Extending trait dispersion across trophic levels: predator assemblages act as top-down filters on prey communities

Studies of community assembly typically focus on the effects of abiotic environmental filters and stabilizing competition on functional trait dispersion within single trophic levels. Predation is a well-known driver of community diversity and composition, yet the role of functionally diverse predator communities in filtering prey community traits has received less attention. We examined functionally diverse communities of predators (fishes) and prey (epifaunal crustaceans) in eelgrass (Zostera marina) beds in two Northern California estuaries to evaluate the filtering effects of predator traits on community assembly, and how filters acting on predators influence their ability to mediate prey community assembly. Fish traits related to bottom orientation selected for more clustered epifauna communities, and epifauna were generally overdispersed while fishes were clustered, suggesting that prey may be pushed to disparate areas of trait space to avoid capture by benthic sit-and-wait predato..., We sampled fish and epifaunal communities in 6 eelgrass beds in Bodega Harbor and Tomales Bay in the summers of 2019 and 2021. We sampled fishes in 6 sets of a custom beach seine net when the water level was at or below 1 m above the seafloor. The seine sampled a circular area of 11 m2. We counted, identified to the lowest possible taxonomic level (typically species), and released animals retained in the seine.
We sampled epifauna at 12 locations within each site separated by at least 10m and spanning a depth gradient of intertidal to shallow subtidal. We collected each sample by everting an open-mouth drawstring mesh bag (500 µm mesh size) over a clump of shoots in the eelgrass bed so that the mouth of the bag was flush with the sediment surface, cutting the shoots, and closing the drawstring to capture shoots, macroalgae, and associated animals. We transferred the shoots to the laboratory on ice, rinsed, and hand-inspected them to dislodge the epifauna, which we then passed through a ..., Code file is written in R; data files are .csv files that can be opened and viewed with Microsoft Excel; phylogeny is a .txt that can be opened in a text editor and manipulated and analyzed in R. Supplementary Tables 1-3 are an .xlsx file viewable in Microsoft Excel. , # Extending trait dispersion across trophic levels: predator assemblages act as top-down filters on prey communities

## Description of the data and file structure

Environmental and species abundance data collected in summer (June-August) 2019 and 2021 from eelgrass beds in Northern California.

**NOTE**: Version created Apr 2024 added file #7.

This dataset consists of 7 data files:

1. Epifauna.list.csv, created July 19, 2023. Invertebrates collected from grab samples of eelgrass (Zostera marina) from 8 sites across the two sampling years (only 6 sites were used in analyses).
* Sample: The code used to identify an individual grab sample, read as: subsite_tidal height, transect number_sample along transect_year
* Bay: The estuary where the samples were collected (BH = Bodega Harbor, DE = Drakes Estero, TB = Tomales Bay)
* Subsite: The site code used to define a community of epifauna (BL = Blake's Landing, CC = Campbell Cove, MM = Mason's Marina, MP = Millerton Point...