Pedestrian use, landscaping, pesticides and man-made improvements pose harm to Fairview Park's ecologically sensitive vernal pools, the U.S. Fish and Wildlife Service has found.

In addition, the service concluded after an 11-month review, the city should take steps, including fencing off the seasonal pools, to protect them and a tiny endangered species that lives in them.

The 11-page report, dated July 24, comes after the federal agency got involved last summer in a dispute that included unpermitted work to a pair of walking trails and the negative effect that work had on the endangered San Diego fairy shrimp in the nearby vernal pools, a wetland-like habitat.

Costa Mesa city officials and their environmental consultants plan to meet soon with the agency to talk about the report, according to a news release issued Monday. The city wants to "clarify the recommended measures, refine the scope of work and develop a work plan to help preserve vernal pools," the release stated.

The federal agency's suggested mitigation measures include various watershed restoration efforts and posting more educational materials about the park's biology.

FWS is also recommending large amounts of new fencing within areas of Fairview Park's roughly 95-acre southwest quadrant, which would severely restrict many areas to which the public now has easy access.

The fencing would create a larger buffer between public-access areas and the protected vernal pools, essentially seasonal ponds that fill with rainfall. As proposed, the fenced-off areas would include flatlands abutting the Harbor Soaring Society runway and the Canyon Drive parking lot.

The FWS also recommends regular monitoring of the fences and biological resources.

FWS' report said vernal pools within the park's popular southwest quadrant have suffered over the years.

The report said pedestrians, dogs, bicycles, cars, pesticides, herbicides, installed landscaping and improvements to Jim Scott Stadium have either harmed or could harm the vernal pools and the fairy shrimp inside them.

Fencing for the stadium, which abuts Fairview Park, has hurt the ability for water — which the fairy shrimp need — to collect in one nearby vernal pool, the letter states.

The park's largest vernal pool, about 3 acres, has had restoration work but is not completely fenced, the report noted. Because of that, there are user-made paths from the unfenced sections going into the basin, it states.

FWS also said tire tracks, walking paths and dogs traveling within the vernal pools near the end of Canyon Drive have disrupted water flow, as has an added parking area off that street.

One vernal pool had been used as part of a temporary parking area, the report noted.

That particular vernal pool, near the Harbor Soaring Society's runway, and two others near the Estancia High School fence line, have since been roped off by the city in September to prevent public access.

The federal report does not address the work done to the decomposed granite trails sometime last July. FWS' law enforcement division is investigating the incident.

Since the Daily Pilot reported about the trails last August, no one has taken responsibility for the job. The city has spent at least $19,000 removing the decomposed granite per an "emergency" actionFWS issued in November