Habitat and flora associated with two ramp/leek species (Allium tricoccum and A. burdickii) in Pennsylvania
Open Access
- Author:
- Stark, Cassie
- Graduate Program:
- Forest Resources
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 18, 2022
- Committee Members:
- Bradley Cardinale, Program Head/Chair
Eric Paul Burkhart, Thesis Advisor/Co-Advisor
Jonathan M Duncan, Committee Member
Douglas Alan Miller, Committee Member
Sarah E Nilson, Committee Member - Keywords:
- ramps
Allium tricoccum
Allium burdickii
Forest farming
Soil moisture
Population discovery - Abstract:
- Allium tricoccum Ait., is a perennial, herbaceous forest plant known as a ramp or wild leek in Pennsylvania (PA). Ramps are a popular, foraged, non-timber forest product, and are consumed for their edible bulbs and leaves which have an onion or garlic flavor. For nearly the past century, a second “ramp” taxon, has been variously recognized outside of PA as a separate race, variety, or species. Recent floristic treatments now address it as a separate species, narrow-leaf ramp (Allium burdickii (Hanes) A.G. Jones). Little is known about the forested site conditions associated with both ramp species in PA. This habitat information could be useful for guiding in situ cultivation (i.e., forest farming) of A. tricoccum and for discovery and conservation of A. burdickii. The latter species is currently only known from a handful of sites in southwestern PA. In this study, habitat and association data was collected from 30 wild A. tricoccum populations on forestlands located in PA. Four additional A. burdickii populations were included and paired with nearby A. tricoccum populations for a comparison of habitats. At each field site, five plots were placed throughout the population area and the following data were collected: floristic associates (all strata), soil chemistry, soil moisture content, topographic position, elevation, and aspect. Results indicate A. tricoccum commonly occurs on moist, east, and north facing lower slopes or floodplains with slightly acidic and fertile soil chemistry. The flora associated with A. tricoccum populations was 50% (27-65%) similar when compared throughout PA. Sugar maple (Acer saccharum Marsh.) and blue cohosh (Caulophyllum thalictroides. (L.) Michx.) were frequently occurring species at ramp sites and an indicator species analysis (ISA) identified them as indicators for ramp habitat on north aspects. Wood nettle (Laportea canadensis (L.) Wedd.) was commonly found later in the season at sites with blue cohosh. This is likely due to the wet, calcium rich habitat these species prefer. Species such as bitternut hickory (Carya cordiformis (Wang) K. Koch), mayapple ((Podophyllum peltatum L), and jack-in-the-pulpit (Arisaema triphyllum (L.) Schott) were associated with ramps on floodplains. These site factors and associated flora can be used for ramp site selection for cultivation. Habitat comparisons between A. tricoccum and A. burdickii at field sites in southwestern PA revealed soil moisture content was significantly higher at A. tricoccum populations while soil pH and nutrients were all greater at A. burdickii populations. Flora associated with A. tricoccum and A. burdickii populations were 44% (35-75%) similar. The most frequent and dominant tree species was sugar maple. The ISA and NMS results were consistent with the statewide A. tricoccum results with blue cohosh, and wood nettle being associated with A. tricoccum populations. The ISA and NMS revealed species such as mayapple, false Solomon’s seal (Maianthemum racemosum (L.) Link), and stonecrop (Sedum ternatum Michx.) were associated with A. burdickii populations. Species associated with A. tricoccum were those that require moist or mesic habitat conditions whereas species associated with A. burdickii can tolerate drier conditions.