Distribution of monocharacter growth form types in mediterranean plant communities of Chile, South Africa and Israel

Abstract

Monocharacter growth fonn types were determined for slected plant communities in Chile along an altitudinal gradient, and in Israel and South Africa along an aridity gradient. More than 60o/o of the species of the plant communities examined are evergreen. Summer deciduous plants are a common feature in ali the sites examined. The percentage of plants shedding ail their leaves in summer vary considerably.Sclerophyily dominates only the temperate mediterranean plant communities examined. Malacophylly is a distinct feature in ail other sites with a considerable percentage of evcrgreen malacophyllous plants.Leaf succulents are found only in the more arid sites of South Africa and Israel and are absent in Chile.Résumé.-L'étude des formes de croissance, à l'aide de monocaractères, est réalisée le long d'un transect altitudinal au Chili ainsi que dans les zones les moins et les plus pluvieuses d'Israël et d'Afrique du Sud.La persistance du feuillage apparaît comme étant le caractère dominant dans les régions étudiées indépendamment de l'altitude et de la pluviosité.Les types méditerranéens de végétation ne sont pas toujours à prédominance de sclérophylles. Un pourcentage considérable de ces espèces sont malacophylles dans les habitats les plus humides et portent des feuilles succulentes dans les habitats les plus arides.La durée de vie des feuilles de la plupart des espèces des sites étudiés n'excèdent que de peu une année.

Leaf patterns, leaf size and ecologically related traits in high Mediterranean mountain on the Moroccan High Atlas

“…Conversely, large leaves (microphyll), which show a relatively low frequency in our study area according to other Mediterranean plant communities (Orshan et al 1984), were evergreen, sclerophyll, often glabrous, Mediterranean forest species whose leaf phenological activity extended throughout the spring until the end of summer in agreement with Cabezudo et al (1992Cabezudo et al ( , 1993, Pérez-Latorre et al (1995), Pérez-Latorre and Cabezudo (2002).…”

“…This agrees with leaf class distributions observed in a mountain matorral from the Andes (Chile) and in a mountain fynbos from Jonkershock (South Africa) (Orshan et al 1984). However, when compared with the leaf size classes in mountain tropical forests, the leaf size is bigger and ranged from micro-to mesophyll (Grubb et al 1963;Ohsawa 1995;Schneider et al 2003).…”

“…Deciduous species are predicted to perform well where winters are cold and summers dry (Griffin 1973) and may be able to grow as on an annual basis as rapidly as evergreens, despite being leafless for part of the year (Mooney and Dunn 1970). Our results show how the leaf patterns and leaf phenology of the High Atlas oro-Mediterranean plant formation follow the general trends established for lowland Mediterranean shrublands with a dry summer period (Orshan 1964(Orshan , 1989Parsons 1976;Orshan et al 1984;Herrera 1984;Díaz Barradas et al 1999;Ackerly et al 2002). Species with small (lepto-and nanophyll) deciduous and malacophyll leaves show an adaptation to the constraints experienced in open Mediterranean ecosystems, such as drought, excessive light or grazing (Milchunas et al 1988;Nobel 1999;Valladares and Pearcy 1999;Moles and Westoby 2000;Jauffret and Lavorel 2003;Navarro et al 2006) and synchronized their leaf phenological activity with the dry months (De Lillis and Fontanella 1992;Navarro et al 1993;CastroDíez et al 2005).…”

“…The botanical nomenclature follows Fennane et al (1999Fennane et al ( -2007. The family and taxonomic group affiliation of each species were added using the APG III (2009) Leaf phenological activity (leaf emergence to leaf shedding) of each species was described using the method by Orshan (1989). We registered (on ten randomly selected plants) the presence or absence of the following phenophases: vegetative growth (increase in length of branches and/or addition of new leaves which are visible to the naked eye) and the beginning of leaf shedding (death of leaves whether they are being shed or remain attached to the stem).…”

“…Deciduous species are common in cooler Mediterranean ecosystems (Mooney and Dunn 1970;Mooney and Kummerow 1971;Hoffmann 1972), where growth and reproduction are restricted to spring and summer (Mooney et al 1977). The phenological adjustment of deciduous species to contrasted seasonality has been considered a symptom of proper acclimation (Orshan 1989;De Lillis and Fontanella 1992;Cabezudo et al 1993;Navarro et al 1993).…”