida social y cultural. En este papel, pretendo ampliar esta literatura por medio de un examen de los jardines domésticos como espacios paradójicos. El papel empieza con una breve descripción de algunos de los motivos por haber elegido estudiar los jardines domésticos contemporáneos. Luego hay un resumen de una variedad de literatura geográfica sobre jardines, jardinería y horticultura. Después el papel presenta datos sobre jardines domésticos y costumbres de jardinería en Hamilton y Aukland, Aotearoa/Nuevo Zelanda para ilustrar que los jardines domésticos son espacios paradójicos donde se ven desestablecidos los binarios naturaleza/cultura, privado/publico, individualidad/socialidad, ocio/trabajo y colonial/poscolonial. El papel concluye por decir que el hecho de que son espacios paradójicos no quiere decir que los jardines domésticos representen una amenaza o peligro por causa de su ambigüedad o que sean sitios de política radical. Más bien los jardines domésticos son espacios donde es posible reforzar geografías hegemónicas y/o crear otras alternativas.

text: Plots, plants and paradoxes: contemporary domestic gardens in Aotearoa/New Zealand Currently, gardens, gardening and horticulture—plots and plants—are receiving increasing attention from geographers and others interested in spatial disciplines because they provide a useful lens for understanding the complex politics surrounding social and cultural life. In this paper I aim to add to this literature by examining contemporary domestic gardens as paradoxical spaces. The paper begins by outlining some of the reasons for choosing to examine contemporary domestic gardens. Following this is a brief review of a range of geographical literature on gardens, gardening and horticulture. The paper then presents data collected on domestic gardens and gardening practices in Hamilton and Auckland, Aotearoa/New Zealand to illustrate that domestic gardens are paradoxical spaces where the binaries nature and culture, private and public, individuality and sociality, leisure and work, and colonial and postcolonial are destabilized. The paper concludes that although domestic gardens are paradoxical spaces, this does not necessarily mean that they pose a threat or danger because of their ambiguity, or that they are sites of radical politics. Rather domestic gardens are spaces where it is possible to reinforce hegemonic geographies and/or create alternative ones.
Les jardins, le jardinage et l'horticulture—les parcelles et les plantes—bénéficient présentement d'une attention accrue de la part de géographes et de ceux qui s'intéressent aux disciplines spatiales, car celles-ci fournissent une lentille utile pour saisir les questions politiques complexes entourant la vie sociale et culturelle. Par cet article, je souhaite apporter une contribution à la littérature de ce domaine en considérant les jardins domestiques contemporains comme des espaces paradoxaux. D'entrée de jeu, cet article présente brièvement les raisons pour lesquelles les jardins domestiques contemporains ont fait l'objet d'une étude et passe en revue la littérature géographique sur les jardins, le jardinage et l'horticulture. Par la suite, cet article présente les données recueillies sur les jardins privés et les pratiques de jardinage à Hamilton et à Auckland, en Aotearoa/Nouvelle Zélande dans le but de montrer que les jardins domestiques sont des espaces paradoxaux dans lesquels les couples nature et culture, privé et public, individualité et socialité, loisir et travail, et colonial et postcolonial sont ébranlés. En terminant, bien que les jardins privés soient des espaces paradoxaux, cela ne signifie pas pour autant qu'ils constituent une menace ou un danger en raison de leur ambiguïté, ou qu'ils représentent des lieux de politiques extrémistes. Les jardins domestiques, en fait, sont des espaces o[ugrave] il est envisageable de consolider des géographies hégémoniques et/ou de d'en concevoir d'autres.
Actualmente los jardines, jardinería y horticultura—parcelas y plantas—reciben cada vez mas atención de los geógrafos y otros interesados en las disciplinas espaciales, ya que ofrecen una manera útil de entender la compleja política de la vida social y cultural. En este papel, pretendo ampliar esta literatura por medio de un examen de los jardines domésticos como espacios paradójicos. El papel empieza con una breve descripción de algunos de los motivos por haber elegido estudiar los jardines domésticos contemporáneos. Luego hay un resumen de una variedad de literatura geográfica sobre jardines, jardinería y horticultura. Después el papel presenta datos sobre jardines domésticos y costumbres de jardinería en Hamilton y Aukland, Aotearoa/Nuevo Zelanda para ilustrar que los jardines domésticos son espacios paradójicos donde se ven desestablecidos los binarios naturaleza/cultura, privado/publico, individualidad/socialidad, ocio/trabajo y colonial/poscolonial. El papel concluye por decir que el hecho de que son espacios paradójicos no quiere decir que los jardines domésticos representen una amenaza o peligro por causa de su ambigüedad o que sean sitios de política radical. Más bien los jardines domésticos son espacios donde es posible reforzar geografías hegemónicas y/o crear otras alternativas.

year: 2006

title: Tracking patterns of tribal identification in the New Zealand census, 1991 to 2006

authors: Kukutai, Tahu

abstract: Despite the growing political and economic importance of iwi in New Zealand, little attention has been given to their changing demography. Using data from the New Zealand Census of Population and Dwellings, we analyse the growth trajectories of four iwi - Ngāi Tahu, Waikato, Ngāti Awa and Tūhoe - between 1991 and 2006. We find a great deal of variation in iwi growth between censuses and over the entire focal period. In most instances, iwi birth cohorts increased rather than decreased in size, and gains from “new” members were especially marked among children, the middle-aged and women. The findings confirm the importance of accounting for non-demographic factors when projecting and planning for future iwi population growth.

text: Tracking patterns of tribal identification in the New Zealand census, 1991 to 2006 Despite the growing political and economic importance of iwi in New Zealand, little attention has been given to their changing demography. Using data from the New Zealand Census of Population and Dwellings, we analyse the growth trajectories of four iwi - Ngāi Tahu, Waikato, Ngāti Awa and Tūhoe - between 1991 and 2006. We find a great deal of variation in iwi growth between censuses and over the entire focal period. In most instances, iwi birth cohorts increased rather than decreased in size, and gains from “new” members were especially marked among children, the middle-aged and women. The findings confirm the importance of accounting for non-demographic factors when projecting and planning for future iwi population growth.

year: 2013