California’s kelp forests struggle to recover a decade after collapse

Mongabay
Mongabay
3M ago
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A decade after the collapse of Northern California's kelp forests due to high ocean temperatures, recovery remains limited, with invasive purple urchins exacerbating the issue.
California’s kelp forests struggle to recover a decade after collapse
A What happened
More than ten years after the collapse of Northern California's kelp forests, recovery efforts are still struggling against the overwhelming presence of purple urchins. The collapse was triggered by unusually high water temperatures from 2013 to 2017, which led to the death of approximately 95% of the region's bull kelp. The sunflower sea star, a key predator of urchins, has seen a drastic population decline due to disease, allowing urchin numbers to soar by an estimated 10,000%. Efforts to remove these urchins have been labor-intensive, with divers clearing over 150,000 from a small area, yet vast stretches of coastline remain impacted. Experts express concern over the long-term viability of kelp forests, emphasizing the need for continued focus on recovery.
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Key insights

  • 1

    Kelp Forest Collapse: High ocean temperatures led to a significant decline in kelp forests.

  • 2

    Urchin Population Explosion: Purple urchins surged due to the loss of their predator, the sunflower sea star.

  • 3

    Recovery Efforts: Divers are actively working to remove urchins to aid kelp recovery.

  • 4

    Long-term Concerns: Experts worry about the future of kelp forests amid ongoing challenges.

Takeaways

The kelp crisis in Northern California highlights the complex interplay between climate change and marine ecosystems.

Topics

Climate & Environment Climate Change Conservation