Soil nutrient heterogeneity modulates ecosystem responses to changes in the identity and richness of plant functional groups
Article first published online: 23 DEC 2010
© 2010 The Authors. Journal of Ecology © 2010 British Ecological Society
Journal of Ecology
Volume 99, Issue 2, pages 551–562, March 2011
How to Cite
García-Palacios, P., Maestre, F. T. and Gallardo, A. (2011), Soil nutrient heterogeneity modulates ecosystem responses to changes in the identity and richness of plant functional groups. Journal of Ecology, 99: 551–562. doi: 10.1111/j.1365-2745.2010.01765.x
- Issue published online: 15 FEB 2011
- Article first published online: 23 DEC 2010
- Received 28 April 2010; accepted 2 November 2010 Handling Editor: Robert Jones
- ecosystem functioning;
- plant functional groups;
- plant resource use strategy;
- plant–soil (below-ground) interactions;
- soil nutrient cycling;
- soil nutrient heterogeneity
1. Recent research has shown that biodiversity may have its greatest impact on ecosystem functioning in heterogeneous environments. However, the role of soil heterogeneity as a modulator of ecosystem responses to changes in biodiversity remains poorly understood, as few biodiversity studies have explicitly considered this important ecosystem feature.
2. We conducted a microcosm experiment over two growing seasons to evaluate the joint effects of changes in plant functional groups (grasses, legumes, non-legume forbs and a combination of them), spatial distribution of soil nutrients (homogeneous and heterogeneous) and nutrient availability (50 and 100 mg of nitrogen (N) added as organic material) on plant productivity and surrogates of carbon, phosphorous and N cycling (β-glucosidase and acid phosphatase enzymes and in situ N availability, respectively).
3. Soil nutrient heterogeneity interacted with nutrient availability and plant functional diversity to determine productivity and nutrient cycling responses. All the functional groups exhibited precise root foraging patterns. Above- and below-ground productivity increased under heterogeneous nutrient supply. Surrogates of nutrient cycling were not directly affected by soil nutrient heterogeneity. Regardless of their above- and below-ground biomass, legumes increased the availability of soil inorganic N and the activity of the acid phosphatase and β-glucosidase enzymes.
4. Our study emphasizes the role of soil nutrient heterogeneity as a modulator of ecosystem responses to changes in functional diversity beyond the species level. Functional group identity, rather than richness, can play a key role in determining the effects of biodiversity on ecosystem functioning.
5. Synthesis. Our results highlight the importance of explicitly considering soil heterogeneity in diversity–ecosystem functioning experiments, where the identity of the plant functional group is of major importance. Such consideration will improve our ability to fully understand the role of plant diversity on ecosystem functioning in ubiquitous heterogeneous environments.