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4. Facilitating Resource Management Category

4.1 FRM 227

Programme Title:	Key poultry welfare indicators (part 2)
Programme Leader:	Lindsay Matthews
Institution:	AgResearch

This research programme is not completed. Further information will be included in Research Results 2005/06.

4.2 FRM 230

Programme Title:	Exotic weed invasions and the management of indigenous forests for timber production
Programme Leader:	Susan Wiser
Institution:	Landcare Research

Summary

To synthesise existing information on exotic weed invasions into indigenous forests that are managed for timber production, and to suggest ways of integrating that information with management practices.

Background

It is now widely expected that forests managed for timber production are to meet sustainable management practice standards, one such being maintenance of biodiversity and ecological values. Exotic plant species that invade indigenous forests following silvicultural disturbance pose a significant threat to these values in New Zealand. Because MAF is obliged to ensure that indigenous forestry meets criteria for sustainable management of forest ecosystems, it follows that MAF is responsible for providing guidelines that minimise invasion of exotic plant species into managed forests. The Forests Act Part IIIA requires managers of indigenous forests to inspect, monitor, and report on exotic weed invasions. While many exotic weed species will be short-lived and persist only until the forest canopy is restored, others that are shade-tolerant and long-lived pose significant threat to forest ecosystem integrity. MAF requires a review of what is known about conditions that predispose forests to weed invasion and the types of weeds that invade so that this information can be used to develop standards and guidelines for managing indigenous forests.

Approach & Outcomes

The project goal was achieved through three objectives:

• By conducting a literature review to summarise environmental factors known to predispose forests to invasion by exotic weeds.
• By synthesising observational and field data to determine how silvicultural operations influence exotic weed invasions.
• By compiling information on the exotic weeds recorded in New Zealand’s indigenous forests, and using plant traits to prioritise each species according to its likely impacts, and suggesting appropriate management approaches for exotic weed species of varying priority.

Outcomes

The literature review identified four key factors that are thought to influence invasion by exotic weeds and spread into unmanaged indigenous forests: disturbance (more disturbed forests have more weeds); propagule pressure (forests in a matrix of weedy vegetation types are more susceptible to invasion); productivity (more fertile and warmer sites have more weeds); and species richness (diverse communities support more weed species). Information from silvicultural trials and surveys of forest managers holding sustainable management plans generally indicated that weed incursions into managed indigenous forests were related to the four factors listed above. Survey responses from forest managers indicated that more information on identifying and managing weeds would be beneficial.

A total of 130 weed species have been reported to occur in indigenous forests in New Zealand. Key attributes that are likely to relate to their impact in indigenous forests include ability to smother regenerating trees (vines, lianes and mat-forming herbaceous plants) and longevity (trees being the longest-lived growth form and therefore most likely to have long-term impacts). A small subset of the 130 weed species were selected that were hypothesised to have the greatest impacts on indigenous forests and these should be prioritised for control. Management approaches were developed using a series of guiding principles . For example, rather than managing weed incursions in isolation, it is useful to consider the wider issues of forest ecosystem integrity and to manage a suite of issues concurrently. Management of exotic animal pests may bring about both direct and indirect benefits, as they are considered to spread exotic weed species and encourage turf development in which exotic weeds thrive. There is a need for MAF to encourage greater interest in weed management, both by directing forest managers towards existing sources of information such as DOC, regional councils, QEII National Trust, and NZERN, and by providing specific guidelines targeted towards those species that are most likely to impact on indigenous forests.

Summary

The goal of this project was to synthesise existing information on exotic weed invasions into indigenous forests that are managed for timber production, and to suggest ways of integrating that information with management practices. This goal was achieved through three objectives.

• By conducting a literature review to summarise the environmental factors known to predispose forests to invasion by exotic weeds.
• By synthesising observational and field data to determine how silvicultural operations influence exotic weed invasions.
• By compiling information on the exotic weeds recorded in New Zealand’s indigenous forests, and using plant traits to prioritise each species according to its likely impacts, and suggesting appropriate management approaches for exotic weed species of varying priority.

The first two objectives identified four key factors that influence exotic weed invasion and spread into unmanaged indigenous forests: disturbance (more disturbed forests have more weeds); propagule pressure (forests in a matrix of weedy vegetation types are more susceptible to invasion); productivity (more fertile and warmer sites have more weeds); and species richness (diverse communities support more weed species). The third objective collated information on 130 weed species reported to occur in indigenous forests in New Zealand. Key attributes likely to relate to their impact in indigenous forests include ability to smother regenerating trees (vines, lianes and mat-forming herbaceous plants) and longevity (trees being the longest-lived growth form and therefore most likely to have long-term impacts). A small subset of the 130 weed species were selected that were hypothesised to have the greatest impacts on indigenous forests and these should be prioritised for control. Management approaches were developed using a series of guiding principles. For example, rather than managing weed incursions in isolation, it is useful to consider the wider issues of forest ecosystem integrity and to manage a suite of issues concurrently. Management of exotic animal pests may bring about both direct and indirect benefits as they are considered to spread exotic weed species and encourage turf development in which exotic weeds thrive. There is a need for MAF to encourage greater interest in weed management, both by directing forest managers towards existing sources of information such as DOC, regional councils, QEII National Trust, and NZERN, and by providing specific guidelines targeted towards those species that are most likely to impact on indigenous forests.

4.3 FRM 231

Programme Title:	Deadwood removal from indigenous forests
Programme Leader:	Susan Wiser
Institution:	Landcare Research

Summary

To review the role of deadwood in indigenous forests and examine principles for harvesting deadwood while maintaining its dynamics and functions in forests. Based on the review, consider how timber harvesting regimes in New Zealand could impact on sustainability of indigenous forests.

Background

Management of indigenous forests for timber production should consider sustainability of both the timber resource and wider ecosystem functions. Standing and fallen dead trees are a significant structural component of forests and fulfil a wide range of important ecosystem functions. Because harvesting of deadwood can be a significant component of some indigenous forestry activities there is a need to evaluate its consequences. Landcare Research was contracted by the Ministry of Agriculture and Forestry to review the dynamics and functions of deadwood in indigenous forests, and to examine guiding principles by which deadwood could be harvested while maintaining ecosystem integrity. This information could be used to revise the Ministry’s implementation of sustainability requirements in the Forests Act.

Approach & Outcomes

Achieving the goal required two tasks:

• Reviewing the New Zealand and international literature on the dynamics and functions of deadwood in forests. We conducted a search of the published literature using Current Contents, Web of Science, New Zealand Science Database, SCIRUS and CAB Abstracts. This sub-search identified nearly 400 articles, which we used as our database for sourcing information.
• Reviewing offshore initiatives that have developed deadwood management principles and using this in combination with our review of deadwood dynamics and functions, to identify features to consider in developing New Zealand guidelines. Again this was based on a search of the published literature and through contact with other researchers studying deadwood management.

Outcomes

Over the last decade knowledge has accumulated on the amounts of deadwood in certain New Zealand forest types. These studies have largely been in beech forests and it would be useful to have similar data for some podocarp and podocarp-hardwood forest types. There has also been some recent research on the function of deadwood in beech forest nutrient cycling, including the implications of harvesting for sustainability. Similarly in some forest types, at particular locations, there is knowledge about relationships between deadwood and components of the biota, such as bird species. So far response functions describing the relationship between the amount of deadwood available and a specific role of deadwood are not available. While there are overseas initiatives attempting to define guidelines for the management of deadwood, few have gone far beyond setting minimum standards or using qualitative assessments to establish the adequacy of deadwood levels. In the long-term it is desirable deadwood management adopts a dynamic and adaptive approach – but this will require considerable additional knowledge.

Indigenous forest management in New Zealand is probably in a position to adopt broad guidelines for deadwood management that then progressively incorporate practices that ensure key ecological functions are maintained as knowledge of these functions grows. At this stage rather than issuing prescriptions, the key to success may be to increase awareness among the forest management community on the functions and values of deadwood; this will assist management to adapt towards the desired goal. The current perception that removal of deadwood is less ecologically damaging than removal of live wood will be false in some instances. We advocate the use of fact sheets and workshops to communicate the types of approaches that can be taken. Management of deadwood is complex and unresolved, and decisions will need to be flexible and context dependent to reflect the naturally dynamic nature of deadwood. The logic for removal of deadwood across one-off minor provisions and long-term plans needs to be standardised. There is also a need to monitor deadwood and ensure that types and amounts do not decline significantly over time in managed areas. Guidelines for the management of deadwood should be available for those developing plans and permits – these would need to be progressively updated as further knowledge becomes available.

A lack of knowledge provides considerable obstacles to deadwood management. Forest owners need access to databases and information sources on deadwood wildlife. Current management plan surveys are unlikely to detect those cryptic species that depend on deadwood, e.g. amphibians, reptiles, bats, fungi and invertebrates. Links between forest management surveys and knowledge of rare bats and birds, ferns and liverworts, invertebrates and fungi should be used to enhance understanding for forest management. Significant progress could be made if knowledge on deadwood dynamics is extracted and summarised from the National Vegetation Survey databank. There is also currently little information on how the rates of wood decay vary among New Zealand’s dominant tree species. There is a need to develop time-dependent decay functions to understand how long deadwood remains in forests and ultimately to use these in forest simulation models that assess management scenarios. Deadwood progressive removal and addition experiments would help identify the role of deadwood in forest types, notably along environmental gradients and in a range of forest types. It would be desirable to examine the impacts of removal on stand dynamics, soil nutrient concentrations, biota, seedling growth and nutrient concentrations in a range of forests. This knowledge could be used to understand the most beneficial way of harvesting and organising residual deadwood.

Summary

The management of indigenous forests for timber production should consider sustainability of both the timber resource and wider ecosystem functions. Standing and fallen dead trees form a significant structural component of forests that fulfils a wide range of important ecosystem functions. This study reviews the role of deadwood in forests and then considers how deadwood harvesting regimes in New Zealand could impact on sustainability of indigenous forests. Achieving this required reviewing literature on the dynamics and functions of deadwood in forests and investigating offshore initiatives that have developed deadwood management principles as part of developing New Zealand guidelines. Indigenous forest management in New Zealand is probably in a position to adopt broad guidelines for deadwood management that are then progressively refined to incorporate practices that ensure key ecological functions are maintained as knowledge of these functions grows.

4.4 FRM 233

Programme Title:	Indicators of sustainable management in podocarp-tawa forests
Programme Leader:	Mark Smale
Institution:	Landcare Research

Summary

To complete remeasurement of, analyse and report on the 1961 sustainable management trial in podocarp/tawa forest at Pureora, to review the accuracy and precision of recruitment, growth, mortality and forest-gap data that will be used by MAF to revise its standards and guidelines for sustainable forest management.

Background

Substantial areas of indigenous forest are now coming under sustainable management. Some 584 plans and permits are currently in operation, involving management of 112 500 hectares of freehold forest. Selection management, the silvicultural system involving the removal at intervals of single trees or small groups of trees selected from throughout a forest stand, was undertaken experimentally in North Island podocarp forests in five trials in the 1960s and 1970s. In this project, an assessment was made of one of the two original (1961) trials in which one-third of merchantable volume was harvested from a widespread tawa-dominant forest type at Pureora.

Approach & Outcomes

The three blocks (one control and two harvested) were re-marked on the ground. All surviving podocarp trees were revisited, identified, tagged and measured for diameter. Dead trees were identified and mode of death recorded. Mortality and periodic mean annual merchantable volume increment rates of podocarps were calculated by species by block for each assessment period. A suite of 16 growth plots in control and harvested blocks was remeasured.

Outcomes

Difficulties with identifying tawa trees led to its abandonment. Despite the loss of nearly two-thirds of tree tags and a small degree of confusion about harvested trees, virtually all surviving podocarp trees were identified with a satisfactory degree of confidence. Harvesting scarcely altered canopy structure and composition and diameter distributions of major species, and did not adversely affect the stability of the residual forest; mortality rates in residual merchantable podocarp trees were similar in the unlogged control (0.7%/yr) and the two harvested blocks (0.6%/yr, 0.8%/yr). Mortality rates and modes of death in residual podocarp trees varied among species. Despite somewhat faster diameter growth rates, productivity (gross volume increment) was lower in harvested blocks (0.3, 0.2 m³/ha/yr) than the unlogged control (0.4 m³/ha/yr) because of tree densities reduced by harvesting and the absence of any podocarp recruitment to the canopy. Net merchantable volume increment was negative in all major species and all blocks, ranging from -0.4 to -0.6 m³/ha/yr. Where closely monitored, selective harvesting was found to accelerate the transition from emergent podocarps to pole tawa, one of the many natural canopy replacement processes in this forest type.

Publications

Smale, M C; Beveridge, A E Long-term impacts of selective harvesting on a New Zealand rain forest. Paper being submitted to Forest Ecology and Management.

4.5 FRM 234

Programme Title:	Indigenous forest restoration guidelines
Programme Leader:	Rob Allen
Institution:	Landcare Research

Summary

The goal of this report was to develop the general principles underpinning restoration silviculture in New Zealand forests.

Background

Forest management practices that favour the removal of a few valuable species can bring about pervasive and long-lasting shifts in forest composition, structure and function. Because of this, there is growing recognition among forest managers that pre-management forest attributes should be restored and maintained in production forests. In New Zealand, a disproportionately large percentage of the privately owned indigenous forests, currently considered for timber production, have been logged-over in the past, most commonly by removing commercially viable conifer species. In some instances, conifer species do not recover their original abundance and hardwood (angiosperm) and tree fern species become overabundant, relative to unlogged forests. Owners of previously logged forests may wish to manage forests for timber production under provisions of the Forest Act, while also restoring forest structure and composition. Most frequently, the restoration goal will be to return a forest to its “pre-management” or sometimes even “prehuman” state. Restoration of pre-management forest attributes first requires that the lost attributes characterising a degraded state are identified and synthesised into an integrated restoration goal. Second, it is necessary to identify constraints on the restorative capacity of a forest. These goals and constraints can be used to develop silvicultural strategies that will allow restoration at meaningful timescales. Information and conclusions from this evaluation may be used by MAF to revise guidelines for indigenous forest management plans to meet the requirements of Part IIIA of the Forests Act.

Approach & Outcomes

The project utilised existing data held by Landcare Research, Ministry of Agriculture and Forestry and the wider literature. This information has accumulated over the last half century and included:

• data, maps, publications to define forest restoration goals;
• data and publications to determine likely constraints on restoration;
• current research, existing data and publications to broadly present restoration strategies.

General principles of restoration silviculture are illustrated using comparative data from logged and unlogged eastern North Island conifer-hardwood-beech forests.

Outcomes

Forest managers will have a range of forest restoration objectives. Where the objective is to restore the structure and composition of formerly dominant tree species in logged-over forest, the most appropriate data are sometimes available from local forest plot records.

A number of factors may constrain the restorative capacity of a logged forest and knowledge of how these factors operate, both alone and in concert, is critical if restoration activities are to be successful. Constraints, in the extreme, account for the irreversibility of damage to indigenous forests and to a lesser extent will markedly influence the rate of recovery due to restorative actions.

For the example forest in eastern North Island, the most significant impact of logging was the reduction in conifer basal-area and stem density and the reciprocal increase in hardwood (notably tawa) basal-area and stem density. For such reasons the restoration goals developed for these forests included increasing the number of conifer seedlings in beech-podocarp forest, and selectively decreasing the basal-area and stem densities of tawa and red beech to allow conifer seedlings to form a mixed tree-diameter-size structure. Revenue from harvesting tawa and red beech could be used to fund establishment of conifer seedlings.

Although, after appropriate trials, conifer seedling planting and manipulations of the hardwood canopy overstorey may be used to increase the conifer component in forests there is a need for simulation models to assess the long-term stand development of such complex forests with mixed size trees.

Conclusions

It has generally been perceived that selectively logged conifer-hardwood-beech forests in the eastern North Island are increasingly dominated by hardwoods and that there is little conifer regeneration. These consequences were verified most convincingly though comparing detailed stand structural data from logged and unlogged forest. The removal of matai trees has been the most devastating and, because of their longevity, will require the longest time frames to restore. The conclusions, however, come with certain provisos: first, the logged and unlogged forest comparisons were not replicated and any differences could be a consequence of, for example, site differences; second, conifer seedlings were not apparently depleted in logged-over tawa-podocarp forest, although the disturbance caused by logging may have been expected to increase the seedling densities of some conifer species. The manipulations required to enhance recruitment of conifers into the canopy and allow their onward growth to form mixed-size stands requires long-term commitment. As yet, demonstrations of such restorative silviculture are not available in New Zealand but are an essential direction to underpin Forest Act provisions and the wider community interests in forest restoration.

Recommendations

Techniques outlined in this report for developing restoration goals must be made more available to those developing forest management plans – for example, through guidelines and popular articles.

Forest management plans need to become more explicit about how forest structure and composition could be manipulated to achieve a different structure and composition. Internationally, there is growing interest in such forest manipulations (e.g., in Europe).

Because of the timescales involved in restorative silviculture there is a need for dynamic forest simulation models capable of projecting the implications of a wide range of potential forest manipulations way out into the future.

Specific research is needed on conifer recruitment, growth and mortality in eastern North Island forests to allow restoration of mixed-size, complex conifer-hardwood beech forest.

Summary

This study develops general principles underpinning restoration silviculture in New Zealand indigenous forests by determining a restoration goal for a previously logged conifer-hardwood-beech forest in eastern North Island, identifying potential restorative constraints that apply to the example forest, and to other indigenous forests in New Zealand, and finally defines a broad strategy for restoration that involves, in part, appropriate restoration silviculture.

4.6 FRM 235

Programme Title:	Forest boundary management
Programme Leader:	Bruce Burns
Institution:	Landcare Research

This research programme is not completed. Further information will be included in Research Results 2005/06.

4.7 FRM 236

Programme Title:	Revision of the scale for assessing the severity of live animal manipulations
Programme Leader:	David J Mellor
Institution:	Massey University

Summary

To review and revise the severity scale currently used nationally in New Zealand to assess the degree of suffering imposed by research, teaching and testing manipulations, and consider public communications about it.

Background

The current scale has been in place since 1997. Accordingly, as part of a process of continuing improvement and in response to some concerns about inconsistent application and misrepresentation of definitions, MAF commissioned research to review the rationale, terminology and explanation of the scale and to compare it with others now used overseas, with the aim of ensuring clarity and minimising ambiguity in definitions, descriptions of purposes and differences between categories.

Approach & Outcomes

A review of the rationale underlying the current NZ severity scale, and its full details, strengths and weaknesses was carried out in order to consider whether or not it meets present needs. A review and evaluation of other severity scales used overseas was then carried out and comparison was made with the current NZ severity scale. The NZ scale was revised following these considerations and peer review of the draft was sought and received from Professor David Morton, University of Birmingham, and Dr John Schofield, University of Otago, and suggested modifications included. The final report includes advice to MAF and NAEAC on implementation of the suggested revisions to the Scale.

These can be summarised as follows:

• The basis of the original system remains appropriate.

• The name of the categorisation system should be the “impact scale”.

• The current 5-point system should be enlarged by the addition of a sixth category (Z) which includes procedures that must not be carried out under any circumstances.

• To ensure greater accuracy, individual animals or groups should be graded, not the whole experiment.

• Animal manipulations in biotechnology are adequately covered by the present system and the addition of special categories is not necessary.

• An exhaustive list of manipulations with recommended gradings is not advisable, both because it will inevitably be incomplete and because it tends to be viewed in a rigid manner.

• A requirement should be made for the predicted impacts of manipulations to be measured against the actual impact, as assessed by researchers, animal-care staff, animal welfare officers and AECs, to ensure that statistics supplied to MAF reflect the real levels of welfare compromise.

• An exhaustive list of manipulations with recommended gradings is not advisable, both because it will inevitably be incomplete and because it tends to be viewed in a rigid manner.

Summary

The severity scale used to assess welfare compromise to animals used in research, testing and teaching was reviewed with the aim of ensuring clarity and minimising ambiguity. The review concentrated on the current workability of the system, including areas where problems had arisen, and drew comparisons with similar international systems. While it was felt that the current system is adequate to deal with animal manipulations in biotechnology, suggested changes included a change in name to the “impact” scale; the addition of a sixth category of “unacceptable” procedures; grading of individual animals not whole experiments; and a requirement for predicted impacts to be measured against actual impacts, and changed if appropriate.

Publications

Williams, V D; Mellor, J; Marbrook (2005). Revision of a Scale for Assessing the Severity of Live Animal Manipulations. Fifth World Congress on Alternatives and the Use of Animal in the Life Sciences, Berlin, Altex (In press).

4.8 FRM 237

Programme Title:	Framework for considering the economic and non-economic effects of changing animal welfare
Programme Leader:	Terry Parminter
Institution:	AgResearch

Summary

A framework that can be used to guide animal welfare policy makers when they are dealing with complex or socially divisive issues.

Background

The objective of this research was to develop principles that could be used as a guide to animal welfare policy. The information will be used by National Animal Welfare Advisory Committee when it is recommending policy or developing interim standards for animal welfare.

In the experience of NAWAC members, many animal husbandry practices are carried out for economic reasons e.g. breeding to increase productivity, housing to optimise feed efficiency, and mutilation to allow higher stocking rates. Changing some of these practices to protect or enhance animal welfare can markedly affect industries using animals but considering these effects is often limited to financial assessments of the effects of changes on producers and consumers. There are few guiding principles available for answering additional questions such as:

• What policy changes are acceptable?
• Which sections of society should be responsible for initiating those changes?
• How and when changes should such changes be made?

Approach & Outcomes

The project was carried out in two stages – both stages were ‘desk studies’. In the first stage, a literature review was carried out into systems theory to identify well substantiated principles for policy design in complex social environments. In the second stage, these principles were codified and applied to three practical policy examples so that the efficacy of the theoretical approach could be examined in more detail. The examples identified by NAWAC were: intensive housing of dairy cows, lamb castration using anesthetics and egg laying production systems for hens.

Outcomes

A policy making process of six steps based upon the work of Howlett and Ramesh (2003) was the focus of this project:

1. Agenda setting: during which issues come to the attention of policy makers
2. Policy analysis: when issues are described and the policy problem specified
3. Policy formulation: when policies options are developed
4. Decision making: to make choices about preferred policy interventions
5. Implementation: during which the policy is put in place in the community
6. Policy evaluation: when monitoring and learning is done.

In the first part of the project, a 4-Windows approach to policy making was developed from the work of Bob Flood (1999). In the second part of the project the 4-Windows approach was applied to policy steps 1–4 to provide insight into:

• How particular issues affect the welfare and biological functioning of individual animals (Window 1)
• How issues affect and are affected by, the farming systems in which they are situated, including factors of industry structure and economic returns (Window 2)
• How issues relate to the norms and values of various sections of society (Window 3)
• How resolving the policy issues will improve social equity, and empower the decision making of the affected stakeholder groups (Window 4)

The insights obtained by using the 4-Windows approach were brought together in an open and transparent way using the Analytical Hierarchy Process (Saaty 1996) to compare their strengths and weaknesses and select the most preferred option for further development and negotiation with the industry.

Applying the 4-Windows to dairy cow housing indicated that it was largely a policy driven issue that could be addressed through a programme of stakeholder education and industry alignment. Anesthetising lambs at castration was shown to be an issue that was largely science driven requiring technology improvements for administrating anaesthetic before policy changes were likely to be effective. Hen laying systems was considered to be a more publicly driven issue that required market changes if the more publicly desired production of barn or free-range eggs was to be encouraged. However, policy interventions could be made to increase the rate of change and to restrict the use of the more controversial practices still being used in the industry.

Summary

The project was intended to develop a framework that could be used to guide animal welfare policy makers when they are dealing with complex or socially divisive issues. A desk study was undertaken into systems theory applicable to policy design followed by case-study applications. A 4-Windows approach enabled the author to bring together economic and non-economic components to animal welfare policy design in a manner which was open, transparent and quantitative.

Publications

A paper to be presented at the New Zealand Agricultural and Resource Economics Society conference in 2006, is proposed.

4.9 FRM 238

Programme Title:	Precision agriculture and its environmental benefits for New Zealand
Programme Leader:	Ian Yule
Institution:	Massey University

This research programme is not completed. Further information will be included in Research Results 2005/06.

4.10 FRM 239

Programme Title:	Relative risk index model for pathogens
Programme Leader:	Malcolm McLeod
Institution:	Landcare Research

Summary

To develop a qualitative relative risk index for the transport of pathogens from farmed animals to waterways, through creation of simple rulesets from existing data and expert opinion. Use of a GIS will enable the development of risk maps that encompass New Zealand, and depict the dominant causal factors in pathogen transmission.

Background

Water-bodies in New Zealand increasingly are becoming contaminated with microbes. Farmed animals may contribute to this microbial contamination. Landcare Research has expertise in how microbes may move through the soil following irrigation with dairy shed effluent. This data was incomplete and required to be put in a spatial framework.

Approach

Spatial presentation is provided of relative risks of microbial transport associated with:

• surface runoff;
• bypass flow through soil;
• flow through the vadose zone.

Relative risk associated with surface runoff and bypass flow are combined to present relative risk of microbial contamination of surface water, and relative risk associated with bypass flow and vadose zone transport are combined to present relative risk of microbial contamination of ground water. Maps are also presented depicting optimal riparian buffer strip width based on the final Best Management Practices Report of the Pathogen Transmission Routes Research Program.

This report models and spatially predicts the risks associated with transport of microbes from farm animals to waterways for the North and South Island of New Zealand at a maximum scale of 1:50 000.

Outcomes

In the central North Island and Taranaki regions, soils and vadose zone material derived from tephra have physical properties which minimize the transmission of microbes to water bodies.

Soils with well-developed soil structure and soils with a drainage impediment both relatively poorly attenuate transmission of microbes through soil.

Skeletal alluvial soils on gravelly vadose zone material relatively poorly attenuate transmission of microbes to ground water.

Microbial transport through the vadose zone is poorly understood.

Summary

This report develops a qualitative relative risk index for the transport of pathogens from farmed animals to waterways, through creation of simple rulesets from existing data and expert opinion.

Relative risks of microbial transport associated with:

• surface runoff;
• bypass flow through soil;
• flow through the vadose zone.

are presented spatially and combined to present relative risk of microbial contamination of surface water and ground water. Maps of optimal riparian buffer strip width based are also presented.

In the central North Island and Taranaki regions, soils and vadose zone material derived from tephra have physical properties which minimize the transmission of microbes to water bodies. Soils with well-developed soil structure and soils with a drainage impediment both relatively poorly attenuate transmission of microbes through soil. Skeletal alluvial soils on gravelly vadose zone material relatively poorly attenuate transmission of microbes to ground water.

Publications

McLeod, M; Close, M E; Collins, R (2005) Relative risk indices for microbial transport from land to water-bodies. Landcare Research Contract Report LC0405/165.

4.11 FRM 240

Programme Title:	Key poultry welfare indicators (2004/05)
Programme Leader:	Lindsay Matthews
Institution:	AgResearch

This research programme is not completed. Further information will be included in Research Results 2005/06.

Contact for Enquiries

Farm Monitoring Programme Manager
Monitoring and Evaluation
MAF Policy
PO Box 2526
Wellington
NEW ZEALAND
Phone: +64 4 894 0623
Fax: +64 4 894 0741
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