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Zaytseva S, Shaw LB, Shi J, Kirwan ML, Lipcius RN. Pattern formation in marsh ecosystems modeled through the interaction of marsh vegetation, mussels and sediment. J Theor Biol 2022; 543:111102. [PMID: 35341780 DOI: 10.1016/j.jtbi.2022.111102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 03/17/2022] [Indexed: 11/16/2022]
Abstract
Spatial self-organization, a common feature of multi-species communities, can provide important insights into ecosystem structure and resilience. As environmental conditions gradually worsen (e.g., resource depletion, erosion intensified by storms, drought), some ecological systems collapse to an irreversible state once a tipping point is reached. Spatial patterning may be one way for them to cope with such changes. We use a mathematical model to describe self-organization of an eroding marsh shoreline based on three-way interactions between sediment volume and two ecosystem engineers - smooth cordgrass Spartina alterniflora and ribbed mussels Geukensia demissa. Our model indicates that scale-dependent interactions between multiple ecosystem engineers drive the self-organization of eroding marsh edges and regulate the spatial scale of shoreline morphology. Spatial self-organization of the marsh edge increases the system's productivity, allows it to withstand erosion, and delays degradation that otherwise would occur in the absence of strong species interactions. Further, changes in wavelength and variance of the spatial patterns give insight into marsh recession. Finally, we find that the presence of mussels in the system modulates the spatial scale of the patterns, generates patterns with shorter wavelengths, and allows the system to tolerate a greater level of erosion. Although previous studies suggest that self-organization can emerge from local interactions and can result in increased ecosystem persistence and stability in various ecosystems, our findings extend these concepts to coastal salt marshes, emphasizing the importance of the ecosystem engineers, smooth cordgrass and ribbed mussels, and demonstrating the potential value of self-organization for ecosystem management and restoration.
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Affiliation(s)
- Sofya Zaytseva
- Department of Mathematics, University of Georgia, Athens, GA, 30602, USA.
| | - Leah B Shaw
- Department of Mathematics, William & Mary, Williamsburg, VA, 23187, USA
| | - Junping Shi
- Department of Mathematics, William & Mary, Williamsburg, VA, 23187, USA
| | - Matthew L Kirwan
- Virginia Institute of Marine Science, William & Mary, Gloucester Point, VA, 23062, USA
| | - Romuald N Lipcius
- Virginia Institute of Marine Science, William & Mary, Gloucester Point, VA, 23062, USA
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2
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Beheshti K, Endris C, Goodwin P, Pavlak A, Wasson K. Burrowing crabs and physical factors hasten marsh recovery at panne edges. PLoS One 2022; 17:e0249330. [PMID: 34986154 PMCID: PMC8730443 DOI: 10.1371/journal.pone.0249330] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 12/08/2021] [Indexed: 11/30/2022] Open
Abstract
Salt marsh loss is projected to increase as sea-level rise accelerates with global climate change. Salt marsh loss occurs along both lateral creek and channel edges and in the marsh interior, when pannes expand and coalesce. Often, edge loss is attributed to erosive processes whereas dieback in the marsh interior is linked to excessive inundation or deposition of wrack, but remains poorly understood. We conducted a two-year field investigation in a central California estuary to identify key factors associated with panne contraction or expansion. Our study explored how an abundant burrowing crab, shown to have strong negative effects on marsh biomass near creek edges, affects panne dynamics. We also explored which physical panne attributes best predicted their dynamics. To our knowledge, ours is the first study of panne dynamics in a California marsh, despite how ubiquitous pannes are as a feature of marshes in the region and how often extensive marsh dieback occurs via panne expansion. Overall, we found that pannes contracted during the study period, but with variable rates of marsh recovery across pannes. Our model incorporating both physical and biological factors explained 86% of the variation in panne contraction. The model revealed a positive effect of crab activity, sediment accretion, and a composite of depth and elevation on panne contraction, and a negative effect of panne size and distance to nearest panne. The positive crab effects detected in pannes contrast with negative effects we detected near creek edges in a previous study, highlighting the context-dependence of top-down and bioturbation effects in marshes. As global change continues and the magnitude and frequency of disturbances increases, understanding the dynamics of marsh loss in the marsh interior as well as creek banks will be critical for the management of these coastal habitats.
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Affiliation(s)
- Kathryn Beheshti
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, United States of America
- Marine Science Institute, University of California, Santa Barbara, CA, United States of America
- * E-mail:
| | - Charlie Endris
- Elkhorn Slough National Estuarine Research Reserve, Watsonville, CA, United States of America
| | - Peter Goodwin
- Center for Environmental Science, University of Maryland Center for Environmental Science, Cambridge, MD, United States of America
| | - Annabelle Pavlak
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, United States of America
| | - Kerstin Wasson
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, United States of America
- Elkhorn Slough National Estuarine Research Reserve, Watsonville, CA, United States of America
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3
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Perry DC, Chaffee C, Wigand C, Thornber C. Implementing adaptive management into a climate change adaptation strategy for a drowning New England salt marsh. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2020; 270:110928. [PMID: 32721353 PMCID: PMC8842880 DOI: 10.1016/j.jenvman.2020.110928] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 05/31/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
Due to climate change and other anthropogenic stressors, future conditions and impacts facing coastal habitats are unclear to coastal resource managers. Adaptive management strategies have become an important tactic to compensate for the unknown environmental conditions that coastal managers and restoration ecologists face. Adaptive management requires extensive planning and resources, which can act as barriers to achieve a successful project. These barriers also create challenges in incorporating adaptive management into climate change adaptation strategies. This case study describes and analyzes the Rhode Island Coastal Resources Management Council's approach to overcome these challenges to implement a successful adaptive management project to restore a drowning salt marsh using the climate change adaptation strategy, sediment enhancement, at Quonochontaug Pond in Charlestown, RI. Through effective communication and active stakeholder involvement, this project successfully incorporated interdisciplinary partner and stakeholder collaborations and developed an iterative learning strategy that highlights the adaptive management method.
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Affiliation(s)
- Danielle C Perry
- Department of Natural Resources Science, University of Rhode Island, 120 Flagg Road, Kingston, RI, 02881, USA.
| | - Caitlin Chaffee
- Coastal Resources Management Council, 4808 Tower Hill, Wakefield, RI, 02879, USA
| | - Cathleen Wigand
- US EPA ORD CEMM Atlantic Coastal Environmental Sciences Division, 27 Tarzwell Drive, Narragansett, RI, 02882, USA
| | - Carol Thornber
- Department of Natural Resources Science, University of Rhode Island, 120 Flagg Road, Kingston, RI, 02881, USA
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Sea-level rise and the emergence of a keystone grazer alter the geomorphic evolution and ecology of southeast US salt marshes. Proc Natl Acad Sci U S A 2020; 117:17891-17902. [PMID: 32661151 PMCID: PMC7395507 DOI: 10.1073/pnas.1917869117] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Human disturbances, climate change, and their combined effects on species distributions and environmental conditions are increasingly modifying the organization of our world’s oceans, forests, grasslands, wetlands, tundras, and reefs. Here, we reveal that these contemporary conditions can trigger the emergence of novel keystone species. Across the southeastern US coastal plain, sea-level rise is outpacing salt marsh vertical accretion, causing these grasslands to be tidally inundated for longer and softening marsh substrates to levels optimal for crab burrowing. Using field experiments, measurements, surveys, and models, we show that these conditions amplify the burrowing and grazing effects of a previously inconspicuous crab, enabling it to redefine predator–prey interactions, eco-geomorphic feedbacks, and the mechanisms by which salt marshes are responding to climate change. Keystone species have large ecological effects relative to their abundance and have been identified in many ecosystems. However, global change is pervasively altering environmental conditions, potentially elevating new species to keystone roles. Here, we reveal that a historically innocuous grazer—the marsh crab Sesarma reticulatum—is rapidly reshaping the geomorphic evolution and ecological organization of southeastern US salt marshes now burdened by rising sea levels. Our analyses indicate that sea-level rise in recent decades has widely outpaced marsh vertical accretion, increasing tidal submergence of marsh surfaces, particularly where creeks exhibit morphologies that are unable to efficiently drain adjacent marsh platforms. In these increasingly submerged areas, cordgrass decreases belowground root:rhizome ratios, causing substrate hardness to decrease to within the optimal range for Sesarma burrowing. Together, these bio-physical changes provoke Sesarma to aggregate in high-density grazing and burrowing fronts at the heads of tidal creeks (hereafter, creekheads). Aerial-image analyses reveal that resulting “Sesarma-grazed” creekheads increased in prevalence from 10 ± 2% to 29 ± 5% over the past <25 y and, by tripling creek-incision rates relative to nongrazed creekheads, have increased marsh-landscape drainage density by 8 to 35% across the region. Field experiments further demonstrate that Sesarma-grazed creekheads, through their removal of vegetation that otherwise obstructs predator access, enhance the vulnerability of macrobenthic invertebrates to predation and strongly reduce secondary production across adjacent marsh platforms. Thus, sea-level rise is creating conditions within which Sesarma functions as a keystone species that is driving dynamic, landscape-scale changes in salt-marsh geomorphic evolution, spatial organization, and species interactions.
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Campbell AD, Wang Y. Salt marsh monitoring along the mid-Atlantic coast by Google Earth Engine enabled time series. PLoS One 2020; 15:e0229605. [PMID: 32109951 PMCID: PMC7048292 DOI: 10.1371/journal.pone.0229605] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 02/10/2020] [Indexed: 11/19/2022] Open
Abstract
Salt marshes provide a bulwark against sea-level rise (SLR), an interface between aquatic and terrestrial habitats, important nursery grounds for many species, a buffer against extreme storm impacts, and vast blue carbon repositories. However, salt marshes are at risk of loss from a variety of stressors such as SLR, nutrient enrichment, sediment deficits, herbivory, and anthropogenic disturbances. Determining the dynamics of salt marsh change with remote sensing requires high temporal resolution due to the spectral variability caused by disturbance, tides, and seasonality. Time series analysis of salt marshes can broaden our understanding of these changing environments. This study analyzed aboveground green biomass (AGB) in seven mid-Atlantic Hydrological Unit Code 8 (HUC-8) watersheds. The study revealed that the Eastern Lower Delmarva watershed had the highest average loss and the largest net reduction in salt marsh AGB from 1999–2018. The study developed a method that used Google Earth Engine (GEE) enabled time series of the Landsat archive for regional analysis of salt marsh change and identified at-risk watersheds and salt marshes providing insight into the resilience and management of these ecosystems. The time series were filtered by cloud cover and the Tidal Marsh Inundation Index (TMII). The combination of GEE enabled Landsat time series, and TMII filtering demonstrated a promising method for historic assessment and continued monitoring of salt marsh dynamics.
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Affiliation(s)
- Anthony Daniel Campbell
- Department of Natural Resources Science, University of Rhode Island Kingston, Kingston, Rhode Island, United States of America
| | - Yeqiao Wang
- Department of Natural Resources Science, University of Rhode Island Kingston, Kingston, Rhode Island, United States of America
- * E-mail:
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Wasson K, Raposa K, Almeida M, Beheshti K, Crooks JA, Deck A, Dix N, Garvey C, Goldstein J, Johnson DS, Lerberg S, Marcum P, Peter C, Puckett B, Schmitt J, Smith E, Laurent KS, Swanson K, Tyrrell M, Guy R. Pattern and scale: evaluating generalities in crab distributions and marsh dynamics from small plots to a national scale. Ecology 2019; 100:e02813. [PMID: 31291466 DOI: 10.1002/ecy.2813] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 06/03/2019] [Accepted: 06/13/2019] [Indexed: 11/11/2022]
Abstract
The generality of ecological patterns depends inextricably on the scale at which they are examined. We investigated patterns of crab distribution and the relationship between crabs and vegetation in salt marshes at multiple scales. By using consistent monitoring protocols across 15 U.S. National Estuarine Research Reserves, we were able to synthesize patterns from the scale of quadrats to the entire marsh landscape to regional and national scales. Some generalities emerged across marshes from our overall models, and these are useful for informing broad coastal management policy. We found that crab burrow distribution within a marsh could be predicted by marsh elevation, distance to creek and soil compressibility. While these physical factors also affected marsh vegetation cover, we did not find a strong or consistent overall effect of crabs at a broad scale in our multivariate model, though regressions conducted separately for each site revealed that crab burrows were negatively correlated with vegetation cover at 4 out of 15 sites. This contrasts with recent smaller-scale studies and meta-analyses synthesizing such studies that detected strong negative effects of crabs on marshes, likely because we sampled across the entire marsh landscape, while targeted studies are typically limited to low-lying areas near creeks, where crab burrow densities are highest. Our results suggest that sea-level rise generally poses a bigger threat to marshes than crabs, but there will likely be interactions between these physical and biological factors. Beyond these generalities across marshes, we detected some regional differences in crab community composition, richness, and abundance. However, we found striking differences among sites within regions, and within sites, in terms of crab abundance and relationships to marsh integrity. Although generalities are broadly useful, our findings indicate that local managers cannot rely on data from other nearby systems, but rather need local information for developing salt marsh management strategies.
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Affiliation(s)
- Kerstin Wasson
- Elkhorn Slough National Estuarine Research Reserve, 1700 Elkhorn Road, Royal Oaks, California, 95076, USA.,University of California, Santa Cruz, 115 McAllister Way, Santa Cruz, California, 95060, USA
| | - Kenneth Raposa
- Narragansett Bay National Estuarine Research Reserve, P.O. Box 151, Prudence Island, Rhode Island, 02872, USA
| | - Monica Almeida
- Tijuana River National Estuarine Research Reserve, 301 Caspian Way, Imperial Beach, California, 91932, USA
| | - Kathryn Beheshti
- University of California, Santa Cruz, 115 McAllister Way, Santa Cruz, California, 95060, USA
| | - Jeffrey A Crooks
- Tijuana River National Estuarine Research Reserve, 301 Caspian Way, Imperial Beach, California, 91932, USA
| | - Anna Deck
- San Francisco Bay National Estuarine Research Reserve, Estuary & Ocean Science Center, San Francisco State University, 3150 Paradise Drive, Tiburon, California, 94920, USA
| | - Nikki Dix
- Guana Tolomato Matanzas National Estuarine Research Reserve, 505 Guana River Road, Ponte Vedra Beach, Florida, 32082, USA
| | - Caitlin Garvey
- University of Connecticut, 75 North Eagleville, Storrs, Connecticut, 06269, USA
| | - Jason Goldstein
- Wells National Estuarine Research Reserve, Maine Coastal Ecology Center, 342 Laudholm Farm Road, Wells, Maine, 04090, USA
| | - David Samuel Johnson
- Virginia Institute of Marine Science, The College of William & Mary, P.O. Box 1346, Gloucester Point, Virginia, 23062, USA
| | - Scott Lerberg
- Chesapeake Bay National Estuarine Research Reserve of Virginia, Virginia Institute of Marine Science, The College of William & Mary, P.O. Box 1346, Gloucester Point, Virginia, 23062, USA
| | - Pamela Marcum
- Guana Tolomato Matanzas National Estuarine Research Reserve, 505 Guana River Road, Ponte Vedra Beach, Florida, 32082, USA
| | - Christopher Peter
- Great Bay National Estuarine Research Reserve, 89 Depot Road, Greenland, New Hampshire, 03840, USA
| | - Brandon Puckett
- North Carolina National Estuarine Research Reserve, 101 Pivers Island Road, Beaufort, North Carolina, 28516, USA
| | - Jenni Schmitt
- South Slough National Estuarine Research Reserve, P.O. Box 5417, Charleston, Oregon, 97420, USA
| | - Erik Smith
- North Inlet - Winyah Bay National Estuarine Research Reserve, Baruch Marine Field Laboratory, University of South Carolina, P.O. Box 1630, Georgetown, South Carolina, 29442, USA
| | - Kari St Laurent
- Delaware National Estuarine Research Reserve, 818 Kitts Hummock Road, Dover, Delaware, 19901, USA
| | - Katie Swanson
- Mission-Aransas National Estuarine Research Reserve, University of Texas Marine Science Institute, 750 Channel View Drive, Port Aransas, Texas, 78373, USA
| | - Megan Tyrrell
- Waquoit Bay National Estuarine Research Reserve, 131 Waquoit Highway, Waquoit, Massachusetts, 02536, USA
| | - Rachel Guy
- Sapelo Island National Estuarine Research Reserve, P.O. Box 15, Sapelo Island, Georgia, 31327, USA
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Raposa KB, McKinney RA, Wigand C, Hollister JW, Lovall C, Szura K, Gurak, Jr. JA, McNamee J, Raithel C, Watson EB. Top-down and bottom-up controls on southern New England salt marsh crab populations. PeerJ 2018; 6:e4876. [PMID: 29868281 PMCID: PMC5984588 DOI: 10.7717/peerj.4876] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 05/10/2018] [Indexed: 11/20/2022] Open
Abstract
Southern New England salt marsh vegetation and habitats are changing rapidly in response to sea-level rise. At the same time, fiddler crab (Uca spp.) distributions have expanded and purple marsh crab (Sesarma reticulatum) grazing on creekbank vegetation has increased. Sea-level rise and reduced predation pressure drive these changing crab populations but most studies focus on one species; there is a need for community-level assessments of impacts from multiple crab species. There is also a need to identify additional factors that can affect crab populations. We sampled crabs and environmental parameters in four Rhode Island salt marshes in 2014 and compiled existing data to quantify trends in crab abundance and multiple factors that potentially affect crabs. Crab communities were dominated by fiddler and green crabs (Carcinus maenas); S. reticulatum was much less abundant. Burrow sizes suggest that Uca is responsible for most burrows. On the marsh platform, burrows and Carcinus abundance were negatively correlated with elevation, soil moisture, and soil percent organic matter and positively correlated with soil bulk density. Uca abundance was negatively correlated with Spartina patens cover and height and positively correlated with Spartina alterniflora cover and soil shear strength. Creekbank burrow density increased dramatically between 1998 and 2016. During the same time, fishing effort and the abundance of birds that prey on crabs decreased, and water levels increased. Unlike in other southern New England marshes where recreational overfishing is hypothesized to drive increasing marsh crab abundance, we propose that changes in crab abundance were likely unrelated to recreational finfish over-harvest; instead, they better track sea-level rise and changing abundances of alternate predators, such as birds. We predict that marsh crab abundance will continue to expand with ongoing sea-level rise, at least until inundation thresholds for crab survival are exceeded.
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Affiliation(s)
- Kenneth B. Raposa
- Narragansett Bay National Estuarine Research Reserve, Prudence Island, RI, United States of America
| | - Richard A. McKinney
- ORD-NHEERL, Atlantic Ecology Division, U.S. Environmental Protection Agency, Narragansett, RI, United States of America
| | - Cathleen Wigand
- ORD-NHEERL, Atlantic Ecology Division, U.S. Environmental Protection Agency, Narragansett, RI, United States of America
| | - Jeffrey W. Hollister
- ORD-NHEERL, Atlantic Ecology Division, U.S. Environmental Protection Agency, Narragansett, RI, United States of America
| | - Cassie Lovall
- Narragansett Bay National Estuarine Research Reserve, Prudence Island, RI, United States of America
| | - Katelyn Szura
- Department of Biological Sciences, College of the Environment and Life Sciences, University of Rhode Island, Kingston, RI, United States of America
| | | | - Jason McNamee
- Rhode Island Department of Environmental Management, Jamestown, RI, United States of America
| | - Christopher Raithel
- Rhode Island Department of Environmental Management, Kingston, RI, United States of America
| | - Elizabeth B. Watson
- Department of Biodiversity, Earth and Environmental Sciences, Academy of Natural Sciences, Drexel University, Philadelphia, PA, United States of America
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A natural history model of New England salt marsh die-off. Oecologia 2018; 186:621-632. [DOI: 10.1007/s00442-018-4078-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 12/20/2017] [Indexed: 10/18/2022]
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