1. Executive Summary
1.1 Project and Client
Landcare Research, and subcontractors Hill Young Cooper Ltd. and Lincoln University, undertook a study on the biophysical and ecological impacts of rural subdivision for MAFPolicy in February to May 1998. The study comprised three parts: biophysical and ecological impacts; resource management methods for managing impacts; and non-market valuation methods.
For this study, rural subdivision was taken to be the subdivision of traditional, large scale farms (pastoral and cropping) into smaller rural lots, ranging in size from 1 to 10 ha. The study focused on effects arising from changes in land use resulting from subdivision, rather than from the conflicts between existing land use and incoming residents and enterprises. Economic effects, and effects associated with transport, landscape and rural character issues were not included in the study.
1.2 Objectives
Biophysical and ecological impacts
- identify biophysical and ecological impacts of rural subdivision;
- characterise and quantify their effects on the environment;
- identify key factors/indicators that could be used for monitoring purposes.
Resource management methods
- identify planning means of remedying, avoiding, or mitigating adverse effects, including the use of biophysical and ecological criteria in an effects-based approach.
Non-market valuation methods
- set out the theoretical background to the valuation of non-market benefits;
- review methods available to value non-market benefits and costs;
- assess the suitability and applicability of these methods to environmental effects of rural subdivision.
1.3 Methods
Biophysical and ecological impacts
Landowner surveys were carried out in West Melton, near Christchurch, and Franklin District, near Auckland, using a written questionnaire and an in-depth interview of a sub-sample of landowners. Effects were listed for water, soil, weeds and pests, indigenous biodiversity, neighbour effects and other issues. Ratings of adversity were assessed and inputs and outputs representing changes since subdivision were listed.
Resource management methods for managing impacts
Methods and processes for managing impacts were identified by reviewing a sample of regional policy statements and plans and district plans, holding discussions with key planners, reviewing case law, and by application of the author's existing knowledge and experience.
Non-market valuation methods
A review of the international literature was undertaken to assess methods available to value non-market environmental effects and their use in rural areas. An assessment was made of their application to effects associated with rural subdivision.
1.4 Results and conclusions
Biophysical and ecological impacts
Effects identified in this study included: water (ground and surface water quality and quantity, waterways condition, stormwater runoff, sediment generation); soils (versatile soils, soil erosion, soil health); weeds and pests (weed diversity, weed spread, mammal pests, insect pests, bird pests, pathogens); indigenous biodiversity (plants, birds, habitat diversity), neighbour effects (noise, spray drift, smell); and other (fire risk, dust in atmosphere).
Within the case study areas, positive environmental effects were found for abundance of indigenous birds, and habitat diversity. Negative environmental effects were found due to decreases in groundwater quality and the stock of versatile soils, and due to increases in weed diversity, weed spread, bird pests, spray drift and fire risk.
Both case study subdivisions had small environmental impacts, and in many cases were little different to those that could be found associated with nearby larger-scale rural land uses. Environmental effects of any rural subdivision is dependent on a range of factors, including environmental setting, size of lots, spatial and temporal pattern of subdivision, mix of land uses, and attitudes and values of land holders.
The case study approach has provided a relatively narrow window for assessing the diversity and severity of effects of rural subdivision. Although we consider West Melton and Franklin as representative of significant areas, it is not appropriate to extrapolate the results across New Zealand. Areas with particularly sensitive environmental settings (e.g., coastal areas), areas where subdivision is of higher density, and areas where there are different land-use change scenarios, may present more severe effects. Particular consideration should be given to cumulative effects, where effects may become significant only in the longer term, through such processes as infill subdivision or further subdivision of surrounding areas. We recommend that further research be undertaken to address environmental impacts of subdivisions into lots of 2 ha or smaller.
The variability in, and the generally low significance of, biophysical and ecological effects arising from rural subdivision means that it is generally inappropriate to devise a set of indicators and to routinely monitor effects of rural subdivisions, unless this is done as a small component of a wider (e.g., district or regional) environmental monitoring programme. It is more appropriate to identify the critical components that are sensitive in the particular area being subdivided, and then monitor to determine if the carrying capacity for the component is being exceeded.
There are a range of other environmental and social issues associated with rural subdivision which were excluded from this study, but which are relevant to the RMA. These include transport and use of fossil fuels and energy, landscapes, and rural character and communities. Feedback during this study indicated that such issues are likely to be highly significant in many areas, and are therefore of concern to the local community and to the managing authorities.
Resource management methods
Control of subdivision (through the district plan) is only one method for managing adverse effects, since the effects are not generated from the act of subdivision, but from the change in land uses, and in the intensity of land use that follows subdivision.
Options for becoming involved with policy and planning processes to influence environmental outcomes associated with effects of rural subdivision under the Resource Management Act include: participation in pre-notification consultation for policy statements and plans, submissions on proposed regional and district policies and plans and plan changes; submissions on resource consent applications; and the initiation of private plan changes. Options in terms of the Local Government Act include submissions on draft annual plans, long term financial strategies, and strategic plans; and in terms of the Biosecurity Act by submissions to proposed pest management strategies. Options for self regulation include promotion of industry standards and codes of practice, and information provision to rural landowners.
Methods for managing adverse effects within the powers and functions of district and regional councils under the Resource Management Act may be regulatory or non-regulatory. They include rules, zones, performance standards, assessment criteria, incentives, information exchange, environmental education, voluntary community actions, provision of works and services, and liaison with other agencies. Pests may be dealt with within pest management plans under the Biosecurity Act.
Since there are few significant adverse effects that are generic to rural subdivision across all land types or land use systems, each local authority should determine the level of significance of effects in particular situations, and develop appropriate policy and planning responses to them.
Non-market valuation methods
Methods for estimating the economic value of non-market environmental effects include those which estimate value by its impact on production, and contingent valuation, which elicits value by surveying a sample of those directly or indirectly impacted by the effect.
Techniques to value environmental effects generally require that these effects are detectable (either in biophysical terms or to those affected) and/or significantly alter the welfare of an economic agent. Where these do not apply to effects of rural subdivision, non-market valuation methods appear to have limited utility.
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