Some lower dunes support various grassland species.

Merychippus radiated into at least 19 additional grassland species.

Towards the end of the period, there is evidence for a fall in sea levels and an increase in grassland species.

Open grassland species have no where to hide from predators, so they tend to be fast runners.

Elsewhere, deeper limestone soils support a diversity of calcareous grassland species.

One familiar grassland species, the bobolink, has suffered a "catastrophic" decline of 90 percent in the Midwest, he said.

Pejman et al. (2009) found support for this idea in an experimental study on grassland species.

The Eastern meadowlark has decreased 9 percent annually over the last four decades, reflecting regional and national declines of grassland species.

Although some grassland species have increased in both range and numbers, they remain vulnerable to hunting with the use of dogs to flush them.

Abandoned burrows are sometimes taken over by other grassland species such as the burrowing owl.