A 1959-1970 bear study suggested a grizzly bear population size of about 176, later revised to about 229. Later estimates have ranged as low as 136 and as high as 540; the most recent is a minimum estimate of 236, but biologists think there may be as many as 1,000 bears in the ecosystem. Although the Greater Yellowstone population is relatively close to recovery goals, the plan's definition of recovery is controversial. Thus, even though the population may be stable or possibly increasing in the short term, in the longer term, continued habitat loss, climate change, and increasing human activities may well reverse the trend.