Geology topics

Shelby A. Weiss

Publications and source records attributed to Shelby A. Weiss.

4 recordsLinked to original sources

USGS2026

Patterns of floodplain forest mortality and recruitment along the Upper Mississippi and Illinois Rivers: Associations with forest fragmentation and flood inundation

Context Different rates of floodplain forest recruitment and mortality can reveal important changes in ecosystem processes that drive forest dynamics, resulting in net changes in forest cover, thereby influencing a wide range of river habitat and morphological characteristics. Objectives We evaluated characteristics of forest change areas in the Upper Mississippi River System. Methods An overlay technique was used to map patches of forest loss, gain, and persistence between 2010 and 2020 in relation to a series of explanatory variables. Results We quantified a net decline in forest cover ranging from 3.2 to 16.8% in the uppermost five study reaches, and a net increase in forest cover ranging from 0.5 to 4.6% in the southernmost three reaches. Patches of forest loss and persistence were similarly tall (> 15 m), dense (> 90% cover), silver maple ( Acer saccharinum ) dominated forests, whereas forest gain patches were short (< 15 m), less dense (< 66% cover) and more likely to be dominated by willow ( Salix) species. Both forest loss and gain patches were smaller than forest persistence patches and were typically found in areas with low neighborhood forest density (< 50% forested 10 ha neighborhood). Areas that experienced more than three flood events per growing season, more than 100 consecutive days of inundation during a single flood event, and more than 60 mean total days of inundation per growing season from 2011 to 2020 showed a net loss of forest cover in all study reaches. In contrast, net increases in forest cover were restricted to areas that experienced less than a single flood event per growing season, less than 40 consecutive days of inundation during a single flood event and less than 30 mean total days of inundation per growing season from 2011 to 2020. Conclusions Forest mortality along these river reaches is associated with forest fragmentation and an increasingly wetter hydrological regime.

Illinois, Iowa, Minnesota, Missouri, Wisconsin↗

USGS2026

Proceedings of the Floodplain Vegetation Monitoring Workshop for the Long Term Resource Monitoring Element of the Upper Mississippi River Restoration Program, January 7–8, 2025, Moline, Illinois

Preface In anticipation for increased funding made possible by the Water Resources Development Act of 2020, the Upper Mississippi River Restoration (UMRR) Program identified a need to conduct river-wide assessments of floodplain vegetation. In January 2025, we assembled a group of subject matter experts to perform the following tasks: Review Upper Mississippi River Restoration’s current floodplain vegetation research portfolio, Identify important features and goals for long-term floodplain vegetation monitoring, Evaluate the suitability of existing datasets for system-wide vegetation assessments, and Discuss emerging opportunities to learn about floodplain vegetation dynamics from local-scale restoration and management projects. This document is a summarization of what occurred at the meeting and provides suggested next steps toward developing the capacity to conduct routine long-term monitoring and assessment of floodplain vegetation as part of the Upper Mississippi River Restoration Program.

Illinois, Iowa, Minnesota, Missouri, Wisconsin↗

USGS2025

Quantifying floodplain forest community change following large-scale flood events in the Upper Mississippi River System

Effects of large-scale flooding on forest composition and structure are a function of flood duration, depth, timing, and frequency. Throughout the Upper Mississippi River System (UMRS), floods in 1993 and 2019 were record-setting events followed by high rates of tree mortality. These events generated interest in species adaptations to flood event characteristics and how forest communities have changed in response to large-scale floods. We investigated associated tree mortality, how the floods differed spatially, and how floodplain forest communities have changed since 1993. Eight UMRS reaches were surveyed in a 1995 study, documenting vegetation species composition, size, and abundance. In 2021, a selection of plots (63%) were revisited and surveyed to quantify 2019 flood effects. For each site, we extracted daily inundation data for flood years and preceding decades from a surface water inundation model. We found post-flood mortality varied spatially and generally reflected inundation duration patterns. Lower latitude reaches experienced longer inundation durations and greater tree mortality in 1993 than in 2019, while higher latitude reaches experienced similar inundation duration and depth and similar mortality between events. Decadal inundation attributes also differed. During 2009–2018, inundation duration was greater and events occurred later than during 1983–1992 in all reaches. Most forest trajectories were Acer saccharinum -dominated and changed relatively little in species composition and structure. The greatest change in composition occurred at plots with high mortality from the 1993 flood, particularly in more flood-prone locations or where there were many small-diameter individuals. In plots dominated by either Quercus spp. or Populus deltoides , species importance shifted toward more shade and flood-tolerant species after 1995 surveys. Self-replacement of these species may be limited by a change in regeneration conditions resulting from an ongoing inundation regime shift in the case of Quercus spp., or succession to more shade-tolerant species in the case of Populus communities. Overall, effects on floodplain forests from the two flood events were heterogeneous. In some cases, forest change was likely just as influenced by shifts in flood regime as it was from singular flood events.

Illinois, Iowa, Minnesota, Missouri, Wisconsin↗

USGS2020

The Fire and Tree Mortality Database, for empirical modeling of individual tree mortality after fire

Wildland fires have a multitude of ecological effects in forests, woodlands, and savannas across the globe. A major focus of past research has been on tree mortality from fire, as trees provide a vast range of biological services. We assembled a database of individual-tree records from prescribed fires and wildfires in the United States. The Fire and Tree Mortality (FTM) database includes records from 164,293 individual trees with records of fire injury (crown scorch, bole char, etc.), tree diameter, and either mortality or top-kill up to ten years post-fire. Data span 142 species and 62 genera, from 409 fires occurring from 1981-2016. Additional variables such as insect attack are included when available. The FTM database can be used to evaluate individual fire-caused mortality models for pre-fire planning and post-fire decision support, to develop improved models, and to explore general patterns of individual fire-induced tree death. The database can also be used to identify knowledge gaps that could be addressed in future research.

Scientific Data↗