To examine the relative importance of bottom-up and top-down control of the eelgrass (Zostera marina) mesograzer community, nutrients (2 levels) and predators (3 levels) were manipulated in a full factorial experimental design (n = 10 replicates per treatment combination) for seven weeks (June 17 – July 28, 2011). 60 artificial seagrass units (ASUs) were randomly arranged in three rows, parallel to the shore in the subtidal Z. marina zone, and distributed such that ASUs were separated by 3 m within and between rows. ASUs were made of frayed rope (length = 35 cm) to mimic seagrass or branching algal habitat, and were used to sample mesograzers on a standard surface area. This data file gives the abundances of the eight mesograzers on ASUs for each treatment. Cage.Trt: the predator exclusion cage treatment (full = full cage/predator exclusion; partial = partial cage/predators have access/cage control; none = no cage/predator have access/control). Nut.Trt: the nutrient addition treatment (0 = no nutrients added; 1 = nutrients added (30 g Osmocote slow release fertilizer))
