Meeting Abstract

107.1  Sunday, Jan. 6  Assembly and Anthropogenic Alterations in Kelp Forest Ecosystems: Historical Perspectives from Deep Time LINDBERG, D.R.*; ERLANDSON, J.M.; GRAHAM, M.; BYRNES, J.; Univ. of California, Berkeley; University of Oregon; Moss Landing Marine Laboratories; University of Massachusetts, Boston drl@berkeley.edu

We examine the assembly and anthropogenic alterations in 20 kelp forest ecosystems – comprised of 15 kelps, and 18 key predators and 22 key herbivores. Our analyses found age and assembly differences between kelp forests in the northern and southern hemispheres. In the northern hemisphere predators are oldest in the lower latitudes. Herbivores are the youngest lineages typically originating after the kelp in the northern hemisphere. The sea otter is the youngest component in North Pacific kelp forests. In the southern hemisphere most herbivores and predators are substantially older than the kelp; the herbivores are the oldest lineages and have low latitude ancestry. Kelp forests in the North Atlantic show patterns similar to the North Pacific; most likely due to the role of recent migration of numerous kelp forest taxa from the North Pacific into the Atlantic. In addition to assembly differences, humans have differentially affected kelp forests. Some of the earliest evidence for intensive marine harvesting by humans is in kelp forest ecosystems, and human impacts on shellfish, apex predators, and other marine fauna affects trophic cascades as well as size class structure of key interacting taxa. These data and analyses from paleontological, geological, archaeological, and historical sources all demonstrate that coastal ecosystems are highly dynamic, and understanding the modern structure of these ecosystems requires deep paleontological and biogeographic perspectives that shed light on their assembly, as well as the long human history of interference and alteration of these systems.