Original paper

Secondary production of invertebrates in a Central European mountain stream (Steina, Black Forest, Germany)

Meyer, Elisabeth I.; Poepperl, Rainer

Abstract

We estimated macroinvertebrate production in the Central European mountain stream Steina over 3 years from November 1985 to October 1988 applying the increment-summation method and additional P/B ratios from literature. Total production differed little between the three study years, amounting to 19.0 (1986), 19.7 (1987) and 20.8gm-2y-1 (1988). Ephemeroptera, Trichoptera and Diptera contributed most to total invertebrate production. Whereas the production of Tricladida, Oligochaeta, Acari, Crustacea, and Coleoptera remained more or less stable over the three study years, it showed in part distinct trends or between-year variation in the three most dominant orders. Mayfly production increased from 4.7 to 7.2 g m-2 y-1 and stonefly production from 1.8 to 2.3 g m-2 y-1. Caddisfly production showed a decreasing tendency from 1986 (6.8gm-2y-1) to 1988 (4.0gm-2y-1). Marked differences, increasing or decreasing values, occurred at some species level. Secondary production of all primary consumers in the Steina was 16.7 (1986, 1987) and 17.9 (1988) gm-2y-1 over the three-year time span. Production of secondary consumers (predators) amounted to 2.3-3.0 g m-2 y-1 of total production, and was 2.7g m-2 y-1 on average. Analysis of the portions of functional groups revealed that suspension feeders and predators accounted for only 12.8-17.8 % of total production, whereas the relative contribution of scrapers was about 24 % in 1986 and 1987, and even reached 38 % in 1988. Production of shredders and deposit feeders reached the same order of magnitude as scrapers, particularly in 1986. However, there was a decreasing tendency in production of shredders and deposit feeders and an increasing tendency in production of scrapers and suspension feeders towards the 3rd year.

Keywords

macroinvertebrate communityinsectsfeeding typesp bincrement-summation method