PARENT SESSION
Poster Session #41: Invasive Species Ecology: Woodlands.
Wednesday, August 7. Presentation from 5:00 PM to 6:30 PM. Exhibit Hall B & C, TCC

Impact of the invasive plant Vincetoxicum rossicum on activity of arbuscular mycorrhizal fungal populations.

GREIPSSON, SIGURDUR^*,1, DITOMMASO, ANTONIO², ¹ TROY STATE UNIVERSITY, TROY, ALABAMA² CORNELL UNIVERSITY, ITHACA, NEW YORK

ABSTRACT- Invasion of the non-native plant Vincetoxicum rossicum (Asclepiadaceae) is a major concern in natural ecosystems of central New York State and the lower Great Lakes Basin. This species reproduces mainly through the production of seed, and forms dominant, mono-specific populations in a wide range of habitats. We examined the impact of V. rossicum on resident arbuscular mycorrhizal fungal (AMF) populations. Soil samples were collected from four sites in central New York where V. rossicum has invaded. Population density of V. rossicum was estimated at each site. The mycorrhizal inoculum potential (MIP) in these soils was determined using corn (Zea mays) as a bait plant. Soil samples were diluted in a 1:5 ratio with quartz sand and bait plants were subsequently grown in a greenhouse for four weeks. AMF root colonization of bait plants was estimated by scoring root pieces (1 cm) for the presence or absence of hyphae, arbuscules and vesicles under bright field microscopy. The percentage of AMF root colonization in bait plants was used as an index of the soil's MIP. The density of V. rossicum tillers at each site was linked to AMF root colonization of bait plants; sites with high populations densities (100 tillers/m²) had low MIP. Findings from this work suggest that invasion of V. rossicum and subsequent population buildup reduces the activity of AMF in resident soils.

KEY WORDS: Arbuscular mycorrhizal fungi, invasion, New York State, Mycorrhizal inoculum potential