The families who placed the Skyline Ranch property under a Nature Conservancy conservation easement are telling the conservancy that development of the property doesn’t meet their preservation intent.

The families are turning their focus to conservancy President and CEO Mark Tercek, who they say is reviewing a decision that development meets the terms of the easement.

At issue is the decision to allow a 14-foot-tall berm and new wetlands on the property — owned by Henderson, Nev., resident Fintan Ryan — that sits just below the Skyline Ranch subdivision.

Pete Jorgensen, whose family was one of three that granted the initial easement, said the property is part of a 6.5-mile corridor of historic ranch lands on both sides of Highway 22 that are preserved by conservation easements. They are part of an unbroken vista that represents the authentic history of Jackson Hole, before golf courses and their amenities, Jorgensen said.

“Should the current activities be permitted to remain, it is only a question of time before the 6.5 miles of historic protection is eroded,” Jorgensen said in a Sept. 2 email to Tercek.

“This current erosion is taking place 35 years after granting the easement,” he wrote. “Acceptance of it as fact today will surely encourage others to see what they can accomplish in a much shorter time period. The outcome of such ‘creeping incrementalism’ will not come close to ‘protection in perpetuity.’”

Conservancy officials have said the work they approved for the property complies with all of the terms of the easement. The berms uphold the aesthetic values of the land, and the new wetlands improve the ecological value, conservancy officials said in a previous interview.

Others, including the families that granted the easement and the author of the easement, have said conservancy officials have completely missed the document’s intentions. They say it clearly seeks to preserve the property’s historical agricultural values. Berms do not fall within that category, they said.

The easement says it is supposed “to preserve and maintain the ecosystems of the property and to ensure the continuous harmony of land uses.

“It is the intent of this easement to prevent any practice on the land which by its nature or in the manner of its conduct endangers the preservation of the ecosystem or aesthetic features of the property,” the document reads.

It also says it was created to preserve the natural ecosystems, aesthetic features and historic use of the property.

The families who granted the easement and the people who worked on the document said that allowing the project to proceed could erode confidence in conservation easements.

Nature Conservancy officials haven’t turned up any wrongdoing in their review of a massive landscaping project on the property along Highway 22 that is protected by one of the first conservation easements in the region.

The review, which was prompted by sharp criticism from the families that placed the iconic property under the easement, now is headed higher within the conservancy’s national structure.

Conservancy Wyoming State Director Andrea Erickson-Quiroz said the group still is waiting for the results of additional reviews it requested.

“To ensure we are upholding all our responsibilities as the organization entrusted with these conservation easements, we have requested an external legal review,” Erickson-Quiroz said Tuesday in an email.

“That review has not yet been finalized in writing and delivered to us. When we have the completed legal review in hand, and we have more information to share, we are committed to providing written confirmation to the easement donors first,” she said.