Aquatic invertebrate food base for waterbirds at Wetland Reserve Program easements in the lower Mississippi Alluvial Valley

Migratory waterbirds depend on invertebrates as a key source of dietary protein, but few studies have quantified aquatic invertebrates or their response to management on privately owned wetlands. Our objectives were to quantify the effects of wetland management provided through the Migratory Bird Habitat Initiative (MBHI) on invertebrate biomass, family richness, and secondary production at Wetland Reserve Program (WRP) easements in Arkansas and Missouri. We collected core and sweep-net samples bi-weekly in autumn 2011 and sweep samples in winter 2012 at WRP easements enrolled in MBHI (n = 13), WRP easements not enrolled in MBHI (n = 12), and intensively managed public wetlands (n = 7) in Arkansas and Missouri. Overall mean (±SE) invertebrate biomass and production during autumn were 11.96 (±1.29) kg/ha and 1.57 (±1.09) kg/ha*season, and during winter were 3.96 (±0.55) kg/ha and 1.38 (±0.11), respectively. Macroinvertebrate biomass and family richness did not differ among wetland types or management practices, including inundation and mowing. Secondary macroinvertebrate production during autumn was 200 % greater on MBHI contracts compared to WRP easements. During winter, production was 40 % greater on MBHI and WRP easements compared to public wetlands. Our results suggest that with management, wetlands enrolled in conservation easement programs can be an important source of invertebrate production for migratory waterbirds.