Climate change impacts on erosion and suspended sediment loads in New Zealand

Neverman, Andrew; Donovan, Mitchell; Smith, Hugh G.; Ausseil, Anne-Gäelle; Zammit, Christian

doi:10.1016/j.geomorph.2023.108607

Cited by 21 publications

(5 citation statements)

References 83 publications

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“…It is likely that the policies used to improve sediment or clarity will also improve E. coli and nutrients. For instance, to achieve sediment load targets, Neverman et al (2019) simulate the impact of whole farm planning and afforestation, which will also improve E. coli and nutrient leaching to waterways.…”

Section: Policy Illustrationmentioning

confidence: 99%

“…At the same time, we also find and control for significant unobserved heterogeneity in WTP. We apply our results to a recent water quality policy proposed by New Zealand's Ministry for the Environment (MFE), to reduce sediment runoff (Neverman et al, 2019). Benefits transfer based on our survey results suggests nationwide annual benefits of about NZ $144 million (2018 NZD) or approximately $99 million USD.…”

Section: Introductionmentioning

confidence: 95%

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Eliciting policy-relevant stated preference values for water quality: An application to New Zealand

Walsh

Guignet

Booth

2023

Agric. Resour. Econom. Rev.

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Governments need tools to analyze trade-offs for freshwater policy, yet valuation estimates from the literature can be difficult to deploy in a policy setting. Obstacles to benefit transfer include (i) difficulties in scaling up local estimates, (ii) water quality attributes that cannot be linked to policy, and (iii) surveys positing large, unrealistic water quality changes. Focusing on freshwater rivers and streams in New Zealand, we develop and implement a nationwide discrete choice stated preference study aimed at future benefit transfer. The stated provision mechanism and environmental commodity being valued are specified at the regional council level, which is the administrative unit for policy implementation. The survey is administered on a national scale with three attributes – nutrients, water clarity, and E. coli levels – which were chosen to align with government policy levers and salience to the public. Estimation results demonstrate positive and significant willingness to pay values for improvements in each attribute, with magnitudes that are comparable to a recent referendum vote on a water quality tax. To illustrate the utility of our study, we apply the results to a recent policy analyzed by New Zealand’s Ministry for the Environment and estimate nationwide annual benefits of NZ $115 million ($77 million USD).

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Section: Policy Illustrationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 95%

Eliciting policy-relevant stated preference values for water quality: An application to New Zealand

Walsh

Guignet

Booth

2023

Agric. Resour. Econom. Rev.

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“…Erosion processes in New Zealand remain very active [14], due to a predisposed natural environment with steep slopes, weak sedimentary rocks, and a climate featuring high annual rainfall and relatively frequent high magnitude rainfall events [15][16][17]. Climate change is predicted to result in large increases in sediment loads, primarily due to increasing storm magnitude-frequency of mass movement erosion in soft-rock hill country [18].…”

Section: Introductionmentioning

confidence: 99%

“…The most common types of mass movement in New Zealand are shallow, rapid slides and flows involving soil and regolith [1,19]. Such landslides are generally triggered either by high-intensity-rainfall events or by small rainfall events on top of saturated soil moisture conditions [18]. Shallow landslides make up the largest source of sediment from pastoral hill country in New Zealand [20].…”

Section: Introductionmentioning

confidence: 99%

Drivers and New Opportunities for Woody Vegetation Use in Erosion Management in Pastoral Hill Country in New Zealand

McIvor¹,

Mackay-Smith²,

Spiekermann³

2024

Soil Erosion - Risk Modeling and Management

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Increases in the magnitude and frequency of rainfall events in New Zealand due to climate change, coupled with existing concerns about sediment and nutrient contamination of waterways, are changing policy and practice around erosion management and land use. We describe the challenges around slope erosion reduction, cover current legislation and management practices, illustrate how modeling can inform erosion management and describe new opportunities, whereby native species can become a new active management tool for erosion control. Passive erosion management depending on natural revegetation by slow growing woody species is used on land retired from grazing but is much less effective than active erosion management in reducing shallow slope erosion. Active erosion management using exotic fast-growing poplar and willow trees strategically placed on hillslopes is effective in reducing erosion, but these trees can be hard to establish on drier upper slopes. An endemic woody tree, Kanuka, grows on drier slopes and is being tested as an erosion control tool. Kanuka seedlings have been successfully established on pastoral slopes, including drier slopes. A spatial decision support tool developed to identify pastoral hillslopes at high risk of erosion has improved decision-making when positioning appropriate trees on these slopes.

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“…Fine sediment is already recognised as a significant threat to global aquatic health, and this is expected to be further exacerbated under future climatic scenarios due to alterations in rainfall and runoff regimes (Neverman et al, 2023). It is, therefore, important that our understanding and management of this pressure is advanced.…”

Section: Introductionmentioning

confidence: 99%

Phenotypic plasticity of a Baetid mayfly larvae (Baetis rhodani) at sites with high levels of deposited fine sediment

McKenzie,

Scott,

Wood

et al. 2024

Ecological Entomology

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Excess fine sediment (particles <2 mm) delivery and deposition in freshwater systems is a significant factor in structuring aquatic communities and populations. Invertebrate gill surfaces can become covered with fine sediment, potentially compromising osmoregulatory function. Ionocytes are specialised structures for osmoregulation found on the tracheal gills of mayflies. The number of cells has been shown to change in order to maintain osmoregulatory demands under environmentally variable conditions. To investigate whether ionocytes vary in response to fine sediment pressure, individuals of Baetis rhodani were collected from two high and low fine sediment cover sites, respectively, in the UK. Tracheal gills were subsequently examined for the number of ionocytes present on the upper and lower gill surfaces, standardised by gill size. Results indicated that the number of ionocytes was significantly higher for mayflies collected from areas with high fine sediment cover. High fine sediment sites were also characterised by lower altitude and dissolved oxygen concentrations. Mayfly gills collected from high sediment cover sites were also significantly larger than those collected from low sediment sites. The results illustrate the potential for mayfly larvae to demonstrate phenotypic plasticity to the pressures associated with fine sediment but that these responses are likely dependent on the composition of fine sediment deposits (organic or mineral) and associated oxygen concentrations.

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Climate change impacts on erosion and suspended sediment loads in New Zealand

Cited by 21 publications

References 83 publications

Eliciting policy-relevant stated preference values for water quality: An application to New Zealand

Eliciting policy-relevant stated preference values for water quality: An application to New Zealand

Drivers and New Opportunities for Woody Vegetation Use in Erosion Management in Pastoral Hill Country in New Zealand

Phenotypic plasticity of a Baetid mayfly larvae (Baetis rhodani) at sites with high levels of deposited fine sediment

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