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Herbivore‐Caused Greenfall in the Southern Appalachians
Author(s) -
Risley Lance S.,
Crossley D. A.
Publication year - 1988
Publication title -
ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.144
H-Index - 294
eISSN - 1939-9170
pISSN - 0012-9658
DOI - 10.2307/1941266
Subject(s) - herbivore , biology , ecology , petiole (insect anatomy) , deciduous , biomass (ecology) , plant litter , decomposer , ecosystem , agronomy , hymenoptera
Freshly fallen green leaves (greenfall) were collected from plots on four forested watersheds differing in aspect and treatment history at the Coweeta Hydrologic Laboratory in southwestern North Carolina. Greenfall was categorized as "herbivore—caused" or "unexplained." In almost all cases herbivore—caused greenfall biomass was significantly greater than was unexplained greenfall. Herbivore—caused greenfall was subdivided into "clipped" (caused by petiole—clipping caterpillars), "petiole—damaged" (caused primarily by petiole borers), "mined" (primarily by microlepidoptera on hickories), and "orts" (discarded leaf fragments). Leaves from 25 species or species groups of deciduous trees and woody vines (°35 species) were represented in foliar litterfall collected from litter traps; all of these contributed to herbivore—caused greenfall. Despite differences in aspect and stand age (10 yr, 23 yr, mature), patterns of greenfall were similar among watersheds. Seasonal inputs of greenfall to the forest floor were <5% of total foliar production but were greater than combined inputs of insect fecal pellets and insect body parts. Greenfall occurred continuously during the growing season and resulted from the activities of numerous species of insect herbivores. We suggest that greenfall is a widespread phenomenon that may be important as a resource for decomposers and that it should be included in measures of herbivory.