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Burek KE, O’Brien JM, Scheibling RE
Wasted effort: recruitment and persistence of kelp on algal turf
Shifts from kelp-dominated communities to turf-algal assemblages are occurring worldwide. Once established, various feedback mechanisms stabilize the turf-algal state by physically inhibiting the settlement and recruitment of kelp. With reduced availability of open rocky substrate, kelps recruit on turf algae. Burek and colleagues examined the extent of recruitment and survival of turf-attached kelp (Saccharina latissimi) in Nova Scotia. Field observations and a manipulative experiment showed that turf-attached kelp generally are smaller, and have a different holdfast (anchoring structure) morphology and lower attachment strength than their rock-attached counterparts. Weak attachment leads to increased dislodgement by waves, removing turf-attached kelp from the population before they are reproductive and reinforcing the turf-algal state.