Seasonal abundance of springtails in two contrasting environments

To analyze the influence of microenvironmental heterogeneity on soil microarthropods, populations of soil and litter springtails (Collembola) of a secondary regrowth forest plot and an adjoining cassava plot in southwestern Nigeria were investigated over an annual cycle. Data on rainfall, moisture content, relative humidity, and soil temperature were simultaneously collected. Although there was a decrease in activity of springtails of the litter layer in the dry season, soil springtail densities were not significantly different in the wet and dry seasons in both the forest and cassava plots. With the exception of Tullbergia sp. that reached a single peak population in the cassava plot, fluctuations in numbers and activity of litter and soil springtails were similar in both the forest and cassava plots. Most springtail genera reached multiple peaks during the annual cycle, a phenomenon which is characteristic of iteroparous and potentially multivoltine species. The relative roles played by soil temperature and moisture content in influencing numbers of springtails extracted from the soil were found to be different in the forest and cassava plots. Relative humidity of the litter layer was found to play a minor role in influencing variation in the activity of epigeal springtails of the forest and cassava plots. It is concluded that population fluctuations are caused by life history phenomena, which are different for the litter springtails compared to the soil springtail genera.