title: Habitat fragmentation has some impacts on aspects of ecosystem functioning in a sub-tropical seagrass bed.
abstract: Habitat fragmentation impacts ecosystem functioning in many ways, including reducing the availability of suitable habitat for animals and altering resource dynamics. Fragmentation in seagrass ecosystems caused by propeller scarring is a major source of habitat loss, but little is known about how scars impact ecosystem functioning. Propeller scars were simulated in seagrass beds of Abaco, Bahamas, to explore potential impacts. To determine if plant-herbivore interactions were altered by fragmentation, amphipod grazers were excluded from half the experimental plots, and epiphyte biomass and community composition were compared between grazer control and exclusion plots. We found a shift from light limitation to phosphorus limitation at seagrass patch edges. Fragmentation did not impact top-down control on epiphyte biomass or community composition, despite reduced amphipod density in fragmented habitats. Seagrass and amphipod responses to propeller scarring suggest that severely scarred seagrass beds could be subject to changes in internal nutrient stores and amphipod distribution.
authors.affiliation: Concordia College, Department of Biology, 901 8th St. S, Moorhead, MN 56562, United States. Electronic address: jsweatma@cord.edu.
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Sweatman
authors.affiliation: North Carolina State University, 127 David Clark Labs, Campus Box 7617, Raleigh, NC 27695-7617, United States. Electronic address: calayman@ncsu.edu.
authors.forename: Craig A
authors.initials: CA
authors.lastname: Layman
authors.affiliation: Florida International University, Department of Biology, 11200 SW 8th St, Miami, FL 33199, United States. Electronic address: fourqure@fiu.edu.
authors.forename: James W
authors.initials: JW
authors.lastname: Fourqurean
mesh_terms: D017753:Ecosystem; D004784:Environmental Monitoring; D060434:Herbivory; D035962:Zosteraceae / Q000502:physiology*
keywords: Amphipod; Disturbance; Epiphytes; Food-webs; Habitat fragmentation; Plant-herbivore interactions; Seagrass; Stoichiometry