Abstract Detail

Ecology

Wells, Jennifer [1], Morrison, Janet [2].

Japanese stiltgrass and garlic mustard:forest invasion and priority effects.

Less is known about the interactions between co-occurring, non-native invasive species than those between non-natives and natives, yet invasive-invasive interactions may be among the most important factors structuring heavily invaded plant communities. We are examining interactions between native plant species, two co-occurring invasive plant species, and white-tailed deer in a factorial field experiment in six central New Jersey forests, starting in 2013. Establishment of one experimentally added invasive plant, Microstegium vimineum (Japanese stiltgrass), has been variable but substantial in many plots (range 0-65%, mean 8.8%, median 2.5%, n=112). The other added species, Alliaria petiolata (garlic mustard), has had little success (range 0-3.8%, mean 0.2%, median 0%, n=112). Therefore, in March 2016 we added a second wave of garlic mustard seeds to the designated plots, which might cause temporal interactions that affect the invasion success of the two species. Experimental evidence from other studies showed that an initial plant invasion can affect a secondary plant invasion by suppressing native plants, litter accumulation, or soil conditioning. We are conducting a greenhouse experiment with Japanese stiltgrass and garlic mustard to determine if there is an effect by an initial invader on a later invader, through competition priority effects or soil legacies. We planted the initial invader at a range of three densities, and it was allowed to grow for a period of time before planting the second invader. We also examined soil legacies by removing the initial invader and planting the second invader in the same soil. Garlic mustard leaf diameters were significantly smaller when grown in a previously established low density of Japanese stiltgrass and even smaller when grown in medium and high densities, compared to no initial invasion of Japanese stiltgrass. A similar pattern occurred when garlic mustard was the initial invader and Japanese stiltgrass was the second invader. In two out of three blocks, Japanese stiltgrass percent recruitment was lower when planted in previously established medium and high densities of garlic mustard, compared to low density and no initial invasion. In the third block, there was no significant difference of Japanese stiltgrass percent recruitment between treatments. In both experiments, removing a high density of the initial invader had no residual soil legacy effects on the growth of the added plant. Dry biomass data from the second invaders, taken at the experiment’s conclusion, will indicate whether these patterns persist or intensify.

1 - The College of New Jersey, Biology, 2000 Pennington Road, Ewing, NJ, 08628, USA
2 - The College Of New Jersey, Department Of Biology, P.O. Box 7718, Ewing, NJ, 08628, USA

Keywords:
suburban forest ecology
invasive species
priority effects.

Presentation Type: Poster
Session: P, Ecology Section Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PEC033
Abstract ID:755
Candidate for Awards:Ecological Section Best Undergraduate Presentation Award