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Changing Seascapes Program

Program Leads
Margot Hessing-Lewis
Hakai Science
Erin Rechsteiner
Hakai Science
Program Summary

The Central Coast is rich with a mosaic of nearshore habitats including kelp forests and seagrass meadows. These ecosystems are among the most productive on our planet, providing a diversity of benefits that coastal communities have relied on economically, socially and culturally for millennia. Together, this abundance of plants and algae buffers the coastline from winter storms, draws-down atmospheric carbon, and provides habitat for diverse assemblages of organisms. Yet, these ecosystems are currently shifting rapidly, due to the recovery of predators (i.e. sea otters) and changing ocean climate (e.g., changes in temperature, salinity and pH).

Moreover, present-day human-induced changes occur within the backdrop of prehistoric and historic alterations. As a result, there is a need to advance our understanding of how humans alter and benefit from the productivity, biodiversity and resilience of kelp forest and seagrass ecosystems; to understand the natural history and ecosystems that govern nearshore ecosystems on the Central Coast; and to inform policies that support coastal communities.

Coastal change in this region is occurring, but the magnitude of change, and the relative weight of the different drivers of change (i.e. sea otter re-colonization, climatic forcing, human influence) has not been quantified. The Changing Seascapes Research Program will quantify this change on the Central Coast’s unique regional geography, assess ecological impacts, and place these findings in the context of global change to temperate coastlines. 

An explosion of kelp occurred four months after approximately 100 sea otters began rafting and foraging around Calvert Island.
Program Description

This Changing Seascapes Program aims to quantify the causes and consequences of change in British Columbia’s Central Coast nearshore ecosystems, focusing on kelp forests and seagrass habitats. Broadly, it aims to understand the local and regional factors driving future, contemporary, historic and prehistoric change in these coastal ecosystems and the ecological & socio-economic consequences of their dynamics.

The Changing Seascapes area of research interest spans the exposed, convoluted outer coast archipelagos of the Central Coast. This is an area rich in nearshore primary production, in the form of plankton communities, rocky-reef macroalgal forests, and soft substrate seagrass meadows. Together, this rich abundance of plants and algae buffers the coastline from winter storms, draws-down carbon from the atmosphere, and provides habitat for diverse communities of associated organisms. However, local, regional, and global drivers of change are leading to dramatic effects in both seagrass- and kelp-dominated ecosystems, thereby affecting their crucial processes.

Sea otters have been recolonizing this area since the late 1980s, but we still know little about their effects across the coastline, including protected bays and inlets, and seasonal changes in their distribution and foraging behavior. We know that otters can have dramatic, nonlinear effects in kelp forest systems, and can induce trophic cascades in some seagrass systems. The context specificity and indirect effects on both kelp and seagrass-associated communities needs further resolution.

Furthermore, as otter populations continue to expand and utilize the full range of potential habitats in this region, we’re interested in the predictive ability of habitat configuration, coupled with otter behavior, to inform our understanding of their distribution and population growth.

Simultaneous to the top-down effects of otter predation in the Changing Seascapes’ study region, bottom-up drivers of change are affecting the dynamics of macrophyte production. These include physical and chemical changes in the water column, such as temperature, salinity and pH effects. Additionally, increasing storm activity affects the severity of wind speed, wave action and light conditions, which also influence kelp and seagrass production, as well as disturbance dynamics.

Parsing apart, and quantifying the relative role of these drivers of change is necessary for predicting the future of the nearshore seascape, and the associated ecological functions. To inform our current understanding of these dynamics, we’ll also dig back in time to understand the historical baselines in habitats and community composition. By assembling an interdisciplinary group of researchers, including marine ecologists, archaeologists, oceanographers and geographers, this Hakai Program uses modeling, observational and experimental approaches to understand the spatial and temporal patterns and process along the Central Coast.

Forage fish find shelter in a seagrass meadow. Photo by Angeleen Olson.
Margot Hessing-Lewis, Hakai Science
Erin Rechsteiner, Hakai Science
Anne Salomon, Simon Fraser University
Trisalyn Nelson, University of Victoria
Linda Nichol, Department of Fisheries and Oceans Canada
Jane Watson, Vancouver Island University
Keith Holmes, Hakai Science
Luba Reshitnyk, Hakai Science
Zach Monteith, Hakai Science
Matthew Morgan Henderson, Hakai Science
Jenn Burt, Simon Fraser University
Kira Krumhansl, Hakai Postdoctoral Fellow
Angeleen Olson, Hakai Science
Carolyn Prentice, Simon Fraser University
Josh Silberg, Hakai Administration/Finance/Media
Kyle Glenn, Simon Fraser University
Leah Honka, Simon Fraser University
Tristan Blaine, Hakai Institute
Derek Van Maanen, Hakai Science