These data represent the responses of eelgrass (Zostera marina) beds to a series of experimental treatments conducted in 2004 and 2005 in the vicinity of Hookton Channel, Humboldt Bay, California, USA. We measured eelgrass density, growth, biomass, and flowering as the primary response variables to clipping, brant (Branta bernicla) fecal addition, clipping and fecal addition, and control treatments in a 2004 destructively sampled randomized block design meant to simulate different effects of brant grazing and test the compensatory growth hypothesis as fully described in an associated publication, Shaughnessy et al. (2021) in Ecosphere. We measured density, growth, and flowering as primary response variables to control, moderate, and severe clipping treatments, all with fecal addition, in a 2005 destructively sampled randomized block design meant to simulate different levels of brant grazing also described in Shaughnessy et al. (2021).

These data and associated methodologies were described and used to draw inferences in Shaughnessy et al. (2021), and complete methods are available there. Data on eelgrass growth rates, above-ground and below-ground biomass, leaf area index (leaf area per unit area), epiphyte weight, shoot length, and shoot count were collected in 140 0.0625 m² sample plots (4 treatments each - control, fecal addition, clipping, and fecal + clipping - in 35 blocks) in 2004 during experiment 1 and 69 0.0625 m² sample plots (3 treatments each - control, moderate clipping + fecal addition, and severe clipping + fecal addition in 23 blocks) in 2005 during experiment 2. Some variables were summarized as within-plot sample means or within-group means prior to visualization or analysis as noted in Shaughnessy et al. (2021) and metadata presented here.

The README.txt file describes each variable included in each of the eight data files presented here, and additional details of methods are available in Shaughnessy et al. (2021) and the associated appendix. Missing values in these data are represented by empty cells.