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Data from: The dynamics of Kelp Forests in the Northeast Pacific Ocean and the relationship with environmental drivers

Cite this dataset

Pfister, Catherine A.; Berry, Helen D.; Mumford, Thomas (2018). Data from: The dynamics of Kelp Forests in the Northeast Pacific Ocean and the relationship with environmental drivers [Dataset]. Dryad.


1.The dynamics of foundation species in ecosystems are key to the fate of many species. Kelp forests are foundation species in temperate ocean ecosystems and contribute to carbon storage, macronutrient dynamics, primary production, and biodiversity of myriad associated species. Downward trends in their abundance globally have been of concern. 2.We analyzed 26 years of aerial censuses (1989-2015) of 2 canopy kelp species in Washington State (USA) waters. We compared these modern censuses with censuses in 1911 and 1912 to determine the persistence of kelp cover over the past century. Using Auto-regressive Integrated Moving Average (ARIMA) models, we compared kelp dynamics with likely environmental drivers, including local environmental variables and ocean indices for this region. 3.Kelp remains at historic levels in many areas, though some eastern populations in proximity to greater human populations are the exception to this pattern. Over the last 26 years, kelp abundance showed high spatial autocorrelation in western areas of Straits of Juan de Fuca, with more variable populations in the annual species and eastward toward Puget Sound. Both species covaried positively in their abundance throughout most of the study area, suggesting environmental factors rather than competition, drove their dynamics. The population dynamics of these kelp species showed that the abundance one year previous was an important predictor, and cyclic dynamics were not indicated using Auto-regressive Integrated Moving Average (ARIMA) models. Kelp abundance correlated inversely with the Pacific Decadal Oscillation and the Oceanic Nino Index, and positively with the North Pacific Gyre Oscillation, indicating that large-scale processes associated with colder seawater temperatures were associated with greater relative abundance of kelp. 4.Synthesis. Kelp beds in the northern California Current Large Marine Ecosystem have mostly remained persistent over the past century and over many km, but some areas may have decreased in abundance. The sensitivity of these populations to indices of ocean climate, our demonstration that a historic 93-year SST record (Race Rocks, Canada) showed a 0.72°C increase, and the classification of some areas as high variability-low abundance, suggest that the viability of these foundational species remain a concern into the future.

Usage notes


Washington State
outer coast of Washington State
northeast Pacific
Strait of Juan de Fuca
Tatoosh Island
Pacific Northwest