Kelp Forest Community Monitoring

School of blue and olive rockfish in a forest of towering stalks of giant kelp
School of blue and olive rockfish in a giant kelp forest. Kelp forests provide structure, food, and hiding places for more than 1,000 species of plants and animals.

NPS / Yasmeen Smalley

Why We Care

The nearshore waters along the coastline southern California host one of the most productive marine ecosystems on earth, giant kelp forests (Macrocystis pyrifera). Like tropical rainforests, these towering seaweeds provide structure, food, and hiding places for more than 1,000 species of plants and animals, providing necessary habitat for species as diverse as giant black sea bass and tiny bluebanded gobies.

Kelp forests are influenced by both natural events and human activities. Strong storms associated with El Niño years and fluctuating water temperatures can cause dramatic changes in kelp forest communities. Human activities also affect the health and survival of kelp forests through coastal development, sedimentation, pollution, and, in particular, fishing. Removal of predators can alter predator-prey interactions. For example,with the elimination of sea otters, and the overharvesting of spiny lobster and California sheephead, herbivore populations like purple sea urchins can increase decimate kelp beds through overgrazing. These areas quickly transition into "barren" landscapes supporting relatively few species and lower biomass. Loss of kelp beds also eliminates nursery grounds for many species whose young live in the kelp until they are large enough to venture into open waters. Without shelter and food from the kelp forest, these populations may be dramatically reduced.

How We Monitor

The Kelp Forest Monitoring Program was established by Channel Islands National Park in 1982 to collect baseline information about the kelp forest ecosystem in the Park. Each year the program collects size and abundance data for 70 categories (taxa) of algae, invertebrates and fish that are indicators of ecosystem health. The current monitoring protocol was adopted in 1997.

Diver floating just above a rocky kelp forest floor, recording data with an underwater pad and pen.
Diver recording kelp forest community monitoring data.


Diver reaching in to an open wire-framed cube and pulling out halved cinder blocks as a garibaldi looks on
A diver checks an Artificial Recruitment Module (ARM) made of cinder blocks in a wire frame. ARMs mimic the inaccessible crevices where juvenile abalone typically hide, but can be disassembled so its inhabitants can be consistently counted each year.

NPS / Yasmeen Smalley

Our Goals

  • Determine the status and health of the islands' kelp forests
  • Document the types of changes occurring in the marine environment
  • Develop management strategies needed to protect the kelp forest ecosystem

Why It Matters for Park Managers

  • Park researchers have documented widespread and dramatic changes in the marine ecosystem around the Channel Islands since the program began, including declines in fished species like abalone and the loss of kelp beds around several of the islands.

  • Information from park monitoring was instrumental in establishing marine reserves, areas of the ocean granted complete protection from fishing and extractive activities, at the Channel Islands, placing nearly 20% of Park waters into state marine protected areas.
  • In 2008, a 5-year review of data collected by the Park and others demonstrated some positive trends in the new marine reserves including:
    • Greater overall biomass inside reserves
    • Larger average body size of some species like kelp bass and spiny lobster in unfinished reserves
    • Kelp beds around the Channel Islands have recently increased, after experiencing substantial declines in the 1980s and 1990s

For More Information

Download 1-2 page PDFs about the Mediterannean Coast Network's monitoring programs.

Source: Data Store Saved Search 3544. To search for additional information, visit the Data Store.

The Mediterranean Coast Network documents its findings in reports published in the NPS Natural Resource Publication Series.

Source: Data Store Saved Search 1508. To search for additional information, visit the Data Store.

Protocols describe in detail the procedures used to collect, manage, analyze and report monitoring data. They follow strict guidelines for content and format, and are reviewed and revised by subject-matter experts in each field.

Source: Data Store Saved Search 1520. To search for additional information, visit the Data Store.

Last updated: December 3, 2018