Daily weather variation and temporal dynamics in an Afrotropical dung beetle community (Coleoptera: Scarabaeidae)

The influence of weather on dung beetle community dynamics was studied in grassland, open woodland and thickets in Gauteng Province, South Africa. To avoid seasonal effects, sampling was restricted to 18 days during November and December. An examination was made both of dung beetle responses to physical variables and of daily changes in their community structure between habitat patches (dung-baited traps). Recruitment of general adults showed a weaker response to physical variables (rainfall, soil hardness, radiant heat, sub-surface soil temperature) than activity of mature adults which was most frequently correlated to rainfall. There was a range in species responses to rainfall from much higher proportional abundance on moist days to somewhat greater abundance on drier days. Such variable responses led to daily changes in the proportional abundance of moist-adapted and dry-tolerant species groups. Daily changes from low to high species richness were also associated with increased rainfall. These changes led to increased diversity and greater functional complexity of the numerically dominant species component. Abundance of most numerically dominant species increased from low to high species richness. Their rank position either increased, decreased or remained similar. It is concluded that during the summer rainy season, incidence of rainfall is an important determinant of temporal dynamics in dung beetle community structure between habitat patches.