SACRAMENTO (CBS13) – A redevelopment project two decades in the making has come to a sudden halt.

For the time being, the Sacramento County Board of Supervisors has scrapped plans to revitalize the former Mather air Force Base. It has a lot to do with a couple of rare species that call the area home and this grassroots organization says they were here first.

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“This is definitely within the development zone,” said Emily Butler.

Butler is with Sacramento Splash, an education and preservation non-profit specializing in what are called vernal pools: areas of seasonal wetlands in Mather, which are home to a number of species, including the Western Spadefoot, which is close to being endangered and the officially endangered fairy and tadpole shrimp.

“It would absolutely break my heart that once upon a time we had these toads at Mather, but we destroyed the last of their habitat,” said Butler.

The county has planned to develop at the location for a long time, allowing the building of homes and more. But within a multi-acre area where vernal pools would be preserved there’s a problem.

“It’s the only vernal pool here at Mather that supports Western Spadefoot Toads, and this is an area slated for development,” said Butler.

The spadefoot and the shrimp have picked two pools inside the development to live. Lu-Anne Spencer-Hartle, an expert with Splash, says the creatures haven’t been seen anywhere else in the area.

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“I don’t know why they are picky; they choose that one pool and they don’t like any place else,” said Spencer-Hartle.

Splash and its supporters went to work, working hard to save the critters and they have for now.

Supervisors Don Notolli with the board agreed to re-evaluate the plans, despite the OK from county planners.

“Really examine where we think we would want to land because once we do permit certain things, it would mean either we are going to preserve them or not,” said Notolli.

Splash said it is not done until its members know these animals’ homes are safe.

“We want these two very special vernal pools that are irreplaceable and unique to be preserved,” said Butler.

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Splash said it also wants to be guaranteed not only the vernal pool preservation is in place, but funding to keep them up, which includes weed abatement and proper signage to keep people clear of the land.