title: Seasonal cycles of species diversity and similarity in a tropical butterfly community.
abstract: 1. Studies of seasonality in ecological diversity rarely extend over more than a few years, and few studies of seasonal diversity have explicitly investigated the influence of environmental factors on seasonal community composition, especially in tropical communities. 2. Our 10 years of monthly sampling in Amazonian Ecuador yielded 20 996 individuals of 137 fruit-feeding butterfly species. Seasonal cycles of rainfall drive annual cycles in species diversity and community similarity. Undetermined processes operating most strongly during the dry season maintain species diversity and high community similarity across years. 3. Seasonal cycles in community diversity and similarity are superimposed on a gradual decline in similarity between community samples on a decadal time-scale because of long-term changes in species abundances. 4. Monitoring and analysis of changes in community composition over a range of time-scales can be used to refine models of community dynamics by incorporating environmental factors necessary to predict the ecological impact of future climate change.
authors.affiliation: Centre for Conservation Biology, Department of Biology, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
authors.forename: Vidar
authors.initials: V
authors.lastname: Grøtan
authors.forename: Russell
authors.initials: R
authors.lastname: Lande
authors.forename: Steinar
authors.initials: S
authors.lastname: Engen
authors.forename: Bernt-Erik
authors.initials: BE
authors.lastname: Saether
authors.forename: Phil J
authors.initials: PJ
authors.lastname: DeVries
mesh_terms: D000818:Animals; D044822:Biodiversity; D002080:Butterflies / Q000145:classification* / Q000502:physiology*; D008954:Models, Biological; D011157:Population Dynamics; D012621:Seasons; D013045:Species Specificity; D013997:Time Factors; D014329:Tropical Climate