Jesús Izco

100 years of plant sociology: A celebration

The international year of biodiversity (2010) coincided with the centenary of the first formal definition of plant association, which marked the birth of plant sociology. It was indeed in 1910 that Flahault and Schröter combined the floristic and physiognomic components of plant communities and defined the plant association as a plant community with a distinct floristic composition that has a uniform physiognomy and grows in uniform habitat conditions. Since then, plant sociology has been evolving in theory and methodology, and the concept of plant association has been refined as to include information on floristic composition as well as on history, chorology, dynamics, and ecology of plant communities. At the same time, the field of investigation enlarged to embrace the analysis of spatial relationships amongst individual communities, under a modern landscape perspective and of advanced multivariate statistical approaches (Burrascano et al. 2009). To celebrate the first 100 years of plant sociology and reflect on the developments and vitality of this discipline within the context of latest technologies and current ecological issues, we invited researchers from different countries to submit articles on new perspectives and approaches and on syntaxonomical subjects of national and international interest. First of all, we wish to thank all the people who contributed to realise the special issue at hand by responding to this call with their articles and ideas. The 22 articles presented in this issue cover a broad range of topics and can be schematically divided into three thematic groups. The first set comprises works that share some focus on the historical developments of plant sociology, though for different objectives and that provide insights into the possible applications of this field for biodiversity conservation and management of natural resources. The contribution from Géhu (2011) offers a concise but effective overview on the development phases of this discipline through the 20th century to clarify the meaning of phytosociology and fix its real starting point, which effectively dates back to 1910. Pott (2011) examines the objectives and methodological evolution of phytosociology in the light of its social and political implications (sustainable use of natural resources and benefits to human society), with a particular reference to the Convention on Biological Diversity. The article by Biondi (2011) revisits plant sociology’s developments to refine the concept of plant association on the basis of the importance of structure, ecological value and characteristic dynamical and topographical relationships. It also presents a sampling approach to vegetation series on the basis of the integration of detailed thematic maps within a Geographical Information System environment. Blasi and Frondoni (2011) point to the ecological nature of plant sociology, at its origin and through its advances, to highlight its potential for environmental quality assessment and ecological modelling. They particularly consider the inter-relationships between vegetation series mapping and ecological land classification, to show the mutual benefits of an integrated approach. The article by Izco and Amigo (2011), the last one of this set, gives an example of the indicator value of syntaxonomical diversity for conservation assessment, through the analysis of the relationships between area and richness of syntaxa in different European territories. Different methodological aspects are treated in the articles included in the second thematic group. Box and Fujiwara (2011) proposes a plot-sorting approach on the basis of the topographic and

Growth form and population density ofSpartina maritima (Curtis) Fernald in northwest Spain

A number of species ofSpartina show two clearly distinguishable growth forms, tall and short. Several authors have suggested that the differences in height reflect differences in soil properties. In the present study, we determined mean shoot height, shoot density, and standing crop in three populations ofSpartina maritima in northwest Spain. Soil properties were also determined at each site. Shoot density was significantly correlated with redox potential and sulfide concentration, but height was not significantly correlated with any of the soil properties considered. This latter result suggests that the observed variability in height among the study populations may be of genetic origin.

Contribution to the nomenclatural knowledge of Fagus sylvatica woodlands of southern Italy

The present paper deals with some nomenclatural notes regarding two important southern Italian beech phytosociological associations such as Aquifolio-Fagetum and Asyneumato-Fagetum which were described about 30 years ago and which still represent the most widespread Fagus sylvatica communities in southern Italy. According to the ICPN, Aquifolio-Fagetum is confirmed to be a nomen illegitimum. This name must be substituted with the name Anemono-Fagetum (Gentile 1970) Brullo 1983. Moreover, Aremonio-Fagetum Hofmann 1961, a beech forest type very similar to the Aquifolio-Fagetum is a nomen invalidum. As far as the Asyneumato-Fagetum Gentile 1970 is concerned, in our opinion it represents a later syntaxonomical synonym of the Ranunculo brutii-Fagetum Bonin 1967. Geranio-Fagion Gentile 1970 and Lamio-Fagenion Gentile 1970 are typified. A new suballiance named Doronico-Fagenion (describing the beech community types of the low montane belt), deriving from the lowering of the rank of the former alliance Doronico-Fagion Ubaldi et al. ex Ubaldi 1995, is proposed.

Análisis y clasificación de la vegetación leñosa de Galicia (España)

Despues de los ensayos anteriores, de los que se hace un analisis historico, de definir la diversidad de la vegetacion gallega se propone una nueva ordenacion basada en criterios actuales (floristicos, sucesionales, corologicos, respecto al Codigo de Nomenclatura Fitosociologica). El analisis se limita, en este caso, a las comunidades lenosas comprendidas en las clases Alnetea glutinosae, Calluno-Ulicetea, Cisto-Lavanduletea, Cytisetea scopario-striati, Pino-Juniperetea, Quercetea ilicis, Querco-Fagetea, Rhamno-Prunetea, Salicetea purpureae y Vaccinio-Piceetea , con un total de 65 asociaciones. Cada clase lleva una pequena descripcion que incluye su distribucion en el territorio, las especies representativas y un comentario de sus afinidades con otras clases. Tras cada asociacion aceptada se relacionan las tablas o grupos de inventarios gallegos que se asimilan a la misma con indicacion del nombre originalmente osado y la referencia bibliografica correspondiente.

La marisma superior cántabro-atlántica meridional: estudio de las comunidades de Juncus maritimus y de Elymus pycnanthus

La vegetacion del «schorre» (marisma) superior de la costa cantabro-atlantica iberica esta constituida por comunidades de Limonio serotini-Juncetum maritimi , Agrostio stoloniferae-Juncetum maritimae y Elymo pycnanthi-Juncetum crithmoidis . Aparte criterios floristicos, ecologicos y corologicos que sostienen los sintaxones mencionados, una tabla sintetica de los Elymeta pycnanthi del «schorre»(marisma) superior descritos hasta ahora clarifica este tipo de vegetacion en la provincia cantabro-atlantica.

Seed morphology of Erica L. sect. Chlorocodon Bentham

Abstract Seed morphology of the only species of Erica sect. Chlorocodon, E. scoparia, has been studied. Four subspecies are recognized: subsp. azorica, subsp. maderincola, subsp. platycodon and subsp. scoparia. Size and shape of seeds and size and shape of surface cells were measured. SEM pictures were performed for whole seeds and detail of the four taxa. Other minor characters such as weight of 100 seeds and seed colour were also studied. One way analysis of variance were performed for the different variables. Surface cells boundaries and anticlinal walls curvature are the main diagnostic characters. The continental subspecies (subsp. scoparia) is easily differentiated from the maca- ronesian taxa. Within these, subsp. azorica and subsp. maderincola have a similar seed type, different from subsp. platycodon seeds. The subspecific rank for these four taxa is recomended. A key to the subspecies is presented.

Las orlas forestales fruticosas orensano-sanabrienses: dos nuevas asociaciones del Valle del Sil

Las orlas arbustivas de los encinares acidofilos y melojares mediterraneos gallegos corresponden a dos nuevas asociaciones. Erico scopariae-Arbutetum unedonis y Genisto falcatae-Ericetum arboreae , de optimo mesomediterraneo y supramediterraneo, respectivamente. Las propuestas se sostienen con 16 y 29 inventarios; ademas una catena del macizo de Trevinca situa ambas comunidades en el geosigmetum.

Systematic relevance of seed coat anatomy in the European heathers (Ericeae, Ericaceae)

The anatomy of the seed coat of the European species of tribe Ericeae (Calluna, Daboecia and Erica) of the Ericaceae family was studied, and the taxonomic importance of their characters was analyzed. The seed coat is mostly formed by a one-cell layer with thick, pitted inner walls and thin outer walls that collapse at maturity over the inner walls. The cell junctions are either raised with anticlinal walls up to four times the height of the periclinal walls or are not raised with similar values for the height of both the anticlinal and periclinal walls. Three main cell junction types were found and described. The thickness of the inner walls is variable, but there is a large overlap among the results for different species. Calluna vulgaris is the only species with no pits, and E. multiflora has a pitted pattern on its inner walls, which is distinctive from the rest of the species. Our main results agree with the external seed morphology, and valuable new data were obtained for certain groups such as the E. cinerea-E. terminalis or the E. scoparia complex. The similarities that are found in seed coat characters are not in accordance with the classical taxonomic delimitation of infrageneric groups within Erica.

Taxonomic value of seed characters in the Erica tetralix L. group (Ericaceae)

A study of the seed morphology of Erica tetralix and the related species E. mackaiana and E. andevalensis was performed to evaluate the taxonomic importance of seed characters. Size and shape of seeds and surface cells were studied, and area, perimeter, main axis lengths, elongation and sinuosity were measured. Levels of intraspecific variation were considered by means of nested analysis of variance. The study of the intraspecific variation of the characters shows significant differences for lower levels, higher than variations between species for most characters. Levels of variation must be based upon the numerical analysis of seed characters for a correct approach to determining systematic value. E. mackaiana and E. andevalensis group together versus E. tetralix for sinuosity of testa cells. This is a good taxonomic character because it shows significant differences between species and no significant differences between populations. E. tetralix has strongly undulated testa cells while E. mackaiana and E. andevalensis have slightly undulated or curved testa cells. These two species can be discriminated by size of the seed, with seeds of 0.37-0.38 mm for E. andevalensis and 0.4 - 0.45 mm for E. mackaiana. Similarities are found in seed morphology for E. mackaiana and E. andevalensis, but we nevertheless consider the species status for the three taxa as the most natural taxonomic assignment. A key to the species is provided.

Estimation of chlorophyll degradation into phaeophytin in Anaptychia ciliaris as a method to detect air pollution

Se estudia la influencia de los siguientes factores sobre el valor del cociente de feofitinizacion DO 435 nm/DO 415 nm en el liquen Anaptychia ciliaris (L.) Korber: edad del liquen, concentracion final de pigmentos, trasplante de los liquenes a areas distintas sobre sustratos diferentes o similares y el valor de pH del sustrato original o el adoptado tras el trasplante. Se discute la utilizacion de A. ciliaris como un bioindicador de la presencia de factorcs acidificantes en la atmosfera o en el agua de lluvia que provoquen la feofitinizacion de las clorofilas.