Meindl, George , Ashman, Tia-Lynn .
Edaphic factors and plant-animal interactions: cascading effects of serpentine soils.
Serpentine plant communities have been a focus of plant ecologists for centuries; however the impact of edaphic factors on plant-animal interactions in these systems has only begun to be explored. Serpentine soils are characterized by a low Ca/Mg ratio, mineral nutrient deficiencies, poor water retention and high concentrations of heavy metals. For plants growing in serpentine soils, these edaphic factors may result in changes in plant morphology and chemistry, which may alter plant-animal interactions. In this study, we investigate the influence of serpentine soil chemistry on plant morphology, chemistry and plant-animal interactions for a serpentine tolerant plant species, Mimulus guttatus (Phrymaceae). Specifically, we address the following questions: (1) Do plants grown in serpentine (S) vs. non-serpentine (NS) soil differ morphologically and/or chemically? (2) Do plants grown in S vs. NS soil interact similarly with herbivores and pollinators? Over two consecutive field seasons, natural S and NS populations of M. guttatus in northern California were described with respect to floral display traits (i.e., inflorescence height, corolla width and number of open flowers per inflorescence), floral chemistry, florivore damage and pollinator visitation. In addition, three separate field experiments were designed to address the influence of S soil on plant morphology, chemistry and plant-animal interactions. In the first experiment, seedlings were collected from natural S and NS populations and grown in either S or NS soil collected from the field (fully crossed design). In the second and third experiments, seedlings were collected from natural populations, grown in the same soil type that corresponded to their collection location, and grown to flowering. These plants were then placed within natural populations and monitored for florivore damage and pollinator visitation. In both natural populations and experimental potted plants, flowers of Mimulus guttatus plants grown in S soil were found to be smaller and chemically distinct from those produced by plants grown in NS soil. In experimental arrays of potted plants, plants grown in S soil received less damage from florivores relative to plants grown in NS soil. While there was no difference in pollinator visitation to experimental potted plants grown in S vs. NS soil, flower size did influence pollinator visitation rates. In contrast, flower size did not influence florivore damage levels. Therefore, we present novel evidence that S soil chemistry can alter biotic interactions both directly, through chemical changes, and indirectly, through morphological changes.
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1 - University Of Pittsburgh, Biological Sciences, 4249 5th Avenue, Pittsburgh, PA, 15260, USA
2 - University Of Pittsburgh, Department Of Biological Sciences, 4249 Fifth Avenue & Ruskin, Pittsburgh, PA, 15260, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Franklin B/Hyatt
Date: Wednesday, July 11th, 2012
Time: 9:15 AM