THE RELATIONSHIPS BETWEEN BEECH (NOTHOFAGUS SP.) SEEDFALL AND POPULATIONS OF MICE (MUS MUSCULUS), AND THE DEMOGRAPHIC AND DIETARY RESPONSES OF STOATS (MUSTELA ERMINEA), IN THREE NEW ZEALAND FORESTS

摘要: SUMMARY (1) There was a significant relationship between seedfall and populations of mice in all forests studied. Good seedfalls were followed by increases density changes population structure not seen years when the failed. Predictability these decreased with increasing diversity forest composition. (2) Stoats responded both numerically functionally to mice. densities stoats summer two forests. (In third, this modified presence nearby many lagomorphs, an important alternative prey for stoats.) The numerical response due increased survival, uterus or nest, young born spring abundant, fecundity adult female stoats. In three forests, ate significantly more summers that abundant. (3) Ship rats (Rattus rattus (L.)) most abundant diverse index R. there after 1976 seedfall, but 1979. A few kiore (R. exulans (Peale)) coexisted forest. (4) did eat fewer birds plenty mice, either autumn, nevertheless negative correlation proportions diet autumn. very weak probably non-existent. (5) 'bird predation index', which takes into account numbers present what they ate, suggests are eaten peak stoats, because strong lack 'buffering' autumn effect is weakened regular seasonal switch from especially mouse year. (6) indirect effects irruptions on New Zealand should be further examined. Control could prevent temporary increase during highest risk period, though whether would benefit unknown.