Fort Indiantown Gap, Southeastern Pennsylvania

"Training-scape" Helps Soldiers, Wildlife

It sounds like a contradiction in terms: An active military base that’s a wildlife hotspot. But at Fort Indiantown Gap in central Pennsylvania (known simply as “the Gap”), staff conservationists are shaping a landscape for military training while simultaneously making and maintaining thousands of acres of wildlife habitat, including native grasslands and young forest, rare and getting rarer in the Northeast where mature forest increasingly dominates the land.

“Fort Indiantown Gap is one of the most biodiverse places I’ve ever been,” reports Forest Program Manager Shannon Henry, “and that’s because we proactively manage it.”

Aerial ignition at Ft. Indiantown Gap

Prescribed fire started via aerial ignition at Ft. Indiantown Gap. Fire renews vegetation, helping grassland and young-forest animals./S. Henry

Henry works closely with Joseph Hovis, who heads the base’s Wildlife Section. On the 17,000-acre base more than 125,000 soldiers train each year. They need ranges where they can drive tanks and practice shooting weapons from rifles to cannons. Hovis’s and Henry’s job is to keep that “training-scape” functioning through prescribed burning, timber harvests, and brush-cutting.

“We keep the vegetation short – less than 10 feet on a shooting range, for example,” says Hovis. “Each year we apply fire to 3,000 to 5,000 acres and harvest timber on another 200 to 300 acres.” Those activities yield the kind of periodic disturbances that once were common – disturbances that set back vegetative growth and give rise to patches of young forest and grassland that move around on the landscape. At the Gap, such ephemeral habitats provide food and cover for a broad range of creatures including woodcock, bobwhite quail, catbirds, towhees, brown thrashers, blue grosbeaks, box turtles, wood turtles, spotted turtles, smooth greensnakes, timber rattlesnakes – the list goes on and on.

Boosting a Rare Butterfly

regal fritillary on little bluestem native grass

Healthy population of regal fritillaries exists at the Gap, thanks to active habitat management./J. Hovis

A premier species for which Hovis and Henry manage habitat is the regal fritillary, a handsome orange, brown, and silver butterfly whose once-generous range has shrunk to the point where only two populations remain in the East. The best of those places is the Gap.

Through burning, and by scattering plant seeds they have collected, staff conservationists replenish native grasslands with food plants fritillaries need during different stages of their life cycle, such as violets, milkweeds, thistles, and bergamots. Next to those grasslands lie literally thousands of acres of young forest.

“One ornithologist told us we probably have the highest concentration of prairie warblers in Pennsylvania,” Hovis says. Despite their name, prairie warblers breed and feed in dense shrubs and young forests. The prairie warbler is considered a Species of Greatest Conservation need in Pennsylvania and 10 other eastern states from Maine to Maryland.

At the Gap, timber rattlesnakes (rare and dwindling in the Northeast) den on top of Blue Mountain, ridging the base’s north boundary. “That’s their winter home,” Hovis says. “They hibernate in the rocks. Their summer territories are lower in elevation, including grasslands and young forest with abundant small mammals for prey.”

timber rattlesnake at Ft. Indiantown Gap, Pennsylvania

Timber rattlesnakes hunt for small mammals in young forest created through prescribed burning and timber harvests./J. Hovis

Hot Tool in the Toolkit

Fire may be the most useful habitat-shaping tool in Hovis’s and Henry’s toolkit. Because military training can start fires, through the use of tracer ammo, lumination flares, artillery rounds, and smoke grenades, Hovis and Henry must continually reduce the amount of woody fuel on the ground so that small fires don’t become big ones that jump out of the training area and threaten base infrastructure or surrounding communities. They use the term prescribed fire to describe their activities, "since it implies a planned fire with clear goals and objectives,” Hovis says.

Hovis and Henry use firebreaks and trained crews to control fires, some of which are set via aerial ignition: From helicopters, technicians shoot small plastic spheres (like little ping-pong balls) filled with chemicals that ignite after they hit the ground, providing the fire-equivalent of two strike-anywhere matches. Using aerial ignition, the conservationists can light a long line of small fires, or pattern fires in certain configurations to meet burn objectives.

After a fire, nutrients are returned to the soil. Grasses and shrubs green up dramatically and grow back densely. Hovis reports that male woodcock display frequently on recently burned areas. Fire also suppress tree species that are less desirable than oaks, which evolved to withstand fires. Healthy oaks yield valuable timber products as well as ample acorns, great food for wildlife.

More than 60 percent of Fort Indiantown Gap is open to public hunting, and Hovis’s Wildlife Section gives tours of fritillary habitat and young-forest improvements.

The Gap is an important island of young forest and native grassland in a region that’s becoming increasingly developed and where modern farming practices may offer little food or cover to wildlife. “What we’re putting into young forest often perpetually stays in young forest,” Hovis notes, “because it provides a landscape that the military can train in. I like to think we’re managing habitat like a Depression-era farmer. We do something, then walk away from it for a few years, then we’re back again to create another set of small disturbances.”

Those disturbances help wildlife as much as they benefit soldiers.

Partners and Funding

Pennsylvania Army National Guard, Pennsylvania Department of Military and Veterans Affairs, U.S. Fish and Wildlife Service, Pennsylvania Game Commission, Pennsylvania Bureau of Forestry, Pennsylvania State University, Northeast Association of Fish and Wildlife Agencies, Wildlife Management Institute

How to Visit

Contact the Wildlife Section to learn about habitat tours and opportunities to observe wildlife: Joseph Hovis can be reached at 717-861-2806 and