With piping plover and least tern chicks hatching on barrier beaches that rim Chappaquiddick and Edgartown, oversand vehicle access will be restricted over the next few weeks.

About two miles of Norton Point Beach has been closed to vehicles because of shorebird nests, The Trustees of Reservations said last week, with the remaining half-mile of beach limited to 100 vehicles at a time. As of July 1 all of Norton Point will be closed to beach traffic.

The Trustees anticipate additional oversand vehicle restrictions on Leland Beach around July 11 because of hatching activity there. Closures are already in effect on parts of Cape Pogue.

Beach closures are perennial events to protect piping plovers and least terns that nest on barrier beaches during the early summer months. State environmental guidelines require protection programs and beach closures to oversand vehicles when nests and chicks are present. Piping plovers have been a state-listed threatened species since 1986. Least terns are a protected species.

Piping plover chick. — Lanny McDowell

The beaches remain open to pedestrians but dogs, horses and beach bicycles are prohibited in nesting areas.

Black skimmers and oystercatchers also lay eggs on barrier beaches, along with the terns and plovers. The birds make nests in exposed scrapes in the sand. Chicks are precocious and can walk and feed themselves soon after they are born. The fledglings are vulnerable to predators, including skunks and crows, as well as oversand vehicles.

Trustees ecology assistant Caitlin Borck said because of storms and higher than normal predation this year, shorebirds have been renesting around Chappaquiddick. As of this week there were 17 pairs of birds, slightly more than average, scattered around Trustees beaches on the Vineyard.

The closures sometimes cause tension with fishermen and oversand vehicle permit holders. “We appreciate the public’s understanding and patience during this important survival time for this species,” Trustees Vineyard superintendent Chris Kennedy said in a statement. “We also understand the frustration that many of our permit holders may be feeling due to these limitations. We manage these beaches for people and for wildlife, which can make vehicle access a challenge, especially during the busy shorebird and summer vacation season.”

The beach closures are subject to change, as shorebird chicks have high morality rates due to storms and predators. The beach access hotline is 508-627-8390 and the Trustees also post information on their Facebook page.

In 1986 the total population of piping plovers in Massachusetts had dwindled to 140 breeding pairs. Due to shorebird protection programs, the numbers have rebounded in recent years. In 2016 the population was 649 breeding pairs, a slight decerease from 2015.

An earlier version of this story had the wrong phone number for the beach access hotline. The number has been corrected.