Research Works (Botany)

Document Type

Technical Report

Date of this Version



Submitted to the Pennsylvania Department of Conservation and Natural Resources


Ridley Creek State Park is a suburban park in a landscape that has a long history of human use. Most of the natural vegetation was removed by the mid to late 1800s. In the past 300 years the landscape has gone from forest to farmland to private estate to heavily used public park.

Today the park is a mosaic of forest remnants, scattered wetlands, successional communities, meadows, and landscaped grounds. Relatively intact natural communities cover 37 percent of the area. Non-native, invasive plants dominate many of the successional areas. These thickets of invasive shrubs and vines interfere with natural patterns of succession and represent inferior habitat for birds and other wildlife.

An overabundance of white-tailed deer compounds the ecological degradation of the park landscape. Deer feed preferentially on native vegetation leaving most non-natives to proliferate. The browsing severity in the park is such that even plants such as spicebush and beech shoots are reduced to well-chewed remnants. Regeneration of canopy trees is virtually non-existent, shrub layers are decimated, and herbaceous plant diversity is reduced. Canopy failure is occurring in areas where blow downs of older trees have occurred.

Management actions to address the habitat degradation that is currently occurring must first focus on achieving a dramatic reduction in deer density.

Action to address the problem of invasive plants should begin with removal of scattered invasives present in the areas of most intact natural communities, the areas coded as #1 in Figure 4. Areas coded as #2 are mostly successional forest stands with an intact canopy composed of native trees. They should be treated as buffers for the more mature forest stands and eventual additions. Continued canopy development as they mature should help to diminish the vigor of non-native invasive shrubs through shading.

Management of the most highly impacted sites (coded #4 and #5 on Figure 4) should be the lowest priority to be undertaken only if time and resources permit. These sites are unlikely to degrade further.

Key Recommendations

  • Reduce deer density throughout
  • Remove scattered occurrences of invasive plants in highest quality natural areas
  • Avoid forest fragmentation by maintaining canopy continuity and minimizing edge
  • Remove occurrences of non-native, invasive plant species that are not yet widely distributed in the park so they do not become bigger problems in the future (see Figure 7)

Included in

Botany Commons



Date Posted: 17 September 2018