Development of a multiple metric index for macroinvertebrates collected from lower Missouri River floodplain wetlands

Abstract

The biological integrity of the aquatic ecosystem has become an important component for assessing wetland condition and quality. Aquatic Invertebrates respond to an assortment of abiotic and biotic factors. Many wetland assessments use multiple tier approaches to quantify wetland health and to identify perturbations that may cause degradation to a system. A study was designed to assess the quality of wetlands in the lower Missouri River floodplain using remote sensing technology, a rapid field landscape and hydrological assessment, a floristic quality assessment, in situ water quality and nutrient measures, and benthic macroinvertebrate collections. A multiple metric index (MMI) development approach was chosen to evaluate the aquatic invertebrate community as a quantifiable measure of how these organisms respond to other wetland parameters and assessment outcomes developed in this study. As an index of biological integrity (IBI), the macroinvertebrate MMI was developed by scrutinizing the stressor-response relationships between the chemical and physical measures and components of the benthic macroinvertebrate community. Results of the macroinvertebrate MMI were consistent with other studies using invertebrate metrics for assessing the biological integrity of aquatic ecosystems when comparing the reference and random sample populations. The developed MMI was then tested for congruency with the other assessment results, relationships to hydrological connectivity, and internal wetland structural features that were evaluated. The macroinvertebrate MMI responded significantly to observed physical and chemical anomalies and provided insight to dominant wetland features, such as landscape, hydrology, water chemistry, and plant community,that influence wetland conditions.