Effects of simulated herbivory on reproduction of a Mediterranean semi-arid shrub (Anthyllis cytisoides L.)

摘要

We investigated the reproductive consequences and health conditions of artificial defoliation of the Mediterranean foraging shrub Aiuhyllh cytisoides L. (Legiimiimsae) in the southeastern Iberian peninsula. The experiment was conducted in February, when new shoots start elongation. We randomly selected 72H plants of different size; 194 were used as controls and the remainder were experimentally defoliated. In addition to this overall defoliation, we studied the effects on individual stems of ninety selected plants. We performed a hierarchical design analysis of variance with 3 levels of defoliation at plant foliage level (10, 50 and 90% of defoliation) and 3 at the stem level (10, 50, and 90% defoliation). Individual plants were classified by base perimeter into three age classes. Additionally, the effects of defoliation cm plant health and seedling establishment were assessed on marked plants under the three herbivory treatments and control. The results from these experiments demonstrated that inflorescence langth and flower number increased, wound 1,6-fokl on average, when defoliation increased from 10 to 90%. Number of seeds produced per marked stum increased 2.5-fold in young plants when defoliation increased from 10 11)50%, und 1.2-fold in mature plants, but declined by 40% in young plants and 9% in mature plants when defoliation increased from SO to 90%. However, senescent plants produced 4.7-fold more seeds when defoliation increased from 10 to 90% herbivory. Opposite trends were found for seed weight under plant herbivory treatments. When we compared stem production in control and defoliated plants, we also observed lower yield in undamaged stems, There was no evidence of a trade-off between seed number and sued mass. Plant health and seedling establishment were not affected 1 yr. after defoliation.