Influences of forest harvest and environmental gradients on aquatic invertabrate communities of seasonal ponds

Appropriate recommendations for managers regarding forest harvest around seasonal ponds are difficult to infer based on available information. Invertebrate communities have often been useful indicators of stress in other aquatic systems. During 1999-2005, we studied aquatic invertebrate communities in 24 small, seasonally flooded wetlands located in aspen-dominated landscapes with adjacent forest ages varying from 10-59+ years in north central Minnesota, USA. Direct gradient analysis indicated that invertebrate communities were influenced by changes in environmental variables, although relationships were complex, with no single variable explaining >9.3% of invertebrate variance. Invertebrate taxon richness was negatively correlated with stand age and was also lower during the period following tree harvest. However, measurable declines in taxon richness were less apparent in harvested old age stands relative to unharvested controls during the post-harvest time period. Our data indicated weak relationships between invertebrate community composition and measured environmental characteristics of seasonal ponds and adjacent uplands. Innovative research strategies are needed because seasonal variance and adaptations of aquatic invertebrates may limit our ability to accurately elucidate responses to natural and anthropogenic gradients in these habitats.