title: Spatially distinct responses within willow to bark stripping by deer: effects on insect herbivory.
abstract: Within individual plants, cervid herbivory may cause positive or negative plant-mediated effects on insect herbivores, depending on where it occurs. Using a combination of field observations and artificial bark-stripping experiments in Hokkaido, Japan, we examined the plant-mediated effects of bark stripping by sika deer (Cervus nippon yesoensis) on insect herbivory in two spatially distinct parts of willow (Salix udensis) trees: resprouting leaves below bark-stripping wounds and canopy leaves above. Natural and artificial bark stripping stimulated resprouting from trunks below wounds. Resprouting leaves on bark-stripped trees had lower total phenolics, condensed tannin, and C/N ratios than did canopy leaves on control trees. Herbivory rates were higher in resprouting leaves on bark-stripped trees than in canopy leaves on controls. Conversely, above-wound canopy leaves on bark-stripped trees had higher total phenolics than did those on controls, while herbivory rates were lower in the canopy leaves of bark-stripped trees than in those on controls. These results demonstrate that plant-mediated effects of bark stripping diverge between plant tissues below and above wounds in individual willow trees. We submit that focusing on multiple plant parts can elucidate plant-mediated effects at the whole-plant scale.
authors.affiliation: Graduate School of Environmental Science, Hokkaido University, 250 Tokuda, Nayoro, 096-0071, Japan.
authors.forename: Motonobu
authors.initials: M
authors.lastname: Tanaka
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D003670:Deer / Q000502:physiology*; D020387:Food Chain; D060434:Herbivory / Q000502:physiology*; D007313:Insecta / Q000502:physiology*; D007564:Japan; D010636:Phenols / Q000032:analysis; D018515:Plant Leaves / Q000737:chemistry / Q000502:physiology; D032108:Salix / Q000502:physiology*; D013634:Tannins / Q000032:analysis
chemical_list: D010636:Phenols; D013634:Tannins