Drones, Planes, and Satellites: A Guide to Mapping Kelp from Sky and Space

A new first-of-its-kind guidebook aims to make kelp mapping and monitoring more accessible.

Fall stormed into coastal British Columbia right on time, and now our wave-battered beaches are strewn with tangles of seaweed—hints of the lush underwater forests that lie just offshore. As the main players in the kelp beds and forests found along coastlines of the northeast Pacific, bull kelp and giant kelp often dominate these wrack piles. Before their ephemeral appearance on beaches, the forests they form play a foundational role in coastal marine ecosystems by providing food and shelter for countless fish and invertebrates; these ecosystems in turn have both economic value for coastal communities and cultural importance for First Nations.

The two large and charismatic kelp species are naturally dynamic, changing in distribution and extent year to year thanks in part to their different cycles of growth and death: bull kelp grows fresh from spores each year, while giant kelp is a perennial that lives for a few years. But they’re also threatened by stressors like warming waters from climate change and voracious grazing by unchecked sea urchins, so regular mapping is essential to understanding what change is normal and what isn’t. Key to our ability to monitor these habitats are their lush canopies that reach to the surface, where they float on a low tide and can be readily identified and mapped from above by our geospatial scientists.

First photo: just offshore from Quadra Island, British Columbia, bull kelp reaches to the surface where it can be mapped from above by drone, satellite, or aircraft (such as the Airborne Coastal Observatory). Photo by Grant Callegari. Second photo: Luba Reshitnyk uses a drone to map kelp on the Central Coast of British Columbia. Photo by Keith Holmes.

The Hakai Institute has been mapping these surface canopy-forming kelps on the Central Coast of British Columbia for about a decade to track how they change between seasons and years. During this time, the tools available for this work have progressed in leaps and bounds: drones, different satellites, and even planes can now be used in mapping habitats like kelp beds. We’re also far from the only ones keeping spatial track of these foundational marine species. There’s been a spike in interest in kelp monitoring in recent years, with groups from government and university scientists to community and nonprofit conservation organizations also monitoring kelp on their respective coastlines throughout the Pacific Northwest. While the rise of the different technological options can make for easier and more efficient work—not to mention better results—it also creates a boatload of questions about how and when to apply different tools and methods.

But now there’s a new guidebook to help navigate this complex kelp-mapping world! The Hakai Institute and the Nature Conservancy in California (TNC CA) have launched a practical, first-of-its-kind guide to help anyone who is involved in mapping, monitoring, or managing kelp to understand this modern field and make decisions about which tools are best suited for their region. 

Co-created by Luba Reshitnyk, lead kelp mapper with the Hakai Institute, along with Vienna Saccomanno of TNC CA, Kyle Cavanaugh from the University of California Los Angeles, and Tom Bell from Woods Hole Oceanographic Institution, the guidebook brings together the knowledge of nearly 50 global experts and uses visual examples and infographics to share their expertise in a digestible, user-friendly format. Alongside guidance for when and how to apply drones, satellites, and planes for different resource management and scientific needs, this kelp-mappers guidebook also features an up-to-date collection of relevant resources, existing datasets, and knowledge on the topic. 

“So many incredibly dedicated and passionate people worked on this project,” says Reshitnyk. “It’s my hope that it can become a resource to other organizations, groups, and individuals mapping kelp beds.” 

The idea for the guidebook came from the Kelp Mappers Community of Practice, a group of technical experts and managers from throughout the northeast Pacific that originated in a workshop held by TNC CA in 2019. Together they recognized that expertise in the field of kelp mapping is rare and that making the group’s collective knowledge more widely available to others, like nonacademic organizations and new researchers, would benefit all—helping to inform kelp forest management, restoration, and conservation.

And that’s important because the loss of kelp would have a devastating impact on the ecosystems that support coastal economies and cultures. Knowing if, when, and where kelp decline is happening is an essential step to keeping these vital species around and thriving on our coasts for years to come.

…

Mapping Canopy-Forming Kelps in the Northeast Pacific: A Guidebook for Decision-Makers and Practitioners is available in both English and Spanish.