Evaluation of soil properties and bulk δ15N to assess decadal changes in floodplain denitrification following restoration
Date
2024-10-29
Journal Title
Journal ISSN
Volume Title
Publisher
Restoration Ecology
Abstract
Stream and floodplain restoration is a popular billion-dollar industry in the United States, with many restorations being conducted to satisfy water pollution regulations and nutrient reduction goals. The long-term efficacy of these restorations is, however, not well studied, and key soil metrics that can be used for performance assessments have not been developed. We evaluated a chronosequence of 12 restoration sites spanning an age range of 0–22 years to assess changes in denitrification rates and associated soil parameters. Restored versus unrestored reaches were compared for denitrification rate and functional gene nosZ, bulk soil δ15N, soil organic carbon (SOC), soil organic matter (SOM), bulk density, and soil moisture. Denitrification, SOM, SOC, and soil moisture were all found to increase with site age at restored sites, with the largest increase for the 10–22 age category. Bulk density decreased with time, with a significant decrease in restored floodplain soils. Bulk soil δ15N was highest immediately after restoration, decreased with restoration age, and was not positively correlated with denitrification. This may reduce its potential as a proxy for denitrification. Overall, this study reveals that selected soil metrics (SOC, SOM, soil moisture, and bulk density) could serve as a valuable proxy for denitrification and could help assess the denitrification effectiveness of floodplain restorations at the decadal time scales. Ideally, the soil metrics should be combined with other short-term assessment measures, such as those for stream and groundwaters, for a robust performance assessment of restored floodplains.
Implications for Practice
- Soil characteristics have not been routinely used for assessing the long-term effectiveness of stream and floodplain restorations, and guidance is needed for their use.
- Soil organic matter, moisture, and bulk density improved over time for restored floodplains and could be used as reliable proxies for denitrification nitrogen removal.
- Site-specific differences in restoration design and construction (e.g. soil amendments such as woody debris/chips) could significantly affect the response of soil metrics.
- Since soil characteristics change slowly over decadal time scales, restoration assessments should also include quicker, short-term performance measures such as those associated with surface and groundwater quality.
Description
This is the peer reviewed version of the following article: Galella, J.G., Rahman, M.M., Yaculak, A.M., Peipoch, M., Kan, J., Sena, M., Joshi, B., Kaushal, S.S. and Inamdar, S. (2025), Evaluation of soil properties and bulk δ15N to assess decadal changes in floodplain denitrification following restoration. Restor Ecol, 33: e14327. https://doi.org/10.1111/rec.14327, which has been published in final form at https://doi.org/10.1111/rec.14327. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited.
© 2024 Society for Ecological Restoration.
This article will be embargoed until 10/29/2025.
Keywords
bulk density, chronosequence, floodplains, mid-Atlantic, organic carbon, soil health, stable nitrogen isotopes, stream restoration, clean water and sanitation, life on land
Citation
Galella, J.G., Rahman, M.M., Yaculak, A.M., Peipoch, M., Kan, J., Sena, M., Joshi, B., Kaushal, S.S. and Inamdar, S. (2025), Evaluation of soil properties and bulk δ15N to assess decadal changes in floodplain denitrification following restoration. Restor Ecol, 33: e14327. https://doi.org/10.1111/rec.14327