Seasonal cycles of diversity and similarity in a Central American rainforest butterfly community

Despite the importance of understanding the effects of tropical seasonality on ecological diversity, few studies have investigated the influence of environmental factors on seasonal community composition, and even fewer use standardized sampling and robust analytical methods that are directly comparable. Our 104 months of sampling in Costa Rican lowland rainforest yielded 12 757 individuals of 106 fruit-feeding butterfly species demonstrated biannual cycles in species diversity, but community similarity showed an annual cycle that peaked in the driest months. We found that community diversity and similarity did not decline with increasing time lag, which we attribute to lack of long-term changes in species abundances. Our findings differ from a similar study in Ecuador, where cycles in weather and community diversity were annual. Long-term intensive monitoring and robust statistical analysis of changes in community composition in relation to environmental factors can help to elucidate the dynamics of communities, and their response to climate change.