Are introduced birds unimportant mutualists? A case study of frugivory in European blackbirds (Turdus merula)

Many types of birds regularly consume fleshy fruits and, as seed dispersers, perform important mutualistic services for plants. Some frugivorous birds have recently been introduced to geographic locales beyond their native range. Are non-native birds important frugivores in their introduced range? To answer this question, I observed native and introduced birds foraging for fruits in a New Zealand forest at approximately 5-day intervals for 5 years.

Ship rat demography and diet following possum control in a mixed podocarp-hardwood forest

Control of one pest species may permit increases in abundance of other pests, thereby reducing the overall net benefit from pest control. We provide evidence that control of introduced possums (Trichosurus vulpecula) may increase ship rat (Rattus rattus) abundance in some New Zealand native forests. Ship rat abundance in a podocarp–hardwood forest was assessed using simple interference indices over 14 years (1990–2004) that included two aerial possum-poisoning operations (1994, 2000).