In this study, the researchers compared various locations to see the relationship between sea otters, invertebrate herbivores, and macroalgae populations. The idea was that in areas with sea otters, there wouldn’t be many herbivores, and thus an abundance of plants. In areas without sea otters, the population of herbivores would be higher, resulting in fewer plants. They selected 153 random sites in the Aleutian Islands and southeast Alaska. For the most part, these sites followed the predicted paradigm, with one exception being Torch Bay. This was because there were disturbances in the sea urchin population, causing the kelp abundance to vary significantly. When sea otters spread into previously unoccupied locations, sea urchin population plummeted by as much as 100%. Due to this, increases in kelp populations were abrupt and highly significant. This study demonstrated that sea otter predation has a predictable and broadly generalizable influence over the structure of Alaskan kelp forests.
Source:
Estes, J. A., & Duggins, D. O. (1995). Sea Otters and Kelp Forests in Alaska: Generality and Variation in a Community Ecological Paradigm. Ecological Monographs, 65, 75-100.
