The Sierra Club's Endangered Species/Wildlife Task Force (ESTF) and the Santa Monica Mountains Task Force (SMMTF) were active in securing the acquisition and preservation of the Ahmanson Ranch.

The ESTF was responsible for filing a Sierra Club lawsuit to prevent developers from violating state environmental laws.

The SMMTF conducted an educational outreach campaign to tell why preserving Ahmanson Ranch was so critically important.

On March 7, 2004. the ESTF conducted their first Ahmanson Ranch Nature Walk outing through habitat of endangered San Fernando Valley spineflower, California horned lizard, the threatened California red-legged frog, and a plethora of land, water, and air wildlife. . Leaders were Gary Embrey, and Dr. Rosemarie White.

ESTF member Ken Murray wrote the following description of the five mile walk:

"A really magnificent day.

Weather was a little on the warm side, as the temperature set records county wide, for the day. But not unreasonable hot. Could not have been more clear, and it was a very enjoyable group of 43.

A real bonus was the experts along on this trip. The one fellow who had been involved in the preservation effort, who gave a chronology of the battle, was fascinating.

Tom Persons, from Treepeople, was amazing to watch, as he flitted from grass to tree to bug, identifying everything. His naturalist talk, in which he identified everything in sight, with a history of how they came to be there, was amazing. It was like watching John Muir. I'm going to make a real effort to include naturalist activities on my hikes, it really enhances the experience. "