Read this text.

In 1975, the grizzly bear was given federal protection as a threatened species; today it is estimated that there are still fewer than one thousand grizzlies in the lower forty-eight states.
Is this an appropriate use of an ellipsis?
"In 1975, the grizzly bear was . . . estimated that there are still fewer than one thousand grizzlies in the lower forty-eight states."

Yes, this is an appropriate use of an ellipsis. It accurately represents that there is missing information between "grizzly bear was" and "estimated that there are still fewer than one thousand grizzlies in the lower forty-eight states."