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Version 3.24
Publication Type J
Authors Castillo, J. M., B. Gallego-Tevar, E. M. Castellanos, M. E. Figueroa and A. J. Davy
Title Primary succession in an Atlantic salt marsh: From intertidal flats to mid-marsh platform in 35 years
Source Journal of Ecology
Author Keywords Atriplex portulacoides elevation emergence marsh facilitation invasion redox potential sediment accretion stress-gradient hypothesis photosynthetic responses spartina-alterniflora ecological succession extreme halophyte plant zonation mechanisms facilitation vegetation salinity growth
Abstract 1. Although salt marsh is a classic example of primary succession, the underlying mechanisms and their time-scales are poorly understood. As salt marsh succession depends on sediment accretion, the amelioration of abiotic conditions associated with increasing elevation suggests potential explanatory roles for facilitation, competition and the stress-gradient hypothesis. 2. We present a 35-year longitudinal study of salt marsh development from intertidal flat to a mid-marsh platform at Odiel Marshes in south-western Iberia. Using permanent plots, this work chronicles changes in elevation and marsh morphology, their evolving effects on sediment redox potential and salinity and the colonisation and changing patterns of dominance of halophytic species. 3. Sporadically colonising clumps of the low-marsh species Spartina maritima trapped sediment to form raised tussocks, which increased in elevation and area. Reduced tidal inundation and locally improved drainage promoted higher redox potentials and allowed colonisation by a sequence of species less tolerant of reducing conditions: Sarcocornia perennis, its hybrid with high-marsh S. fruticosa, and Atriplex portulacoides. Unlike its centrifugally colonising predecessors, A. portulacoides invaded from the tussock edges. Transplant experiments designed to investigate its late establishment on tussocks showed that seedling survival depended on elevational differences as small as 4 cm. 4. After increasing in elevation by c. 1 m (c. 29 mm/year), coalescence of the tussocks formed a marsh platform at a level corresponding to mean high tides. This supports a theoretical punctuated transition from 'submergence marsh' to 'emergence marsh', previously postulated for this tidal elevation. 5. Synthesis. The unexpected rapidity of this primary succession highlights the central role of facilitation. Vertical sediment accretion, locally engineered by colonising species, progressively alleviates abiotic stress and allows colonisation by species that are less tolerant of chemically reducing conditions but are ultimately better competitors.
Author Address [Castillo, Jesus M.; Gallego-Tevar, Blanca; Enrique Figueroa, Manuel] Univ Seville, Fac Biol, Dept Biol Vegetal & Ecol, Seville, Spain. [Castellanos, Eloy M.] Univ Huelva, Fac Ciencias Experimentales, Dept Ciencias Integradas, Huelva, Spain. [Davy, Anthony J.] Univ East Anglia, Sch Biol Sci, Ctr Ecol Evolut & Conservat, Norwich, Norfolk, England. Castillo, JM (corresponding author), Univ Seville, Fac Biol, Dept Biol Vegetal & Ecol, Seville, Spain. manucas@us.es
ISSN 0022-0477
ISBN 0022-0477
29-Character Source Abbreviation J. Ecol.
Digital Object Identifier (DOI) 10.1111/1365-2745.13692
Unique Article Identifier WOS:000657446300001

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