title: Interactions between goldenrod (Solidago altissima L.) and its insect herbivore (Trirhabda virgata) over the course of succession.
abstract: Consumers can mediate the composition of plant communities and alter ecosystem processes. Although herbivores usually increase N availability in the short term, they might decrease it in the long term. I investigated the long-term effect of insect herbivores on leaf tissue quality and soil N availability in goldenrod (Solidago altissima) fields using two approaches: (1) I compared plots from which herbivores had been excluded for 17 years with adjacent plots that had experienced normal levels of herbivory, and (2) I examined a chronosequence of nine goldenrod fields representing three successional stages: early, middle, and late. These parallel approaches showed that, in the long term, herbivores decrease the quality of leaf litter and soil N availability in goldenrod fields. These long-term effects appear to compensate for various short-term effects that increase N availability in the soil (e.g., added frass, increased light penetration). Furthermore, herbivores decrease leaf litter quality and N availability by reducing the quality of leaf tissue within the same species. This pattern may result from insect herbivores preferentially grazing on plants with a high N content thereby increasing the amount of recalcitrant litter over the course of succession.
authors.affiliation: Section of Ecology and Systematics, Corson Hall, Cornell University, Ithaca, NY 14853, USA e-mail: mu16@cornell.edu Tel.: +1-607-2544280, Fax: +1-607-255-8088, , , , , , US.
authors.forename: M
authors.initials: M
authors.lastname: Uriarte
keywords: Key words Herbivores; Nitrogen; Positive feedback; Solidago; Succession