Abstract Detail

Ecological Section

Huebner, Cynthia [1], Miller, Gary [1].

Microstegium vimineum’s germination, survival, and growth in closed-canopy deciduous forests.

Microstegium vimineum (Japanese stiltgrass) is a shade-tolerant exotic grass capable of invading closed-canopy deciduous U.S. forests. Its growth under shade is reduced compared to its growth under high-light conditions. Our research evaluated the germination, survival, and growth response of M. vimineum planted in fenced forests under four relatively low light levels: 1) closed-canopy, 1% of full sunlight), 2) low light, 2%, 3) medium light, 4%, and 4) high light, 5%. These light levels are typical of closed canopy deciduous forests, however, they differ by increased understory and subcanopy re-growth in the higher light treatments. We measured shoot heights of transplanted two-week old seedlings and tallied germinations in buried pots with and without litter cover every two weeks from early June until early August of 2009. We removed, dried, and weighed both shoots and roots. Germination rates without litter were higher in the high-light treatment than the control treatment, but below 8%. Germination rates with litter (6%) showed no significant difference among light levels. Mortality was due to herbivory (snails and small rodents). Low-light treatment shoots were significantly taller than those in the medium and control treatments. The high-light treatment did not differ significantly from the other treatments. The plants grown under the low-light treatment showed less herbivory than all other treatments. By the last week, low-light treatments averaged 30 shoots 15 cm or taller, while control, medium, and high-light treatments averaged 15, 21, and 16 shoots, respectively. The tallest shoot occurred in the high-light treatment at 30.0 cm, with the second tallest in the low-light treatment at 29.5 cm. Shoot and root dry weights did not differ significantly among the light treatments though the low-light treatment had the highest values. Microstegium vimineum survival and growth are impacted by herbivory in forested areas with greater understory cover, which suggests a healthy understory layer may not only keep light levels down but also facilitate predation of M. vimineum stems.

Broader Impacts:
Microstegium vimineum survival and growth are impacted by herbivory in forested areas with greater understory cover, which suggests a healthy understory layer may not only keep light levels down but also facilitate predation of M. vimineum stems.

1 - Northern Research Station, USDA Forest Service, 180 Canfield St., Morgantown, WV, 26505, USA

Keywords:
Microstegium vimineum
Japanese stiltgrass
closed-canopy forests
herbivory.

Presentation Type: Oral Paper:Papers for Sections
Session: 24
Location: 555B/Convention Center
Date: Tuesday, August 3rd, 2010
Time: 8:00 AM
Number: 24001
Abstract ID:148