Abstracts

Presented by Blake J Mitchell - Email: bjmitch@iastate.edu

Duckling survival has potential to drive population dynamics and has been related to conditions experienced on wetlands including forage availability. Specifically, invertebrate forage is linked to early growth and greater energy reserves for young ducklings, both of which improve overall body condition and thus survival. Although invertebrates comprise a significant portion of duckling diets, not all invertebrate species are consumed equally and selection of sampling gears and timing could have substantial impact on inferences of wetland quality for ducklings. We evaluated two sampling strategies -- surface activity traps and sweep nets -- to evaluate their utility in effectively gauging invertebrate forage availability in landscape-level brood studies. We found that surface activity traps captured invertebrate groups that are mobile and live near the surface, such as cladocerans and copepods, more consistently than sweep net samples. Benthic and vegetation-dwelling invertebrates, including gastropods and some hemipteran and beetle taxa, were more common in sweep net samples. Additionally, surface activity traps provided samples that were relatively free of sediment and vegetation, and therefore reduced processing time by 152 hours over sweep net samples for 29 wetlands. In this presentation, we will present on our results discussing opportunities and tradeoffs for sampling aquatic macroinvertebrates in prairie wetlands on the landscape scale.