Towards the reestablishment of community equilibrium of native and non-native landbird species in reponse to pest control on islands in the Eastern Bay of Islands, New Zealand

Abstract

Disequilibrium of bird communities, due to introduced pests and human-caused habitat changes, is a fundamental property to be understood in restoration of island biota. In this paper, we suggest that the reestablishment of native forests and food webs favour long-established and native species, and is less favourable to more recently introduced species. To test this hypothesis, we compared population trends of native and non-native birds on five islands in the Ipipiri Group in the north of New Zealand. We used over 900 station counts starting in 2008 when habitat recovery and pest (rat [Rattus], mouse [Mus musculus], and stoat [Mustela erminea]) removal began, as well as comparing to a set of earlier counts. In general, we found that detection rates of most long-established endemic native species significantly increased, while non-native species mostly decreased, suggesting population increases and decreases, respectively. Of the native species, six are relatively recent natural immigrants to New Zealand, and most of these declined or remained unchanged. We suggest that the increase in long-established natives is likely due to increased size and quality of native bush areas making habitat more favourable to these natives, as well as reduced predation and competition from the pest mammals.

Citation

Ralph, C. John; Ralph, Carol P.; Long, Linda L. 2020. Towards the reestablishment of community equilibrium of native and non-native landbird species in reponse to pest control on islands in the Eastern Bay of Islands, New Zealand. Notornis. 67: 437-450.