Cooperative Ecosystem Studies Unit, Great Rivers CESU

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The USGS is offering a funding opportunity to a CESU partner for research in how large-scale flood disturbance events impact tree survivorship and resulting floodplain forest community dynamics along the Upper Mississippi River. Understanding and predicting patterns of forest succession in floodplains is difficult due to the fact that they are strongly influenced by patterns of disturbance, which are often stochastic in nature. Flooding is the most common disturbance event on floodplains and often determines the distribution of forest species and communities with only slight changes in elevation. The degree to which flooding influences tree survival is a function of how different species and size classes can tolerate differences in flood frequency, duration, intensity, and timing. Most floodplain trees are adapted to survive moderate frequency, moderate intensity and short duration flooding when it occurs during plant dormancy between late summer and early spring. Tree mortality increases with flood frequency, intensity, and duration or when flooding occurs during the growing season, particularly for smaller size classes. Infrequent, large-intensity flooding is generally considered natural and may actually be a driving force of species and community distribution and development, successional patterns, and the recruitment of new tree cohorts required for forest sustainability at the landscape level. A recent large-scale flood disturbance event in 2019 has provided an opportunity to better understand how differences in major flood attributes impact tree survivorship and resulting forest community dynamics in the Upper Mississippi River System (UMRS).

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