Nothofagus produces heavy crops of seed infrequently, and then house mouse (Mus musculus) populations increase greatly. In the Orongorongo Valley, near Wellington, seedfall of hard beech (Nothofagus truncata) and the numbers of house mice were measured for 22 years. Four heavy seedings were recorded and the numbers of mice were significantly correlated with the beech seedfall. Most mouse stomachs contained remains of arthropods, especially caterpillars and spiders, as well as plant material. Moths emerging from the litter of the forest floor in summer were sampled for seven years; the numbers of Tingena epimylia (Oecophoridae), whose larvae are litter-feeders, were strongly correlated with beech seedfall. The correlation between the numbers of moths and mice was slightly stronger than that between the numbers of beech seed and mice. Because the numbers of T. epimylia varied so greatly, components of the litterfall were also measured for three years. In a seeding year spent male flowers were a substantial part of the litterfall and might be responsible for the higher numbers of moths. These results indicate that factors other than quantity of seed may be important in the beech seed -mouse relationship and need to be explored further.

The abundance and seasonality of invertebrates were studied in 3 forest communities near Wellington, New Zealand by pitfall trapping at equal intensity for 14 months. Of 238 species trapped (93 461 individuals), 172 (50 204) occurred in mixed broadleaf-podocarp, 98 (23 072) in hard beech (Nothofagus truncata), and 107 (20 185) in silver beech (Nothofagus menziesil) forest. The composition of the invertebrate fauna differed amongst forest communities. Although many invertebrates were active throughout the year, significantly more were caught in autumn, and fewest in winter. The temporal distribution of several species was correlated positively with temperature, but very few species showed a correlation with rainfall. More species and individuals occurred in the more botanically diverse broadleaf-podocarp forest than in the beech forests. Species composition was more diverse in the lowland broadleaf-podocarp forest than in the high-altitude silver beech forest.

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.

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||This study investigates further the possibility that eruptions of house mice in forests of southern beech (Nothofagus spp ) in New Zealand after mast seedings are triggered by increases in the populations of some arthropods, especially Lepidoptera larvae and spiders that are common foods of mice, rather than by the beech seed It reports on a 5-year study of arthropods of the forest floor in hard beech and silver beech forest in the Orongorongo Valley, near Wellington, in relation to (1) litter and seedfall, and (2) the numbers and diet of mice Litter-feeding larvae of Lepidoptera in both the litter and fermentation layers of the forest floor feed on the fallen male flowers of beech, and most species were more common after heavy flowering of the beeches A few of the common spiders (including Miturga sp , the main spider eaten by mice) were also more abundant after beech seeding Analysis of the long-term records of hard beech seeding, numbers of mice, and numbers of adults of the moth Gymnobathra tholodella (Oecophondae) showed that the number of mice was positively correlated with both the number of beech seeds and the number of moths These results indicate a more complex web of interactions in beech forest than was earlier suggested, but because the intensity of flowering in spring largely determines the numbers of both Lepidoptera larvae and beech seeds, the role of each in the population increase of mice can not be determined

Invertebrates were collected with equal sampling intensity from sites in two native-forest communities near Wellington, New Zealand for 14 months. More species and individuals occurred in the more botanically diverse lowland broadleafpodocarp forest than in the less diverse high-altitude silver beech forest. Of the 124 species caught (270 758 individuals), 91 (156 285) occurred in broadleaf-podocarp and 81 (114473) in silver beech (Nothofagus menziesil) forest (68 species were common to both forests). Although many invertebrates were caught throughout the year, catches were significantly higher in autumn than in other seasons. The catches of many invertebrates were positively correlated with temperature but not with rainfall. Invertebrates were caught over a longer period of the year than reported from temperate forests in the Northern Hemisphere. This feature is a reflection of the oceanic climate of New Zealand where climatic extremes are moderate and therefore the invertebrate activity is not curtailed.

No abstract

Invertebrates were studied with equal sampling intensity on sites in broadleaf-podocarp and hard beech (Nothofagus truncata) forests near Wellington, New Zealand for 13 months. Of the 107 species caught (72 500 individuals), 71 (41 931) occurred in broadleaf-podocarp and 78 (30 569) in hard beech forest. Mites (75.3% of individuals), Collembola (9.6%), insect larvae (4.9%), and beetles and weevils (3.6%) were most common. In broadleaf forest numbers were higher in summer than in other seasons and in hard beech forest numbers were higher in spring than in other seasons. The seasonal changes in numbers of many invertebrate species were correlated with temperature but only few with rainfall. Invertebrate diversity was similar in the two forests studied, but the density was greater in broadleaf than in hard beech.