Abundance, Productivity and Energy Flow of a Population of Coleps hirtusNitzsch (Protozoa, Ciliophora) during the First Stage of Colonization in an Experimental Ricefield

Abstract

Summary Estimates of abundance, production and respiration energy losses by the ciliate population Coleps hirtus Nitzsch , were made in an experimental ricefield located in the province of Reggio Emilia (Northern Italy) during the first stage of colonization (May 10 to 20, 1983) corresponding to the period between the first flooding and the first drying up of the ricefield. Among ciliate populations, Coleps hirtus was the first colonizer of the ricefield, and by the third day reached a peak density of more than 60 × 10 3 1 −1 , remaining the dominant ciliate species for a week. However, on the 8th d a drastic reduction in density due to predation and natural mortality was observed. Production and respiration rates were estimated to be 9.6 kJ · m −2 and 6.1 kJ · m −2 respectively during the time period considered. The net production efficiency was 61 %.