This fact sheet details the Giant African snail (Achatina fulica) which is a tropical snail not currently established in New Zealand. The main biosecurity risk lies in the introduction of the snail to New Zealand attached to plant material, crates, containers, machinery or motor vehicles.

A register of MPI export plant approved organisations.

Increasingly frequent and intense extreme weather events such as Cyclone Gabrielle are likely to impact seafloor marine ecosystems by accelerating soil erosion and sediment transport to the ocean by rivers.

The objective of this project was to understand sediment impacts from the February 2023 Cyclone Gabrielle event on marine environments of the Hawke’s Bay and Gisborne regions to enable rapid fisheries management decisions.

We conducted two vessel surveys in June and October 2023 focusing on offshore seabed environments deeper than 15 metres. As part of these surveys we mapped selected areas of the seafloor, surveyed life on the seabed using a towed underwater camera, and obtained sediment core samples.

An ocean current and sediment transport model was designed and implemented to investigate the transport and deposition of sediments after Cyclone Gabrielle. Concentrations of suspended sediments and other parameters in the surface ocean along the east coast of the North Island were estimated from satellite images. This satellite information was used to inform the sediment transport model and to characterise the spatial extent and longevity of the offshore sediment plumes generated by Cyclone Gabrielle. A Seafloor model was used to explore impacts and recovery of seafloor ecosystems following the cyclone.

The analysis of satellite images suggest that the influence of Cyclone Gabrielle lasted approximately two to three months across the Hawke’s Bay and Gisborne coastal marine areas, with surface ocean parameters largely returning to normal by May. The concentrations of suspended sediment at the ocean surface in February were significantly elevated, but they did not exceed values typical of winter months.
Seabed mapping revealed areas of significant sediment erosion, and deposition up to about one metre in thickness, at Pania Reef, Tangoio Reef and Clive outfall area in Hawke Bay. Elsewhere, sediment core observations suggested the presence of fresh muddy deposits of up to about 15 centimetres. Swell waves were resuspending muddy sediments at shallow locations for several months after the cyclone, as was evident by the low underwater visibility during camera deployments.

The abundance and diversity of the sediment fauna sampled in Hawke’s Bay and Gisborne before (2010) and after Cyclone Gabrielle (June and October 2023) tended to increase away from the shore and into deeper waters. Sediment fauna were less abundant in June 2023 when compared with 2010, but appeared to be recovering by October 2023.

Seafloor animal and plant communities are highly likely to have been impacted by sediments at 11 of the 36 locations we surveyed using the towed underwater camera, as assessed by observations including (1) fresh mud layer on the seafloor, (2) animal/plant life in poor condition, and/or (3) absence of seaweed at shallow depths. However, for most of these locations a direct link to Cyclone Gabrielle cannot be demonstrated because no information on the distribution of seafloor organisms is available from before the cyclone. The likely exception is Wairoa Hard in Hawke Bay, where available information shows that kelp and sponges were present before the cyclone but were almost completely or completely absent after the cyclone. Whether this loss of habitat has led to reductions in associated fish populations is unclear.

Although limited by the availability of data, the ocean current and sediment transport model produced realistic predictions of suspended sediment concentrations and deposition at the seafloor. In the days following the cyclone, sedimentation in Hawke Bay was predicted to occur mainly close to shore in the western and central parts of the bay. In the Gisborne region, there was deposition of up to about 10 centimetres of sediments offshore of Poverty Bay and along a narrow band of the coast to the north near Tokomaru and Tolaga bays. These model predictions are broadly consistent with observations from the sediment core samples.

The Seafloor model showed small declines in structure-forming organisms such as sponges for Hawke’s Bay following Cyclone Gabrielle. These declines were not substantial, most likely because the region is already impacted by decades of fishing and increased sedimentation. The Seafloor model predicted weaker cyclone impacts for Gisborne than Hawke’s Bay and indicated that continued trawling may slow down recovery of seafloor communities following extreme weather events.

The lack of pre-cyclone information was a major obstacle in assessing the potential impacts of the cyclone on seabed ecosystems. Information collected as part of this project now form a valuable baseline that will inform future impact assessments in the region. Another limitation is the inability to use towed cameras to survey inshore habitats for extended periods because of poor underwater visibility. A precautionary approach could be warranted in the period following an extreme weather event until key habitats and ecosystems can be surveyed, and fish stocks and catch levels should be carefully monitored in the years following the event.

Sediment transport modelling is a promising tool for rapidly identifying areas most at risk from sedimentation following extreme weather events. However targeted sampling of sediment and water parameters under normal and flood conditions would help improve the accuracy and reliability of model predictions. The Seafloor model could be used to explore how spatial changes in fishing effort could enhance recovery following extreme weather events and could be improved through better information on the distribution of seafloor sediment and reefs and their associated animal and plant communities, particularly in the Gisborne region.

The impact of extreme weather events is made worse by decades of increased sedimentation in New Zealand’s marine environments. Addressing the long-term issue of sedimentation in marine ecosystems and the impacts of extreme weather events will require addressing the factors that have made New Zealand’s catchments more prone to erosion.

Evaluation of the impact and direct effect of climate change on the productivity of New Zealand's planted forest systems.

This report aims to generate productivity surfaces for indigenous forest species and Pinus radiata for New Zealand. These surfaces were generated for current and anticipated future climatic conditions for pinus radiata. For indigenous forests, the work used predictive modelling techniques to produce spatial models of tree diameter increment. Estimating the growth rate of these forests accurately will enable optimal siting of future plantations and enhance national policy formulation.

The objective of this study is to quantify the risk posed by wind damage to
planted forests in New Zealand and to investigate different options that owners of
forests registered under the Emissions Trading Scheme can use to manage this risk.

This study looks at likely impacts of assumed values of climate change on plantation productivity, focusing on the relationships between climate and forest productivity.

The objective of this report is to identify how New Zealand planted forest
management could change to effectively manage carbon sequestration and
carbon-price risk. This study involved evaluating existing knowledge in a literature review, and carrying out a comprehensive stand and estate-level modelling exercise. Results were used to identify core knowledge gaps and provide a research plan for addressing these gaps.

This paper focuses on the possible threat that four key pests pose to New Zealand's plantation forestry resource under climate change.

This report quantifies the annual carbon emissions associated with current rates of annual disturbance in New Zealand’s pre-1990 and post-1989 forests, within the context of the Durban Agreement. The Durban Agreement includes definitions and a suggested approach to deriving the baseline level of natural disturbance, but the relevant best practice guidance is yet to be finalised. This adds a significant element of methodological uncertainty.

Plant diseases, a major constraint on New Zealand's horticultural production, are likely to be affected by temperature and rainfall changes resulting from global climate warming. This study undertook a quantitative analysis for key diseases affecting major horticultural crop sectors using disease risk models in use within those sectors, to ascertain likely changes in regional disease and allow the horticultural industry to plan for the future.

Scion, Landcare Research and the University of Canterbury reviewed national and international best practice in steepland plantation forests to understand and minimise the damage from post-harvest landslide and debris flows.

Note, while this document is marked 'confidential', it has since been approved for public release.

Carbon sequestration in plantation forests can be used to offset greenhouse gas emissions to meet New Zealand's international climate change obligations in the Kyoto Protocol. Although Pinus radiata grows quickly, species with higher wood density, such as Eucalyptus fastigata, are likely to be more suitable for plantations aimed at carbon sequestration. The aim of this study was to provide robust tools and models for predicting carbon sequestration for Eucalyptus fastigata.