Methodology\u00a0from\u00a0Gambrel, B.\u00a0and\u00a0Lasker, H.R., 2016
\n
To further examine the spatial distribution of colonies and potential competition among them,\u00a0nearest neighbor data\u00a0were collected along the belt\u00a0transects from\u00a0each site. Each transect had 20 sampling\u00a0points arranged\u00a0at the corners of every 1 m2 quadrat\u00a0along the\u00a0first 9 m of each transect. The octocoral\u00a0colony closest\u00a0to each sampling point was selected, identified,and the distance between its base and the\u00a0base of\u00a0its nearest branching octocoral neighbor\u00a0was measured\u00a0to the nearest centimeter (Fig. S1\u00a0in the\u00a0Supplement). The height, width, and length\u00a0of each\u00a0colony was measured to the nearest\u00a0centimeter to\u00a0calculate\u00a0cross-sectional\u00a0area (height \u00d7 length)\u00a0and volume\u00a0(height \u00d7 width \u00d7 length), and the\u00a0proximity of\u00a0the colony\u2019s branches to nearby octocorals\u00a0was also\u00a0noted. Due to the water flow and the\u00a0resulting oscillation\u00a0of colony branches, measurements\u00a0were made\u00a0when the branches were vertical in the\u00a0water column\u00a0to optimize the precision of our measurements.To increase sample sizes, an additional 9\u00a0m transect\u00a0parallel to the other 5 was sampled at\u00a0each site.
\n
The nature of the spatial distribution of\u00a0octocorals at\u00a0each site was determined from the nearest-neighbor data\u00a0following Clark & Evans (1954).\u00a0Observed and\u00a0expected mean distances between the\u00a0octocoral neighbors\u00a0were calculated using the total\u00a0distance between\u00a0neighbors, sample size (120 pairs of\u00a0octocorals per\u00a0site) and the density of octocorals at each site(calculated from the belt transect data). The ratio (R)of the observed and expected (given a randomly\u00a0distributed octocoral\u00a0community) mean distances between octocoral neighbors describes the\u00a0octocoral distribution\u00a0at each site, where R = 1 denotes a\u00a0random distribution, R < 1, an aggregated distribution,and R > 1, a uniform distribution (Clark & Evans1954). The significance of R was determined by\u00a0analyzing the\u00a0standard variate of the normal curve (c), since the measured distances between neighbors in\u00a0a randomly\u00a0dispersed community are expected to\u00a0follow a\u00a0normal distribution.
\n
The effects of colony\u2212colony proximity on colony size were assessed by correlating the distance\u00a0between\u00a0neighbors at the base with the sum of\u00a0their sizes\u00a0(Pielou 1962). If competition affects growth, then the closer\u00a0the organisms\u00a0are, the smaller their expected sizes will be (Pielou 1962). Implicit in these analyses is the notion that size is both an indicator of resource use and of success in acquiring resources.
\n
The relationships among the distance between octocoral neighbors at the base (divided into 3 distance groups to make the data categorical: 5\u221214 cm, 15\u221224\u00a0cm\u00a0and 25\u221234 cm), branch proximity and site were analyzed using a hierarchical log-linear test in SPSS. The relationship between the distance between neighbors and branch proximity was further analyzed in a separate log-linear test in SPSS.
Data supporting Gambrel, B. and Lasker, H.R., 2016
BCO-DMO Data Processing Notes:
\n
- filled blank cells with \"nd\"
\n- replaced spaces with underscores
\n- replaced species codes with full names
\n- added latitudes and\u00a0longitudes to data