Weed Management Plan
Christmas Island Phosphates (CIP)
Christmas Island has unique biodiversity values but after 120 years of settlement and poor quarantine numerous plant species have been introduced either intentionally or by accident. Some species such as paw paw, chilli and rubber tree have been brought to the Island for food, industry, traditional medicine, ornamentals or historic rehabilitation. In all more than 175 species of introduced plant species exist on the Island and many are now entrenched in National Park and Crown Land. Some species are spread by birds or wind and are already present in the soil seedbank throughout natural areas of the island, waiting for an opportunity to germinate and grow.
Weed management activities on a tropical island is challenging with high rainfall and fast growth making control difficult. All areas of the mining lease have been previously cleared and mined by previous companies and contain a variety of introduced plant species. Some control activities can have potential to cause further environmental harm through spray drift, compaction and removal of vegetation cover. Even if is predominantly introduced species, this vegetation may be important for fauna on the Island, particularly for the Christmas Island red crab which requires shade to live and migrate. Several introduced plants provide habitat and food for the Island’s Threatened fauna species so have values which must be considered before undertaking control activities. Other species may add nitrogen to the soil, which is usually nitrogen and prone to compaction, and help in soil amelioration rehabilitation of old minesites. This makes weed management a complex issue, with the benefits of control of individual weed species needing to be balanced against the negative environmental impacts of control activities.
From 2014 to 2017 Range to Reef undertook field surveys and a process of agency consultation to develop an alternative approach to weed management on the Christmas Island minesites. Range to Reef developed a weed management strategy in conjunction with multiple Island land managers, including Parks Australia and Department of Industry and Regional Development. The integrated weed management plan identifies cost-effective and practical approaches while still protecting the Island’s unique environment from the most damaging and high risk environmental weeds. The process involved a risk assessment of weeds on the island to determine which were the greatest threat to conservation areas, future agriculture on the Island, or which posed a biosecurity risk to the Australian mainland with the expert assistance of tropical botanist David Fell. This assessment included a review of current spread on Island, biological needs-in particular the ability to tolerate shade conditions, ability to spread by natural and artificial vectors, capacity to effect sustainable control in the longer term, environmental benefits of control and the risks to conservation areas and species. At the end of this process, 23 high risk weeds were identified that had the potential to cause economic damage, such as Parthenium weed, or which had the potential to invade the Island’s natural areas, including the Christmas Island National Park. These species will be the target of weed control activities on the mining lease and fulfil weed control conditions of clearing permits and the Company’s Environmental Management Plan commitments.
Development of the plan was not possible without consultation with Parks Australia, Department of Agriculture and Food Western Australia’s Biosecurity Regulation department, Department of Industry and Regional Development and Department of Environment.
The Christmas Island Phosphates Weed Management Plan has now been endorsed by the Commonwealth. “The Weed Management Plan is a well considered, comprehensive and practical plan for managing weeds on current CIP mining tenements on Christmas Island.”
Vicki Middleton, Executive Director, Local Government and Territories