Interactions between plant species and earthworm casts in a calcareous grassland under elevated CO{sub 2}
The authors tested the hypothesis that the spatial proximity of a plant species to nutrient-rich earthworm casts (e.g., 100% more ammonium and 30% more phosphate than in adjacent soil) is an important determinant of a plant`s responsiveness to elevated atmospheric CO{sub 2}. In 1995 the authors mapped the location of both earthworm surface casts and plants in each of 16 1.2-m{sup 2} plots in a species-rich calcareous grassland in northwestern Switzerland. Eight plots have been maintained under current ambient CO{sub 2} concentrations and eight have been maintained at elevated CO{sub 2} since March 1994. In addition, total ramet production of each species, as a measure of performance, and cumulative cast production at each location (cell) were recorded at peak community biomass in 1995. Plant species within functional groups differed markedly in their degree of association with casts; however, after two growing seasons elevated CO{sub 2} had no effect on plant species or functional group associations with casts. No statistically significant relationship could be demonstrated between plant-species response to elevated CO{sub 2} and the degree of association with casts within any of the functional groups. However, a positive relationship was observed between the mean response of graminoid species to elevated CO{sub 2} and their mean degree of association with surface casts at ambient CO{sub 2}.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 338476
- Journal Information:
- Ecology, Journal Name: Ecology Journal Issue: 3 Vol. 80; ISSN 0012-9658; ISSN ECOLAR
- Country of Publication:
- United States
- Language:
- English