Mr David Aguirre1, Mr Beau Masters1, Miss Ella Lis1, Mr Hochang Yoo1
1Massey University, Albany, New Zealand
Kelp forests dominate temperate coasts globally, acting as ecosystem engineers that promote high biodiversity and contribute substantial biomass to fuel coastal systems. Despite a global increase in commercial kelp aquaculture, wild kelp forests are currently declining at an alarming rate. Kelp forest canopies reduce solar insolation, wave action, sedimentation, competition from other macroalgae and herbivory from grazers. These ecosystems engineered by adult kelp populations then facilitate the establishment and growth of conspecific kelp recruits forming a nursery for developing sporophytes. Negative feedbacks created in the absence of adult populations are a major hinderance to passive restoration efforts in highly degraded reefs with extensive kelp forest loss. Active kelp reforestation and afforestation programmes have focused on re-introducing kelp back into systems without the presence of adult populations, however the proximity to existing wild kelp forests has been identified as one of the key drivers of survival of new recruits. While kelp reforestation and afforestation have been given little attention in New Zealand, kelp forests dominated by Ecklonia radiata are in decline, following the global trend. Here, we have examined the survivorship and growth rate of Ecklonia radiata seedlings attached to culture ropes placed inside and outside of an existing Ecklonia radiata forest as well as an adjacent sand flat to quantify the strength of the nursery effect of adult kelp populations on kelp grown on artificial substrates. Understanding the spatial extent of the nursery effect will be critical for both future kelp reforestation, afforestation, and commercial kelp cultivation in New Zealand.
Presentation Slides – David Aguirre
