Jones, Ian Matthew , Koptur, Suzanne , Gallegos, Hilma R , Tardanico, Joseph P , Trainer, Patricia A .
Changing Light Conditions in Pine Rockland Habitats Affect the Outcome of Ant-Plant Interactions.
Introduction: Extrafloral nectar (EFN) mediates food-for-protection mutualisms between plants and ants. Such mutualisms exist within a complex web of biotic interactions, and in a framework provided by the abiotic environment. Both biotic and abiotic factors, therefore, affect the outcome of ant-plant interactions. We conducted an experiment to determine the effects of ant activity, and light intensity, on herbivory rates, growth, and reproductive fitness in Senna mexicana var. chapmanii, a perennial legume native to south Florida pine rockland habitats.
Methods: Forty plants were divided among four treatments in a factorial experimental design with two independent variables: ant activity and light intensity. Plants were divided equally between sunny and shady habitats, and ants were excluded from half of the plants in each habitat type.
Results: In shaded habitats, the presence of ants had no effect on herbivory rates, seed set, or plant size. In sunny habitats, however, plants with ants suffered less herbivore damage, produced more seeds, and grew larger over the duration of the one year study.
Conclusions: Ants represent an important biotic defense against herbivores in S. chapmanii; however, their effects on plant fitness are dependent on light conditions. Pine rockland habitats in south Florida have been widely destroyed or mismanaged. In fragments that remain, disruption of fire regimes has led to increased canopy closure and shading of the understory. These changes will likely negatively impact ant-plant interactions. We highlight the importance of conservation efforts to preserve the pine rocklands and their many native plant species.
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1 - Florida International University, Biology, 2792 West Trade Avenue, Miami, FL, 33133, USA
2 - Florida International University, Department Of Biological Sciences, 11200 SW 8th St, Miami, FL, 33199, USA
3 - Florida International University, Biological Sciences, 11200 SW 8th Street, Miami, FL, 33199, USA
Senna mexicana var. chapmanii.
Presentation Type: Oral Paper
Session: 15, Ecology Section: Forest Ecology
Location: 104/Savannah International Trade and Convention Center
Date: Tuesday, August 2nd, 2016
Time: 9:30 AM
Candidate for Awards:Ecological Section Best Graduate Student Paper