Campus Connection

UWL professor receives grant in collaboration with USACE, USGS and NGRREC

UWL Biology Professor Meredith Thomsen, along with representatives from Army Corps of Engineers, U.S. Geological Survey, and National Great Rivers Research and Education Center, have received a $63,129 grant to study floodplain forest habitats along the Upper Mississippi River and their ability to regenerate. Using high-resolution elevation and ground-cover imagery, researchers will identify natural places where young trees should flourish. They will then field-check the vegetation in those gaps, and evaluate how flooding and invasive species explain their ecological fate.

Abstract summary

Over the last decade, forested habitats within the Upper Mississippi River (UMR) floodplain have received increasing attention from management and research agencies. One of the primary reasons for this increased attention is that we infrequently observe forest regeneration within the UMR floodplain. Although floodplain forest regeneration is likely episodic, we lack historic baseline data on the scale and frequency of forest regeneration, and current information on the degree to which changes in hydrology or the presence of invasive species are affecting successional processes. As a result, there are concerns that the eventual loss of floodplain forest cover may be extensive and lead to a more savanna-like ecosystem, with cascading effects on fish and wildlife habitat and nutrient export to the UMR. The degree to which floodplain forests are regenerating and the specific causes for declines in floodplain forest cover are unclear. In some cases, changes in the hydrological regime since the time of floodplain forest establishment may limit recruitment in the forest understory. In other cases, invasive herbaceous species may colonize small canopy gaps as individual trees reach their maximum lifespan and further expand as adjacent forests senesce. The current age structure of floodplain forests suggests that many of the dominant cohorts are nearing their longevity and additional invasive pests (Dutch elm disease and the emerald ash borer) may further increase the rate of forest loss.

Professor summary

[caption id="attachment_52670" align="alignright" width="240"] Meredith Thomsen, Biology Professor[/caption] Floodplain forests along the Upper Mississippi River provide habitat for many species of birds, mammals, and even fish – which spawn in forested areas during periods of high water. Land managers in our area are concerned about how changes in seasonal flooding and invasive species limit the floodplain forest’s ability to regenerate itself. Wetter conditions and competition from invaders can kill off young trees. This could displace the forest with other habitats over time. This project will identify when and where the floodplain forest regenerates successfully, so we can produce similar conditions in other sites, leading to more effective habitat conservation and restoration efforts. Using high-resolution elevation and ground-cover imagery, we will identify natural treefall gaps – places where young trees should flourish. We will then field-check the vegetation in those gaps, and evaluate how flooding and invasive species explain their ecological fate. The grant will also provide for the training of a graduate student, who will gain experience at the interface between science and natural resource management.