Predicting water availability in the Antarctic dry valleys using GIS and remote sensing

Water is one of the most important ingredients for life on Earth. The presence or absence of biologically available water determines whether or not life will exist. In Antarctica most water exists as ice and is not available for sustaining life. It is usually only during December and January that temperatures will rise above zero and melt water becomes available (Kennedy, 1993). For this reason Antarctica is regarded as the driest desert in the world (Peck et al., 2006, McKnight et al., 1999)

Population need and geographical access to general practitioners in rural New Zealand

To use a geographical information system (GIS) approach to demonstrate the extent to which different areas in New Zealand vary in their geographical access to GPs, and to analyse the extent to which spatial access varies in relation to different population groups. Methods Three methods; population/GP ratios, least cost path analysis (LCPA), and an allocation method (which considered the capacity constraint of GPs) were used to demonstrate differences in geographic accessibility to GPs. Travel time, and distance to the closest GP, was calculated for every census enumeration district in New Zealand (n=38336)—thus enabling population-based accessibility statistics to be calculated and aggregated to the territorial local authority level. These calculations include the average travel time if everybody visited a GP once and the population more than 30 minutes from a GP. The composition of this population is analysed according to three criteria of need: the level of deprivation (NZDep2001), ethnicity (%Maori), and age (% <5 years, and %65 years and over). Results There are significant regional variations in geographical accessibility in New Zealand, and these differences are dependent upon the method to calculate accessibility. Ratio measures give a different picture of GP access than the other two indicators, reflecting the fact that TAs with similar ratios often have wide variations in travel times as well as the size and proportion of the population living more than 30 minutes from the closest GP. TAs with larger numbers and a higher proportion of their populations living in such areas tend to be more deprived and have a higher proportion of Maori, especially in the North Island. There appears to be no significant trend by age. Conclusion Given the health and service consequences of poor access, the results suggest that more attention needs to be paid to extending the spatial information base in primary care, in order to achieve more effective planning of services for disadvantaged populations

Developing a conceptual model of marine farming in New Zealand

Survey and Geographic Information System (GIS) data analysis describes the relative influence of biophysical and human variables on site choices made by marine farmers in New Zealand. Community conflicts have grown in importance in determining farm location and different government planning strategies leave distinct signature patterns. Recent legislation empowers local governments to choose among three strategies for future regional aquaculture development. This paper suggests each strategy could result in different spatial outcomes. Simulation modelling of the type described here can provide a better understanding of farmer responses to management approaches and the range of futures that could result from planning choices made today

Bringing nature back into cities: urban land environments, indigenous cover and urban restoration

1. The restoration of urban ecosystems is an increasingly important strategy to maintain and enhance indigenous biodiversity as well as reconnecting people to the environment. High levels of endemism, the sensitivity of species that have evolved without humans, and the invasion of exotic species have all contributed to severe depletion of indigenous biodiversity in New Zealand. In this work, we analysed national patterns of urban biodiversity in New Zealand and the contribution that urban restoration can make to maximising and enhancing indigenous biodiversity. 2. We analysed data from two national databases in relation to the 20 largest New Zealand cities. We quantified existing indigenous biodiversity within cities, both within the core built up matrix and in centroid buffer zones of 5, 10 and 20 km around this urban centre. We analysed the type and frequency of land environments underlying cities as indicators of the range of native ecosystems that are (or can potentially be) represented within the broader environmental profile of New Zealand. We identified acutely threatened land environments that are represented within urban and periurban areas and the potential role of cities in enhancing biodiversity from these land environments. 3. New Zealand cities are highly variable in both landform and level of indigenous resource. Thirteen of 20 major land environments in New Zealand are represented in cities, and nearly three-quarters of all acutely threatened land environments are represented within 20 km of city cores nationally. Indigenous land cover is low within urban cores, with less than 2% on average remaining, and fragmentation is high. However, indigenous cover increases to more than 10% on average in the periurban zone, and the size of indigenous remnants also increases. The number of remaining indigenous landcover types also increases from only 5 types within the urban centre, to 14 types within 20 km of the inner urban cores. 4. In New Zealand, ecosystem restoration alone is not enough to prevent biodiversity loss from urban environments, with remnant indigenous cover in the urban core too small (and currently too degraded) to support biodiversity long-term. For some cities, indigenous cover in the periurban zone is also extremely low. This has significant ramifications for the threatened lowland and coastal environments that are most commonly represented in cities. Reconstruction of ecosystems is required to achieve a target of 10% indigenous cover in cities: the addition of land to land banks for this purpose is crucial. Future planning that protects indigenous remnants within the periurban zone is critical to the survival of many species within urban areas, mitigating the homogenisation and depletion of indigenous flora and fauna typical of urbanisation. A national urban biodiversity plan would help city councils address biodiversity issues beyond a local and regional focus, while encouraging predominantly local solutions to restoration challenges, based on the highly variable land environments, ecosystems and patch connectivity present within different urban areas

Modeling population access to New Zealand public hospitals

This paper demonstrates a method for estimating the geographical accessibility of public hospitals. Cost path analysis was used to determine the minimum travel time and distance to the closest hospital via a road network. This analysis was applied to 38,000 census enumeration district centroids in New Zealand allowing geographical access to be linked to local populations. Average time and distance statistics have been calculated for local populations by modeling the total travel of a population if everybody visited a hospital once. These types of statistics can be generated for different population groups and enable comparisons to be made between regions. This study has shown that the northern and southern parts of New Zealand have high average travel times to hospital services

The mechanisms of subnational population growth and decline in New Zealand 1976-2013

This article summarises key findings from the strand of the Tai Timu Tangata. Taihoa e? project that examined the mechanisms of subnational population change in New Zealand for 143 towns, 132 rural centres and 66 territorial authority areas (hereafter TAs), for the 37-year period 1976-2013. Because of space constraints we present the information as a set of 10 summary observations. For the underlying analyses please refer to Jackson, Brabyn and Maré (2016); Jackson and Cameron (2017), Jackson, Brabyn, Maré, Cameron and Pool (forthcoming); and Jackson and Brabyn (forthcoming)

Spatial modelling of wetness for the Antarctic Dry Valleys

This paper describes a method used to model relative wetness for part of the Antarctic Dry Valleys using Geographic Information Systems (GIS) and remote sensing. The model produces a relative index of liquid water availability using variables that influence the volume and distribution of water. Remote sensing using Moderate Resolution Imaging Spectroradiometer (MODIS) images collected over four years is used to calculate an average index of snow cover and this is combined with other water sources such as glaciers and lakes. This water source model is then used to weight a hydrological flow accumulation model that uses slope derived from Light Detection and Ranging (LIDAR) elevation data. The resulting wetness index is validated using three-dimensional visualization and a comparison with a high-resolution Advanced Land Observing Satellite image that shows drainage channels. This research demonstrates that it is possible to produce a wetness model of Antarctica using data that are becoming widely available

Declining towns and rapidly growing cities in New Zealand: developing an empirically-based model that can inform policy

Understanding and predicting spatial patterns in population change has significant implications for infrastructure, property investments, and national spatial planning. It is also at the core of understanding what motivates people to move to different places, and the underlying geographical conditions that are important to people. During recent times, the population growth of large cities in New Zealand (particularly Auckland, but Tauranga has had faster growth) has resulted in severe social and infrastructural problems, such as sky-rocketing house prices, homelessness, and congestion of roads. At the same time, many small towns have had significant population decline, with no proposed solutions apart from acceptance or undertaking so-called “managed decline” (McMillan 2016; Wood 2017). As will be described in this article, net migration has been a significant component of the spatial variation in population change, while natural change does not have a significant spatial variation and has been generally positive for all urban places. A policy response to the spatial variation of net migration needs to be based on an empirically based understanding of what drives net migration

Landscape classification using GIS and national digital databases

This study considers whether visual landscape character can be classified using GIS. Landscape classification is needed to give landscape researchers and planners a frame of reference for communicating and comparing their research. Such classification is difficult because of the complex nature of landscapes and because it must be explicit. Classification needs to be based on theory, but there is a distinct lack of landscape theory. It is argued that to effectively develop landscape theory a classification is required and that a classification evolves with theory. GIS provides a suitable platform to facilitate this evolution. A set of criteria is established to which a landscape classification should adhere. To be useful for evaluative and cognitive research, a landscape classification needs to distinguish the important characteristics that affect landscape. These characteristics are identified from what little landscape theory exists: a landscape classification needs to incorporate landform, vegetation, naturalness, and water; the classes should be based on the public's perception; the classes should be general and involve compositions; and the classes should incorporate movement and exploration. Besides these criteria, more general criteria that have been used on other land based classifications also apply, particularly the need for a classification to be repeatable. GIS and national digital databases can incorporate these criteria in a landscape classification and this is demonstrated on a transect of the South Island of New Zealand, using mainly a 1:250,000 topographical database and a vegetation database. Difficulties associated with these databases are discussed. A three-phase landscape classification process is developed: 1) Selection of attributes, 2) Definition and classification of the attributes to six levels of generalisation, and 3) Creation of landscape classes from compositions of the attributes. The sensitivity of the process to different operational definitions is considered, and it was significant in some cases. An important analysis function that enables GIS to classify landscapes is the focal neighbourhood function. This in effect analyses the study area from many different points. Once a landscape classification is developed, it can be used with GIS for description, mapping, and inventory purposes. Uniqueness and variety of landscapes can also be determined. A range of observer perspectives can be recognized in the classification by using an application of fuzzy set theory that incorporates entropy. Automating landscape classification requires developing appropriate operational definitions that balance the human concept model of landscapes, the characteristics of national digital databases, and GIS capabilities. Operational definitions can be formulated using four abstractions: classification, generalisation, association, and aggregation, and then represented using GIS analysis techniques. Classifying landscapes automatically is an exercise in generalisation, as there is a considerable amount of information to consider. The challenge is to produce a meaningful generalised classification, rather than a very detailed classification. Expressing association is also important because landscapes are a composition of different landscape components. Focal neighbourhood functions enable the spatial influence of different components to be expressed and from this landscape compositions can be identified. The national digital databases used in this study do not contain conceptualised information on morphological landforms. Height contour databases are available from which it is possible to classify landforms and a substantial part of this study investigates this. Hammond's manual landform classification was automated and applied to the study area. Some problems were identified and a modified process was subsequently developed

Quantified vegetation change over 42 years at Cape Hallett, East Antarctica

This paper reports on the remapping of a carefully documented vegetation plot at Cape Hallett (72°19′S 170°16′E) to provide an assessment of the rates of vegetation change over decadal time scales. E.D. Rudolph, in 1962, mapped in detail the vegetation of a site approximately 28 m by 120 m at Cape Hallett, Victoria Land, Antarctica. This site was relocated and remapped in January 2004 and changes were assessed using GIS techniques. This appears to be the longest available time period for assessing vegetation change in Antarctica. The analysis indicated that considerable change had occurred in moss and algae distribution patterns and this seems to have been caused by increased water supply, particularly in wetter areas. There was also evidence of some change in lichen distribution. The extent of the change indicates that vegetation cover can be used for monitoring change in areas as extreme as the Ross Sea region. For this analysis to be successful it was important that the mapping techniques used were totally explicit and could easily be replicated. Fortunately, Rudolph had defined his cover classes and the site was also clearly marked. The application of GIS mapping techniques allows the mapping to be more explicitly defined and easily replicated