Mammals

One of the park's many gray squirrels.

NPS Photo/C. Davis

Gettysburg National Military Park is home to many of the common species of mammals found in south-central Pennsylvania. Among the most common mammals found in the park, the most visible are Gray Squirrels and Red Squirrels that inhabit park trees and Eastern Chipmunks that inhabit burrows in woods and the numerous stone walls around the park. The woods also support the Southern Flying Squirrel and a variety of rodents such as the White-footed mouse and moles.

Pennsylvania is the home of eastern White-tailed Deer, a species that has flourished in the Commonwealth over the past 80 years. Hunted in state game lands and on private property outside of park boundaries, deer instinctively made the battlefield a permanent home, which resulted in extensive damage to the natural environment as well as crops and pastureland. The National Park Service has undertaken an extensive deer control program which has reduced the population of white-tailed deer within the park boundary over the past ten years. Though the population of deer has been reduced in the park, there are still many of these hearty animals that can still be observed, usually around dusk when they come out to graze in meadows and tall grass.

The most common flying mammal at Gettysburg is the Eastern Brown Bat or "Little brown myotis". Bats are an important part of the natural environment and help control the insect population. Bats are night flyers and can be spotted on park grounds in the early evening, from March through November.

The battlefield is home to many other mammals not always seen by park visitors. Among these are the Eastern Cottontail Rabbit, Opossum, Raccoon, ground hogs, and Red and Gray foxes. And like the rest of Pennsylvania, Gettysburg is home to the Striped Skunk, one of nature's mammals that one would be wise to avoid.

 

NPS Photo

Plum Run Beaver Dam

• The North American beaver is a species native to Pennsylvania. By the end of the nineteenth century, uncontrolled trapping and habitat loss eliminated beavers in Pennsylvania and most eastern states. Today this aquatic furbearer is back and has repopulated most of its historical range.

• The presence of beavers within the Plum Run riparian corridor is not new. They have inhabited this space periodically for over a decade and have expanded their range to most park waterways during that time.

• In 1863, the Plum Run riparian corridor was a significant wetland serving as an obstacle to troop movements during the battle at Little Round Top. It remains a functioning wetland today and still able to be interpreted as an obstacle. The Plum Run Valley was also significant as an avenue of approach, representing low ground situated between the Round Tops and Houck’s Ridge. The topography of the site remains intact today.

• When evaluating how to manage beaver activity, we consider National Park Service (NPS) policy and the park’s management goals and whether their presence interferes with our ability to achieve those goals.

• The periodic presence of beavers in the Plum Run riparian corridor is considered a natural process. In accordance with NPS Management Policies (2006), the NPS does not intervene in natural biological or physical processes except in limited certain circumstances. Our General Management Plan (1999) supports preserving and improving environmental conditions, including wetlands, while maintaining cultural resources. It also recognizes that the results of landscape rehabilitation would not fully reflect the conditions present in 1863. The Little Round Top Cultural Landscape Report (2012) specifically outlines two key management objectives for the Plum Run riparian corridor: (1) Promote species diversity and (2) Preserve key historic views from the Plum Run Valley to Little Round Top. Management for species diversity in this area is recognized as a rare, intentional “deviation from historic conditions” due to the ecological significance of the wetland and its special and unique biodiversity.

• Beavers contribute positively to these goals by reducing woody vegetation that obstructs historic views to the summit of Little Round Top, enhancing wetland function and habitat for rare species such as the North American least shrew (PA endangered), Least bittern (PA endangered), and American bittern (PA endangered), protecting archeological resources and reducing flood-related damage to cultural features.

• Where possible, the NPS approach is to integrate the management of both natural and cultural resources within parks, but we also recognize they have separate and specific needs. The cultural resources within the Plum Run riparian corridor that could be impacted by the activities of beavers have been inventoried and are being monitored.

• When the needs of cultural and natural resources conflict we take the minimum action necessary achieve our management goals. Over the last three years the following actions have been taken to manage the impacts of beavers:

1. Installation of a total of six beaver deceivers to address existing water levels as well as be proactive in preventing additional water impoundment should new beaver activity occur. This action has also restored visibility of the Plum Run stream channel in the lower portion of the valley.

2. Regular removal of small dams in unwanted locations such as under the footbridge at Plum Run.

3. Maintenance of public access to all cultural resources (monuments, flank markers, trolley line, etc.).

4. Implemented work to better understand the status and distribution of beavers in the Plum Run watershed and throughout the park and seek best practices for co-existence.

• Within the Plum Run watershed primary beaver activity occurs from above Wheatfield Road to the Slyder Farm with the largest beaver colony at the south end of the park where Plum Run exits the park at Knight Road. Beaver activity has also been documented within Willoughby Run, on the Harman Farm, and within Rock Creek.

 

Devil's Den and the Valley of Death as seen from the summit of Little Round Top.

NPS Photo

• The presence of beavers along Plum Run is not new. They have inhabited this space off and on for many years. In the past, they have been present for a year or two before moving on, likely as a result of exhausting their food supply.

• It is the policy of the National Park Service to maintain all native plant and animal species within parks. When intervention is determined to be necessary to protect other park resources, human health and safety, or facilities such intervention will be kept to the minimum necessary to achieve the stated management objectives.

• Natural and cultural resource management staff are currently monitoring the beaver colony and it’s impacts on water levels in the surrounding area. At the point that negative impacts are documented to the roadway or critical elements of the cultural landscape appropriate action will be taken. Re-location of the beaver colony will be considered only as a last resort.

• Beavers are considered keystone species – those that modify the environment in such a way as to encourage the presence of other species.