HELENA, Mont. — Scientists searching for Yellowstone National Park's lesser-known life forms — beyond its famed bison, bears and wolves — found more than 1,200 species, including several never known before to exist in the park.

A one-day study of the park in late August found microscopic worms, mushrooms, a bluish-green lichen, a slender grass and a colorful tiger beetle, among other creatures, in about two square miles of Yellowstone, according to initial results released this week.

Some 125 scientists and volunteers spent 24 hours canvassing an area in northern Yellowstone during the "bioblitz" — a scientific mad dash to document as many species as possible over the course of a day.

The park's wolves, bears, bison and elk are a popular topic for study but rarely do scientists turn their attention to insects and other smaller creatures that provide the ecological building blocks for those larger mammals to survive, said Kayhan Ostovar, an assistant professor of environmental science at Rocky Mountain College in Billings, Mont.

"There are a lot of them, and we don't even know which ones are there," said Ostovar, who helped organize the one-day study in Yellowstone.

Ann Rodman, a Yellowstone scientist who helped organize the event, said the study "lets people see the value of Yellowstone is not just the big mammals we preserve that people drive down the road and see. There's a whole lot more here."

And while the worms, mushrooms and beetles may not inspire cuddly plush toys for sale at America's first national park, they do add to the scientific knowledge that has favored Yellowstone's charismatic mammals and breathtaking network of geysers and hot springs.

It could be months or longer before the inventory is finished. But the initial report showed a rich biodiversity including 46 kinds of bees, 373 plant species, 86 mushroom types, five kinds of bats, 24 butterflies and more 300 kinds of insects.

The finished list won't provide a complete picture of what's living in the park. The inventory only notes species found on that particular day and in an area that is just a fraction of the park's 3,400 square miles.

But it provides enough for comparative use in the face of climate change and other stressors that can sometimes cause rapid changes and declines, Rodman said.