Drought and warming induced changes in P and K concentration and accumulation in plant biomass and soil in a Mediterranean shrubland |
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Authors: | J Sardans J Peñuelas P Prieto M Estiarte |
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Institution: | (1) Ecophysiology and Global Change Unit CSIC-CEAB-CREAF, CREAF (Center for Ecological research and Forestry Applications), Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain |
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Abstract: | A field experiment involving drought and warming manipulation was conducted over a 6-year period in a Mediterranean shrubland
to simulate the climate conditions projected by IPCC models for the coming decades (20% decreased soil moisture and 1°C warming).
We investigated P and K concentration and accumulation in the leaves and stems of the dominant species, and in soil. Drought
decreased P concentration in Globularia alypum leaves (21%) and in Erica multiflora stems (30%) and decreased K concentration in the leaves of both species (20% and 29%, respectively). The general decrease
of P and K concentration in drought plots was due to the reduction of soil water content, soil and root phosphatase activity
and photosynthetic capacity that decreased plant uptake capacity. Warming increased P concentration in Erica multiflora leaves (42%), but decreased it in the stems and leaf litter of Erica multiflora and the leaf litter (33%) of Globularia alypum, thereby demonstrating that warming improved the P retranslocation and allocation from stem to leaves. These results correlate
with the increase in photosynthetic capacity and growth of these two dominant shrub species in warming plots. Drought and
warming had no significant effects on biomass P accumulation in the period 1999–2005, but drought increased K accumulation
in aboveground biomass (10 kg ha−1) in Globularia alypum due to the increase in K concentration in stems. The stoichiometric changes produced by the different responses of the nutrients
led to changes in the P/K concentration ratio in Erica multiflora leaves, stems and litter, and in Globularia alypum stems and litter. This may have implications for the nutritional value of these plant species and plant–herbivore relationships.
The effects of climate change on P and K concentrations and contents in Mediterranean ecosystems will differ depending on
whether the main component of change is drought or warming. |
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Keywords: | Climate change Drought Erica multiflora Fertility Globularia alypum Global change Biomass K concentration Nutrient availability Nutrient content Biomass P concentration Sclerophylly Warming Water stress |
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