The influence of forest vegetation variables on the distribution and diversity of dragonflies in a northern Minnesota forest landscape: a preliminary study (Anisoptera)

Dragonfly communities were surveyed at 24 sites in 2 adjacent study regions, during the summer of 1994. In each of the 2 regions, 12 sites were grouped into 3 different study areas based on forest status. Forest status was determined by stand age and time since last logging disturbance, resulting in study areas defined as old-growth forest, mature second-growth forest, or recently clear-cut areas. Study sites within each forest-status study area included stream, pond, lake, and bog/swamp habitats. Recently-cleared forest areas exhibited the lowest species number and species diversity, while the greatest species number and diversity were found in the old-growth study areas. These differences were correlated with different vegetation structure variables characteristic of each forest-status study area. Furthermore, Beta-diversity, indicating changes in species composition across the forest-status gradient in each study area, was greater between the sites adjacent to the smallest old-growth forest “habitat island”. These findings may be of importance in understanding dragonfly response to forest disturbance in the northern Minnesota landscape mosaic.