Quantitative Untersuchungen an Insektenpopulationen in Fichtenforsten des Solling

Abstract

During a period of three years (1971–1973) ca. 180,000 insect imagines (only Pterygota) were caught by means of „groundphoto-eclectors“ in two spruce stands (F1 ca. 90 years old; F3 ca. 45 years old) in the Solling. The catch results are indicative of „emergence abundance“ and „activity density in enclosed rooms“. In the investigation period c. 2700 – 4300 ind./m² × year of insect imagines were caught in the two areas. The „production of imagines“ (biomass-sum of imagines emerging from soil) varied from 5,2–14,3 kg dry weight/ha × year (immigrant-populations included). Assuming a calorific value of 5,5 cal/mg dry weight this means a production of imagines between 29 × 10³ and 79 × 10³ kcal/ha × year. Every year c. 53–67% of the determined production of imagines fell to the populations of only 4–6 species. On the assumption that the energy turnover of the total of insect populations (Pterygota) is by one decimal exponent higher than the production of imagines, the studied partial zoocoenosis has an energy turnover of 290–630 × 10³ kcal/ha × year in F1 (without the portion of the immigrant Xyloterus domesticus) and 340–610 × 10³ kcal/ ha × year in F3.

Ergebnisse des Solling-Projekts der DFG (IBP), Mitteilung Nr. 196.