Providing temporal context to channel morphological dynamics in Great Plains intermittent streams

Authors: MENAPACE, BENJAMIN - North Dakota State University; MEEHAN, MIRANDA - North Dakota State University; HECKER, GARRETT - North Dakota Trust Lands; O'Brien, Peter

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/2/2025
Publication Date: 10/8/2025
Citation: Menapace, B., Meehan, M., Hecker, G., O'Brien, P.L. 2025. Providing temporal context to channel morphological dynamics in Great Plains intermittent streams. Rangeland Ecology and Management. https://doi.org/10.1016/j.rama.2025.09.001.
DOI: https://doi.org/10.1016/j.rama.2025.09.001

Interpretive Summary: Rangeland managers often use classification frameworks to understand the productivity of their land and guide management decisions. However, the ecological status of rangelands is dynamic, so the frameworks need to include tools to describe how and why these changes occur. We altered a commonly used tool in upland rangeland systems, state-and-transition models (STMs), to be applied in riparian areas. We developed riparian STMs by assessing changes in stream characteristics over the course of five to seven years at 26 locations across North Dakota. We found that streams could be effectively categorized as stable, stabilizing, or unstable, and most streams were changing to become more stable. Despite this general trend, stabilizing streams were at the greatest risk for degradation, so management decisions in those streams may be especially impactful. This study is the first effort to measure these characteristics at two different times, so it provides critical context for how long it takes streams to change stability status. This work will guide researchers in further refining riparian STMs, as well as benefit technical service providers when giving management recommendations. These findings will also directly benefit land managers by providing concrete, actionable information about the ecological status of their riparian areas.

Technical Abstract: State and transition models (STMs) are used by landowners to make land management decisions by providing insight into the processes that govern degradation and recovery of ecosystems. Intensive monitoring and inclusion of long-term data is critical for an advanced understanding of riparian ecosystem dynamics and stream channel morphology. This study used repeated measures of stream channel morphology on intermittent streams in low gradient alluvial valleys to assess transitions for improved riparian STM development. Cross sectional and longitudinal surveys of channel morphology were conducted five to seven years apart. Each site was assigned a channel type and stability class so transitions between classifications could be compared. Analysis of multiple channel stability metrics and the multivariate trajectory of sites over time revealed general trends toward stability across the study area. Channels that were initially observed in a stabilizing state and channels that changed stability class had the greatest degree of change over time. This study supports the theory that destabilized channels will always seek an alternative stable state. Stabilizing channels are in a state of building resistance and resilience. Management of stabilizing channels should include practices that promote floodplain development through the establishment of riparian plant communities. This study provides context for the length of time that the stages of channel evolution take on intermittent streams in the Northern Great Plains. Managers are able to make well-informed decisions when provided with a time frame for the changes a management practice is expected to support.