ECOLOGY Correction for “Recovery of a top predator mediates negative eutrophic effects on seagrass,” by Brent B. Hughes, Ron Eby, Eric Van Dyke, M. Tim Tinker, Corina I. Marks, Kenneth S. Johnson, and Kerstin Wasson, which appeared in issue 38, September 17, 2013, of Proc Natl Acad Sci USA (110:15313–15318; first published August 27, 2013; 10.1073/pnas.1302805110).
The authors note that Fig. 2 appeared incorrectly. The authors note that they “unintentionally labeled Fig. 2C ‘Grazer biomass (g DW) *shoot (cm)−1’ instead of ‘Grazer biomass (mg DW) *shoot (cm)−1.’ ” The corrected figure and its legend appear below. This error does not affect the conclusions of the article.
Fig. 2.
(A) Interaction web of top-down and bottom-up effects in the eelgrass study system. The top predator is the sea otter (E. lutris), the mesopredators are crabs (Cancer spp. and Pugettia producta), the epiphyte mesograzers are primarily an isopod (I. resecata) and a sea slug (P. taylori), and algal epiphyte competitors of eelgrass primarily consist of chain-forming diatoms, and the red alga Smithora naiadum. Solid arrows indicate direct effects, dashed arrows indicate indirect effects, and the plus and minus symbols indicate positive and/or negative effects on trophic guilds and eelgrass condition. C, competitive interaction; T, trophic interaction. (Original artwork by A. C. Hughes.) (B–E) Survey results testing for the effects of sea otter density on eelgrass bed community properties (Tables S2 and S3). Elkhorn Slough (sea otters present and high nutrients) eelgrass beds (n = 4) are coded in red, and the Tomales Bay reference site (no sea otters, low nutrients) beds (n = 4) are coded in blue. (B) Crab biomass and size structure of two species of Cancer crabs; (C) grazer biomass per shoot and large grazer density; (D) algal epiphyte loading; and (E) aboveground and belowground eelgrass biomass. DW, dry weight; FW, fresh weight.