Humans, and the invasive species we bring with us, are frequently viewed as destroying ecosystems. But we alter them just as often, inadvertently picking winners and losers from among the species as we transform their environment. A paper out in today’s Nature describes a case where our actions made a butterfly species a winner, but then changed the game so fast that the local population went extinct.

All of this because one man died and his cattle ranch shut down.

The cast

This is a story with a lot of moving parts, so we’ll take some time to introduce them. The protagonist is Edith’s checkerspot butterfly, or Euphydryas editha. A native to the west coast of the United States, one of its populations lived on a site called Schneider’s Meadow, named after the rancher whose cattle grazed there. These and other populations of the butterfly lay eggs on a plant called Collinsia parviflora. That plant provides a good growth environment for the butterflies’ offspring, but the plant is a bit fickle, prone to sudden die-backs that lead to a reasonably high rate of caterpillar mortality.