Dataset: Species interaction and annual colonization experimental (ACE) data from the rocky intertidal zone, Oregon Coast from 2011 to 2023

Species interaction experiments called ACE, Annual Competition Experiment includes six treatments to test the main and interactive effects of predation, competition and disturbance on annual colonization of rocky substrates in the mid-zone of the rocky intertidal along the Oregon Coast (see site list attached). The experiment began in 2011 and is repeated annually. All plots are 15 x 15cm and fixed,  and the experiment is repeated in the same location each year.  Each spring (usually April or May), all plots are cleared of all biomass using scrapers and oven cleaner to reset the community. The exception is the control plots  (CO) which were started in 2021 and are nearby plots that have never been intentionally disturbed.   There are 6 treatment that  include 1) undisturbed controls of the climax community which is typically mussel-dominated, 2) marked plots that are cleared annually to capture annual prey colonization and serve as controls for the interaction experiments, 3) 2) partial cages that serve as cage controls for the interaction experiments 3) predator exclusion cages where an open-topped metal cage is placed around the plot to deter entry by predatory whelks and sea stars and where mussel and barnacle colonization occurs undeterred (to test predation), 4)  predator exclusion + barnacle removal cages  in which predator are excluded plus barnacle settlers removed (to test facilitation by barnacles of mussels), and 5)  predator exclusion + mussel removal cages  in which predator are excluded plus mussel settlers removed  (to test competition effects of mussels on barnacles). All plots are photographed approximately monthly, and treatments are maintained by removing predators that in the cages and by clearing the relevant competitors (mussels or barnacles). Photos are analyzed by overlaying a 5 x5 grid onto the photo in Image J (so that each square is 4% cover) and estimating the % cover of each major space holder to the nearest 1%.  Space holders include: free space, algal crusts, acorn barnacles, gooseneck barnacles, mussels, articulated coralline algae, foliose algae and other sessile invertebrates. We also count the number of sea stars, whelks, and other herbivores.  Each spring, all plots are cleared and biomass collected (except controls). Biomass of functional groups is measured as wet and dry mass of mussels, barnacles, gooseneck barnacles, mobile predators, herbivores, and other.