Monitoring the effects of animal pests on Chatham Islands vegetation

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Summary

The Wellington Conservancy terrestrial habitat monitoring strategy identified the need for a specific plan to monitor the effects of animal pests on Chatham Islands vegetation. That need was recently reinforced by Chatham Islands Area staff. This 10 year plan identifies monitoring to help answer animal pest management questions, and has the following objectives:

• Monitor long-term changes in selected forests to understand the effects of animal pests on forest structure, regeneration, and species diversity.
• Quantify the effects of possums on Chatham Island forests, and identify the intensity of control needed to alleviate possum pressure.
• Quantify the regenerative processes of vegetation under grazing and non-grazing regimes on Pitt Island.

To achieve these objectives, this plan identifies gaps in current monitoring effort, where monitoring is to be added, and where to discard unnecessary monitoring. The focus is on palatable plant regeneration and restoration of terrestrial vegetation structure. This supports current and ongoing management, such as the parea protection project, which has resources allocated for vegetation monitoring to help assess the effectiveness of
possum control. This project contributes most of the resources available for vegetation community monitoring throughout the Chatham Islands.

In addition to monitoring animal pest impacts on terrestrial vegetation, monitoring of wetland environments is also required, due to impacts from feral stock. Other threats to wetlands include fire and invasion by weeds.

A specific plan is required for these environments. The development of a specific Chatham Islands foredune management strategy is also necessary to deal with threatened species and ecosystem restoration issues.

Following a review of past and current monitoring, the Department intends to:

• Continue the permanent vegetation plot network on Chatham Island to monitor long-term changes in forests (with suggested changes).
• Expand monitoring of animal pest impacts within forested habitats in the southern tablelands and northern reserves of Chatham Island.
• Continue the permanent vegetation plot network on Pitt Island to monitor long-term changes in forests (with suggested changes).