Fort Indiantown Gap in northern Lebanon County has announced the weekends of July 1-2 and 8-9 as the 2016 dates for tours of the grasslands that support the only population of rare regal fritillary butterflies in Pennsylvania.

The regal fritillary is found in the Great Plains states from eastern Montana east across the northern U.S. to Maine, according to Xerces Society. However, it is very rare or at best locally frequent in its entire range.

It is restricted to tall-grass prairie remnants and is rare or absent from former range east of the Appalachians. Fort Indiantown Gap is a rare exception.

The regal fritillary is not listed under the Endangered Species Act, but it is listed as endangered in Michigan, New York, Ohio, and Wisconsin; as threatened in Illinois; and as a species of concern in five states, including Pennsylvania.

The tours at Fort Indiantown Gap, which have been offered for more than 10 years, allow the public to see the rare butterfly and its rare grassland habitat on military training ranges, as well as many other natural wonders on the 17,000-acre military post, which serves as the Pennsylvania National Guard's headquarters.

The regal fritillary, which is the official symbol of the Pennsylvania Natural Heritage Program, is just one of many rare species found at the military installation, which provides a wide variety of habitats for 40 species of mammals, 143 breeding species of birds, 36 species of reptiles and amphibians, 27 species of fish, more than 800 species of plants and many notable species of invertebrates to include 86 species of butterflies and 386 species of moths. Fort Indiantown Gap also provides habitat for more than 100 species of conservation concern in Pennsylvania.

The majority of species of conservation concern in Pennsylvania require early-successional habitat like grasslands, thickets, shrub lands and young forests. That type of habitat is found at Fort Indiantown Gap--due to fires and disturbance--from years of military training that created and maintained 1,000 acres of scrub oak and pitch pine barrens and more than 4,500 acres of native grassland habitat, the largest in the state.

Each daily tour will depart at 10 a.m., but participants are asked to arrive no later than 9:30 a.m. to fill out the required paperwork, attend a mandatory safety/orientation briefing and receive driving instructions.

Participants must gather at the Fort Indiantown Gap Recreation Center in Building 13-190, located at the intersection of Asher Miner Road, Clement Avenue and Rt. 443.

Tours will last approximately three hours, but attendees may leave earlier if needed.

Visitors of all ages and abilities are encouraged to bring cameras and binoculars and should wear appropriate clothing and footwear for a nature walk on gravel trails or mowed paths. They should also consider bringing insect repellent, sun screen and other personal comfort items. Drinking water will be provided.

The tours also will include information about efforts to restore native grassland habitat across Pennsylvania and to raise regal fritillary caterpillars from eggs in a lab with support from the Pennsylvania Wild Resource Conservation Program and in partnership with ZooAmerica North American Wildlife Park and Temple University. The ultimate goal is to return the regal fritillary to areas where they were located historically.

Fort Indiantown Gap is the only live-fire, maneuver military training facility in Pennsylvania. It balances one of the region's most ecologically diverse areas with a military mission that annually supports 19,000 Pennsylvania National Guard personnel and more than 130,000 other states' guard, military, law enforcement and civilian personnel.