Effects of opossum browsing on northern rata trees in the Orongorongo Valley, Wellington, New Zealand

Abstract

Browsing damage caused by opossums (Trickosurus vulpecula) was assessed visually, against a simple index, on 24 northern rata trees (Metrosideros robusta A. Cunn.) every 2 months from November 1969 to November 1974. All 24 trees showed some damage, and 3 died as a result of continued heavy browsing; 7 of 26 other rata trees in the study area have died similarly since 1969. When opossums were excluded from 5 previously browsed trees, all recovered. Stick insects (Phasmatidae) contributed about 3% to the total damage, but with other defoliating insects may be more important in other parts of New Zealand.