Deer diet on Stewart Island, and its significance in relation to the impact of deer on New Zealand forests

Based on the analysis of 160 rumen samples from northeast Stewart Island, white-tailed deer (Odocoileus virginianus) relied mainly on the fruit and foliage of trees and climbers that typically grew above the reach of the deer. Broadleaf (Griselinia littoralis) and supplejack (Ripogonum scandens) together comprised over 50% of annual diet, with much of this material being eaten only after it had fallen from the canopy. Seedling material appeared to be an unimportant component of diet, the deer population being sustained largely by plants that established prior to the deer invasion 60-80 years ago. The interaction between deer and forest plants may therefore require several more centuries to reach a stable equilibrium, at which point deer carrying capacity will be much lower that at present.