Alternating patch characteristics in Alliaria petiolata (garlic mustard).
Bauer, Jonathan*,1, Anderson, Roger1, Anderson, M Rebecca1, 1 Illinois State University, Normal, IL, United States
ABSTRACT- Garlic mustard is a Eurasian biennial herb that is invasive in deciduous forests in northeastern United States and adjacent southern Canada. Garlic mustard appears to successfully compete with and displace native understory species. We are investigating competitive interactions among first- and second-year garlic mustard and native vegetation in two forests in ParkLands Foundation Merwin Preserve in McLean County, Illinois. We sampled cover of first- and second-year garlic mustard plants in 240 50 cm x 50 cm plots in May and early June of 2004 and late May of 2005. In 2005, plots were randomly assigned to control or one of two treatments in which second-year garlic mustard was removed in early March or early May. In 2004, cover of second-year plants (mean+SE, 14.31+1.04) was high. However, in 2005 there was a significant reduction in second-year plants (0.74+0.38) with few plants present in control plots, but cover of first-year plants was significantly higher in 2005 than in 2004 (6.45+0.69 vs. 32.3+1.76 in 2004 and 2005, respectively). These results support the hypothesis that garlic mustard grows in alternating patch types. Our data suggests that this pattern results from competitive interactions between first- and second-year plants. Due to near absence of second-year plants, we found no treatment effects on native species or on first- or second-year garlic mustard plants in 2005. We predict that treatments will affect first-year plants in 2006 due to removal of second-year plants in 2005.′
Key words: invasive species, Alliaria petiolata garlic mustard, eastern deciduous forest
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