Developing a shared understanding of the Upper Mississippi River: the foundation of an ecological resilience assessment

Abstract

. 2018. Developing a shared understanding of the Upper Mississippi River: the foundation of an ecological resilience assessment. Ecology and Society 23 (2) ABSTRACT. The Upper Mississippi River System (UMRS) is a large and complex floodplain river ecosystem that spans the jurisdictions of multiple state and federal agencies. In support of ongoing ecosystem restoration and management by this broad partnership, we are undertaking a resilience assessment of the UMRS. We describe the UMRS in the context of an ecological resilience assessment. Our description articulates the temporal and spatial extent of our assessment of the UMRS, the relevant historical context, the valued services provided by the system, and the fundamental controlling variables that determine its structure and function. An important objective of developing the system description was to determine the simplest, adequate conceptual understanding of the UMRS. We conceptualize a simplified UMRS as three interconnected subsystems: lotic channels, lentic off-channel areas, and floodplains. By identifying controlling variables within each subsystem, we have developed a shared understanding of the basic structure and function of the UMRS, which will serve as the basis for ongoing quantitative evaluations of factors that likely contribute to the resilience of the UMRS. As we undertake the subsequent elements of a resilience assessment, we anticipate our improved understanding of interactions, feedbacks, and critical thresholds will assist natural resource managers to better recognize the system's ability to adapt to existing and new stresses.

Warmer Winters Increase the Biomass of Phytoplankton in a Large Floodplain River

“…In the upper reaches, the main channel and the floodplain are well connected, even outside of impounded areas, and there are abundant connected side channels and backwaters (De Jager et al., 2018; Sparks et al., 1998). As a result, the UMRS contains a gradient of lentic and lotic areas ranging from backwater lakes to the main river channel (Bouska et al., 2018) that cover a wide range in residence time and hydraulic connectivity to the mainstem river flow. These physical differences set up gradients in water velocity (Table 1), temperature (Jankowski et al., 2020), and nutrient concentrations (Carey et al., 2019; De Jager & Houser, 2012) that can influence wintertime biological productivity.…”

Aquatic vegetation responses to island construction (habitat restoration) in a large floodplain river

“…They include restoring and enhancing habitat for a range of biota, including native mussels, fishes, and waterfowl, and re‐establishment of more natural hydraulic, biogeochemical, and geomorphic features (USACE, ; USACE, ; USACE, ). There is an increasing emphasis within the UMRR on project designs that strengthen desirable ecological feedbacks and impart ecosystem resilience (Bouska, Houser, De Jager, & Hendrickson, ). Resilience can be provided, in part, by creation of refugia similar to more natural areas of the river (such as the +REF area described here), where organisms can persist through unfavourable conditions.…”

Prioritizing native migratory fish passage restoration while limiting the spread of invasive species: A case study in the Upper Mississippi River

“…The Upper Mississippi River (UMR), including its many large tributaries and their headwaters, is a highly complex social-ecological system that supports both high biological diversity and numerous ecosystem services (Bouska et al, 2018). Variability in natural landscape conditions within the region (e.g., glacial/non-glacial landforms, geology, and climate) has resulted in a wide range of chemical, hydrologic, and thermal conditions among streams (Wang et al, 2001;Lyons et al, 2009;De Jager and Houser, 2016).…”

“…This range in stream conditions has given rise to a diversity of fishes occurring within the basin, with over 140 fish species identified (Garvey et al, 2010). The UMR and the basin it drains supports numerous socioeconomic activities including commercial and recreational fisheries (Garvey et al, 2010, Klein et al, 2018, extensive agricultural production, and urban development (Bouska et al, 2018). Dams located throughout the UMR provide economic benefits such as shipping, hydropower generation, and recreation, however, they have also resulted in extensive stream habitat fragmentation along the UMR mainstem and tributaries (Cooper et al, 2017).…”