Sleutelrol voor halfparasieten in de biogeochemie van soortenrijke graslanden

Abstract

Hemiparasitic plants are keystone species in semi-natural grasslands and impact on structure and species composition of the plant community by both parasitism and litter pathways. Because of the suppression of hosts and insufficient nutrient use, total biomass decreases and space becomes available to other species. By producing high-quality litter, hemiparasites increase nutrient availability, compensating som of the biomass decrease due to parasitism. We studied the litter pathway and the overall net effect of Rhinanthus angustifolius and Pedicularis sylvatica on the vegetation. The parasitism pathway proved more important than the litter pathway. Compared to Pedicularis, Rhinanthus has a bigger impact on its plant community – reducing total biomass more and therefore promoting less abundant species as light becomes more available. The litter pathway provides an additional way through which hemiparasites might impact on species composition and promotes fast-growing species. Introduction of hemiparasites can be considered as a means to facilitate the restoration of species-rich grasslands, if applied properly