When The Nature Conservancy of California asked Silicon Valley venture capitalist Seth Neiman for a multimillion-dollar contribution to help protect local open space, no one involved had the slightest notion that they were about to step into one of the deepest and most difficult questions in conservation worldwide: how to develop ways of measuring whether their conservation efforts really are achieving their goals. The Conservancy’s fundraising team was just trying to raise enough money to buy conservation easements on Mount Hamilton, an island of natural habitat in an encroaching sea of suburbs south of San Jose.

Neiman asked how the Conservancy knew the investment would provide lasting protection for the oak woodlands and the creatures that live there. He wasn’t interested in preserving a piece of land for just 30 years. ‘That would be an act of vanity,’ he says. He wanted to know whether it would be protected for hundreds of years.