Data from: Modeling effects of climate change and phase shifts on detrital production of a kelp bed

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

Modeled Kelp Parameters with Simulated Destructive Grazing by Sea Urchins. A Canadian Healthy Oceans Network Ecosystem Function Project, EF-11

Modeled 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

Modeled Future Kelp Parameters With Climate Change. A Canadian Healthy Oceans Network Ecosystem Function Project, EF-11

Modeled 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

Appendix F. Fit of the Gaussian distribution to daily displacement distance measured for Strongylocentrotus droebachiensis.

Fit of the Gaussian distribution to daily displacement distance measured for Strongylocentrotus droebachiensis

Appendix B. Details of the von Mises distribution of turning angles for Oreaster reticulatus.

Details of the von Mises distribution of turning angles for Oreaster reticulatus

Appendix E. Details of the procedures used in uncertainty and elasticity analyses.

Details of the procedures used in uncertainty and elasticity analyses

Modeled Historical Kelp Data. A Canadian Healthy Oceans Network Ecosystem Function Project, EF-11

Modeled 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

Appendix C. Initial conditions of Model 1 (for Oreaster reticulatus) and Model 2 (for Strongylocentrotus droebachiensis).

Initial conditions of Model 1 (for Oreaster reticulatus) and Model 2 (for Strongylocentrotus droebachiensis)

Appendix A. Detailed description of modeling methods and parameters.

Detailed description of modeling methods and parameters