<?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%">Puerto, A</style></author><author><style face="normal" font="default" size="100%">Rico, M</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Trees as a homogenizing factor of the herbaceous community structure and nutrient content in Mediterranean grasslands</style></title><secondary-title><style face="normal" font="default" size="100%">AGROCHIMICA</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">1996</style></year></dates><publisher><style face="normal" font="default" size="100%">IST CHIMICA AGRARIA</style></publisher><pub-location><style face="normal" font="default" size="100%">UNIV PISA VIA S MICHELE DEGLI SCALZI, 2 PISA 56100, ITALY</style></pub-location><volume><style face="normal" font="default" size="100%">40</style></volume><pages><style face="normal" font="default" size="100%">197-208</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">The dehesa system consists of two subsystems, situated under the tree&lt;br/&gt;crowns and in the open spaces. They differ clearly in structure and&lt;br/&gt;function. The locations under trees are less variable, tending to&lt;br/&gt;greater similarity in species diversity, homogeneity, plant biomass,&lt;br/&gt;percentage of biomass of constituent families, and plant tissue nutrient&lt;br/&gt;content (N, P, K, Na, Ca and Mg), thus showing a certain independence in&lt;br/&gt;relation to the topographic situation. By contrast, the open spaces are&lt;br/&gt;very much influenced by the position they occupy in the slope gradients.&lt;br/&gt;It seems that homogenizing factors interact with others which tend to&lt;br/&gt;intensify heterogeneity. The less variable structures (under trees)&lt;br/&gt;could be interpreted as agents pumping fertility from the subsoil and&lt;br/&gt;presenting it for the use of herbaceous species. The most influenced&lt;br/&gt;structures are undoubtedly those situated under the tree crowns, but the&lt;br/&gt;whole system is influenced in this way. Consequently, topography and&lt;br/&gt;trees create a large number of habitats for herbaceous species,&lt;br/&gt;especially due to the overlapping of both factors. The harmony of the&lt;br/&gt;combination of the two factors gives stability to the system and has&lt;br/&gt;permitted its survival, without degradation, for many centuries.</style></abstract></record></records></xml>