Effects of Apex Consumers Cascade Dynamically across Trophic Levels
نویسنده
چکیده
Simple ecosystems in the northern Pacific Ocean are particularly suitable to test the hypothesis. In 1970’s, communities at islands lacking sea otters were characterized by high density of sea urchins and a distinct lack of macrophytic vegetation.. In contrast, communities at islands with sea otters had relatively high kelp densities and low sea urchin biomass (Estes and Palsamino 1974). However, in 1990’s, sea otter populations declined unexpectedly over large areas and the increased killer whale predation was supposed to be the likely cause of these declines (Estes et al. 1998).
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