Effects of edge/interior and patch structure on reproduction in Zostera marina L. in Chesapeake Bay, USA

We examined the effects of location (patch edge vs. interior) and shoot density (individual, patchy, continuous) on reproduction in three natural and two transplanted Chesapeake Bay (USA) stands of the submerged marine angiosperm Zostera marina L. (eelgrass; Zosteraceae). There were no edge effects on demographic-based reproductive effort or reproductive output (propagule production), and patch structure (individual, patchy, continuous) alone never accounted for the majority of variability in any metric. Transplant site was the most important predictor of eelgrass reproduction response, and relationships among metrics were predictable within sites. Our results suggest that, in Chesapeake Bay eelgrass, environmental factors acting at a regional scale (km) have a stronger impact on reproductive investment than those at a patch scale (I -10 m). Since tradeoffs between clonal and sexual production are mediated primarily by exogenous environmental factors, site selection may be more critical than transplant configuration for producing self sustaining stands, and achieving long-term restoration success. (C) 2007 Elsevier B.V. All rights reserved.