Interactive effects of hydrogeomorphology on fish community structure in a large floodplain river

Abstract

Biocomplexity is an emergent property of ecosystems that captures the interplay of structures and processes at multiple scales. These interactions can establish a dynamic habitat template that serves as a filter to define ecological organization across landscapes. Studies of biocomplexity in floodplain rivers typically focus on hydrological variability or geomorphic heterogeneity separately, with their interactions being an output rather than the direct focus of investigations. This study examines the interaction of hydrological variability and geomorphic heterogeneity across 25 off‐channel habitats (OCHs) of the Upper Mississippi River, USA. Questions posed were as follows: What are the interactive effects of hydrological variability and geomorphic heterogeneity shaping the physical habitat template of OCHs? and How does the organization of the physical habitat template influence fish community composition within OCHs? Three distinct OCH groups emerged from this study: where hydrological variability defined Group 1 (Lake group); Group 2 was organized via geomorphic heterogeneity (Backwater group); and a combination of hydrological and geomorphological variables defined Group 3 (Slackwater group). Thus, the differential interaction of hydrology and geomorphology defined the dynamic physical habitat template of OCHs in this riverine landscape. No significant difference between the association matrices of the hydrogeomorphic template and fish community composition for the 25 OCH sites was recorded. A priori grouping of fish into the three OCH groups revealed marked differences in fish community composition. A subset of hydrogeomorphic variables that defined the physical character of the OCHs acted as an environmental filter for the fish community composition of the three OCH groups. A conceptual model explaining hydrogeomorphic–ecological interactions across the OCHs of this floodplain river system is provided.

Functional process zones and their fish communities in temperate Andean river networks

“…However, the results of this study align with previous research demonstrating associations between hydrogeomorphic and fish communities in river systems (cf. Boys & Thoms, ; Delong, Thoms, & Sorenson, ). Future studies incorporating more intense sampling of each of the FPZ are recommended to evaluate our hypothesis put forward in this study of Andean river systems.…”

Ecological thresholds and regime shifts within hydrologically modified rivers: A 75+ year retrospective analysis

“…The region of the UMR in this study, in contrast, is an anabranching system with numerous off-channel aquatic habitats, and the 'pool' effect above dams is markedly smaller than that of the LOR (Delong et al, 2019). Greater physical heterogeneity of the UMR is likely the contributing factor in minimizing the influence of hydrology on the trophic status of fish.…”

“…Hydrology and geomorphology act directly and indirectly to define the physical and ecological characteristics of riverine landscapes (Thorp et al, 2008). Differential interactions of hydrology and geomorphology establish a template that determines ecological form and function of river ecosystems (Delong, Thoms, & Sorenson, 2019). This dynamic interaction can lead to feedback loops whereby changes in physical characteristics shift ecological structure and/or function to alternate functional states (Dent et al, 2002).…”

“…Geomorphological character of riverine landscapes establishes the template on which ecological structure and function are determined (Delong et al, 2019). The degree of physical heterogeneity defines availability of basal resources, composition of communities, and food web character within geomorphic patches (Nelson, Johnson, Deegan, Spivak, & Sommer, 2019).…”

Academic Freedom and Librarians’ Research and Scholarship in Canadian Universities

“…In the most recent 8Rs Redux: CARL Human Resources Study, it is reported that "a total of 37% of librarians have earned at least two graduate degrees (MLIS plus 32% with a second Master's degree; 5% with a PhD)." 61 In addition, the survey results reveal that collective agreement language does not necessarily provide librarians the freedom to pursue their own research agenda. There is often consider-able managerial control by supervisors.…”