Halophyte recruitment in a salt marsh restoration site

In restored salt marshes, seedling recruitment can be limited where large areas of soil are exposed and physical conditions are harsh. On a 0.7-ha excavated marsh plain, we studied recruitment as a function of abiotic (elevation) and biotic factors in 2 × 2 m plots planted with 0, 1, 3, or 6 species from the pool of 8 native halophytes. The random draws of 3-species and 6-species assemblages produced approximately equal numbers of plants per species for the experiment as a whole, yet only three species recruited> 10 seedlings per plot.Salicornia virginica andSalicornia bigelovii each produced> 15,000 seedlings in 1998, andSuaeda esteroa produced> 2,500 seedlings in 1999. For these 3 species, seedling recruitment increased with elevation in 1998, but this trend weakened in 1999, when species richness affected recruitment (fewer seedlings in more species-rich plots). Abiotic effects preceded biotic interactions in determining seedling recruitment patterns early in the development of the salt marsh. Effects of species richness appeared to be scale-dependent in that having all species present in the site likely enhanced overall recruitment (all species had 2 or more seedlings), while plantings of 6 species in a 2 × 2 m plot reduced seedling density.S. virginica was the only species that increased its presence and relative cover in the experimental site over the 4-yr study. Protocols for planting southern California salt marsh restoration sites could omit this species, but all others probably need to be introduced to restore diverse vegetation.

[1]  G. Sullivan.  Establishing vegetation in restored and created coastal wetlands , 2000 .

[2]  P. Vitousek,et al.  The Effects of Plant Composition and Diversity on Ecosystem Processes , 1997 .

[3]  D. Tilman,et al.  Productivity and sustainability influenced by biodiversity in grassland ecosystems , 1996, Nature.

[4]  A. Snow,et al.  Plant zonation in an Alaskan salt marsh. I: Distribution, abundance and environmental factors , 1984 .

[5]  J. Zedler,et al.  Differential effects of four abiotic factors on the germination of salt marsh annuals. , 2000, American journal of botany.

[6]  H. Gholz,et al.  Canopy structure, light penetration and tree growth in a slash pine (Pinus elliottii) silvo-pastoral system at different stand configurations in Florida , 1991 .

[7]  Joy B. Zedler,et al.  Handbook for Restoring Tidal Wetlands , 2000 .

[8]  P. Torstensson.  The demography of the annual halophyte Spergularia marina on a baltic seashore meadow , 2004, Vegetatio.

[9]  S. Milton,et al.  Vegetation change in semiarid communities , 1996, Vegetatio.

[10]  J. Bakker,et al.  GERMINATION AND EARLY ESTABLISHMENT OF LOWER SALT-MARSH SPECIES IN GRAZED AND MOWN SALT-MARSH , 1992 .

[11]  Joy B. Zedler,et al.  SALT MARSH CANOPY ARCHITECTURE DIFFERS WITH THE NUMBER AND COMPOSITION OF SPECIES , 2002 .

[12]  J. Zedler,et al.  Nitrogen Assessments in a Constructed and a Natural Salt Marsh of San Diego Bay. , 1991, Ecological applications : a publication of the Ecological Society of America.

[13]  Cliff R. Hupp,et al.  Hydrological and geomorphological impacts on riparian plant communities , 2000 .

[14]  J. Izco,et al.  Relationships between vegetation zonation and altitude in a salt-marsh system in northwest Spain , 1996 .

[15]  Scott N. Martens,et al.  Spatial distributions of understory light along the grassland/forest continuum: Effects of cover, height, and spatial pattern of tree canopies , 2000 .

[16]  Charles C. Elton.  The Ecology of Invasions by Animals and Plants , 1959, Biodiversity & Conservation.

[17]  John H. Lawton,et al.  Biodiversity and plant productivity in a model assemblage of plant species , 1996 .

[18]  David Tilman,et al.  COMMUNITY INVASIBILITY, RECRUITMENT LIMITATION, AND GRASSLAND BIODIVERSITY , 1997 .

[19]  P. Reich,et al.  The Influence of Functional Diversity and Composition on Ecosystem Processes , 1997 .

[20]  Charles C. Elton,et al.  The Ecology of Invasions by Animals and Plants. , 1959 .

[21]  K. Lertzman,et al.  Forest dynamics, differential mortality and variable recruitment probabilities , 1995 .

[22]  R. J. Vogl.  Salt‐Marsh Vegetation of Upper Newport Bay, California , 1966 .

[23]  Howard P. Hinde.  The Vertical Distribution of Salt Marsh Phanerogams in Relation to Tide Levels , 1954 .

[24]  K. Kershaw,et al.  Vegetation patterns in James Bay coastal marshes. III. Salinity and elevation as factors influencing plant zonations , 1989 .

[25]  J. Lefeuvre,et al.  Factors affecting the population dynamics of Suaeda maritima at initial stages of development , 2000, Plant Ecology.

[26]  G. Vivian‐Smith.  MICROTOPOGRAPHIC HETEROGENEITY AND FLORISTIC DIVERSITY IN EXPERIMENTAL WETLAND COMMUNITIES , 1997 .

[27]  David A. Adams,et al.  Factors Influencing Vascular Plant Zonation in North Carolina Salt Marshes , 1963 .

[28]  P. Herman,et al.  Seed Dispersal of Halophytes in Tidal Salt Marshes , 1995 .

[29]  M. Bertness,et al.  Structural interdependence : an ecological consequence of morphological responses to crowding in marsh plants , 1996 .

[30]  David Tilman,et al.  Plant diversity increases resistance to invasion in the absence of covarying extrinsic factors , 2000 .

[31]  W. G. Beeftink.  Population dynamics of annual Salicornia species in the tidal salt marshes of the Oosterschelde, The Netherlands , 1985, Vegetatio.

[32]  M. Bertness,et al.  EXPERIMENTAL EVIDENCE FOR FACTORS MAINTAINING PLANT SPECIES DIVERSITY IN A NEW ENGLAND SALT MARSH , 1999 .

[33]  J. Ewel,et al.  Tropical Soil Fertility Changes Under Monocultures and Successional Communities of Different Structure. , 1991, Ecological applications : a publication of the Ecological Society of America.

[34]  M. Palmer,et al.  Ecological Theory and Community Restoration Ecology , 1997 .

[35]  Jw Wilson.  Estimation of foliage denseness and foliage angle by inclined point quadrats , 1963 .

[36]  R. Jefferies,et al.  POPULATION BIOLOGY OF THE SALT MARSH ANNUAL SALICORNIA EUROPAEA agg. , 1981 .

[37]  B. Trenbath,et al.  Biomass Productivity of Mixtures , 1974 .

[38]  M. Bertness,et al.  Positive interactions in communities. , 1994, Trends in ecology & evolution.

[39]  M. Khan,et al.  Seed Polymorphism and Germination Responses to Salinity Stress in Atriplex triangularis Willd. , 1984, Botanical Gazette.

[40]  F. E. Egler,et al.  Vegetation of the Wequetequock‐Pawcatuck Tidal‐Marshes, Connecticut , 1950 .

[41]  T. Herben,et al.  Grassland canopy composition and spatial heterogeneity in the light quality , 1999, Plant Ecology.

[42]  Clyde Young Kramer,et al.  Extension of multiple range tests to group means with unequal numbers of replications , 1956 .

[43]  Marcel Rejmánek,et al.  Invasibility of plant communities , 1989 .

[44]  M. Bertness,et al.  Effects of biomass removal and elevation on species richness in a New England salt marsh , 1997 .

[45]  J. Bakker,et al.  Effects of resource competition and herbivory on plant performance along a natural productivity gradient , 2000 .

[46]  J. Zedler,et al.  Restoring Urban Habitats: A Comparative Study , 2000, Ecological Restoration.

[47]  C. Craft,et al.  TWENTY‐FIVE YEARS OF ECOSYSTEM DEVELOPMENT OF CONSTRUCTED SPARTINA ALTERNIFLORA (LOISEL) MARSHES , 1999 .

[48]  J. Zedler.  Salt marsh community structure in the Tijuana Estuary, California , 1977 .

[49]  I. Mendelssohn,et al.  Response of two oligohaline marsh communities to lethal and nonlethal disturbance , 1998, Oecologia.

[50]  M. Hutchings,et al.  The seed regeneration dynamics of an emergent salt marsh , 1989 .

[51]  M. Bertness,et al.  Cooperative and Competitive Interactions in the Recruitment of Marsh Elders , 1994 .