• long-term sampling;
  • species abundance distribution;
  • tropical butterfly communities;
  • spatial effects;
  • vertical distribution;
  • temporal effects;
  • conservation

To test the veracity of previous studies and illuminate major community patterns from an intact community, a guild of nymphalid butterflies was sampled at monthly intervals for five consecutive years by trapping in the canopy and understorey of five contiguous forest plots in the same rainforest. Significant numbers of species belonged to either the canopy or understorey fauna, confirming fundamental vertical stratification, and showing that sampling in one vertical position is a poor estimator of diversity. Significant monthly variation showed that intermittent or short-term sampling would underestimate diversity, and significant variation among years and areas showed that diversity was strongly influenced by sampling year. Even when the underlying communities were the same, temporal interactions strongly affected species diversity in both horizontal and vertical dimensions. An unprecedented seasonal inversion of species richness and abundance was detected between the canopy and understorey that occurred at the onset of all rainy seasons. This investigation suggests that long-term studies evaluating spatial and temporal patterns of species diversity among many sites may be required for a better understanding of tropical communities and how best to conserve them.