Scope and Method of Study: Japanese mamushi (mamushi, hereafter) have been impacted from killing and hunting by humans, and many populations in many places appear to be declining or are already extirpated. The purpose of this study was to investigate the effects of mamushi hunting on key morphological, behavioral, life history, and reproductive traits in the affected (i.e., compromised) populations, and to test a hypothesis that the changes in trait states in compromised versus uncompromised populations would be the result of response to selection imposed by mamushi hunting. My study has taken advantage of the existence of several local populations of mamushi in Hokkaido, Japan, that have been experiencing (i) regular hunting (compromised) and (ii) little or no hunting (uncompromised). It can be seen as a 'natural experiment' where uncompromised populations serve as a 'before selection' condition and compromised populations as an 'after selection' condition. This setting provided me with an opportunity to explore how fundamental ecological and evolutionary processes work, while simultaneously obtaining basic ecological, behavioral, and evolutionary data important in conservation and management of this species.

Findings and Conclusions:

My study showed that hunting and killing have produced a strong phenotypic selection force that has generated population-wide changes in body size, antipredator behavior, microhabitat use, movements, and life history in the mamushi populations. These changes appear to be, in part, genetically based, and hence, evolutionary responses to intensive human predation pressures. An important conservation and management implication is that a genetic-based change can be slow or hard to reverse, even when selection forces caused by humans stop, and such a change in one trait will inevitably cause changes in other correlated traits, which can negatively affect fitness. Such a genetic-based change and potential correlated changes in fitness-associated traits can accelerate the process of population decline and increase the probability of local extirpation in harvested populations.