Population dynamics and production studies of species of centropyxidae (Testacea, Rhizopoda) in an aspen woodland soil

Abstract

Summary Twelve species of Centropyxidae and 1 species of Plagiopyxidae were observed as live cells or empty tests throughout the study period in an aspen woodland soil. Only 3 centropyxid species were considered constant and comprised 4% of the mean annual abundance, 19% of the mean annual biomass, 2 % of the total production numbers and 10.5 % of the total secondary production for all species of Testacea. Including the total production biomass for C. sylvatica , an incidental species, the total centropyxid production for the year increased to 20 % of the total testacean production. For the Centropyxidae, mean annual biomass and total annual production were measured as 0.14 and 41.1 g wet weight · m−2 respectively, while total annual ingestion, respiration losses and egestion losses were calculated as 274, 68.5 and 164.4 g · m −2 respectively. The annual production biomass varied from 115 to 225 times (mean 160) the standing crop of Centropyxidae in all the soil layers. The dry weight of carbon respired annually by the centropyxids was estimated as 3.22 g · m −2 , which amounted to 1.2 % of the total annual carbon input.