Absence of effects on nutrient budgets after insect defoliation

Abstract

Nutrient export via streamflow after the defoliation by Gonipterus scutellatus Gill. in a Eucalyptus globulus Labill. watershed in Galicia (NW Spain) was monitored from 1999 to 2006. The effects of such defoliation on nutrients balance had not been previously evaluated. Insect defoliation caused no significant changes in streamflow nutrient concentrations during the period of study compared with the pre-perturbation period and nutrient exports in streamflow were compensated via precipitation in all cases. The results presented here show that in spite of the reduction in E.globulus growth caused by the defoliation, nutrient balances were positive, suggesting a minor impact in the soil-plant system nutrient budget.