Drones and other unmanned aerial systems will be restricted in parks and preserves administered by the Santa Clara Valley Open Space Authority.

At its Nov. 12 meeting, the district’s board of directors voted to immediately prohibit the launching, landing and operation of unmanned aerial systems on or above its owned and managed lands.

Besides drones, unmanned aerial systems include model aircraft and quadcopters. The policy does not supersede or change any laws regarding Federal Aviation Administration-regulated airspace.

In part because they are less expensive now than in the past, unmanned aerial systems have become increasingly commonplace in public park lands. They have been detected flying in sensitive wildlife areas and can disturb, stress and harm wildlife. According to a recent study published in the peer-reviewed journal Current Biology, overhead drones cause a measurable stress response in wild animals.

Unregulated use of unmanned aerial systems can disturb wildlife by interrupting feeding and sleeping patterns, disrupt nesting and mating animals, and cause direct injury and mortality, according to the authority. Drones also can increase the risk of fire and intrude on human privacy and the quiet enjoyment of nature.

“The authority’s primary responsibility as a public agency is to protect visitors, wildlife and natural habitat,” said Derek Neumann, the agency’s field operations manager. “This policy will help foster the safety of visitors and of the birds and animals that live in and travel through our preserves.”

The policy makes exceptions for search and rescue operations, fire protection and law enforcement. It also allows permits to be issued for use of drones to support scientific studies, resource management and other mission-related purposes.

“Implementation of this policy will include preserving signage plus instructive materials via printed and electronic media, to educate the public on the potential harmful impacts of drones to people and wildlife, as well as the responsible use of drones to further scientific research within our open space preserves,” said Marc Landgraf, the agency’s external affairs manager.

He added that drones have been spotted flying above the authority’s preserves in recent times.

“And we have received complaints from visitors about them. We wanted to get out ahead of this, before it became a larger issue,” Landgraf said.

However, he noted there won’t be any financial penalties for flying drones.

“Our open space technicians out in the field will kindly point any violators to the notices about our policy. In the past, this had been effective with other policies. If a violator persists, we have the ability to call on our law enforcement partners for assistance,” Landgraf said.