Effect of four species of cladocerans (Crustacea) on the population growth of Brachionus patulus (Rotifera) [Einfluss von vier Cladoceren-Arten auf das populationswachstum von brachionus patulus (Rotifera)]
Por:
Nandini S., Sarma S.S.S., Hurtado-Bocanegra M.D.
Publicada:
1 ene 2002
Resumen:
In freshwater ecosystems, rotifers and cladocerans often dominate, in terms of both, numbers and biomass. However, between these groups, competition leads to an inverse relation. We quantified the effect of cladocerans (at fixed density = 0.5 ind mL-1; and biomass = 9.6 ?g mL-1 (dry weight)) on the population growth of Brachionus patulus, using Daphnia pulex, Simocephalus vetulus, Moina macrocopa, and Ceriodaphnia dubia at 0.5 · 106 cells mL-1 and 1.5 · 106 cells mL-1 of Chlorella vulgaris. The initial density of rotifers in the controls and in the mixed cultures was 5 ind mL-1, while the density and the biomass of cladocerans (experiments conducted separately) was kept constant. Our results showed that regardless of food density, the presence of cladocerans had a significantly negative effect on the maximal population density and the rate of population growth of B. patulus. Control rotifer populations increased with increasing food density. Population density of B. patulus was least affected by Ceriodaphnia dubia, while the maximum negative effect was caused by the presence of Daphnia pulex. The rate of population increase per day (r) of B. patulus in controls was (0.27 ± 0.01) d-1 and (0.32 ± 0.01) d-1 under low and high food levels, respectively. The r values were negative in the presence of D. pulex regardless of food density while in the presence of S. vetulus, a negative r value was obtained only at the lower food level.
Filiaciones:
Nandini S.:
División de Investigación y Posgrado, Proyecto CyMA, Universidad Nacional Autónoma de México, AP 314, Tlalnepantla, Edo. de México, Mexico
Sarma S.S.S.:
Laboratorio de Zoología Acuática, División de Investigación y Posgrado, Universidad Nacional Autónoma de México, AP 314, Tlalnepantla, Edo. de México, Mexico
Hurtado-Bocanegra M.D.:
División de Investigación y Posgrado, Proyecto CyMA, Universidad Nacional Autónoma de México, AP 314, Tlalnepantla, Edo. de México, Mexico
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