Benthic community structure within Eelgrass (Zostera marina) beds in southern Nova Scotia
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Seagrass beds are productive coastal habitats that provide numerous ecosystem services. Declines in seagrass beds worldwide will have profound influences on the trophic structure and overall functioning of coastal ecosystems. My objective was to relate benthic community structure to seagrass bed characteristics and to understand the potential effects of fragmentation on trophic structure. Core samples were taken from Port L’Hebert (PH) and Port Joli (PJ) from bare (no seagrass, >5m from bed edge), edge (within seagrass, <1m from edge), and interior (>10m from any seagrass-mud interface). Macroinvertebrate (>500 um) abundance, functional group abundance, community structure, seagrass leaf length and shoot density, and sediment grain size and organic matter were quantified in each core. Total macroinvertebrate abundance was highest in PH’s edge habitat. Predator and detritivore abundances did not differ among sites or habitats. Grazer abundance was significantly higher in the interior and edge than in bare at both sites. Suspension feeder abundance was significantly higher in the bare and edge habitats than interior habitats at both PH and PJ. Species richness was significantly higher in edge and interior than in bare habitats, and higher in PJ than PH. Average leaf length and shoot density was greater in interior habitats than edge habitats at both PH and PJ. Sediment particle size was overall larger in PJ and PH. Organic content was significantly different between PH edge and PH interior and bare. Ordinations showed that community structure differed among habitat types at PJ. This study provides insight of how seagrass loss will influence trophic structure of seagrass beds, and offers basic information for restoration and conservation projects.