DOI: 10.5061/dryad.np274
title: Data from: Modeling effects of climate change and phase shifts on detrital production of a kelp bed

description: The exchange of energy and nutrients between ecosystems (i.e., resource
 subsidies) plays a central role in ecological dynamics over a range of
 spatial and temporal scales. Little attention has been paid to the role of
 anthropogenic impacts on natural systems in altering the magnitude,
 timing, and quality of resource subsidies. Kelp ecosystems are highly
 productive on a local scale and export over 80% of kelp primary production
 as detritus, subsidizing consumers across broad spatial scales. Here, we
 generate a model of detrital production from a kelp bed in Nova Scotia to
 hindcast trends in detrital production based on temperature and wave
 height recorded in the study region from 1976 to 2009, and to project
 changes in detrital production that may result from future climate change.
 Historical and projected increases in temperature and wave height led to
 higher rates of detrital production through increased blade breakage and
 kelp dislodgment from the substratum, but this reduced kelp biomass and
 led to a decline in detrital production in the long term. We also used the
 model to demonstrate that the phase shift from a highly productive kelp
 bed to a low-productivity barrens, driven by the grazing activity of sea
 urchins, reduces kelp detrital production by several orders of magnitude,
 an effect that would be exacerbated by projected increases in temperature
 and wave action. These results indicate that climate-mediated changes in
 ecological dynamics operating on local scales may alter the magnitude of
 resource subsidies to adjacent ecosystems, affecting ecological dynamics
 on regional scales.
description: Modeled Historical Kelp
 Data. A Canadian Healthy Oceans Network Ecosystem Function Project,
 EF-11Modeled mean and max
 yearly values of kelp biomass, production, blade erosion, dislodgement,
 mortality, and total detrital production based on recorded temperature
 (meanT, maxT) from 1976-2009. Also modeled were mean and max proportion of
 blade area grazed by Lacuna vincta (meanL, maxL), and blade coverage by
 Membranipora membranacea (meanM, maxM)Modeled_Historical.xlsxModeled Kelp Parameters with Simulated Destructive Grazing by Sea Urchins. A Canadian Healthy Oceans Network Ecosystem Function Project, EF-11Modeled mean, maximum, and minimum kelp biomass, production, kelp blade erosion, dislodgement, mortality, and total detrital production during the transition from a kelp bed to an urchin barren over 34 years. This transition is caused by the progression of a simulated sea urchin grazing front.UrchinFrontSimulation.xlsxModeled Future Kelp Parameters With Climate Change. A Canadian Healthy Oceans Network Ecosystem Function Project, EF-11Modeled relative change (%) in kelp biomass, production, erosion, dislodgement, and mortality with simulated increases in temperature and significant wave height that are expected to occur in the next 10, 20, and 30 years. Also shown are modeled changes in kelp blade grazing (as proportion of blade grazed) by Lacuna vincta, and kelp blade coverage by Membranipora membranacea. Data are from simulations where temp and SWH are increased independently, and in combination. Simulations were also run with and without a sea urchin grazing front.ClimateChangeSimulations.xlsx