Increasing Salt Marsh Elevation Using Sediment Augmentation: Critical Insights from Surface Sediments and Sediment Cores.

Autor: Fard E; Department of Geography, University of California, 1255 Bunche Hall, Box 951524, Los Angeles, CA, 90095, USA. efard@ucla.edu., Brown LN; Department of Geography, University of California, 1255 Bunche Hall, Box 951524, Los Angeles, CA, 90095, USA.; Biological Sciences Department, Bowling Green State University, Bowling Green, OH, 43403, USA., Ambrose RF; Institute of the Environment and Sustainability, La Kretz Hall, University of California, Suite 300, Box 951496, Los Angeles, CA, 90095-1496, USA., Whitcraft C; Biological Sciences Department, California State University, 1250 Bellflower Blvd, MS 9502, Long Beach, CA, 90840-9502, USA., Thorne KM; U.S. Geological Survey, Western Ecological Research Center, One Shields Ave, Davis, CA, 95616, USA., Kemnitz NJ; Department of Earth Sciences, University of Southern California, 3651 Trousdale Pkwy., Los Angeles, CA, 90089-0740, USA., Hammond DE; Department of Earth Sciences, University of Southern California, 3651 Trousdale Pkwy., Los Angeles, CA, 90089-0740, USA., MacDonald GM; Department of Geography, University of California, 1255 Bunche Hall, Box 951524, Los Angeles, CA, 90095, USA.; Institute of the Environment and Sustainability, La Kretz Hall, University of California, Suite 300, Box 951496, Los Angeles, CA, 90095-1496, USA.
Jazyk: angličtina
Zdroj: Environmental management [Environ Manage] 2024 Mar; Vol. 73 (3), pp. 614-633. Date of Electronic Publication: 2023 Nov 01.
DOI: 10.1007/s00267-023-01897-8
Abstrakt: Sea-level rise is particularly concerning for tidal wetlands that reside within an area with steep topography or are constrained by human development and alteration of sedimentation. Sediment augmentation to increase wetland elevations has been considered as a potential strategy for such areas to prevent wetland loss over the coming decades. However, there is little information on the best approaches and whether adaptive management actions can mimic natural processes to build sea-level rise resilience. In addition, the lack of information on long-term marsh characteristics, processes, and variability can hamper development of effective augmentation strategies. Here, we assess a case study in a southern California marsh to determine the nature of the pre-existing sediments and variability of the site in relation to sediments applied during an augmentation experiment. Although sediment cores revealed natural variations in the grain size and organic content of sediments deposited at the site over the past 1500 years, the applied sediments were markedly coarser in grain size than prehistoric sediments at the site (100% maximum sand versus 76% maximum sand). The rate of the experimental sediment application (25.1 ± 1.09 cm in ~2 months) was also much more rapid than natural accretion rates measured for the site historically. In contrast, post-augmentation sediment accretion rates on the augmentation site have been markedly slower than pre-augmentation rates or current rates on a nearby control site. The mismatch between the characteristics of the applied sediment and thickness of application and the historic conditions are likely strong contributors to the slow initial recovery of vegetation. Sediment augmentation has been shown to be a useful strategy in some marshes, but this case study illustrates that vegetation recovery may be slow if applied sediments are not similar or at a thickness similar to historic conditions. However, testing adaptation strategies to build wetland elevations is important given the long-term risk of habitat loss with sea-level rise. Lessons learned in the case study could be applied elsewhere.
(© 2023. The Author(s).)
Databáze: MEDLINE
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