<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Zavala, M A</style></author><author><style face="normal" font="default" size="100%">ESPELTA, J M</style></author><author><style face="normal" font="default" size="100%">RETANA, J</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Constraints and trade-offs in Mediterranean plant communities: The case of holm oak-Aleppo pine forests</style></title><secondary-title><style face="normal" font="default" size="100%">The Botanical Review</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Aleppo pine</style></keyword><keyword><style  face="normal" font="default" size="100%">disturbance regimes</style></keyword><keyword><style  face="normal" font="default" size="100%">forest dynamics</style></keyword><keyword><style  face="normal" font="default" size="100%">holm oak (voyant)</style></keyword><keyword><style  face="normal" font="default" size="100%">light intensity</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean plant-communities</style></keyword><keyword><style  face="normal" font="default" size="100%">Water availability</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year></dates><volume><style face="normal" font="default" size="100%">66</style></volume><pages><style face="normal" font="default" size="100%">119-149</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In this paper we review those aspects that are relevant to the development of a mechanistic ecological theory to account for the structure and dynamics of Mediterranean forests, focus- ing our attention on mixed forests of holm oak (Quercus ilex L.), a shade-tolerant, slow- growing species that resprouts vigorously after disturbance, and Aleppo pine (Pinus halepen- sis M.), a fast-growing, nonresprouting, shade-intolerant species. The main objectives of this report are: to introduce some of the primary features of these forests, showing their structural complexity and historical peculiarities; to show that much of this complexity can be concep- tually reduced to two main factors of variation, soil-moisture gradients and a complex inter- action of historical management and disturbance regimes; and to contrast the unique features of Mediterranean systems with other communities that have inspired generalization in ecol- ogy. Plants in Mediterranean-climate regions must face several environmental constraints dur- ing their life cycle: water limitation, competition for light, and a complex set of disturbance regimes, mainly fire, herbivory, and human exploitation. The response of co-occurring spe- cies to a given set of environmental constraints depends on a combination of physiological and morphological traits. In holm oak-Aleppo pine forests, the lower limit of distribution along a soil-moisture gradient appears to be controlled by dry-season water stress on seedling performance, and the upper limit seems to be controlled by shade tolerance relative to com- petitors. The processes that generate and maintain these patterns are related to the responses of the two species to the water and light environments that result from interacting gradients of disturbance and resource availability. The dynamics of mixed holm oak-Aleppo pine forests may be represented along two major environmental axes: water availability and light intensity; namely, time since last disturbance. At the regional scale, the presence of holm oak and Aleppo pine is expected to be driven mainly by the precipitation regime, with the proportion of Aleppo pine in- creasing toward the driest border and with holm oak being the dominant species in areas with higher precipitation. Changes of dominance of holm oak and Aleppo pine also re- spond to water availability at the local scale. In this case, variations between species de- pend on different factors in a complex way, because reduced soil-moisture levels may re- sult either from low precipitation or from topography and edaphic features. The dynamics of holm oak-Aleppo pine forests are also determined by temporal changes in canopy clo- sure; that is, forest recovery after disturbance. In this case, the proportion of Aleppo pine would increase in recently disturbed stands (i.e., with high light intensity reaching the for- est floor), whereas regeneration of holm oak would be dominant under partially closed canopies. Theories of forest dynamics developed in humid regions may apply only poorly to Medi- terranean plant communities, where vegetation change is qualitatively or quantitatively dif- ferent. Thus, succession in temperate forests appears to be driven by differences in light availability and shade tolerance; but in Mediterranean plant communities, water limitation is of greater importance for the distribution of forest species. In Mediterranean landscapes the interaction of life-history strategies with changing environments is difficult to infer from observational and experimental studies. A mechanistic approach, in which competi- tion or plant performance is measured as a function of resource availability, seems more feasible. The idea should be to develop multispeeies models calibrated specifically for Mediterranean forests in a combined program of modeling, field research, and experimenta- tion.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Zavala, M. A.</style></author><author><style face="normal" font="default" size="100%">Espelta, J. M.</style></author><author><style face="normal" font="default" size="100%">Retana, J.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Constraints and trade-offs in Mediterranean plant communities: The case of holm oak-Aleppo pine forests</style></title><secondary-title><style face="normal" font="default" size="100%">The Botanical Review</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Aleppo pine</style></keyword><keyword><style  face="normal" font="default" size="100%">disturbance regimes</style></keyword><keyword><style  face="normal" font="default" size="100%">forest dynamics</style></keyword><keyword><style  face="normal" font="default" size="100%">holm oak (voyant)</style></keyword><keyword><style  face="normal" font="default" size="100%">light intensity</style></keyword><keyword><style  face="normal" font="default" size="100%">mediterranean plant-communities</style></keyword><keyword><style  face="normal" font="default" size="100%">Water availability</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2000</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2000///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/3u77576376314080.pdf</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">66</style></volume><pages><style face="normal" font="default" size="100%">119 - 149</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In this paper we review those aspects that are relevant to the development of a mechanistic ecological theory to account for the structure and dynamics of Mediterranean forests, focus- ing our attention on mixed forests of holm oak (Quercus ilex L.), a shade-tolerant, slow- growing species that resprouts vigorously after disturbance, and Aleppo pine (Pinus halepen- sis M.), a fast-growing, nonresprouting, shade-intolerant species. The main objectives of this report are: to introduce some of the primary features of these forests, showing their structural complexity and historical peculiarities; to show that much of this complexity can be concep- tually reduced to two main factors of variation, soil-moisture gradients and a complex inter- action of historical management and disturbance regimes; and to contrast the unique features of Mediterranean systems with other communities that have inspired generalization in ecol- ogy. Plants in Mediterranean-climate regions must face several environmental constraints dur- ing their life cycle: water limitation, competition for light, and a complex set of disturbance regimes, mainly fire, herbivory, and human exploitation. The response of co-occurring spe- cies to a given set of environmental constraints depends on a combination of physiological and morphological traits. In holm oak-Aleppo pine forests, the lower limit of distribution along a soil-moisture gradient appears to be controlled by dry-season water stress on seedling performance, and the upper limit seems to be controlled by shade tolerance relative to com- petitors. The processes that generate and maintain these patterns are related to the responses of the two species to the water and light environments that result from interacting gradients of disturbance and resource availability. The dynamics of mixed holm oak-Aleppo pine forests may be represented along two major environmental axes: water availability and light intensity; namely, time since last disturbance. At the regional scale, the presence of holm oak and Aleppo pine is expected to be driven mainly by the precipitation regime, with the proportion of Aleppo pine in- creasing toward the driest border and with holm oak being the dominant species in areas with higher precipitation. Changes of dominance of holm oak and Aleppo pine also re- spond to water availability at the local scale. In this case, variations between species de- pend on different factors in a complex way, because reduced soil-moisture levels may re- sult either from low precipitation or from topography and edaphic features. The dynamics of holm oak-Aleppo pine forests are also determined by temporal changes in canopy clo- sure; that is, forest recovery after disturbance. In this case, the proportion of Aleppo pine would increase in recently disturbed stands (i.e., with high light intensity reaching the for- est floor), whereas regeneration of holm oak would be dominant under partially closed canopies. Theories of forest dynamics developed in humid regions may apply only poorly to Medi- terranean plant communities, where vegetation change is qualitatively or quantitatively dif- ferent. Thus, succession in temperate forests appears to be driven by differences in light availability and shade tolerance; but in Mediterranean plant communities, water limitation is of greater importance for the distribution of forest species. In Mediterranean landscapes the interaction of life-history strategies with changing environments is difficult to infer from observational and experimental studies. A mechanistic approach, in which competi- tion or plant performance is measured as a function of resource availability, seems more feasible. The idea should be to develop multispeeies models calibrated specifically for Mediterranean forests in a combined program of modeling, field research, and experimenta- tion.</style></abstract><issue><style face="normal" font="default" size="100%">March</style></issue></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Bussotti, F.</style></author><author><style face="normal" font="default" size="100%">Ferretti, M.</style></author><author><style face="normal" font="default" size="100%">COZZI, A.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Crown status of holm oak (Quercus ilex L.) trees as related to phenology and environmental stress</style></title><secondary-title><style face="normal" font="default" size="100%">Water, Air, &amp; Soil …</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">abscission</style></keyword><keyword><style  face="normal" font="default" size="100%">crown condition</style></keyword><keyword><style  face="normal" font="default" size="100%">holm oak (voyant)</style></keyword><keyword><style  face="normal" font="default" size="100%">leaves</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1995</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1995///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/p7472u8l15164pk6.pdf</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">85</style></volume><pages><style face="normal" font="default" size="100%">1269 - 1274</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In order to study the possible interactions between air pollution and climate coaditions in Mediterranean evergream broadleaf species, since 1987 we have been monitoring the annual and infra-annual variations in crown density of Quercus ilex L. (holm oak) in a permanent sample plot. The behaviour of crown density has been compared with litterfall pattern and aging processes in leaves. The results of this study confirm the important impact of climate on crown condition in Meditea-raneeaa broadleaves, so that even the role of non- acute pollution can be disguised. Xeromorph adaptations in holm oak leaves are also a mechanism providing a greater protection against poltutants.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Bussotti, F</style></author><author><style face="normal" font="default" size="100%">Ferretti, M</style></author><author><style face="normal" font="default" size="100%">Cozzi, A</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Crown status of holm oak (Quercus ilex L.) trees as related to phenology and environmental stress</style></title><secondary-title><style face="normal" font="default" size="100%">Water, Air, &amp; Soil …</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">abscission</style></keyword><keyword><style  face="normal" font="default" size="100%">crown condition</style></keyword><keyword><style  face="normal" font="default" size="100%">holm oak (voyant)</style></keyword><keyword><style  face="normal" font="default" size="100%">leaves</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1995</style></year></dates><volume><style face="normal" font="default" size="100%">85</style></volume><pages><style face="normal" font="default" size="100%">1269-1274</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">In order to study the possible interactions between air pollution and climate coaditions in Mediterranean evergream broadleaf species, since 1987 we have been monitoring the annual and infra-annual variations in crown density of Quercus ilex L. (holm oak) in a permanent sample plot. The behaviour of crown density has been compared with litterfall pattern and aging processes in leaves. The results of this study confirm the important impact of climate on crown condition in Meditea-raneeaa broadleaves, so that even the role of non- acute pollution can be disguised. Xeromorph adaptations in holm oak leaves are also a mechanism providing a greater protection against poltutants.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Fernandes, J C</style></author><author><style face="normal" font="default" size="100%">Henriques, F S</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Metal contamination in leaves and fruits of holm-oak (Quercus rotundifolia Lam.) trees growing in a pyrites mining area at Aljustrel, Portugal</style></title><secondary-title><style face="normal" font="default" size="100%">Water, Air, &amp; Soil Pollution</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">acorns</style></keyword><keyword><style  face="normal" font="default" size="100%">holm oak (voyant)</style></keyword><keyword><style  face="normal" font="default" size="100%">leaves</style></keyword><keyword><style  face="normal" font="default" size="100%">Metal pollution</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1989</style></year></dates><volume><style face="normal" font="default" size="100%">48</style></volume><pages><style face="normal" font="default" size="100%">409-415</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Pyrites extraction at Aljustrel mines, south Portugal, is causing severe metal pollution of soil, water and air, leading to a growing concern with environmental degradation in the mining area and its surroundings. In this work we measured levels of Fe, Mn, Zn, Cu, and Pb in leaves and fruits of holm-oak (Quercus rotundifolia Lain.) trees growing at the outskirts of the mining area. The trees showed pronounced stunting, reduced leaf size and extensive necrotic and chlorotic spotting. The leaves from trees growing in the area under study had much higher concentrations of metals than the controls - ca. 50 times higher for Cu, 20 times for Pb and Zn, 10 times for Fe, and 2 times for Mn - but is is possible that part of the metals associated with the leaves are actually retained in the dense hair cover present on their lower surface. The acorns from the contaminated areas were also metal polluted, particularly with Fe, Zn, and Cu, and this finding raises the threat of animal and human health hazards, since these fruits are commonly used for feeding livestock and are occasionally consumed directly by man. 1.</style></abstract></record><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Fernandes, J. C.</style></author><author><style face="normal" font="default" size="100%">Henriques, F. S.</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Metal contamination in leaves and fruits of holm-oak (Quercus rotundifolia Lam.) trees growing in a pyrites mining area at Aljustrel, Portugal</style></title><secondary-title><style face="normal" font="default" size="100%">Water, Air, &amp; Soil Pollution</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">acorns</style></keyword><keyword><style  face="normal" font="default" size="100%">holm oak (voyant)</style></keyword><keyword><style  face="normal" font="default" size="100%">leaves</style></keyword><keyword><style  face="normal" font="default" size="100%">Metal pollution</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">1989</style></year><pub-dates><date><style  face="normal" font="default" size="100%">1989///</style></date></pub-dates></dates><urls><web-urls><url><style face="normal" font="default" size="100%">http://www.springerlink.com/index/P4Q3632K02WW308X.pdf</style></url></web-urls></urls><volume><style face="normal" font="default" size="100%">48</style></volume><pages><style face="normal" font="default" size="100%">409 - 415</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">Pyrites extraction at Aljustrel mines, south Portugal, is causing severe metal pollution of soil, water and air, leading to a growing concern with environmental degradation in the mining area and its surroundings. In this work we measured levels of Fe, Mn, Zn, Cu, and Pb in leaves and fruits of holm-oak (Quercus rotundifolia Lain.) trees growing at the outskirts of the mining area. The trees showed pronounced stunting, reduced leaf size and extensive necrotic and chlorotic spotting. The leaves from trees growing in the area under study had much higher concentrations of metals than the controls - ca. 50 times higher for Cu, 20 times for Pb and Zn, 10 times for Fe, and 2 times for Mn - but is is possible that part of the metals associated with the leaves are actually retained in the dense hair cover present on their lower surface. The acorns from the contaminated areas were also metal polluted, particularly with Fe, Zn, and Cu, and this finding raises the threat of animal and human health hazards, since these fruits are commonly used for feeding livestock and are occasionally consumed directly by man. 1.</style></abstract></record></records></xml>