Erratum to: Oecologia (2007) 154:219–226 DOI 10.1007/s00442-007-0811-2

The third to last sentence of the ‘Methods’ subsection entitled ‘Experiment 4: Isolating the chemical mechanism’ should read: ‘No aquatic trophic structure was established and colonists were removed every 3–6 days (mean = 4.3)’. The last sentence of this paragraph should read: ‘The experiment ran from 30 June to 17 July 2006’.