Ecological Studies in Four Contrasting Lowland Rain Forests in Gunung Mulu National Park, Sarawak: II. Litterfall, Litter Standing Crop and Preliminary Observations on Herbivory

SUMMARY (1) Small litterfall (leaves, wood ?2 cm diameter, renroductive parts, and trash) was compared on sites of 1 ha in each of four types of lowland forest in Gunung Mulu National Park, Sarawak, for quantity, seasonal distribution and the concentrations of nitrogen, phosphorus, potassium, sodium, calcium, magnesium and total phenols. The sampling period was 50 weeks for the sites in alluvial forest (AF), dipterocarp forest (DF) and heath forest (HF) and 42 weeks for the forest over limestone site (LF). (2) The total small litterfall was (t ha-' year-' ? 95% confidence limits): for the AF, 11.5 ? 1.9; DF, 8.8 ? 0.6; HF, 9.2 ? 1.2; and LF, 12.0 ? 1.3. A peak of litterfall occurred on all four sites during a May-June period of high rainfall before the driest time of the year. (3) The element concentrations in the litterfall differed greatly between each forest type. The concentrations of all elements (except calcium in samples from the LF) were below or within the ranges reported for other tropical forests and there was no consistent seasonal variation. The low calcium concentration in the DF litterfall and low nitrogen in the KF litterfall were notable. (4) Total polyphenol concentrations in the leaf litterfall were ranked HF > LF > DF > AP. (5) Large-wood litterfall was measured over a shorter period than the small litterfall. Virtually no wood over 10 cm diameter fell in the collection quadrats and the results for