Comparable sites were examined on Rahui Island, Lake Waikareiti, which is free of introduced mammals, and on the adjacent mainland, which is not. The forest understorey density in Nothofagus fusca, N. menziesii forest has been reduced on the mainland. In the mainland forest there are fewer plants of Pseudopanax and Coprosma spp. and more plants of Dracophyllum pyramidale and Dicksonia lanata. Regeneration of Nothofagus menziesii.
Results of some control campaigns suggest that the characteristic features of response to reduction of numbers (improved physical conditions, higher reproductive rates) are suppressed when the control technique disrupts the ability of survivors to exploit preferred components of the habitat.