Relationships between forest age and soil macroinvertebrate biodiversity.

Abstract

Succession is a process describing directional, continuous and non-seasonal changes in the species richness and abundance of ecological communities. Fire disturbance in six burn plots spanning a 102-year period has spurred secondary succession in tree communities and macroinvertebrate communities, providing a burn chronosequence along which links between these communities can be characterized. In this study, we aimed to address the following questions: 1. Does soil macroinvertebrate diversity change with forest age? 2. Is there a relationship between macroinvertebrate community diversity and tree community diversity? 3. Are there correlations between tree species and soil macroinvertebrate orders, and how do these potential relationships change over time?. Soil macroinvertebrates were sampled four times from four pitfall traps in each of the six burn plots (years: 1911, 1936, 1948,1954, 1980, and 1998), along with concurrent measurements of overstory and understory plant species abundance.. Soil macroinvertebrates diversity did not increase with forest age. Tree species succession in the burn plots conformed to the Intermediate Disturbance Hypothesis (diversity was lowest immediately following fire disturbance [1911 – 1948], increase to a climax at its midpoint [1954], and decreased thereafter). Macroinvertebrate diversity did not follow this pattern. Chi-Square analysis revealed significant short-term and long-term changes in soil macroinvertebrate communities. We found significant positive correlations between larvae and bigtooth aspen, millipedes and red oak, spiders and red oak, beetles and white pine, and a negative correlation between beetles and bigtooth aspen. Further research needs to be conducted to explore underlying factors affecting soil macroinvertebrate community change after disturbance events.