Seasonality of forest invertebrates in Hong Kong, South China

Abstract

Because of its position on the northern margin of the tropics (22° 17′N) and the southern coast of a huge continent, Hong Kong has a climate in which both temperature and rainfall are highly seasonal. Although summer temperatures are equatorial, the January mean is only 15.8 °C,and the absolute minimum recorded at sea level is 0 °C (Dudgeon & Corlett 1994). As a result, all aspects of the ecology of Hong Kong show seasonal changes. The most dramatic changes occur in the bird fauna, with the majority of species migratory (Carey et al. 2001). The winter fruiting peak in secondary shrublands and the forest understorey coincides with the arrival of partially frugivorous migrant robins and thrushes (Corlett 1993). However, while resident insectivore-frugivores consume almost entirely fruit during this period (Corlett 1998), all the winter visitors continue to eat insects and some (e.g. Phylloscopus warblers) are entirely insectivorous. The study of insect seasonality reported here formed part of a 30-mo study of the seasonality of a forest bird community in Hong Kong (Kwok & Corlett 1999, 2000). Plant names follow Corlett et al. (2000).