Russell Predator-Free 2050 – a programme to remove key invasive animal predators of native wildlife on the Russell Peninsula, is part of a broader strategy to make the Peninsula more attractive for native wildlife, plants and ecosystems. Other actions proposed include removing invasive plants – at least from key locations – constraining or removing other invasive animals (e.g., feral goats and pigs), conducting surveillance for new invasive species and the spread of others, and planting diverse native species to provide high-quality food sources for native wildlife and creating more suitable habitat for wetland wildlife. 

We will also search for rare species such as the long-tailed bat, which have not been seen recently but may still be present. Lastly, we hope to reintroduce several wildlife species that were present in the early twentieth century once the habitat is suitable for them. A suggested priority species is the North Island kōkako, or blue-wattle crow, which has a haunting and melodic call and, like kukupa, is an important disperser of large native seeds such as puriri, taraire and tawa.

Long-tailed bats roost in cavities in old trees, moving frequently and rarely occupying a site for more than one night. A social bat group can use more than 100 different roosting trees. Protecting standing dead trees and old trees with hollows /cavities provides useful habitat for bats. Preferred trees include the New Zealand cabbage tree, kanuka, totara, puriri, and pukatea. 95% of the trees used are in open lowland forests, with the forest edge at least 500m away. Approximately 30% of the trees used for roosting are dead standing trees.  The long-tailed bat has a lifespan of 7 to 11 years.

A systematic survey using appropriate bat-detection equipment is recommended to clarify whether long-tailed bats are on or near the Peninsula.

If, after an extensive survey of likely habitat, no long-tailed bats are found, then work could begin to prepare an application for a reintroduction.

Much of the Kōkako diet consists of broad-leaved species. The taller emergent trees, such as kahikatea and rimu, are particularly important as perches for broadcasting territorial calls and as sources of fruit. Kōkako eat at least 35 species of fruit and may once have been almost as important as native seed dispersers as kukupa. However, they do not fly well and have smaller territories. To ensure that kōkako can move freely, there should be less than 100m between the forest patches they inhabit. 

To prepare the habitat for a potential kokako release, the area of continuous, diverse native forest would need to be increased. 

The first step would be to establish forest corridors linking the forests and shrublands of the Pipiroa and Te Wahapu catchments, as well as the northwestern shore of Waikare Inlet, with those of Tikitikiore-Paroa Bay and the eastern parts of the Russell Peninsula. Another important step would be to plant suitable native broadleaved species alongside existing forest patches, as well as appropriately sited kahikatea, totara, matai, miro and rimu.

Invasive plants can cause considerable damage to natural environments. They can significantly damage or destroy ecological integrity or naturalness.  Coastal margin communities are particularly vulnerable, including coastal faces and cliffs, rock stacks, shell barrier beaches, salt meadows, dunes and wetlands.

To prepare the habitat for a potential kokako release, the area of continuous, diverse native forest would need to be increased. 

Invasive vines (e.g., banana passionfruit, Japanese honeysuckle, moth plant, and climbing asparagus) can dominate the canopy, pulling over and smothering canopy trees and shrubs. 

They can also prevent regeneration by smothering and preventing seedling and sapling growth. Invasive trees that can grow under shade can eventually replace native canopy trees in existing forests. In other situations, invasive trees (e.g., tree privet, tobacco weed, Taiwan cherry, monkey apple, wattles, pines) can grow rapidly and form a new forest type that is not favoured by many native plant and animal species.

Dense, invasive forest understory plants prevent the regeneration of most native species, whether trees, shrubs, or ground cover. They can also adversely affect some native wildlife. For example, dense ginger rhizomes adversely affect kiwi, which probe the ground with their bills to find worms and other food.

Images from DOC – doc.govt.nz