Nature and Nurture: Local Adaptation, Life History Diversity, and Salmonid Conservation

Because of strong homing instincts and fine-scale site fidelity for spawning, salmonid populations often become more or less reproductively isolated, leading to adaptations to local environmental conditions.  The diversity of life-history forms arising from this local adaptation has recently been cited as having a “portfolio effect”, dampening the variance in ecosystem services provided by salmon populations (Schindler et al. 2010).  An implicit understanding of local adaptation has a long history in salmonid research, management, and conservation; e.g., Ricker’s concept of salmon stocks and the concept of Evolutionarily Significant Units (ESU’s).  Direct experimental evidence for local adaption, however, is difficult to obtain, and recently plasticity of life-history strategies in salmonids (e.g. partial migration) has led to discussions as to the relative roles of nature vs. nurture.  Waples et al. (2008) noted that a review of local adaption is overdue.  Although evidence for local adaptation is incomplete, what is clear is that salmonid conservation will need to continue to forward without perfect knowledge. According to renowned ecologist John Wiens, the levels of uncertainty commonly applied to peer-reviewed scientific research may preclude effective conservation; he suggests conservationists may need to settle for evidence that is “good enough” while avoiding levels of uncertainty that might lead to “doing something stupid” (Wiens 2008).  In this session I wish to further the dialogue on how research on local adaption and life history ecology may play a role in conservation of salmonid populations.  How much evidence is needed before a population can be considered unique for conservation purposes?  What are the best experimental approaches to identify the existence of local adaptation, or the lack thereof?  How will current and future advances in genetics and population biology shape salmonid research and conservation?  My goal is to provide an international perspective on these questions.