Succession of microarthropods in northern forest litter 90, 47 and 3 years after fire.

Abstract

Burn plots used for the study of forest succession at UMBS were examined for succession in soil microarthropods (Acarina and five Collembola families). Plots of 90-years, 47-years and 3-years -old were sampled to determine the relative abundance, absolute abundance and diversity of soil microarthropods to compare with predictions of succession theory. Succession theory predicts that diversity after disturbance will be low initially, rise to a maximum and then decline to an intermediate level. Relative abundance of these six taxa of soil microarthropods differed significantly among plots over time (X2=120.87, df=10, p<0.001). Since relative abundances changed over time, then community structures have changed, indicating that succession had occurred. Absolute abundance was evaluated with pH as a covariate and no significant values were noted for Acarina among plots, but pH was positively correlated with the abundance of all Collembolan fmailies collectively (R=0.754, df=13, p=0.001). Soil microarthropod diversity changed in a way consistent with predicted successional development (3-year-old plot: H'=0.849, 47-year-old plot: H'=0.804; 90-year-old plot: H'=0,787), but similar to the pattern observed by Paquin and Coderre (1997; Oecologia 112: 104-111) for soil macroarthropods in a boreal forest after fire. This inconsistency is explained through the intermediate plot where species richness was greatest (3-year-old plot: S=7; 47-year-old plot: S=12; 90-year-old plot: S=8), and the evenness was the lowest (3-year-old plot: E=0.263; 47-year-old plot: E=0.142; 90-year-old plot: E=0.215). These data study suggest that succession of soil microarthropod communities is occurring over time.