Research
The research activities of the AERG can be specified in four main categories:
1. Environmental Change in the Mountains/Impacts of Human Disturbance
2. Plant Interactions and Strategies
3. Physical/Chemical Mountain Environment
4. Conservation and Sustainable Management in Mountain Ecosystems
1. Environmental Change in the Mountains/Impacts of Human Disturbance
Snow insulates and protects alpine plants from the harshest conditions of winter. Reduction of winter snow cover in New Zealand will potentially greatly increase the severity of temperatures experienced by alpine plants. This overlooked aspect of global climate change in the alpine zone is likely to be a critical factor affecting plant survival and therefore may be the most important threat facing the conservation of alpine species and associated ecosystems.
A few projects AERG is involved in:
A. Predicting the impacts of experimental manipulation of snow cover using the frost tolerance and reproductive schedules of alpine plants
This project represents the first attempt internationally, that we are aware of, to experimentally reduce winter snow cover in a range of alpine areas. We are addressing the following questions: 1) Can morphological and physiological attributes of alpine vascular plant species predict how they will respond to reduced snow cover? 2) Are species which overwinter under snow, less physiologically tolerant than species that normally overwinter in relatively snow-free areas at a similar altitude? 3) How does the reduction of snow cover affect the overwinter survival of flower buds, and the timing of spring flowering? Four large snow traps have been established on the "Snowfarm", Pisa Range, Otago, with the aim of reducing snow cover in areas of natural alpine vegetation. A reciprocal transplant experiment involving large turfs of alpine vegetation, and lichen-encrusted rocks (Dr Knight) has been established in two snowbank complexes on the Rock and Pillar Range, Otago, and variations in plant phenology are being studied. In addition to these new manipulations, vegetation response to increased snow cover is being measured around a snowfence established in 1959 on the Old Man Range, Central Otago. This is possibly the oldest continuously monitored snow fence in the world. At all three sites, climate data has been collected throughout 2003, and changes to plant community structure and composition will be investigated annually. In addition, data on seasonal changes in frost tolerances and how this interacts with natural and induced levels of winter exposure, are being measured for selected Asteraceae on the Rock and Pillar Range (Professor Bannister and Tania Maegli)
B. Establishing and maintaining GLORIA sites in southern New Zealand
Two GLORIA sites have been established by Dr Halloy, Professor Mark and other members of AERG. One site was established in Febuary 2003 on the Pisa Range, Central Otago, at c. 1700 m. The other site was established in 2001/2002 on Mt Burns, in Fiordland National Park. GLORIA (Global Observation Research Initiative in Alpine Environments) is a global observation and monitoring network which directly contributes to the Mountain Research Initiative of the International Geosphere Biosphere Programme, and GTOS (Global Terrestrial Observing System) established by FAO, ICSU, UNEP, UNESCO and WMO. GLORIA uses standard, internationally recognised protocols to establish longterm climate and vegetation monitoring programmes in high mountain ecosystems.
C. Research database for the Rock and Pillar Range, Otago.
The Rock and Pillar Range, Central Otago, has been the site of much alpine ecological research over the last 50 years, but as this research has been carried out by different people in different Departments there are surprisingly no long-term datasets from the area. The Alpine Ecology Research Group is committed to ongoing monitoring of climate and vegetation at two sites, with the aim of examining alpine plant responses to climate change. This project will establish a permanent, accessible database of other sites on the Range for which species or climate data exists, and revisit a subset of those sites. The short-term benefit would be that visitors and collaborators could access this database, for example to establish an invertebrate diversity study in a site where climate is already being monitored. In the medium and long term, sites can be revisited and, if further funding is available, ongoing climate monitoring can be established at key sites. Having long-term data on climate, and species distributions and abundances in an alpine area, will be a valuable asset to alpine ecological research. In future the Rock and Pillar Range could become a focal site for alpine research along the lines of the Colorado University Mountain Research Station, Rocky Mountains, USA, and Finse Alpine Research Station, Norway.
2. Plant Interactions and Strategies
AERG is interested in plant-plant/plant-animal interactions and plant-environment relationships. We are investigating the impacts of environmental contraints on current plant strategies and interactions and aim to identify plant responses to changing environmental conditions. AERG also examines pollination processes, for instance, the role of color and flower physiognomy in alpine plant species in New Zealand.
A. Community Dynamics of Alpine Cushion Plants: A biogeographical comparison
B. Trans-Tasman comparison of plant strategies along localised snowmelt gradients
C. Trait-mediated response of plants to altered snow cover
Chief Investigator: Dr John Morgan , La Trobe University, Australia
Co-investigators: Dr Susanna Venn, Ms Annika Korsten, Prof Alan Mark, Prof Katharine JM Dickinson
Background
A snow fence was erected in alpine vegetation at Old Man range, South Island, New Zealand to study how snow augmentation affects the structure and function of alpine ecosystems. While plant species composition change has been noted, the mechanism that underpins these responses are unclear. In plant community assembly theory, environmental filters are the abiotic conditions and resources that exclude species with unviable physiological limitations (defined by their functional traits) from entering or persisting in a community. As such, measures of functional trait diversity (and their shifts) can be used to determine community responses to current and future environmental filters. In alpine vegetation, growing season length is governed by timing of snowmelt. Hence, strong environmental filters operate over short spatial scales, and the strength of these filters is likely to change with global climate change. Understanding the plant traits that allow plants to increase, persist, or decline with environmental change would therefore seem like a profitable (but under-studied) avenue of research. Traits such as leaf dry matter content (LDMC), leaf nitrogen content (LNC) and specific leaf area (SLA) have all been proposed to be important indicators of plant response to environment and hence, may aid predictions about the types of plants that will establish in a given climate due to environmental changes. Hence, we use the strong snowmelt gradient that has been imposed at the Old Man Range snowfence to study whether trait-mediated plants responses help explain the vegetation change that has been observed there. We use the Old Man Range data as a replicate and match it with a snowfence experiment established in 1993 at Niwot Ridge, Colorado.
3. Physical/Chemical Mountain Environment
In collaboration with our colleague Kimberly Hageman (Chemistry Department, Otago University) our research focuses on the fate and transport of organic contaminants in the environment. One particular interest involves the atmospheric transport of contaminants to remote alpine ecosystems and their accumulation at such sites due to mountain cold trapping. In one project, we measured pesticides and other contaminants in air at Arthur's Pass National Park and developed an approach for determining their geographic sources. We are also measuring contaminants in snowmelt and assessing potential impacts on alpine stream macroinvertebrates (with Christoph Matthaei from the Zoology Department).
AERG is also interested in the texture and nutrient cycling of alpine soils. Soil components in the area of the 50year old snowfence at the Old Man Range as well as in adjacent snowbanks are currently under investigation. ⇒
4. Conservation and Sustainable Management in Mountain Ecosystems
The conservation and sustainable management of New Zealand's mountain ecosystems are both critical for the country's present and future welfare, given the important ecosystem services they provide for human welfare, particularly water production, soil conservation, indigenous biodiversity and ecotourism. Given the serious environmental degradation suffered throughout the South Island rain-shadow rangeland regions as a result of aggressive pastoral farming since European settlement combined with considerable ecological ignorance, and the unmanaged feral deer herds on the remaining regions, sympathetic conservative management will be necessary for the foreseeable future. Recent government policies of rangeland tenure review resulting in retirement of most uplands and the efficient commercial hunting of wild animals using helicopters in the more remote, now mostly conservation lands, are both strongly endorsed but newly introduced policies favouring the private covenanting of retired rangelandsand the establishment of a Game Animal [Management] Council, are likely to be retrogressive towards achieving sustainability and restoring indigenous biodiversity to these vulnerable mountain ecosystems..