Importance of the fiddler crab Uca pugnax to salt marsh soil organic matter accumulation

Thomas, Cassondra R.; Blum, Linda K.

doi:10.3354/meps08708

Cited by 60 publications

(42 citation statements)

References 45 publications

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“…Burrovidng crabs turn over marsh sediments by bringing buried material to the surface. This results in more rapid oxidation of organic matter and increases the amount of material that can be exported by tidal flushing (Katz, 1980;McCraith et al, 2003;Montague, 1982;Paramor and Hughes, 2004;Thomas and Blum, 2010). During the past few decades, these processes could have caused erosion, subsidence of the marsh platform, and, consequently, increased flooding frequency.…”

Section: Discussionmentioning

confidence: 99%

Hydrology, Herbivory, and the Decline of Spartina patens (Aiton) Muhl. in Outer Cape Cod Salt Marshes (Massachusetts, U.S.A.)

Smith¹,

Medeiros²,

Tyrrell³

2012

Journal of Coastal Research

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I www.JCRonlinc.org SMITH, S.M.; MEDEIROS, K.C., and TYRRELL, M.C., 2012. Hydrology, herbivory, and the decline of Spartina patens (Aiton) Muhl. in outer Cape Cod salt marshes (Massachusetts, U.S.A.). Joumal of Coastal Research, 28(3) 602-612 West Palm Beach (Florida), ISSN 0749-0208.Salt marsh diehack in different regions of the United States exhibits considerable variability in symptoms, processes, and theoretical or proven causes. On Cape Cod (Massachusetts), where losses within the low-marsh zone (elevations helow mean high tide, dominated hy smooth cordgrass [Spartina alterniflora Loisel.]) have been particularly severe, recent studies suggest that intense grazing pressure from increased ahundances of a native, herhivorous, purple marsh crab (Sesarma reticulatum) is to blame. Low-marsh dieback is spatially heterogeneous because it is closely related to the distrihution of the crahs' preferred suhstrate (peat vs. sand or mud). However, vegetation losses have also occurred in the high marsh, which is comprised of mainly saltmeadow cordgrass {Spartina patens [Aiton] Muhl). In contrast to the low marsh, high-marsh losses consistently occur along the seaward-most edge of this zone, suggesting a link with hydrology (flooding frequency). In this study, we attempted to determine the relative contribution of environmental factors and crab herbivory to high-marsh diehack. To do this, we (1) characterized tidal regimes in dieback vs. healthy areas, (2) assessed the extent of herbivory on S. patens using crab-exclosure cages, (3) documented the ability of S. patens to recover from simulated grazing (chpping) in different marshes and in different areas of individual marshes, and (4) estimated densities of S. reticulatum in two high-marsh diehack areas. The results indicate that S. patens losses are likely the result of a combination of Stressors. Flooding frequency and salinities are higher in dieback areas, which impart a higher level of physiological stress. Plants growing there also seem to have a much-reduced capacity to recover from both simulated and actual grazing hy the herbivorous crab, S. reticulatum. Continued losses of high-marsh vegetation could eliminate this community from coastal wetlands on Cape Cod, Massachusetts. ADDITIONAL INDEX WORDS: Salt marsh, Spartina patens, vegetation loss. Cape Cod.Mean dying = 48% (SE = 5%); mean healthy = 18% (SE = 4%).

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Section: Discussionmentioning

confidence: 99%

Hydrology, Herbivory, and the Decline of Spartina patens (Aiton) Muhl. in Outer Cape Cod Salt Marshes (Massachusetts, U.S.A.)

Smith¹,

Medeiros²,

Tyrrell³

2012

Journal of Coastal Research

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“…Crab burrowing may increase the decomposition rate of below-ground biomass by increasing oxygen concentrations in the soil (Bertness and Miller 1984, Otani et al 2010, Thomas and Blum 2010. To compare decomposition rates among creek head zones and the marsh platform, we deployed litter bags (1 mm mesh) filled with ~25 g of dried Spartina roots and rhizomes at a depth of 10 cm below the marsh surface at six zones (platform, live, live/dead, dead, mud, and revegetated) of a single creek head on Sapelo Island, GA (31.4775° N, 81.2417° W) in November, 2012 (n = 10 bags/zone).…”

Section: Decomposition Of Below-ground Biomassmentioning

confidence: 99%

Ecosystem engineers drive creek formation in salt marshes

̨ski

Pennings

2017

Ecology

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Ecosystem engineers affect different organisms and processes in multiple ways at different spatial scales. Moreover, similar species may differ in their engineering effects for reasons that are not always clear. We examined the role of four species of burrowing crabs (Sesarma reticulatum, Eurytium limosum, Panopeus herbstii, Uca pugnax) in engineering tidal creek networks in salt marshes experiencing sea level rise. In the field, crab burrows were associated with heads of eroding creeks and the loss of plant (Spartina alterniflora) stems. S. reticulatum was closely associated with creek heads, but densities of the other crab species did not vary across marsh zones. In mesocosm experiments, S. reticulatum excavated the most soil and strongly reduced S. alterniflora biomass. The other three species excavated less and did not affect S. alterniflora. Creek heads with vegetation removed to simulate crab herbivory grew significantly faster than controls. Percolation rates of water into marsh sediments were 10 times faster at creek heads than on the marsh platform. Biomass decomposed two times faster at creek heads than on the marsh platform. Our results indicate that S. reticulatum increases creek growth by excavating sediments and by consuming plants, thereby increasing water flow and erosion at creek heads. Moreover, it is possible that S. reticulatum burrows also increase creek growth by increasing surface and subsurface erosion, and by increasing decomposition of organic matter at creek heads. Our results show that the interaction between crab and plant ecosystem engineers can have both positive and negative effects. At a small scale, in contrast to other marsh crabs, S. reticulatum harms rather than benefits plants, and increases erosion rather than marsh growth. At a large scale, however, S. reticulatum facilitates the drainage efficiency of the marsh through the expansion of tidal creek networks, and promotes marsh health.

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“…Its range recently has expanded northward where it has been observed on the coast of New Hampshire (Johnson 2014). The effect of fiddler crabs on C storage has been studied in Virginia salt marshes where Thomas and Blum (2010) found that 74% more root material was decomposed in marshes with fiddler crab burrows. Unless potential predators and competitors accompany crab migration, this range extension could lead to significant release of CO 2 to the atmosphere from northern salt marsh C sinks.…”

Section: Salt Marsh and Mangrove Response To A Changing Climate And Amentioning

confidence: 99%

Wetlands In a Changing Climate: Science, Policy and Management

Moomaw

Chmura

Davies³

et al. 2018

Wetlands

300

142

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Part 1 of this review synthesizes recent research on status and climate vulnerability of freshwater and saltwater wetlands, and their contribution to addressing climate change (carbon cycle, adaptation, resilience). Peatlands and vegetated coastal wetlands are among the most carbon rich sinks on the planet sequestering approximately as much carbon as do global forest ecosystems. Estimates of the consequences of rising temperature on current wetland carbon storage and future carbon sequestration potential are summarized. We also demonstrate the need to prevent drying of wetlands and thawing of permafrost by disturbances and rising temperatures to protect wetland carbon stores and climate adaptation/resiliency ecosystem services. Preventing further wetland loss is found to be important in limiting future emissions to meet climate goals, but is seldom considered. In Part 2, the paper explores the policy and management realm from international to national, subnational and local levels to identify strategies and policies reflecting an integrated understanding of both wetland and climate change science. Specific recommendations are made to capture synergies between wetlands and carbon cycle management, adaptation and resiliency to further enable researchers, policy makers and practitioners to protect wetland carbon and climate adaptation/resiliency ecosystem services.

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Importance of the fiddler crab Uca pugnax to salt marsh soil organic matter accumulation

Cited by 60 publications

References 45 publications

Hydrology, Herbivory, and the Decline of Spartina patens (Aiton) Muhl. in Outer Cape Cod Salt Marshes (Massachusetts, U.S.A.)

Hydrology, Herbivory, and the Decline of Spartina patens (Aiton) Muhl. in Outer Cape Cod Salt Marshes (Massachusetts, U.S.A.)

Ecosystem engineers drive creek formation in salt marshes

Wetlands In a Changing Climate: Science, Policy and Management

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