From Microhabitat Ecohydraulics to an Improved Management of River Catchments: Bridging the gap Between Scales

Abstract

Ecohydraulic studies in rivers range from local-scale studies, which target a better understanding of the mechanisms underlying biological responses to microhabitat hydraulics, to large-scale studies, which address the influence of hydro-morphological management on catchment biodiversity. A major challenge in the field is to bridge the gap between local-and large-scale studies, in order to base the large-scale physical management of rivers on general and transferable ecohydraulic processes. This Special Issue includes ten articles that illustrate progresses and difficulties to bridge this gap. It gathers microhabitat-scale studies focused on the identification of major ecohydraulic mechanisms, reachscale studies that typically target generality and transferability across reaches, and examples of catchment scale management based on general ecohydrological knowledge. The Special Issue illustrates how ecohydraulics have evolved to better integrate dynamic physical processes, ecological concepts and the consideration of ecosystem services. Although this remains challenging in practice, the Special Issue shows the need to integrate dynamic hydraulic descriptors of the environment for improving the cost-effectiveness of large-scale river management and restoration. These articles were presented at the 10th International Symposium on Ecohydraulics in Trondheim, Norway (2014), where the first symposium on ecohydraulics was organised 20 years before. The 10th issue of the symposium celebrated 20 years of ecohydraulic research and had about 300 delegates, giving 194 talks and presenting 86 posters.

Predictive models of fish microhabitat selection in multiple sites accounting for abundance overdispersion

“…In many studies, microhabitat selection models involved one or a few species and a limited number of surveys (dates × sites combinations). This often limits the possibility to test the transferability of models to independent rivers of different catchments and to apply habitat models at the larger scale of "riverscapes" (Harby, Capel, & Lamouroux, 2017). For that purpose, it is crucial to improve methodological developments of such models for enlarging their application in river management.…”

Mesohabitat modelling in fish ecology: A global synthesis

“…Considerable progress in remote sensing and computing capacity allows quick surveying of large areas of the riverscape and, thus, developing holistic, large‐scale studies in river management (Bizzi et al., 2016; Carbonneau et al., 2012). However, the issue of upscaling still remains a challenge and mesohabitat modelling is likely going to play an important role in bridging the gap between the local‐ and catchment‐scale management of rivers (Harby, Martinez‐ Capel, & Lamouroux, 2017; Linnansaari, Stickler, Alfredsen, Berg, & Harby, 2010). For the latter, mesohabitat models have shown potential to support regionally applicable environmental flow strategies (Parasiewicz et al., 2018; WMO, 2019) and facilitate large‐scale river restoration planning ( e.g .…”

Advancing ecohydraulics and ecohydrology by clarifying the role of their component interdisciplines

“…Gradually, purely "instream flows" No doubt that the emergence of "Big Data" and Artificial Intelligence will also provide new tools to increase the spatial scale of application while conserving fine resolution. However, the question remains of the upscaling of ecohydraulics study results to entire catchments and few studies exist in that respect (Harby et al 2017;Wheaton et al 2017). One wonders if the same tools and disciplines can be used for the characterization and study of rivers as diverse as chalk streams or large floodplain.…”