Recent Topics Posters
Duchicela, Jessica , Schultz, Peggy , Bever, James .
Plant-soil microbial interactions on invaded sites at the highlands of Santa Cruz Island, Galapagos Archipelago.
Plant invasion is widely considered to be one of the main threats to native diversity and ecosystem function, and it has been considered a major threat to biodiversity conservation in restricted environments such as islands. The factors that determine the success of plant invasion are not well understood, especially those related to soil microorganisms that have the potential to interact with plants and alter plant-plant interactions. In particular, the role of arbuscular mycorrhiza fungi (AMF) an ancient and widespread fungus that establishes association with plants almost ubiquitously, in a wide range of terrestrial ecosystems. Given that soil microbial communities, specifically AMF has the potential to influence plant performance and feedback dynamics, we conducted a series of experiments to test whether the exotic plant species at the Galapagos Islands differ in their dependencies on mycorrhizal fungi compared to the native plant species. First, we analyzed the flora database held by the Charles Darwin Research Station to examine the mycorrhizal status of the flora of highlands of Santa Cruz Island. We observed a greater proportion of non-native species from plant families that typically do not associate with mycorrhizal fungi, as compared to native species. This result was consistent with a greenhouse experiment that was conducted to test the soil microbial inoculation responsiveness of five native and four nonnative plants.Preliminary observations of the pot experiment showed that nonnative plants have a greater response to inoculation with soil microbes than native plants.This suggests that the nonnative plants are more dependent on soil microbes to survive. This variation of plant response to soil microbial dependence could impact ecosystem properties. Thus, we tested how native/nonnative plant density affects biological and physical-chemical soil properties. We conducted floristic surveys and soil analyses in six sites dominated either by native or nonnative plants at the highlands of Santa Cruz Island.We compared vegetation richness, nitrogen, phosphorous, organic matter, water stable aggregates and mycorrhizal fungi diversity and density. The effects of nonnative plants on soil properties were very variable. Water stable aggregates proportion was higher in sites with greater density of non-native species. In order to test if this condition will further improve nonnative plants growth we would like to establish an experiment, manipulating soil from the different sites with variation of non-native density to evaluate the effect on a non-native plant growth.
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1 - Indiana University, Biology, 1001 E. 3rd St. Jordan Hall 142, Bloomington, IN, 47405, USA
2 - Indiana University, Bloomington, IN
Exotic alien plant
arbuscular mycorrhizal fungi
soil aggregate stability
plant-soil microbial interactions
Presentation Type: Recent Topics Poster
Location: Battelle South/Convention Center
Date: Monday, July 9th, 2012
Time: 5:30 PM