DOI: 10.5061/dryad.ghx3ffbxv
title: Data from: Invertebrate community composition in a New England fouling community

description: Fouling communities are tractable ecological systems that form on manmade
 structures added to the marine environment. Their proximity to the water’s
 surface allows hypotheses about community assembly, disturbance, and
 invasion biology to be tested and these communities have become model
 systems in the marine realm. Much of this work has focused on sessile
 invertebrates but, on hard substrates in the marine environment,
 invertebrates and macroalgae, organisms from two different kingdoms, can
 compete for the same limiting resource, space. On rocky reefs, macroalgae
 and invertebrates are partitioned between horizontal and vertical walls
 respectively, but invertebrates are able to persist on horizontal surfaces
 if algae are excluded by shading, suggesting that algae presence may
 exclude invertebrates or impact invertebrate post-settlement mortality. I
 conducted four manipulative experiments on floating docks to test if algae
 also excluded invertebrates in fouling communities, including potential
 mechanisms for this by using mimicked (putative plastic) and modified
 (distal thalli removed) algae. In three out for four experiments,
 macroalgae did not exclude invertebrates but did alter invertebrate
 community composition, communities with algae tending to have more native
 species whereas communities without algae were dominated by invasive ones.
 In one experiment, macroalgae also appeared to facilitate invertebrate
 settlement in the early stages of community assembly, mediated by both
 algae structure and natural chemical cues. If macroalgae can confer
 invasion resistance i.e., its presence in a community can shift
 assemblages towards those composed of more native versus invasive species,
 then managing floating docks to enhance algae persistence can help prevent
 species invasions. Recommendations include constructing docks out of
 materials that allow sufficient light for photosynthesis, orienting docks
 towards the sun, and adding surfaces and structures that can enhance algae
 growth and persistence. Marinas should also be managed to reduce sediment
 and pollutants, factors that negatively impact algae survival.
 Furthermore, to advance the field of invasion biology, more studies should
 investigate facilitation, indirect effects, and interactions between
 organisms from different taxonomic groups.
description: I conducted four experiments in a New England fouling communities
 to investigate if macroalgae exclude sessile invertebrates on the shallow
 sunlit sides of floating docks, as well as potential mechanisms for this.
 The experiments were carried out at a depth of 1m on polycarbonate
 settlement plates suspended vertically off floating docks at Dorchester
 Yacht Club, Boston, Massachusetts, (42.305556°N, 71.046111°W). The fouling
 community was composed of sessile algae and invertebrates typical of this
 region, including red and green algae, sponges, bryozoans, polychaetes,
 molluscs, barnacles, and colonial and solitary ascidians.
 At the end of the experiments, settlement plates were collected,
 all algae and arborescent invertebrates trimmed to enable primary space
 occupiers to be identified, and communities photographed using an Olympus
 Stylus Tough 8010 camera. Digital photographs were later enlarged on a
 screen and percent cover and species richness of space occupying sessile
 invertebrates quantified using 200 random points overlaid on the central
 12x12 cm area of a settlement plate to avoid edge effects.
description: # Data from: Invertebrate community composition in a New England fouling
 community
 [https://doi.org/10.5061/dryad.ghx3ffbxv](https://doi.org/10.5061/dryad.ghx3ffbxv) The data represent the percent cover of sessile invertebrates in a New England Fouling Community for four different experiments. At the end of the experiment settlement plates were collected, all algae and arborescent invertebrates trimmed to enable primary space occupiers to be identified, and communities photographed using an Olympus Stylus Tough 8010 camera. Digital photographs were later enlarged on a screen and percent cover and species richness of space occupying sessile invertebrates quantified using 200 random points overlaid on the central 12x12 cm area of a settlement plate to avoid edge effects. ## Description of the data and file structure The data are arranged in columns. The first column gives the name of the experiment, the second column the name of the treatment within the experiment, and the third column lists the replicate number for each treatment. All remaining column headers are species of sessile invertebrates present in the fouling community. The numbers within the tables represent how many times that particular species for that particular experiment, treatment and replicate were found under one of the two hundred dots that overlaid photos of the community (NB. As two hundred dots were used, to get percent cover the number must be divided by 2). In the table 'x' represents that a species was found within the community but was either rare (i.e. did not fall under a dot) or that it was not occupying primary space (i.e. was found on another species). 'Null' means that a species was not found under a dot for a particular replicate or anywhere else in the plate/ community. This data can be used by other researchers wishing to compare community structure between fouling communities in different locations or just to get a simple species presence-absence list.