Patterns of plant population dieback and recvery alter drought episodes in Mediterranean forests and shrublands. Climate Change-Forest Ecosystems & Landscape Zvolen (Slovakia).

Lloret F, Peñuelas J, Estiarte M, Ogaya R (2005) Patterns of plant population dieback and recvery alter drought episodes in Mediterranean forests and shrublands. Climate Change-Forest Ecosystems & Landscape Zvolen (Slovakia). Forest Research Institute Zvolen and the European Forest Institute.

Decreased mushroom production in a holm oak forest in response to an experimental drought

Ogaya R., Peñuelas J. (2005) Decreased mushroom production in a holm oak forest in response to an experimental drought. Forestry. 78: 279-283.
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Doi: 10.1093/forestry/cpi025

Resum:

A holm oak forest located in the Prades mountains (north-east Spain) was subjected to an experimental drought, reducing soil water moisture by 15 per cent by the use of plastic strips and funnels that partially excluded rain throughfall and by ditch exclusion of water runoff. We monitored mushroom production per plot once a week during 1999 and 2000. Drought treatment did not delay mushroom appearance, but reduced mushroom production by 62 per cent on average. This suggests that in a drier environment - as predicted for Mediterranean areas in the near future - there is likely to be a decrease in mushroom production, and as a result, changes in some ecological parameters such as soil organic matter decomposition, and also a reduction in the economic and recreational value of these Mediterranean forests. © Institute of Chartered Foresters, 2005. All rights reserved.

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Tissue-water relations of two co-occurring evergreen Mediterranean species in response to seasonal and experimental drought conditions

Serrano L., Peñuelas J., Ogaya R., Savé R. (2005) Tissue-water relations of two co-occurring evergreen Mediterranean species in response to seasonal and experimental drought conditions. Journal of Plant Research. 118: 263-269.
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Doi: 10.1007/s10265-005-0220-8

Resum:

Tissue-water relations were used to characterize the responses of two Mediterranean co-occurring woody species (Quercus ilex L. and Phillyrea latifolia L.) to seasonal and experimental drought conditions. Soil water availability was reduced ∼15% by partially excluding rain throughfall and lateral flow (water runoff). Seasonal and experimental drought elicited physiological and morphological adaptations other than osmotic adjustment: both species showed large increases in cell-wall elasticity and decreased saturated-to-dry-mass ratio. Increased elasticity (lower elastic modulus) resulted in concurrent decreases in relative water content at turgor loss. In addition, P. latifolia showed significant increases in apoplastic water fraction. Decreased saturated-to-dry-mass ratio and increased apoplastic water fraction were accompanied by an increased range of turgor maintenance, which indicates that leaf sclerophyllous traits might be advantageous in drier scenarios. In contrast, the degree of sclerophylly (as assessed by the leaf mass-to-area ratio) was not related to tissue elasticity. An ∼15% reduction in soil water availability resulted in significant reductions in diameter growth when compared to control plants in both species. Moreover, although P. latifolia underwent larger changes in tissue water-related traits than Q. ilex in response to decreasing water availability, growth was more sensitive to water stress in P. latifolia than in Q. ilex. Differences in diameter growth between species might be partially linked to the effects of cell-wall elasticity and turgor pressure on growth, since Q. ilex showed higher tissue elasticity and higher intrinsic tolerance to water deficit (as indicated by lower relative water content at turgor loss) than P. latifolia. © The Botanical Society of Japan and Springer-Verlag 2005.

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