Editing Population viability analysis (section)

==History==
{{Unreferenced section|date=April 2016}}
In the 1970s, [[Yellowstone National Park]] was the centre of a heated debate over different proposals to manage the park’s problem [[grizzly bears]] (''Ursus arctos'').  In 1978, Mark Shaffer proposed a model for the grizzlies that incorporated random variability, and calculated extinction probabilities and [[minimum viable population]] size.<ref name=":0" /> The first PVA is credited to Shaffer.<ref name=":0">{{Cite journal |last=Shaffer |first=Mark L. |date=1983 |title=Determining Minimum Viable Population Sizes for the Grizzly Bear |url=https://www.bearbiology.org/wp-content/uploads/2017/10/Shaffer_Vol_5.pdf |journal=Bears: Their Biology and Management |volume=5 |pages=133–139 |doi=10.2307/3872530 |jstor=3872530 |issn=1936-0614}}</ref>

PVA gained popularity in the United States as federal agencies and ecologists required methods to evaluate the risk of extinction and possible outcomes of management decisions, particularly in accordance with the [[Endangered Species Act]] of 1973, and the [[National Forest Management Act]] of 1976.

In 1986, Gilpin and Soulé broadened the PVA definition to include the interactive forces that affect the viability of a population, including genetics.
The use of PVA increased dramatically in the late 1980s and early 1990s following advances in personal computers and software packages.