Production and turnover ofHyalella aztecain central Ontario, Canada compared with other regions

Abstract

1. Hyalella azteca (Amphipoda) inhabiting macrophyte beds in eight Canadian Shield lakes were sampled during the ice-free seasons of 1984 and 1985. These amphipods were found to be predominantly univoltine in contrast to suggestions from a previous study. 2. Annual production determined by the size-frequency method ranged from 1.21 to 2.77g dry wt m"^ year"', and are the highest rates recorded for this species in temperate waters. 3. Turnover rates (P/B ratios) ranged from 2.27 to 3.48 and are among the lowest values that have been measured. A synthesis of these data indicates that H. azteca turnover rates increase sigmoidally with degree-days above 5°C.

Inter-relationships among demographic traits comprising amphipod production and turnover

“…Milstead & Threlkeld (1986) also found Hyalella to be capable of maintaining a fairly constant turnover rate despite wide fluctuations in other demographic variables. Hyalella turnover rates do vary, however, across geographic regions through a strong dependence of voltinism on temperature (France, 1993).…”

“…Sampling methods and data compilation are described in France & Stokes (1988) and France (1990). Derivation of production ecology metrics are detailed in France (1993).…”

“…Growth rates were calculated for young, juveniles and adults as in Biette (1969) based on analysis of population length-frequency distributions (France, 1993). Rates for different life stages were summed for a single lake-specific value for the present analysis.…”

“…As with growth, mortality rates were summed for different life stages for the present analysis. Annual production and biomass were determined from size-frequency analysis (France, 1993) as in Lindeman & Momot (1983). Final production estimates were reduced with application of a times-loss factor so that the apparent negative production values obtained in the youngest size classes were not included (Benke, 1984).…”

The relationship of metals, bifenthrin, physical habitat metrics, grain size, total organic carbon, dissolved oxygen and conductivity toHyalella sp.abundance in urban California streams

“…[30] Unfortunately, in-stream vegetation is not measured as part of standard physical habitat assessments in California. [17] In the natural aquatic environment, Hyalella azteca lives in algal mats [31] , macrophyte beds [32] or rocky habitats. [33] Wienert [34] found that unlike many other genera of amphipods, Hyalella is not inclined to burrow into the substrate for shelter but rather finds shelter in branching aquatic plants such as Chara.…”