Competition in Heathland along an Experimental Gradient of Nutrient Availability

Competition under high and low nutrient levels among three grassland species occupying different positions in a successional sequence

“…Surprisingly, species adapted to nutrient-poor environments are not better at capturing nutrients : they do not invest more in their roots (Olff et al, 1990 ;Elberse & Berendse, 1993 ;Vijver et al, 1993 ;Gleeson & Tilman, 1994), nor do they not have generally greater specific root length (SRL) (Ryser & Lambers, 1995) or more root absorption capacity (Chapin, 1980). Although there is some evidence that slow-growing species can respond proportionally more to nutrient patches and pulses (Robinson & Van Vuuren, 1998), the key characteristic of species from nutrient-poor environments is their lower biomass turnover (Berendse et al, 1987 ;Aerts et al, 1990 ;Schla$ pfer & Ryser, 1996) which is responsible for a more efficient nutrient economy (Berendse & Elberse, 1990). Thus it can be stated that species adapted to nutrient-rich environments are characterized by high SSH and SLA, whereas species adapted to nutrient-poor habitats are characterized by low biomass turnover.…”

“…This unexpected recovery needs an explanation. According to current theory, species adapted to nutrient-poor environments are characterized by low biomass turnover, which results in lower rate of nutrient loss (Grime, 1979 ;Berendse & Elberse, 1990 ;Aerts et al, 1990 ;Aerts, 1995) and increases the efficiency of their nutrient economy. However, the biomass of Festuca increased markedly in early spring.…”

Effects of litters with different concentrations of phenolics on the competition between Calluna vulgaris and Deschampsia flexuosa

“…To date, the effect of phenolics on the competition between heather and grasses has not been investigated. Previous experiments on competition between heather species and dominant grasses have focused primarily on the direct effect of additional inorganic nitrogen on the outcome of the competition (Berendse and Aerts 1984;Aerts and Berendse 1988;Aerts et al 1990;Mickel et al 1991;Alonso et al 2001;Britton et al 2003;Barker et al 2004). Our hypothesis is that due to ericoid mycorrhizal fungi, ericaceous plants compete more efficiently with D. flexuosa on nutrient-poor soils amended with litter rich in phenolics than on nutrient-poor soils amended with litter with low phenolics concentrations.…”

Potential Approaches to Developing Lichen-Based Critical Loads and Levels for Nitrogen, Sulfur and Metal-Containing Atmospheric Pollutants in North America

“…Despite this range of circumstantial evidence and indications, competition experiments in the Netherlands have shown a significant effect of nitrogen addition between C. vulgaris and grass species only in young (low stature and cover) heaths (Heil and Diemont, 1983;Roelofs, 1986;Heil and Bruggink, 1987;Aerts et al, 1990). A combination of mesocosm, field and modelling studies across Europe has made it clear over the last decade that the observed changes can only be explained by increased nitrogen deposition as part of a complicated and interacting sequence of events at different time scales, rather than by a simple change in competitive strength.…”

“…Heil and Diemont, 1983). However, C. vulgaris clearly is a better competitor than grass species in mature heath vegetation even at high nitrogen loads if its canopy remains closed (Aerts et al, 1990;Aerts, 1993).…”