Browsing by Author "Joy MK"
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- ItemA fish index of biotic integrity (IBI) for horizons regional council(Horizons regional Council, 2016-06-01) Joy MK
- ItemFreshwater fish predictive modelling for bio-assessment; a scoping study into fish bio-assessment models as national indicators(Wairesearch Limited, 2013-01-01) Joy MKThe match between the biota expected at a site in the absence of impacts and what is found there when testing is a robust and popular bioassessment method in many countries worldwide. The difference between the assemblage found and that expected is measured as the observed/expected ratio and is the basis of the RIVPACS approach initially developed in the United Kingdom using invertebrates. When the observed and expected assemblages match the O/E score is 1. An O/E score less than 1 means some impact and more than 1 suggests better than expected biota. This scoping trial of the feasibility of a fish predictive RIVPACS type bioassessment using the New Zealand Freshwater Fish Database (NZFFDB) and predictive models of fish distribution from the Freshwater Ecosystems of New Zealand (FENZ) was not successful. This study revealed that the predictive bioassessment approach in this case failed mainly due to the lack of suitable predictive models for this not because of problems with the predictive bioassessment approach. The problem with the available FENZ fish predictions used in this study is that they were developed to predict how the fish assemblages are today allowing for many land-use impacts rather than the predictions of the assemblages that would be expected in the absence of impacts crucial to RIVPACS type models. Regional O/E fish models have been successfully applied with fish in New Zealand by taking all the steps in the RIVPACS process but have generally not been taken up by resource managers. To validate the data used in this study an Index of Biotic Integrity (IBI) was successfully applied to the observed (NZFFDB) and predicted fish assemblages (FENZ) and revealed their suitability for bioassessment. However, an assessment of the observed/expected IBI results was, like the fish community O/E unsuccessful, again because the predictions are for actual rather than expected fish communities. The conclusions from this study are that predictive bioassessment models have great potential for use in New Zealand but there are no shortcuts. Consequently, new predictive models must be produced based on reference sites and using habitat descriptors that are least influenced by human impacts. In the meantime the IBI is a useful measure of the biotic integrity of freshwater in New Zealand, and improvements in sampling will mean that the IBI can be updated and improved.
- ItemNutrient criteria to achieve New Zealand's riverine macroinvertebrate targets(PeerJ, Inc, 2021) Canning AD; Joy MK; Death RG; Brauns MWaterways worldwide are experiencing nutrient enrichment from population growth and intensive agriculture, and New Zealand is part of this global trend. Increasing fertilizer in New Zealand and intensive agriculture have driven substantial water quality declines over recent decades. A recent national directive has set environmental managers a range of riverine ecological targets, including three macroinvertebrate indicators, and requires nutrient criteria be set to support their achievement. To support these national aspirations, we use the minimization-of-mismatch analysis to derive potential nutrient criteria. Given that nutrient and macroinvertebrate monitoring often does not occur at the same sites, we compared nutrient criteria derived at sites where macroinvertebrates and nutrients are monitored concurrently with nutrient criteria derived at all macroinvertebrate monitoring sites and using modelled nutrients. To support all three macroinvertebrate targets, we suggest that suitable nutrient criteria would set median dissolved inorganic nitrogen concentrations at ~0.6 mg/L and median dissolved reactive phosphorus concentrations at ~0.02 mg/L. We recognize that deriving site-specific nutrient criteria requires the balancing of multiple values and consideration of multiple targets, and anticipate that criteria derived here will help and support these environmental goals.
- ItemProtecting the future of New Zealand’s freshwater ecosystems(Society for Conservation Biology (Oceania), Sydney, 1/09/2014) Weeks E; Kingsford RT; Taylor A; Joy MKFreshwater is New Zealand’s greatest asset and is a taonga of paramount importance. It is valued for its contribution to biodiversity, recreation, the economy and overall well - being of New Zealanders. New Zealand’s rivers, lakes, wetlands and groundwater support a unique array of flora and fauna. They are also a vital element of whakapapa and provide valuable resources such as mahinga kai, and underpin the country’s ever - growing tourism industry. Reinforcing this importance, New Zealanders consider water quality to be the most important environmental challenge facing New Zealand. This Conservation Science Statement uses the latest scientific understanding of New Zealand’s unique freshwater ecosystems to propose approaches to policy and management that safeguard these resources for future generations. We identify six clear priorities to protect New Zealand’s freshwater ecosystems: 1. address the cumulative impacts of land use change and resulting diffuse pollution of rivers and streams ; 2. build capacity to sustainably manage freshwater ecosystems at the regional level ; 3. support whole farm environmental management to control water quality impacts ; 4. develop a management agenda for wetlands and groundwater ecosystems ; 5. enhance the understanding of the ecological requirements to sustain native fish habitat through Department of Conservation, the Land and Water Forum site and other agencies and; 6. identify impacts of increased allocation on surface and ground water ecosystems and synergies with declining water quality.
- ItemThe true cost of milk: Environmental deterioration vs. profit in the New Zealand dairy industry(AgEcon, 29/08/2014) Foote K; Joy MKOver the past two decades, major increases in production have occurred in the New Zealand dairy industry. This has required the use of externally sourced inputs, particularly fertiliser, feed supplements, and irrigation. Contemporary New Zealand dairy farming practice incurs environmental externalities: impacts that are not paid for by the dairy farmer. Hence, the public is left to deal with these externalities, both regarding the economic responsibility and environmental degradation. This study estimated that the economic cost of environmental externalities is higher than the 2012 dairy export revenue of $11.6 billion.
