Ecological Archives M083-005-A4

Pamela L. Reynolds, John F. Bruno. 2013. Multiple predator species alter prey behavior, population growth, and a trophic cascade in a model estuarine food web. Ecological Monographs 83:119–132.

Appendix D. Macroalgal composition.

To graphically compare species composition between experimental communities in the community experiment, we generated a nonmetric multidimensional scaling analysis (NMS) on a distance matrix of Bray–Curtis similarities generated from macroalgal wet mass in PC-ORD (McCune and Grace 2002). A NMS step-down procedure was performed and the NMS scree plot and results of a Monte Carlo test were evaluated to select a 2D configuration for generation of the NMS ordination. A 2D NMS ordination was then performed with a maximum of 250 iterations, 20 real data runs, and 20 randomized data runs. The 2D NMS ordination plot was graphed with R statistical software v2.11.0 (R Foundation for Statistical Computing, Vienna, Austria).


FIG. D1. NMS plot of macroalgal community composition across predator and grazer treatments in the five-week community experiment. (r² NMS 1 = 0.85, NMS 2 = 0.14; stress level 3.24). Grazers were absent in light symbols, and present in dark symbols.


McCune, B., and J. B. Grace. 2002. Analysis of ecological communities. MjM Software, Glenenden Beach, Oregon, USA.

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