Ecological analysis of beetle (Coleoptera) density and diversity as bioindicators of accelerated succession in the UMBS FASET experiment.

Abstract

This study assessed beetle (order: Coleoptera) density and diversity as bioindicators for changes in northern Michigan forests undergoing succession. At UMBS, forests are succeeding from an aspen and birch dominated canopy to that of oak, pine, and maple. To accelerate succession, the Forest Accelerated Succession Experiment (FASET) girdled all the aspen and birch trees during spring of 2008 allowing climax species to take hold. This site is compared to an ecologically similar control site, Ameriflux. We collected beetle specimens at both sites at three forest levels (ground, 1-meter, and canopy) over a five day period. We grouped beetles to according to species and identified to family. We found the FASET sites more diverse than the Ameriflux site in both Shannon's and Simpson's diversity indices. Statistically, there was no significant difference between the two plots in species composition, number of total individuals, or number of families present. There were, however, significant differences between the three forest levels in the total number of individuals and the total number of species. From the aggregate data of the two plots, the ground traps displayed the least similarity to the higher levels in Sorenson's similarity. We identified 14 families from 157 individual beetles. These families represent trends in association of families to specific habitats, however there was no clear trend of detritivore-abundance in the FASET plot as we predicted. Distribution of families Staphylinidae, Cucujidae, and Tenebrionidae showed clustering in one or two forest-heights with the near exclusion of the other/s, further suggesting a correlation between habitat specificity and family. Distribution patterns both between trap-heights and between plots varied according to several groupings and will be discussed further as biondicators of change in the FASET forest.