48 research outputs found

    Ecology and structure of Drosophyllum lusitanicum (l.) Links populations in the south-west of the Iberian Peninsula

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    Ecolog√≠a y estructura de poblaciones de Drosophyllum lusitanicum (L.) Link en el suroeste de la Pen√≠nsula Ib√©rica. Drosophyllum lusitanicum es una planta aut√≥gama y nautoc√≥rica cuyo tama√Īo y estructura de poblaci√≥n han sido estudiados en dos √°reas del suroeste de la Pen√≠nsula Ib√©rica. Su car√°cter cenol√≥gico se documenta mediante una tabla fitosociol√≥gica sint√©tica basada en inventarios ya publicados y datos nuevos. En la Sierra de Monchique (Portugal) se cartograf√≠an 21 poblaciones cuyo tama√Īo medio es de 165 individuos. Sin embargo, en el Campo de Gibraltar (Espa√Īa), se encontr√≥ la poblaci√≥n de mayor tama√Īo, con varios miles de individuos en la Sierra del Aljibe. Aqu√≠ se estudi√≥ el tama√Īo de las plantas, el di√°metro de la roseta basal y el grado de lignificaci√≥n de 700 individuos, lo que se utiliz√≥ como indicador indirecto de la estructura de edades de 19 poblaciones.Drosophyllum lusitanicum tiene un cierto car√°cter pionero. Se presenta mayoritariamente en los brezales aclarados de Ericion umbellatae (Stauracantho-Drosophylletum, Querco lusitanicae-Stauracanthetum, Genisto tridentis-Stauracanthetum, etc.). Es capaz de colonizar medios alterados, como cunetas de carreteras y cortafuegos, y es un ap√≥fito en las comunidades basales de Drosophyllo-[Stauracanthenion], siendo adem√°s esta especie favorecida por los frecuentes incendios de la zona. En los alcornocales abiertos de Myrto-Quercetum suberis y en los brezales densos de Erica australis predominan los individuos grandes, siendo √©stas poblaciones maduras. Finalmente, se aportan algunos datos poco conocidos de su reproducci√≥n y ecolog√≠a que indican la necesidad de un mayor esfuerzo para la conservaci√≥n del √°rea portuguesa estudiada

    Ensambles de plantas vasculares asociadas a humedales temporales a lo largo del gradiente mediterr√°neo-templado en Chile

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    Plant species composition and geographical distribution of vernal pools in Mediterranean Chile are poorly studied. Inorder to overcome this gap we collected 73 floristic samples in the Mediterranean-temperate gradient from Chile (31-44¬įS). Additionally, we carried out an exhaustive collection of published phytosociological relev√©s made in this areaincluding some relev√©s from the East side of the Andes in Argentina. The resulting dataset contains 228 observations of269 species. Hierarchical clustering was applied in order to get co-occurrence assemblages. These sets were compared withdiagnostic groups defined a priori, life forms and their status in South America (introduced vs native species). In order todetect geographic and climatic distribution patterns of the assemblages, we extracted climatic summary variables fromthe WorldClim database and performed a principal component analysis (PCA). We detected seven species assemblageswith a significant correspondence to diagnostic groups defined a priori (P < 0.01), though their association is relativelylow (Cram√©r‚Äôs V = 0.49). Native species dominate over adventive ones in each assemblage suggesting low risk of outcompetitionby introduced species adapted to these habitats. The annual life form is over represented in most of the cooccurrencegroups. Despite the huge temperature and precipitation gradient in the studied transect, plant assemblagesare occurring almost along the whole range, supporting the hypothesis of azonality (low dependence on macro-climate).Assemblages defined in this work can be potentially used for further supervised classification strategies in order to defineplant community types within vernal pool vegetation.Actualmente se conoce muy poco sobre la composici√≥n flor√≠stica y la distribuci√≥n geogr√°fica de humedales temporales enChile mediterr√°neo. Con el fin de llenar este vac√≠o, se realizaron 73 inventarios flor√≠sticos en el gradiente mediterr√°neotempladode Chile (31-44¬įS). Adem√°s, se llev√≥ a cabo una b√ļsqueda bibliogr√°fica exhaustiva de inventarios fitosociol√≥gicosen publicaciones cient√≠ficas, incluyendo algunos inventarios de la parte argentina de la Cordillera de los Andes. Se obtuvouna matriz con 228 observaciones y 269 especies. Se aplic√≥ una clasificaci√≥n jer√°rquica para generar ensambles de coocurrencia.Dichos ensambles fueron comparados con grupos de especies diagn√≥sticas definidas a priori, con formas devida y tipos de origen (especies introducidas en Sudam√©rica vs especies nativas). Para determinar patrones de distribuci√≥ngeogr√°fica y clim√°tica, se extrajeron variables del modelo WorldClim y se aplicaron a un an√°lisis de componentes principales(PCA). Seg√ļn la clasificaci√≥n jer√°rquica se determinaron siete ensambles de especies con una alta correspondencia a losgrupos definidos a priori (P < 0,01), sin embargo con un nivel relativamente bajo de asociaci√≥n (√≠ndice V de Cram√©r =0,49). En la vegetaci√≥n estudiada dominan las especies nativas sobre las introducidas, lo que sugiere un bajo riesgo deextinci√≥n por competencia con especies introducidas adaptadas a este tipo de ambientes. La forma de vida anual est√°sobrerrepresentada en la mayor√≠a de los ensambles. Pese al enorme gradiente de temperatura y precipitaci√≥n incluido en elrango de las muestras, los ensambles se distribuyen a lo largo de todo este gradiente, apoyando la hip√≥tesis de azonalidad(indiferencia al macro-clima). Los ensambles definidos en este trabajo pueden ser potencialmente utilizados para posterioresclasificaciones supervisadas con el fin de definir tipos de comunidades vegetales en lagunas temporales

    The role of rock habitats for niche conservatism and as refugia for plants: three case studies

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    Numerous phylogenetic studies look for speciation without ecological radiation (PNC = phylogenetic niche conservatism). However, they ask only rarely for the role of the habitats for niche constancy. Starting from the hypothesis of DAVIS (1951) and SNOGERUP (1971) that the rock environment is 1) an evolutionary trap, conserving many old lineages (phylogenetic relicts) and that 2) it serves as a refugium under climate change, the rock vegetation is analysed for relic-tic species and niche conservatism. Three case studies, based upon phytosociological data sets from subtropical Africa, the Mediterranean area and the Eastern Alps are analysed. Molecular phylogenetic trees from selected taxa indicate the time of the splitting of lineages and the dura-tion of niche constancy. The comparison of succulent communities on rocks in SW-Arabia (class Kleinio-Carallumetea) and on the Canary Islands (Kleinio-Euphorbietea) shows numerous vicarious taxa (synvicariism). The phylogenetic tree of Campylanthus allows assuming the origin of this vicariance pattern in a geo-graphical separation of the ancestors in Mid Tertiary. The aridisation of Northern Africa about 6 Mya ago resulted in this high distance disjunction between Macaronesia and the Eritreo-Arabian region. The separated taxa underwent allopatric speciation, without ecological radiation. They remained in their niches. The vegetation of halve-caves with soaking water (class Adiantetea capilli-veneris) in the Mediterra-nean area and adjacent subtropics shelters local endemics, forming a mosaic of vicarious species. They belong to the genus Pinguicula in the NW-Mediterranean, to Hypericum (section Adenosepalum) in the SW-Mediterranean, and to Primula subgenus Sphondylia on the Arabian Peninsula and its surroundings. These vicariance patterns date back to the Late Tertiary and the climatic conditions in the Quaternary. The constant water supply - quite independent from the macroclimatic condi-tions - and the stenothermic rock surface favour in-situ resilience and make the Adiantetea to outstanding refugia for phylogenetic and geographical relicts. The example of the Caricetum firmae demonstrates relict phenomena, dating back to the last ice age. The rock fissures and calciphilous, alpine rock turfs of the massifs fringing the Eastern Alps shelter endemic cushion plants from genera such as Potentilla, Primula, Androsace, and Gentiana. These taxa of low dispersal capacity are still located in their glacial refugia. The actual species combination of rock communities mirrors historical events. The floristic and spatial patterns are influenced by former climatic conditions, by evolutionary processes and by dispersal limitations. Because of the high variety of micro-habitats, rocks offer refugia and shelter relicts. It is a habitat of outstanding niche conservatism, resulting in patterns of vicarious species and parallel evolution

    Juncus maroccanus Kirschner, a new record to the european flora

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    Juncus maroccanus Kirschner, novedad para la Flora Europaea Palabras clave. Juncaceae, Pen√≠nsula Ib√©rica, Espa√Īa, Estrecho de Gibraltar,¬† dunas. Keywords. Juncaceae, Iberian Peninsula, Spain, Straits of Gibraltar, dunes

    Distribution, ecology, and population structure of Senecio lopezii (Asteraceae) in the Serra de Monchique (SW Portugal)

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    The Serra de Monchique, a mountain chain in the hinterland of the Algarve Province, is characterized by a remarkable degree of floristic richness and endemism. Senecio lopezii, a tall-growing hemicryptophyte, is one of these endemic plants. We studied the local distribution, the ecological requirements, and the size and vitality of the populations in order to evaluate the vulnerability of this species with regard to disturbance by man and landuse changes. Between April and June 2001, populations observed in an area of 84 km² (= the central part of the Serra) were analysed in detail by non-destructive methods. A synopsis of the phytosociology and ecology of the species, based on literature including the Spanish populations in the Campo de Gibraltar (SW Andalusia), is presented. Senecio lopezii was discovered in the Serra de Monchique at only 5 localities, all in mid altitude (500 to 600 m a. s. l.) in the mesomediterranean bioclimatic belt on the northwestern, windward side of the Serra. The species is associated with the Sanguisorbo-Quercetum suberis quercetosum canariensis and its shaded fringes. It persists in Castanea sativa coppices, cultivated on sites with semi-deciduous oak forests as climax, when the topsoil remains intact. Population size ranges from 30 to 350 individuals, the total number is 920 specimens. Plant size and phenological stage were recorded for 258 individuals. Most of them (89 %) are sterile adults, which persist in dark conditions under a closed tree canopy. Flowering starts at a specific plant size and increases with growing rosette diameter, respectively, increasing number of leaves. To get information about the age structure, the life cycle, the role of the seed bank, and the effect of clearings of the shrub layer, further investigations are necessary. Senecio lopezii is a rare species as regards distribution, habitat specification and population size. It must be considered as a potentially endangered species, because it will not tolerate the transformation of oak forests into Eucalyptus plantations

    Contribution à l'étude des groupements rupicoles des Bokkoya (Littoral du Rif Central, Maroc)

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    The coastal limestone massif of the Central Rif Mountains, the Bokkoya, is the driest part of the Moroccan mediterranean coast. After a brief introduction of its physical and phytochorological conditions, the rock communities are described in an phytosociological approach. The northern exposed cliffs are covered by the Sedo wilczekiani-Soncheium masguindalii ass. nov., which is endemic in the subsector Nekor-Bokkoya of the phytochorological sector Nekor-Triffa. On southern slopes, we observe other fragmentary groups of he Poterion ancistroidis. Shady and nitrified rock fissures are colonized by the Mercurialis ambigua- Theligonum cynocrambe community, holders by Succowia balearica. In halve caves there grow Sarcocapnos enneaphylla populations. The contact series are illustrated. A syntaxonomical scheme is given for the rock communities of Northern Morocco. Finally, the associations and their vicariants are discussed in the Westmediterranean context.Le massif calcaire des Bokkoya du littoral rifain est la partie la plus s√®che des c√ītes m√©diterran√©ennes du Maroc. Apres une introduction aux conditions physiques et phytochorologiques de la r√©gion, les groupements rupicoles sont d√©crits scion la methode phytosociologique. Les falaises septentrionales sont couvertes par le Sedowilczekiani-Sonchetummasguindalii ass. nov., une association end√©mique du sous-secteur Nekor- Bokkoya (secteur Nekor-Triffa). Sur les pentes m√©ridionales, on observe d' autres groupements appauvris du Poterion ancistroidis. Les fissures oinbrag√©es et nitrifi√©es au pied des falaises sont colonis√©es par le groupement √° Mercurialisambigua et Theligonum cynocrambe, les √©boulis par celui √° Succowia balearica. Sous des surplombs vivent des peuplements √° Sarcocapnos enneaphylla. Les s√©ries de contact sont illustrees par une figure. Un sch√©ma syntaxonomique des groupements rupicoles du Nord du Maroc est present√©. Finalement, les associations et leurs vicariantes sont discut√©es dans le contexte ouest-m√©diterran√©en

    Fitogeograf√≠a y vegetaci√≥n del Sector Alj√≠bico (C√°diz-M√°laga, Espa√Īa)

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    Phytogeography and vegetation of the Aljibico sector (Cadiz-Malaga, Spain). In this study, the flora and vegetation of the southern Iberian Peninsula (Cadiz and Malaga provinces, Andalusia, Spain) are analized for delimitating and dividing the phytogeographical unit of the Aljibe mountains. This unit includes most of the Gaditanian Peninsula. It is characterized in its physical conditions by the geomorphologic ¬ęflysch¬Ľ of the Campo de Gibraltar and the siliceous base of the Serran√≠a de Ronda, and in its climatic aspect by an atlantic temperature regime and by a mediterranean precipitation regime. As a result, the Aljibico sector is delimited as follows: towards the West by the dune systems of the Cadiz Gulf (Onubense sector), towards the South by he Gibraltar Strait and the Tingitanian Peninsula, towards the East by the Alboran Sea and the Guadalhorce Valley (Malacitano-Axarquiense sector) and towards the North by the Serran√≠a deRonda (Bermejense and Ronde√Īo sectors towards NE) and the Guadalquivir Valley (Hispalense sector towards NW). Based on the chorology of the flora and the vegetation and upon the abiotic conditions, four subsectors are considered: Aljibico, the central part with siliceous sandstones, humid-hyperhumid ombroclimate and some continental characteristics; Algecire√Īo, the southern area with similar geology and ombroclimate but with an oceanic precipitation regime and frequent orographic fogs; Marbell√≠, the eastern area with saltes and micaschists and a subhumid-humid ombroclimate; and Sidonense, the western area with a heterogeneous geology of sandstones, limestones, vertic argils, sands, a dry-subhumid ombroclimate and a thermic continental regime. The Aljibico sector is included in the Tingitano-Onubo-Algarviense province. This province reaches from Aveiro (Portugal) to Bajo Loukkos (Morocco). It is also part of the Iberomarroqui- Atlantica superprovince that connects the Eurosiberian and the Macaronesian areas through the Mediterranean region. The vegetation series considered in the Aljibico sector are the following: Myrto-Querceto suberis S, Teucrio-Qtterceto suberis S, Rusco-Querceto canctriensis S, Cytiso-Querceto pyrenaicae S, Tamo-Oleeto sylvestris S. Clematido-Ceratonieto siliquae S, Arisaro-Alneto glutinosae S, Frangulo-Rhododendreto baetici S, Ficario-Fraxineto angustifoliae S, Genisto-Ericeto ciliaris S, Crataego-Populeto albae S, Polygono-Tamariceto africanae S, Agrostio-Tamariceto canariensisS and Rubo-Nerieto oleandri S. Likewise has plenty of rupiculous, dunes and aquatic plant communities, while the swamp communities are very limited. Tamo-Oleetum sylvestris (oleetosum and fraxinetosum angusttfoliae) and Polygono-Tamaricetum africanae aretosum italici are lectotypified. As new syntaxa, Crataego-Populetum albae. Rusco-Querceturn canariensis quercetosum broteroi, Asparago-Calicotometum villosae juniperetosum turbinatae, Equiseto- Saliceturn pedicellatate salicetosum albae and Asperulo-Ulicetunt scabri anthyllidetosum cytisoidis are proposed. Furthermore, nine dominance communities are described here. They are characterized by the following species: Juniperus oxycedrus, Quema lusitanica- Ilex aquifolium, Dianthus lusitanus, Potamogeton nodosus, Potamogeton pectinatus, Myriophyllum alterniflorum, Callitriche stagnalis, Callitriche regis-jubae and Ranunculus tripartitus. Cytiso-Querceto pyrenaicae S is a new record for Europe. Crataego-Populeto albae S is proposed as a new series of vegetation. The suborder status for Tin guarrenalia siculae is proposed. The alliance Campanulion velutinae is included in this suborder.Se analiza la flora y vegetaci√≥n del sur de la Pen√≠nsula Ib√©rica (Andaluc√≠a, provincias de C√°diz y M√°laga) con el fin de delimitar y subsectorizar la unidad fitogeogr√°fica Alj√≠bica. Hemos reconocido 4 subsectores en base a la bioclimatolog√≠a, flora y vegetaci√≥n: Alj√≠bico, Algecire√Īo, Marbell√≠ y Sidonense. Inclu√≠mos el sector Alj√≠bico en la provincia Tingitano-Onubo-Algarviense. Dicha provincia forma parte de la superprovincia lberomarroqu√≠-Atl√°ntica que enlaza las regiones Eurosiberiana y Macaronesica con la Mediterr√°nea. Las series de vegetaci√≥n reconocidas en el sector Alj√≠bico han sido las siguientes: alcornocales de Myrto-Querceto suberis S y Teucrio-Querceto suberis S, quejigares de Rusco-Querceto canariensis S, robledales de Cytiso-Querceto pyrenaicae S, acebuchales de Tamo-Oleeto sylvestris S, algarrobales de Clematido-Ceratonieto siliquae S, alisedas de Arisaro-Alneto glutinosae S, hojaranzales de Frangulo- Rhododendreto baetici S, fresnedas de Ficario-Fraxineto angustifoliae S, brezales higr√≥filos de Genisto- Ericeto ciliaris S, choperas de Crataego-Populeto albae S, tarajales de Polygono-Tamariceto africanae S y de Agrostio-Tamariceto canariensis S y adelfares de Rubo-Nerieto oleandri S.¬†Se lectotipifican Tamo-Oleetum sylvestris oleetosum y fraxinetosum angustifoliae y Polygono- Tamaricetum africanae aretosum italici. Como nuevos sintaxones se proponen Crataego-Populetum albae, Rusco-Quercetum canariensis quercetosum broteroi, Asparago-Calicotometum villosae juniperetosum turbinatae, Equiseto-Salicetum pedicellatate salicetosttm albae y Asperulo-Ulicetum scabri anthyllidetosum cytisoidis. Se describen nueve comunidades caracterizadas cada una por: Juniperus oxycedrus, Quercus lusitanica e Ilex aquifolium, Dianthus lusitanus, Potamogeton nodosus, Potamogeton pectinatus, Myriophyllum altermflorum,Callitriche stagnalis, Callitriche regis-jubae y Ranunculus tripartitos. Se cita como nueva serie para el subcontinente europeo Cytiso-Querceto pyrenaicae S y se propone una nueva serie, Crataego-Populeto albae S. Se incluye la alianza Campanulion velutinae en Tinguarrenalia siculae a la cual se le asigna el rango de suborden

    Contribuci√≥n a la clasificaci√≥n fitosociol√≥gica de los pastizales de la provincia de C√°diz (Espa√Īa)

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    Contribuci√≥n a la clasificaci√≥n fitosociol√≥gica de los pastizales de la provincia de C√°diz (Espa√Īa). En el presente trabajo se estudian las comunidades de pastos del centro y suroeste de la provincia de C√°diz en base a 521 inventarios fitosociol√≥gicos. Todos ellos han sido sometidos a dos an√°lisis multivariantes, uno de ordenaci√≥n (PCA) y otro de clasificaci√≥n. Con ambos m√©todos se han obtenido 50 grupos de vegetaci√≥n correspondientes a asociaciones pertenecientes a diferentes clases fitosociol√≥gicas: Corynephoretea canescentis, Poetea bulbosae, Molinio-Arrhenatheretea, Polygono arenastri-Poetea annuae, Ruderali-Secalietea cerealis, Juncetea bufonii, Littorelletea, Phragmitio-Magnocaricetea y Frankenietea pulverulentae. Como resultado del tratamiento estad√≠stico se describe un nuevo orden- Phalaridetalia coerulescentis, una alianza -Gaudinio fragilis-Hordeion bulbosi, tres asociaciones -Deschampsio strictae-Agrostietum curtisii, Hedysaro coronarii-Phalaridetum coerulescentis y Poo sylvicolae-Festucetum atlantigenae y dos subasociaciones -Gaudinio fragilis-Agrostietum castellanae hypochaeridetosum platylepidis y Poo sylvicolae-Festucetum atlantigenae scirpetosum maritimi
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