MEPS 533:109-120 (2015)  -  DOI:

Roles of dispersal and predation in determining seedling recruitment patterns in a foundational marine angiosperm

Stephen R. Manley1,*, Robert J. Orth1, Leonardo Ruiz-Montoya2,3

1Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, VA 23062, USA
2The University of Western Australia Oceans Institute, Crawley, 6009 Western Australia, Australia
3School of Plant Biology, The University of Western Australia, Crawley, 6009 Western Australia, Australia
*Corresponding author:

ABSTRACT: Seed dispersal and seed predation are 2 important processes in the early life history of plants. These mechanisms have been described extensively in terrestrial plants and have resulted in the creation of various models to describe seedling recruitment with increasing distance from the parent plant. However, it is unclear whether theoretical models derived from terrestrial studies apply to marine angiosperms. We performed observational and experimental tests of seed dispersal mechanisms in a marine environment to elucidate patterns of seed dispersal and predation in a foundational marine angiosperm, eelgrass Zostera marina. We also modeled seed dispersal and predation to explore how recruitment varies under different scenarios of predator activity and abundance. We found that seed densities were highest within and adjacent to vegetated areas. Predation pressure was low overall, and there was no significant difference in predation pressure between vegetated and unvegetated areas. Seedling densities were highly correlated with seed densities from the previous year, suggesting that seed predation had a limited impact on population recruitment. These results are consistent with the invariant survival model, which states that seed survivorship has no spatial trend. The theoretical scenarios we generated suggest that a low abundance of highly mobile, generalist predators may explain the patterns observed in our system. Therefore, seedling establishment rates are almost solely attributable and inversely proportional to distance from the parent plant. The results from this study have important implications for the recovery and restoration of these highly threatened coastal ecosystems.

KEY WORDS: Seeds · Dispersal · Predation · Seedling recruitment · Zostera marina · Janzen-Connell · Hubbell · McCanny

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Cite this article as: Manley SR, Orth RJ, Ruiz-Montoya L (2015) Roles of dispersal and predation in determining seedling recruitment patterns in a foundational marine angiosperm. Mar Ecol Prog Ser 533:109-120.

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