Abstract Detail

Biogeography

Vaughn, Mitchell [1], Goolic, Ryan [1], Morrison, Janet [2].

A clash of continents within New Jersey suburban forests.

Suburban forests are novel ecosystems shaped by anthropogenic changes. A key change relative to more pristine forests is the consistent introduction of many non-native taxa that alter species interactions, including those between plants and their competitors, herbivores, and detritivores. We aimed to investigate how species’ geographic origins may influence these three important types of interactions in North American, suburban forests. Across three forests in central New Jersey, we measured the percentage of target plants with neighbors of a different species within 0.25 m² that shared an origin or had a different origin, based on a total of 120 North American-origin targets and 98 Asian-origin targets. 18.9% of Asian plants had at least one different Asian neighbor, while 58.3% of North American plants had at least one Asian neighbor. 95.9% of Asian and 92.5% of North American plants had at least one different North American neighbor. Most plants, regardless of origin, were exposed to interspecific competition with a native, North American species, but native plants were more likely than Asian plants to be exposed to interspecific competition with an Asian species. Asian-Asian interspecific competition may be weaker than Asian-North American competition because of a shared evolutionary history of interactions among the Asian species, leading to their relative tolerance of each other. The Asian species in these suburban forests are successful invasives, and therefore are likely strong competitors in any case, making the native species doubly vulnerable. Interestingly, very few plant species in the forests were of European origin, even though contact between New Jersey and Europe was established well before that with Asia. This lack of European plant species may be attributed partly to the presence of herbivorous, European slugs, which often kill seedlings. In feeding trials to determine the preference of New Jersey-collected European slugs (Deroceras reticulatum) for different forest plant species, only lettuce (the control) and the European invasive Alliaria petiolata were consumed (lettuce, 7/12 trials; Alliaria, 3/28 trials). In contrast, our data on plant-detritivore interactions in the suburban forests revealed a positive correlation between the abundance in 16 m² plots of Asian earthworms, Amynthas sp. and the Asian grass Microstegium vimineum, which we had added from seed (Kendall’s tau = 0.31; P = 0.03, n = 32). We also had added A. petiolata from seed, but M. vimineum dominated. We hypothesize that Asian worms promote Asian plants, while European slugs suppress European plants.

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

Keywords:
geographic origin
ecological interactions
suburban forest ecology.

Presentation Type: Poster
Session: P, Biogeography 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 6:15 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: PBG008
Abstract ID:825
Candidate for Awards:None