Evolutionary history of Pacific salmon in dynamic environments

摘要: Contemporary evolution of Pacific salmon (Oncorhynchus spp.) is best viewed in the context evolutionary history species and dynamic ecosystems they inhabit. Speciation was complete by late Miocene, leaving c. six million years for intraspecific diversification. Following most recent glacial maximum, large areas became available recolonization. Current diversity thus product overlaid onto divergent historical lineages forged during recurrent episodes Pleistocene glaciation. In northwestern North America, dominant habitat features have been relatively stable past 5000 years, but remain because disturbance regimes (volcanic eruptions, landslides, wildfires, floods, variations marine freshwater productivity) that occur on a variety temporal spatial scales. These disturbances both create selective pressures adaptive responses inhibit long-term divergence periodically extirpating local populations creating episodic dispersal events erode emerging differences. Recent anthropogenic changes are replicated pervasively across landscape interrupt processes allow natural recovery. If can be shaped to produce more closely mimic (in space time) those under which evolved, should well-equipped deal with future challenges, just as throughout their history.