Identify and suppress invasive exotic plants in priority hemlock ecosystems: Delaware Water Gap National Recreation Area
Hilaire L, Strubert W, Schuon J, Deutsch K. 2023. Identify and suppress invasive exotic plants in priority hemlock ecosystems: Delaware Water Gap National Recreation Area. Natural Resource Report. NPS/DEWA/NRR—2023/2505. National Park Service. Fort Collins, Colorado. https://doi.org/10.36967/2297282
Eastern hemlock (Tsuga canadensis) is a keystone species having many factors currently contributing to a steep decline in numbers across most of its native range; these include the hemlock wooly adelgid (HWA) (Adelges tsugae), elongate hemlock scale (EHS) (Fiorinia externa), deer browsing, climate change, and the spread of invasive plants. Because of their ecological and cultural importance, efforts are being made to promote the continued health of these stands. In recent years however, strong storms have damaged and uprooted weakened trees in some areas, opening locations conducive to invasive species encroachment. The goals of this project are to identify, prioritize, and treat invasive plants in stands of eastern hemlock in the Pennsylvania portion of Delaware Water Gap National Recreation Area (DEWA). Site prioritization was based on an importance rating scale from “Invasive Species/Habitat Management Prescription Workbook (ISMPT) (Gover 2016).” Eleven (11) hemlock sites were investigated totaling 424.46 acres. Of these 11 areas, invasive plant species were identified and treated within the riparian areas of six. Treated areas included Adams Creek, Childs Park, Dingmans Creek, Hackers Trail, Raymondskill Creek, Toms Creek in 2021. In 2022, an additional 98.83 acres were treated. Ground cover of invasive species within these downed hemlock areas comprised a percent average of 23% in 2021 before treatment, and 4% in 2022 before retreatment. Treatment resulted in a marked decline of invasive species prevalence which allows for the potential of natural regeneration of native flora.
- Type
- Published Report
- Authors
- Hilaire, Lawrence; Strubert, Weston; Schuon, Joseph; Deutsch, Kara
- Date of Issue
- 2023-04
- Publisher
- National Park Service
- DOI
- 10.36967/2297282
- Units
- DEWA , NRSS
- Keywords
- Eastern hemlock, invasive plant control, Invasive plants
- Subjects
- Ecological Framework: Biological Integrity | Invasive Species | Invasive/Exotic plants , Ecological Framework: Biological Integrity | Focal Species or Communities | Vegetation Complex