New Zealand Journal of Ecology (1996) 20(2): 215- 240

Distribution and abundance of small mammals in relation to habitat in Pureora Forest Park

Research Article
C. M. King 1
J. G. Innes 2
M. Flux 3
M. O. Kimberley 4
J. R. Leathwick 2
D. S. Williams 5
  1. Department of Biological Sciences, Waikato University, Private Bag 3105, Hamilton, New Zealand
  2. Manaaki Whenua - Landcare Research, Private Bag 3127, Hamilton, New Zealand
  3. 230 Belmont Hill Road, Lower Hutt, New Zealand
  4. New Zealand Forest Research Institute Ltd, Private Bag 3020, Rotorua, New Zealand
  5. Department of Conservation, P.O. Box 1146, Rotorua, New Zealand

Populations of ship rats (Rattus rattus), Norway rats (R. norvegicus), feral house mice (Mus musculus), stoats (Mustela erminea), weasels (M. nivalis), and ferrets (M. furo) were sampled with killtraps every three months from November 1982 to November 1987 in logged and unlogged native forest and in exotic plantations of various ages at Pureora Forest Park, central North Island. Mice (n=522 collected) were fewest in unlogged native forest, more abundant in road edge cutover forest, and most abundant in a young (5-10 year old) plantation. Traps catching most mice were set in dense ground cover under a low, sparse canopy. Ship rats (n=1793) were absent from the young plantation, present but not abundant in older exotic forest, and abundant in all native forest regardless of logging history. Traps set on warmer, steeper sites caught most ship rats, and those set in early successional habitats caught fewest. There was a marked reciprocal relationship between the distributions of ship rats and of mice: the proportion of mice in the total catch of rodents decreased significantly at the least, disturbed forest sites (P <0.001). Most (81%) Norway rats (n=43) were caught in a single trap in unlogged native forest on the bank of a stream. Stoats (n=57) were most abundant in the older exotic plantations; weasels (n=16) in the young plantation and along road edges in native forest; and ferrets (n=11) in unlogged native forest. Hedgehogs (n=290) were common in unlogged native forest far from any roads and also in older exotic forest. Our data suggest that selective logging and conversion to exotics have different effects on each of the six species we monitored. We hypothesise that (1) selective logging is likely to stimulate temporary increases in the numbers of mice and weasels, but not rats or stoats, and (2) after conversion to exotic forest, mice and occasionally weasels will be abundant at first but will gradually be replaced by ship rats and stoats as the forest matures.