Acknowledging Long-Term Ecological Change: The Problem of Shifting Baselines

Our relationship with marine systems has deep historical roots. People have lived adjacent to coasts and oceans for millennia, relying upon their resources for food and other goods and services (Rick and Erlandson 2008 ). Due to this long history, most systems today have been signifi cantly altered by people (Jackson et al. 2001 ; Lotze et al. 2006 ; Myers and Worm 2003 ). Even degradation that appears recent often has its beginnings not decades, but centuries in the past, with human use impacting natural systems over signifi cantly longer time periods than currently acknowledged or accounted for by science or management (Jackson et al. 2001 ; Pandolfi et al. 2003 ). This lack of awareness has considerable implications for the future of our oceans. For example, if system health is a goal for the future, appreciation of conditions prior to intense anthropogenic pressures can offer unique insight into healthier ecosystem structure, function, and dynamics. This is signifi cant for appreciating our marine resources and managing them more successfully (also see Steneck and Carlton 2001 ; Smith and Link 2005 ; Jackson et al. 2011 ). This chapter introduces the shifting baselines syndrome, a foundational concept for understanding our troubling ignorance of the past, especially in the marine realm. First, we need to defi ne what a baseline is. A baseline describes a reference or starting point used to evaluate change or difference. In ecological studies, this