The where and why of large wood occurrence in the Upper Mississippi and Illinois Rivers

Molly Van Appledorn; Kathi Jo Jankowski; Kaija Gahm; Serenity Budd; Douglas Baumann; Barbara Bennie; Richard A. Erickson; Roger J. Haro; Jason J. Rohweder

doi:10.1002/esp.5911

USGS · 70255133

The where and why of large wood occurrence in the Upper Mississippi and Illinois Rivers

Molly Van Appledorn·Kathi Jo Jankowski·Kaija Gahm·Serenity Budd·Douglas Baumann·Barbara Bennie·Richard A. Erickson·Roger J. Haro·Jason J. Rohweder

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Abstract

Large wood (LW) plays important geomorphic and ecological roles in rivers and is widely used as a restoration tool. Changes to floodplain land use and historical removal have altered wood dynamics in fluvial systems globally. We know little about the distribution and dynamics of LW in great rivers (approximately >10 5 km 2 ) like the Upper Mississippi and Illinois Rivers despite its ecosystem importance and use in restoration projects. We assessed LW occurrence data collected by the fisheries component of the Upper Mississippi River Restoration Program's Long Term Resource Monitoring element. We analysed 25 years of data collected across six reaches of the Upper Mississippi and Illinois Rivers that represented contrasting physiographic settings, and across four aquatic area types comprising gradients of hydrology, connectivity and geomorphology. We tested hypotheses on drivers of LW occurrence using generalised linear mixed effects models, where occurrence was predicted by reach- and local-scale environmental variables. Occurrence varied significantly across reaches and aquatic area types. In general, wood occurred more frequently upriver and in side channels compared to other aquatic areas. Large wood was most strongly predicted systemically by reach identity but not local-scale variables, underscoring the importance of broad-scale physiographic gradients in defining hydrogeomorphic processes. Floodplain forests and shoreline revetment were consistently important predictors across reaches. Our findings show that the spatial variability of LW occurrence reflects the physical variability of the Upper Mississippi and Illinois Rivers. They also reveal the value in using geomorphic classifications as frameworks for understanding physical processes like LW dynamics because of their ability to contextualise site-scale conditions. The baseline understanding of LW abundance across different hydrogeomorphic gradients and scales presented here can give insight into how to more effectively target restoration efforts in great rivers and contribute to a broader understanding of LW dynamics where such studies have been lacking.

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Earth Surface Processes and Landforms Article

Source-reported bounding extent: 36.650083721260515° to 45.12080357067936° latitude; -93.73578092131349° to -88.69332581972627° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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BibTeX RIS

Molly Van Appledorn, Kathi Jo Jankowski, Kaija Gahm, Serenity Budd, Douglas Baumann, Barbara Bennie, Richard A. Erickson, Roger J. Haro, Jason J. Rohweder. 2024-06-11. The where and why of large wood occurrence in the Upper Mississippi and Illinois Rivers. https://doi.org/10.1002/esp.5911

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