In this webinar, Dr. Estes will summarize our current understanding of how large apex consumers influence the structure and function of ecosystems and I will argue that the global decline of these animals has been one of human-kind’s most pervasive influences on biodiversity. Following a brief introduction to the relevant concepts, the body of the presentation will be divided into two parts. The first of these is an overview of the work that my colleagues and I have done on sea otters and kelp forest ecosystems in the North Pacific Ocean over the past 40 years. I will explain the critical role that sea otters play in maintaining kelp forests and describe some of what we have learned about the follow-on influence of this so called “trophic cascade” on other species and ecosystem processes. The second part of the talk will look more broadly toward other species of apex consumers and the manners in which they influence their associated ecosystems. We will see from this that the sea otter’s keystone role in kelp forest ecosystems is not unique—similar top-down influences on plant assemblages and strong effects on associated landscapes occur from the tropics to the poles, on land, in lakes and streams, and in the oceans. I will conclude the webinar with a brief discussion of the implications of these findings for the management and conservation of natural resources.
