Aug 7, 2017, NEW HAVEN — Atop a granite cliff in Siberia this past winter, I stood gazing at what became, 100 years ago, the first in the world’s largest system of most protected nature reserves. To my west glistened mile-deep Lake Baikal. To the east rose snowy mountains, including one that reminded me of sharp-cut Half Dome, an icon of America’s Yosemite National Park. I was looking across Barguzinsky Zapovednik, a conservation area protecting more than 600,000 acres so free from human impact that visitors may not enter.