PARENT SESSION
Poster Session 37: Forest Ecology.
Thursday, August 5 Presentations from 5:00 PM to 6:30 PM, Exhibit Hall A 1.
The secondary compounds of invasive plants are toxic to larval amphibians.
Maerz, John*,1, Brown, Carrie1, Chapin, Carmen2, Blossey, Bernd1, 1 Ecology and Management of Invasive Plants Program, Ithaca, NY, USA2 National Parks Service, Ashalnd, WI, USA
ABSTRACT- Understanding how invasive plants impact recipient communities is important for effective management. Prior research shows nonnative Lythrum salicaria invasions reduce American toad (Bufo americanus) survival, but mechanisms behind this effect are unknown. We found increased concentrations of soluble reactive phenolics in L. salicaria and other nonnative plants, so we screened several native and nonnative plant extracts for their toxicity to 3 larval amphibian species (B. americanus; spotted salamanders, Ambystoma mauclutum; grey treefrogs, Hyla versicolor). In our first experiment, we exposed small groups of toads and salamanders on natural diets to plant extracts. In our second experiment, we exposed individual treefrogs on artificial diets to plant extracts. Survival rates of toads were significantly reduced when exposed to L. salicaria extract, and salamander survival was reduced by exposure to nonnative P. australis extracts. Treefrog survival was not effected by any native or nonnative plant extract. To confirm results were due to differences between amphibian species and not artifacts of experimental differences, we measured benthic phenolic concentrations and toad and treefrog performance in 4 year old L. salicaria and T. latifolia mesocosms. Consistent with prior experiments, toad survival was negatively correlated with phenolic concentration, but treefrog survival was not. These results confirm that high or novel natural plant compounds, such as those found in nonnative plants, can be toxic to larval amphibians; however, effects are plant and amphibian species-specific. Species-specific responses to invaders suggest that (1) generalizing invader impacts even to closely related species may be premature and (2) plant invasions could alter interactions within guilds. Screening impacts of multiple invasive plants against suites of species are needed to evaluate the general risk and higher-order impacts of invasive plants on native communities.
Key words: secondary compounds, invasive plants, amphibian