RT info:eu-repo/semantics/article
T1 Facilitation of Quercus ilex in Mediterranean shrubland is explained by both direct and indirect interactions mediated by herbs
A1 Cuesta Poveda, Bárbara
A1 Villar Salvador, Pedro
A1 Rey Benayas, José María
A1 Puértolas Simón, Jaime
A1 Michalet, Richard
K1 Chlorophyll fluorescence
K1 Herb competition
K1 Quercus ilex
K1 Retama sphaerocarpa
K1 Seedling size
K1 Water potential
K1 Ciencia
K1 Medio Ambiente
K1 Science
K1 Environmental science
AB 1. Competitive and facilitative interactions shape plant communities. Whereas a number of studies have addressed competition and direct facilitation among plants in dry ecosystems, indirect facilitation has received little attention.2. We investigated the relative importance of direct and indirect facilitation by the nurse plant Retama sphaerocarpa on late-successional Quercus ilex seedlings mediated by herb suppression in a Mediterranean shrubland in 2006 and 2007. We also studied whether facilitation outcome depended on the size of the facilitated seedlings. 3. A field experiment was carried out to test the effect of (i) position of Q. ilex seedling with respectto shrub canopy (under shrubs or in gaps), (ii) herb competition (presence or absence), and (iii) seedlingsize. 2006 was an average rainfall year while 2007 had a much more humid spring and a dryersummer than 2006.4. In both years, nurse shrubs reduced seedling mortality whereas herbs increased it. In the averagerainfall year, seedling mortality under shrubs was unaffected by herbs whereas in gaps it was signifi-cantly higher in presence of herbs. This showed that the nurse shrub indirectly facilitated the seedlingsby reducing the competitive capacity of herbs. Conversely, facilitation was predominatelydirect during the humid spring and dry summer year since herbs hindered seedling survival similarlyunder the nurse shrub and in gaps. The nurse shrub directly facilitated the seedlings by reducingseedling photoinhibition and water stress.5. Improvement of environmental conditions by Retama benefited smaller seedlings but not largerseedlings since the nurse shrub reduced mortality of smaller seedlings relative to that in gaps, butthis effect was not observed for larger seedlings. This indicates that individuals within a seedlingpopulation may not have the same response to facilitation.6. Synthesis. Both indirect and direct facilitation are important mechanisms for Q. ilex regenerationin Retama shrubland and their importance seems to vary with climatic conditions. Indirect facilitationby release of herb competition under nurse shrubs is important in years of dry springs whencompetition between nurse shrubs and herbs is high, whereas direct facilitation mediated by microclimateamelioration increases with summer aridity
PB John Wiley & Sons
SN 1365-2745
YR 2010
FD 2010
LK http://hdl.handle.net/10017/21314
UL http://hdl.handle.net/10017/21314
LA eng
NO Ministerio de Educación y Ciencia
DS MINDS@UW
RD 20-abr-2024