Wetland microbial community composition in sites with contrasting historical hydrology

Historical flood patterns impose an environmental filter that structures soil microbial community composition, and composition can affect ecosystem function. An important microbial ecosystem service in wetlands is the removal of nitrate via denitrification, but this has been difficult to restore in freshwater wetlands. It is possible that the historical hydrology of a site has already filtered microbial taxa that differ in denitrification capacity, and dispersal limitation between wetlands prevents recruitment of new denitrifier taxa. We surveyed microbial and denitrifier community composition in wetlands that were categorized to have contrasting historical flood patterns. Historical hydrology influenced composition at least to some degree. The lowest denitrification response was observed in mesocosms inoculated by communities from wetlands with high variability in flood patterns from year to year.