Fig. 1

Lugworm exclusion plots with ephemeral algal growth. In spring 2003, colonies of the tuft-forming diatom Berkeleya rutilans were growing on exclusion plots in the mid intertidal (a) and most colonies were attached to tubes of the spinoid polychaete Polydora cornuta (b). In summer 2004, green algal tufts were growing on lugworm exclusion plots in the low intertidal (c). Most algal strings were attached to sand-tubes of the polychaete Lanice conchilega (d). Broken lines indicate the edges of lugworm exclusion plots