Effect of UV radiation on Eisenia fetida populations

ARIADNA HAMMAN; FERNANDO R. MOMO; ANDRES DUHOUR; LILIANA FALCO; M. CECILIA SAGARIO; M. EUGENIA CUADRADO

PEDOBIOLOGIA

ELSEVIER GMBH

Año: 2003 vol. 47 p. 842 - 845

0031-4056

The objective of this work was to evaluate the effect of different UV radiation doses on the population dynamics of Eisenia fetida. The experiment was performed under laboratory conditions (20 °C, 12 hours light period) in 5 L boxes with soil and cattle manure with five earthworms per box. Three treatments were established: 1) without UV radiation, 2) with a normal dose of UV radiation (45 ± 5 Watts/m2) and 3) with an increased UV dose (60 ± 5 Watts/m2). Four replicates of each treatment were established. Adult earthworms, juveniles and cocoons were counted weekly over a period of 2 months. Cocoons were removed and incubated and the percentage of fertile cocoons was recorded. Populations under the three treatments showed a positive rate of increase. However, UV radiation caused a diminution in E. fetida fecundity from 6.4±0.5 cocoons per individual per week in the treatment (1) to 4.7 ± 0.5 cocoons per individual per week in the treatment (3). UV radiation also caused a decrease in the cocoons’ fertility of around 70 %. The intrinsic rate of increase (r) of the population varied from 0.19 to 0.07 month-1 following the UV radiation increment. These results indicate that earthworm populations can be seriously affected by the enhancement of the UV radiation due to the ozone depletion.