Stoichiometry and Spatial and Temporal Variability in Abundance and Secondary Production of Baetis tricaudatus Dodds (Baetidae: Ephemeroptera) in the Walker River system, Lyon County, Nevada and Mono County, California

Abstract

Abstract: River and stream biological communities vary in response to characteristics of the environment. In 2007 and 2008, populations of Baetis tricaudatus Dodds (Baetidae: Ephemeroptera) were examined to assess spatial and temporal variability in its length-mass relationships, secondary productivity and stoichiometry in the Walker River, California and Nevada. Baetis tricaudatus was most abundant at higher elevations and in woody debris habitats. Its abundance, body mass, and body length were greatest during spring and summer. Body length and mass relationships varied temporally and spatially. Carbon (C):phosphorus (P) ratios were low during summer and autumn, and high during spring and winter. Low C:P raitos during summer and autumn matched spring and winter body and length growth patterns, suggesting that optimal grazing took place during summer and autumn when food quality was high. Stoichiometry and diet analysis suggested that food quality affects Baetis tricaudatus growth and abundance in the Walker River. This study documents that Baetis tricaudatus growth, body length and mass, and stoichiometry varies spatially and temporally in the Walker River through physical and chemical constraints.