Abstract Title

Session S-02E: Kelp Trends

Presenter/Author Information

Jane Watson, Vancouver Island UniversityFollow

Keywords

Habitat

Start Date

30-4-2014 1:30 PM

End Date

30-4-2014 3:00 PM

Description

The changes in kelp forest community structure, associated with the reintroduction and spread of sea otters along the west coast of Vancouver Island, was monitored from 1987-2013. Changes in kelp abundance and species composition were documented annually at 5 permanently- marked sites and intermittently at 40 randomly-selected sites located in areas occupied by sea otters. Although the presence of kelp was predictable, the species composition and abundance of algae was both spatially and temporally variable, largely reflecting successional changes following the removal of sea urchins by sea otters. Along with succession, water temperature, episodic algal recruitment and demographic processes all appeared to affect the relative abundance and species composition of kelp forests. In general, annual species such as Acid Weed (Desmarestia spp,) were highly variable in abundance, whereas the long-lived stalked kelps (Pterygophora californica and Laminaria setchellii), underwent a gradual decline and slow recovery over the 26 year period. The canopy forming Bull Kelp (Nereocystis luetkeanna) was generally associated with early successional stages or disturbance events and the Giant Kelp (Macrocystis pyrifera = integrifolia) was recruited in less exposed areas.

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Apr 30th, 1:30 PM Apr 30th, 3:00 PM

Spatial and temporal variation in kelp forest composition off the NW coast of Vancouver Island, British Columbia.

Room 613-614

The changes in kelp forest community structure, associated with the reintroduction and spread of sea otters along the west coast of Vancouver Island, was monitored from 1987-2013. Changes in kelp abundance and species composition were documented annually at 5 permanently- marked sites and intermittently at 40 randomly-selected sites located in areas occupied by sea otters. Although the presence of kelp was predictable, the species composition and abundance of algae was both spatially and temporally variable, largely reflecting successional changes following the removal of sea urchins by sea otters. Along with succession, water temperature, episodic algal recruitment and demographic processes all appeared to affect the relative abundance and species composition of kelp forests. In general, annual species such as Acid Weed (Desmarestia spp,) were highly variable in abundance, whereas the long-lived stalked kelps (Pterygophora californica and Laminaria setchellii), underwent a gradual decline and slow recovery over the 26 year period. The canopy forming Bull Kelp (Nereocystis luetkeanna) was generally associated with early successional stages or disturbance events and the Giant Kelp (Macrocystis pyrifera = integrifolia) was recruited in less exposed areas.