Influence of Adjacent Uplands and Groundwater on the Hydrology and Invertebrate Community Composition of Seasonal Forest Ponds in North Central Minnesota

Abstract

Seasonal ponds are common throughout northern Minnesota's forested areas. Seasonal ponds typically flood due to snow-melt and high precipitation rates in early spring, then dry by mid-late summer. The dynamic hydroperiods of seasonal ponds create a unique fishless habitat hosting an abundance of many endemic aquatic species. Hydroperiod has long been considered a major controller of biological communities in seasonal ponds, but few data are available for testing hydrological linkages among seasonal ponds, their surrounding watersheds and their resident invertebrate communities. To identify hydrological pond function, I placed peizometers and monitoring wells in 8 sites in the Buena Vista State Forest in Beltrami County, MN, and 8 sites in the Paul Bunyan State Forest in Hubbard County, MN (16 sites total). Water levels were monitored weekly (2006-2009) from spring melt until ponds dried and water tables fell below readable depths. Invertebrate communities were also sampled weekly during 2008 and 2009. Results indicate that high but variable water exchange occurs between seasonal ponds and ground water. Hydrological patterns of seasonal ponds were related to several physical parameters including hydrological function, maximum depth, and canopy cover. Most relationships appear to be consistent between the 2 forest areas; however, some differences are notable, such as soil characteristics and influence of pond surface area on hydroperiod. Patterns in pond invertebrate communities were also related to hydrological function and hydroperiod, and these patterns appear consistent between the 2 forest areas, suggesting that many invertebrates are generalist users of these areas.