LINKAGES BETWEEN RIPARIAN FOREST COMPOSITION AND SHREDDER VOLTINISM

Life history patterns and seasonal growth rates of eleven shredder spe cies inhabiting an Appalachian mountain stream (Pennsylvania, U.S.A.) were determined and conceptually linked to the species composition of the riparian forest. Thirty-two woody plant species were represented i n the riparian forest, with a near-equal compliment of foliage cover w ithin each of the three leaf processing categories (slow, medium, fast ). Relative cover of individual species was highly correlated with the proportions of standing stock biomass of individual species of stream leaf detritus. With two exceptions, each shredder species was univolt ine; Tallaperla maria exhibited a semivoltine life cycle, while Pteron arcys proteus appeared to require four years to complete nymphal devel opment. Paracapnia angulata, Taeniopteryx maura, Tallaperla maria, Lep idostoma (Nosopus) modestum group sp., Pycnopsyche gentilis, P. lucule nta, and Brillia flavifrons exhibited either autumn and/or winter grow th. In contrast, Amphinemura nigritta, A. wui, and L. (Mormomyin) sp. displayed either spring and/or summer growth. Overall, the study strea m appears to be an appropriate system for analyzing the riparian-shred der link because (1) the riparian assemblage is diverse within a broad range of leaf-processing rates, and (2) the shredder guild is corresp ondingly diverse with a wide array of seasonal growth patterns.