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There is a strong negative relationship between soil phosphorus and species richness in grasslands

Ann-Mari Fransson1
1 Swedish University of Agricultural Sciences

O 5.3 in Linking biodiversity and biogeochemistry

15.07.2014, 11:40-12:00, H19

Competition for below-ground resources is a strong force in niche differentiation of plants, preventing competitive exclusion, which would otherwise decrease species richness. Soil phosphorus is a resource of particular interest due to its diverse speciation and immobility in soils. The multidimensional phosphorus resource could support a high niche dimensionality and be of great importance for plant species richness. We have studied differences in soil phosphorus and nitrogen between grassland plots with different species richness, and the relationships between species richness, biomass and nutrient uptake in the field. This study was performed using a pairwise design in semi-natural grasslands in southern Sweden. The levels of easily available soil phosphorus, potentially available soil phosphorus, and extractable soil nitrogen were lower in plots with higher species richness. We found a strong inverse linear relationship between easily available soil phosphorus and species richness. The phosphorus uptake efficiency of the vegetation increased although the competition for phosphorus was more intense in plots with lower concentrations of easily available soil phosphorus and higher species richness. Our results highlight the importance of soil phosphorus for grassland species richness. The results also suggest that soil phosphorus and nitrogen have different effects on grassland species richness.



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last modified 2014-02-12