Cows create homes for tadpole shrimp

Endangered tadpole shrimp are flourishing this week in massive mud puddles on a flat-top foothill -- and they owe their good time to a bunch of grass-munching cows. Well-timed rain and a cool spring have set the stage for the shrimp to reproduce in abundance, but nothing much would have happened here without those visiting cows. Over several years, state officials have brought in the cows to clear out the grass that was stealing water from the huge temporary pools that form in winter and spring - vernal pools - where the shrimp live. Biologists say bovine intervention has actually nurtured a swath of nature on the Big Table Mountain Ecological Preserve northeast of Fresno where wildflowers, tadpole shrimp and many other creatures needed help. Though the effort won't get the shrimp off the endangered-species list, it is a step in the right direction, state biologists say. And it took courage. State officials got opposition from environmentalists who knew poorly timed grazing could lead to trampled pastures and streams. The table top had been privately owned in the past, and cattle had grazed on it for many years, officials said. Officials didn't realize the cows were thinning out the invasive grass that had been introduced by European settlers more than a century before. After acquiring the property, state officials tried to return it to a more natural state by removing cows in the early 1990s. But the elegant ecosystem was overrun with grasses that are not native to California...Fresno Bee