title: Vegetation and climate of Auckland, New Zealand, since ca. 32 000 cal. yr ago: support for an extended LGM

authors: Newnham, Rewi M.

subjects: LGM

abstract: Auckland occupies a climatically sensitive position close to a major biogeographic boundary in the southern mid-latitudes. A new pollen record from Kohuora maar crater, Auckland, displays vegetation and climatic changes for the past ca. 32 000 years. Of particular interest are the inferred climatic patterns for the first part of the interval, encompassing the Last Glacial Maximum (LGM). The Kohuora record corresponds closely with pollen records from other Auckland sites indicating that the patterns observed are at least regional in extent. It is also broadly consistent with a variety of palaeoenvironmental evidence from across New Zealand, including the glacial record from Westland, other palynological records from North Island, other palaeoecological records from the South Island, and aeolian quartz sequences from western North Island. These records show that glacial conditions prevailed across most, if not all, of New Zealand during the interval ca. 29-19 k cal. yr BP, longer and earlier than the LGM sensu stricto. We suggest that the term extended LGM (eLGM) may be more appropriate for the New Zealand region. Within this predominantly cold interval, the Auckland pollen records indicate a climatic amelioration for the interval ca. 26-24 k cal. yr BP, also consistent with other palaeocological data from Canterbury, that fall within a period of climate amelioration recognised between the first two eLGM glacial advances in Westland. We refer to this warming interval as the eLGM Interstadial. The ca. 27 k cal. yr BP Kawakawa/Oruanui tephra is instrumental in most of these inter-site comparisons and occurs after the first peak of eLGM cooling in a short-lived comparatively mild phase. A subsequent return to apparently colder climate in the Auckland records may indicate a volcanic cooling effect or, more likely, widespread landscape disturbance following this major eruption event. Strong correspondence between biotic responses, glacial fluctuations and aeolian quartz deposition linked to major shifts in strength and latitudinal extent of the southern westerlies suggest that both the eLGM and eLGM Interstadial may be more widely registered, at least across the Southern Ocean. Support for this assertion comes from parallel investigations in western and southernmost South America and isotopic and palaeoecological records from Southern Ocean marine cores. Recent reconstructions of the globally averaged ice-equivalent sea-level history are in line with this evidence from the Southern Hemisphere, suggesting that the eLGM may have a global registration. In light of these observations, we suggest a re-examination of the defined timing of the LGM along with renewed effort to establish climatic patterns during this period and understand their causes. Copyright © 2007 John Wiley & Sons, Ltd.

text: Vegetation and climate of Auckland, New Zealand, since ca. 32 000 cal. yr ago: support for an extended LGM Auckland occupies a climatically sensitive position close to a major biogeographic boundary in the southern mid-latitudes. A new pollen record from Kohuora maar crater, Auckland, displays vegetation and climatic changes for the past ca. 32 000 years. Of particular interest are the inferred climatic patterns for the first part of the interval, encompassing the Last Glacial Maximum (LGM). The Kohuora record corresponds closely with pollen records from other Auckland sites indicating that the patterns observed are at least regional in extent. It is also broadly consistent with a variety of palaeoenvironmental evidence from across New Zealand, including the glacial record from Westland, other palynological records from North Island, other palaeoecological records from the South Island, and aeolian quartz sequences from western North Island. These records show that glacial conditions prevailed across most, if not all, of New Zealand during the interval ca. 29-19 k cal. yr BP, longer and earlier than the LGM sensu stricto. We suggest that the term extended LGM (eLGM) may be more appropriate for the New Zealand region. Within this predominantly cold interval, the Auckland pollen records indicate a climatic amelioration for the interval ca. 26-24 k cal. yr BP, also consistent with other palaeocological data from Canterbury, that fall within a period of climate amelioration recognised between the first two eLGM glacial advances in Westland. We refer to this warming interval as the eLGM Interstadial. The ca. 27 k cal. yr BP Kawakawa/Oruanui tephra is instrumental in most of these inter-site comparisons and occurs after the first peak of eLGM cooling in a short-lived comparatively mild phase. A subsequent return to apparently colder climate in the Auckland records may indicate a volcanic cooling effect or, more likely, widespread landscape disturbance following this major eruption event. Strong correspondence between biotic responses, glacial fluctuations and aeolian quartz deposition linked to major shifts in strength and latitudinal extent of the southern westerlies suggest that both the eLGM and eLGM Interstadial may be more widely registered, at least across the Southern Ocean. Support for this assertion comes from parallel investigations in western and southernmost South America and isotopic and palaeoecological records from Southern Ocean marine cores. Recent reconstructions of the globally averaged ice-equivalent sea-level history are in line with this evidence from the Southern Hemisphere, suggesting that the eLGM may have a global registration. In light of these observations, we suggest a re-examination of the defined timing of the LGM along with renewed effort to establish climatic patterns during this period and understand their causes. Copyright © 2007 John Wiley & Sons, Ltd.

year: 2007-06

title: Light requirements of Australian tropical vs. cool-temperate rainforest tree species show different relationships with seedling growth and functional traits

authors: Lusk, Christopher H.

subjects: Conduit diameter

abstract: Background and Aims A trade-off between shade tolerance and growth in high light is thought to underlie the temporal dynamics of humid forests. On the other hand, it has been suggested that tree species sorting on temperature gradients involves a trade-off between growth rate and cold resistance. Little is known about how these two major trade-offs interact.
Methods Seedlings of Australian tropical and cool-temperate rainforest trees were grown in glasshouse environments to compare growth versus shade-tolerance trade-offs in these two assemblages. Biomass distribution, photosynthetic capacity and vessel diameters were measured in order to examine the functional correlates of species differences in light requirements and growth rate. Species light requirements were assessed by ﬁeld estimation of the light compensation point for stem growth.
Results Light-demanding and shade-tolerant tropical species differed markedly in relative growth rates (RGR), but this trend was less evident among temperate species. This pattern was paralleled by biomass distribution data: speciﬁc leaf area (SLA) and leaf area ratio (LAR) of tropical species were signiﬁcantly positively correlated with compensation points, but not those of cool-temperate species. The relatively slow growth and small SLA and LAR of Tasmanian light-demanders were associated with narrow vessels and low potential sapwood conductivity.
Conclusions The conservative xylem traits, small LAR and modest RGR of Tasmanian light-demanders are consistent with selection for resistance to freeze–thaw embolism, at the expense of growth rate. Whereas competition for light favours rapid growth in light-demanding trees native to environments with warm, frost-free growing seasons, frost resistance may be an equally important determinant of the ﬁtness of light-demanders in cool-temperate rainforest, as seedlings establishing in large openings are exposed to sub-zero temperatures that can occur throughout most of the year.

text: Light requirements of Australian tropical vs. cool-temperate rainforest tree species show different relationships with seedling growth and functional traits Background and Aims A trade-off between shade tolerance and growth in high light is thought to underlie the temporal dynamics of humid forests. On the other hand, it has been suggested that tree species sorting on temperature gradients involves a trade-off between growth rate and cold resistance. Little is known about how these two major trade-offs interact.
Methods Seedlings of Australian tropical and cool-temperate rainforest trees were grown in glasshouse environments to compare growth versus shade-tolerance trade-offs in these two assemblages. Biomass distribution, photosynthetic capacity and vessel diameters were measured in order to examine the functional correlates of species differences in light requirements and growth rate. Species light requirements were assessed by ﬁeld estimation of the light compensation point for stem growth.
Results Light-demanding and shade-tolerant tropical species differed markedly in relative growth rates (RGR), but this trend was less evident among temperate species. This pattern was paralleled by biomass distribution data: speciﬁc leaf area (SLA) and leaf area ratio (LAR) of tropical species were signiﬁcantly positively correlated with compensation points, but not those of cool-temperate species. The relatively slow growth and small SLA and LAR of Tasmanian light-demanders were associated with narrow vessels and low potential sapwood conductivity.
Conclusions The conservative xylem traits, small LAR and modest RGR of Tasmanian light-demanders are consistent with selection for resistance to freeze–thaw embolism, at the expense of growth rate. Whereas competition for light favours rapid growth in light-demanding trees native to environments with warm, frost-free growing seasons, frost resistance may be an equally important determinant of the ﬁtness of light-demanders in cool-temperate rainforest, as seedlings establishing in large openings are exposed to sub-zero temperatures that can occur throughout most of the year.

year: 2013

title: Nā Wai Koe? Our tūpuna call us home: Maremare whānau thinking about connections to whenua tupuna

authors: Sampson, Jasmine

subjects: Whenua Tūpuna

abstract: This research focuses on the Maremare whānau from Tiniwaitara Marae, Turakina, in order to explore the importance of our relationship with our whenua tupuna and the related concept of returning home. 

Although many academics have carefully attended to the concept of ‘disconnection’ from whenua tupuna in order to describe the effects of Māori mobility, this term unfortunately reinforces the colonial attempt to detach our people from the things that provide us with our sense of belonging. I argue that thinking about relationship with whenua tupuna through terms like ‘disconnection’ and ‘reconnection’ are unhelpful and problematic; instead, when we understand this relationship in Māori terms, our connection to our whenua tupuna is an everlasting relationship that is woven into the fabric of our whakapapa.

The research combines interviews with three generations of the Maremare whānau, including people with diverse experiences of relationships with Turakina, with critical reflection on relevant concepts from Te Ao Māori. Specifically, mobilising a Kaupapa Māori Theory approach, the thesis draws on an oriori, ‘He Oriori mō Wharaurangi’ as the methodology and foundation of this thesis. In this way, the thesis both argues and demonstrates the value of researchers, and in particular kairangahau Māori, look to mātauranga Māori to guide us in our research about Māori topics. This oriori is iwi specific, it holds kōrero tuku iho that pertains to my whakapapa as an uri of Ngā Wairiki Ngāti Apa and it is very relevant to both my kaupapa and the people participating in the rangahau.

Ultimately, whakapapa rests at the core of connection to whenua tupuna. It is the foundation in which we stand and it connects us as a people to the land that birthed us. This thesis looks at the different ways that our tūpuna call us home, the different ‘returning home’ experiences within the Maremare whānau and how people within the whānau view their connection with our whenua tupuna in Turakina. Nā wai koe? Our tūpuna call us home.

text: Nā Wai Koe? Our tūpuna call us home: Maremare whānau thinking about connections to whenua tupuna This research focuses on the Maremare whānau from Tiniwaitara Marae, Turakina, in order to explore the importance of our relationship with our whenua tupuna and the related concept of returning home. 

Although many academics have carefully attended to the concept of ‘disconnection’ from whenua tupuna in order to describe the effects of Māori mobility, this term unfortunately reinforces the colonial attempt to detach our people from the things that provide us with our sense of belonging. I argue that thinking about relationship with whenua tupuna through terms like ‘disconnection’ and ‘reconnection’ are unhelpful and problematic; instead, when we understand this relationship in Māori terms, our connection to our whenua tupuna is an everlasting relationship that is woven into the fabric of our whakapapa.

The research combines interviews with three generations of the Maremare whānau, including people with diverse experiences of relationships with Turakina, with critical reflection on relevant concepts from Te Ao Māori. Specifically, mobilising a Kaupapa Māori Theory approach, the thesis draws on an oriori, ‘He Oriori mō Wharaurangi’ as the methodology and foundation of this thesis. In this way, the thesis both argues and demonstrates the value of researchers, and in particular kairangahau Māori, look to mātauranga Māori to guide us in our research about Māori topics. This oriori is iwi specific, it holds kōrero tuku iho that pertains to my whakapapa as an uri of Ngā Wairiki Ngāti Apa and it is very relevant to both my kaupapa and the people participating in the rangahau.

Ultimately, whakapapa rests at the core of connection to whenua tupuna. It is the foundation in which we stand and it connects us as a people to the land that birthed us. This thesis looks at the different ways that our tūpuna call us home, the different ‘returning home’ experiences within the Maremare whānau and how people within the whānau view their connection with our whenua tupuna in Turakina. Nā wai koe? Our tūpuna call us home.

year: 2021