Alien plant and animal control and aspects of ecological restoration in a small ‘mainland island’: Wenderholm Regional Park, New Zealand

Since 1965, ecosystem-focused ecological restoration has been undertaken in a small (60ha) mainland island at Wenderholm Regional Park (134 ha), which lies on a peninsula on the east coast north of Auckland. A 60 ha coastal forest has been fenced to exclude livestock and retired pastureland has been reforested. Brushtail possums (Trichosurus vulpecular and rats (Rattus rattus and R. norvegicus) have been reduced to very low densities and feral cats (Felis catus) and mustelids (Mustela spp.) have been controlled. Forest health and New Zealand pigeon (Hemiphaga novaeseelandiae) breeding success have improved and large invertebrates are now more abundant. By early 1999, Wenderholm was deemed suitable for experimental releases of birds, which had become locally extinct on the northern North Island mainland. In the first release, 21 North Island robins (Petroica australis were translocated from nearby Tiritiri Matangi Island in March 1999. During the past two years, survival of site-attached robins has been high and they have fledged 46 young, thus the robins have been useful indicators of successful control of some invasive alien mammals. However, despite high productivity, recruitment has been insufficient to compensate for adult losses. Poor recruitment may be due to high rates of juvenile dispersal from the mainland island because of its small size. Linkages with nearby forest areas allow robins to disperse easily, and the ultimate success of the translocation is therefore uncertain. The dispersal distances of species intended for release need to be taken into account in the planning of any new mainland island.

Author Lovegrove, T. G., Zeiler, C. H.. Greene, B. S., Green, B. W.. Gaastra, R. and MacArthur, A. D.
Year 2002
Secondary title International Conference on Eradication of Island Invasives
Publisher IUCN Invasive Species Specialist Group
Pages 155-163
Region NZ