I feel as though my first lesson in web food ecology was learning about the dynamics between the Sea Otter, Sea Urchin, and the Kelp Forest. When one is out of balance (i.e. population is up or down) then it affects all of the other species.  When Europeans settled along the West Coast of North America, they hunted Sea Otters for their pelts. The Sea Otters nearly went extinct. Environmental protection from the Endangered Species Act and the Marine Mammal Protection Act increased the Sea Otter population, but not everywhere.  The Sea Otters are not found off the coast of Northern California, just North of Monterey Bay where the Kelp Forests have decreased by 90% over the past decade. However, in Monterey Bay the Kelp Forests have only decreased by 60% (still not great, but significantly better than to the North). The reason? There is a presence of Sea Otters in Monterey Bay and they are keeping the Sea Urchin population in check. Link to Article: https://www.kpbs.org/news/2021/may/04/sea-otters-guardians-monterey-bays-kelp-forest/