Experimental evidences of climate change effects on plant recruitment in the Western Mediterranean Basin.

Lloret F, Peñuelas J, Estiarte M, Ogaya R (2004) Experimental evidences of climate change effects on plant recruitment in the Western Mediterranean Basin. In Arianoutsou M, Papanastasis VP (eds) Ecology, conservation and management of Mediterranean climate ecosystems. Millpress, Rotterdam. Edició en CD-ROM (ISBN-90-5966-016-1).

Experimental evidence of reduced diversity of seedlings due to climate modification in a Mediterranean-type community

Lloret F., Penuelas J., Estiarte M. (2004) Experimental evidence of reduced diversity of seedlings due to climate modification in a Mediterranean-type community. Global Change Biology. 10: 248-258.
Enllaç
Doi: 10.1111/j.1365-2486.2004.00725.x

Resum:

We are still lacking in experimental evidence of the effects of climate change on the richness of plant species under field conditions. We report a decrease in the species richness of recruited seedlings in a Mediterranean shrubland in experimentally induced drought and warming over 4 consecutive years. Drought decreased the number of emerging seedlings and their respective species richness. Warming also decreased seedling species richness, but it did not affect the number of emerging seedlings. Species that produce fewer recruits are more likely to disappear in drier or warmer scenarios. However, when the effect of induced climate treatment was greatest, the more abundant species in control stands were not necessarily the ones least affected by treatment; in other words, species-idiosyncratic responses may occur. These results show that demographic processes are sensitive to minor climate changes, with probable consequences on the diversity and structure of the future plant communities. © 2004 Blackwell Publishing Ltd.

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Complex spatiotemporal phenological shifts as a response to rainfall changes

Peñuelas J., Filella I., Zhang X., Llorens L., Ogaya R., Lloret F., Comas P., Estiarte M., Terradas J. (2004) Complex spatiotemporal phenological shifts as a response to rainfall changes. New Phytologist. 161: 837-846.
Enllaç
Doi: 10.1111/j.1469-8137.2004.01003.x

Resum:

• Climatic warming produces significant gradual alterations in the timing of life-cycle events, and here we study the phenological effects of rainfall-pattern changes. • We conducted ecosystem field experiments that partially excluded rain and runoff during the growing season in a Mediterranean forest and in a mediterranean shrubland. Studies of time-series of leaf-unfolding, flowering and fruiting over the last 50 yr in central Catalonia were carried out, and greenup onset in the Iberian Peninsula was monitored by satellite images. • Experimental, historical and geographical changes in rainfall produced significant, complex and strongly species-specific, as well as spatially and temporally variable, phenological effects. Among these changes, it was found that in the Iberian Peninsula, greenup onset changes from spring (triggered by rising temperatures) in the northern cool-wet regions to autumn (triggered by the arrival of autumn rainfalls) in the southern warm-dry regions. Even in the mesic Mediterranean central Catalonia (NE of the peninsula) rainfall had a stronger relative influence than temperature on fruiting phenology. • The results show that changes in rainfall and water availability, an important driver of climate change, can cause complex phenological changes with likely far-reaching consequences for ecosystem and biosphere functioning and structure. The seasonal shift in the Iberian Peninsula further highlights this importance and indicates that vegetation may respond to climate change not only with gradual, but also with abrupt temporal and spatial, changes in the timing of greenup onset.

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