PARENT SESSION
Poster Session 20: Invasive Species
Wednesday, August 10, 5:00 PM - 6:30 PM, Exhibit Hall 220 A-E, Level 2, Palais des congrès de Montréal

Regeneration strategies of Japanese barberry (Berberis thunbergii DC) in coastal forests of Maine.

D'Appollonio, Jennifer ^*,1, Livingston, William¹, Wagner, Robert¹, ¹ University of Maine, Orono, ME

ABSTRACT- Invasive exotic plants can threaten biodiversity and ecosystem functions. One invasive species that has successfully invaded forests is the introduced shrub Japanese barberry (Berberis thunbergii DC.). Despite this threat, little has been published about the basic biology or ecology of the species. This study addresses the questions: (1) What is the density and origin of regenerating Japanese barberry and other species before and after removal of the Japanese barberry overstory? (2) Does a portion of Japanese barberry seeds remain viable for at least a year under natural conditions? (3) Do varying temperature and moisture regimes affect the germination success of seeds with and without the presence of fruit pulp? These questions will be addressed by two studies. The first study encompasses questions 1 and 2 and consists of a field and greenhouse component. A continuous stand of Japanese barberry was delineated at each of two coastal sites in Maine, and twenty 1m radius plots were cleared and sampled in each stand during late summer 2004 before the current year′s fruits ripened. A pair of 14X14X10cm soil samples was also collected from each plot. One soil sample was placed in a greenhouse setting, and Japanese barberry seedlings were counted as they emerged. The other soil sample is in cold storage and will be processed in spring 2005. Additional soil samples will be collected from each site in spring 2005. All sample plots will be sampled in late summer 2005 to gather additional regeneration data. The second study consists of collecting ripe fruits from the two sites, stratifying seed at 2° C, and germinating intact fruits, extracted seeds, and commercially collected control seeds in growth chambers. Replicates of 25 seeds of each type will be incubated in growth chambers to identify the optimum temperature and moisture regimes for germination. The influence of fruit pulp on germination will also be assessed. Preliminary analysis of Japanese barberry regeneration as of fall 2004 showed that 93% of 606 stems in the plots originated from seed, while 7% were sprouts. Incubating 38 soil samples in the greenhouse during fall 2004 yielded only three Japanese barberry seedlings over a period of 3.5 months, indicating that there is no seedbank. Growth chamber studies will yield results by summer 2005.

Key words: berberis thunbergii, invasive species, coastal forest, Maine