CHEYENNE, Wyo. (AP) — Grand Teton National Park officials on Wednesday announced several changes to the park's annual elk hunt, including the closing of an area where a grizzly bear mauled an elk hunter in 2011 and where two elk hunters killed a grizzly that charged them last fall.

Grand Teton also will limit the amount of ammunition hunters may carry. The idea is to encourage hunters to pull the trigger only for well-placed shots that kill elk instead of just wound them.

Wounded elk can become targets for the park's growing population of grizzly bears. Both grizzlies involved in conflicts with hunters over the past two years were feeding on and behaving protectively of elk carcasses at the time, park spokeswoman Jackie Skaggs said.

"Is there a way that we can make hunters be more responsible with the shot they fire, to take that individual animal, and make it a clean shot and a killing shot?" Skaggs said.

Hunters will be allowed to carry no more than seven cartridges per day under the new rules. Additionally, hunters who open fire at a group of running elk will not be allowed to take more than one shot, also with the goal of fewer wounded elk.

The park announced the changes a week after releasing a report on its investigation into the shooting of a grizzly by two elk hunters last Thanksgiving.

Grizzlies are a federally protected threatened species and killing one is punishable by up to a year in prison and fines up to $50,000. Federal prosecutors decided not to file charges against the two youths, then 17 and 20, who were hunting in the park with their father.

The father, David Trembly, of Dubois, fired bear spray after the grizzly charged from 42 yards away. His sons held fire until the bear was just 10 feet from them, according to the investigation report.

The run-in happened in a thickly wooded area of Snake River bottomlands where park officials have been concerned about hunters not being able to see grizzlies and vice versa. In 2011, a grizzly mauled but did not severely injure elk hunter Timothy Hix, of Jackson, in the same area.

A new, more open area will be opened up to hunting, but park officials recognize that grizzlies and hunters will likely cross paths there sooner or later, Skaggs said.

"We realize bears will shift to where the food source is," she said.

In fact, she said, wildlife biologists have begun to recognize that gut piles left by hunters in the Yellowstone ecosystem are an important autumn food source as grizzlies fatten up ahead of hibernation. The ecosystem's grizzly population has grown rapidly in the past couple decades and now numbers at least 600 animals.

Once rare in Grand Teton, grizzlies have become a fairly common sight for tourists in the park.

Grand Teton's elk hunt is provided for under the park's authorizing legislation and has been held all but two years since the park was established at its present boundaries in 1950.

Other changes to the hunt rules include required use of non-lead ammunition. The park already requires all hunters to carry bear spray.

Meanwhile, Grand Teton plans to change the timing and possibly the length of this year's hunt, in part to better reflect the migration of elk from their summer ranges in the park to their winter range on the National Elk Refuge just south of the park.

Grand Teton is among just a few national parks that allow hunting. Rocky Mountain and Theodore Roosevelt national parks, in Colorado and North Dakota, also have elk hunts.

The purpose of the hunt is to help wildlife managers control the size of the Jackson elk herd, which numbers roughly 11,000 animals. Starting last year, the hunt was limited to females only — no bull elk — to help make hunting a more precise way to control the herd size.

Last year's hunt began Oct. 6 and ended Dec. 2. Out of 537 permits issued to hunt in the park, hunters took 188 elk for a success rate of 35 percent, according to Skaggs.