Edoardo Biondi

Modelling Environmental Responses of Plant Associations: A Review of Some Critical Concepts in Vegetation Study

The definition of vegetation types at different hierarchical levels, both to study the vegetation processes and for practical cartographic representation, is still considered a critical issue in many circles of plant ecologists. The problems are mainly related to the misleading idea that classification of the vegetation system, as developed by European phytosociologists during the last century within the discipline called syntaxonomy, would imply the assumption of the organismic concept of the plant community. After a short discussion on the role of Braun-Blanquet approach in plant ecology and in landscape ecology, the methods to detect multispecies responses along environmental gradients are briefly reviewed. In the main part of this article, we intend to stress that concepts considered critical, such as plant association and its ecological niche, are just operational tools that have nothing to do with the individualistic or organismic interpretation of plant communities in vegetation studies. Important to our views on vegetation, we believe that plant associations as well as the higher syntaxa can be regarded as fuzzy sets in an operational context for describing vegetation along ecological gradients in synthetic ways and can further the understanding of vegetation variation.

Inquadramento fitosociologico di alcune formazioni prative del territorio collinare anconetano

Abstract Phytosiciological identification of some meadow formations of the hill territory around Ancona - A phytosociological study of some meadow formations found in the hill territory near the city of Ancona in the Marches region, is presented. Two new associations of meso-hygrophilous meadows are described. These associations are related respectively to the climactic series of the peliticousarenaceous substrata (Asparago acutifolii-Ostryeto carpinifoliae sigmetum) and to the edaphous-hygrophilous substratum of the recent alluvial terraces (Symphyto bulbosi-Ulmeto minoris sigmetum): Senecio erucifolii-Inuletum viscosae and Pastinaco urentis-Arrhenatheretum elatioris. The marked presence of mediterranean species allows both the associations to be distinguished from analogous associations spread throughout the other areas of Europe having a temperate climate. In addition, the new submediterranean alliance Inulo viscosae-Agropyrion repentis is proposed, uniting the post-cultivation associations of the marl...

Bois fossiles et végétations arborescentes des régions méditerranéennes durant le Tertiaire

Abstract Fossil woods and arborescent vegetations of mediterranean regions during the Tertiary. - A tentative reconstruction of Tertiary arborescent vegetation around the mediterranean based exclusively upon paleoxylologic data is suggested. Particular emphasis is given to North Africa, Sardinia and the French Massif Central. Maps, compiled for each stage, are presented and discussed. By means of certain indicatory taxa, an attempt is made to detect the first appearance of temperate or mediterranean elements in the different regions and to trace their relationship with thermophile species. The penetration into Europe of African elements by way of land bridges such as Sardinia is also evoked.

Effects of environmental factors on seed germination of Anthyllis barba-jovis L.

Abstract The influence of the main environmental factors on seed germination of Anthyllis barba-jovis L. were analysed. This work is part of a broader investigation aimed at the reintroduction of this species on Mount Conero, Ancona (central Italy), where it is at present extinct. The seeds were collected from the Gargano headland (southern Adriatic coast). Experimental analyses were carried out to determine: (i) dormancy levels of seeds collected in successive years, and also collected from the soil seed bank; (ii) effects of usual pre-treatments for overriding the physical dormancy of the seeds; (iii) optimal temperature range for maximum germination; (iv) effects of fire on seed germination; and (v) effects of NaCl on germination and on early stages of seedling development. Our results confirm that A. barba-jovis seeds have a physical dormancy due to their teguments, which are water-impermeable. This barrier persists in naked seeds that remain in the soil. Regularly water-drenched seeds show a high germinative ability. The optimal seed germination temperature is 20°C, with germination decreasing progressively at lower temperatures, and falling drastically over 20°C. Fire and high temperatures positively affected germination. The seeds were shown to be strongly resistant to salt stress, thus enabling the plants to colonize a habitat suitable for halophytes.

II paesaggio vegetale del territorio collinare anconetano

Abstract Plant landscape of the hill territory around Ancona. — The phytosociological study of the vegetation of the arenaceous, peliticous-arenaceous, arenaceous-peliticous and alluvial lands of the hilly Ancona sector, in the eastcentral part of the Italian peninsula on the Adriatic side, permitted the reconstruction of different vegetation series which are distributed in close relationship with the areas lithological formations. The edaphous-xerophilous series of the arenaceous substrata corresponds to the Roso sempervirentis-Queroeto pubescentis sigmetum; the climatophilous series of the peliticous-arenaceous substrata is represented by the Asparago acutifolii-Ostryeto carpinifoliae sigmetum, while the climatophilous series of the Lonicero xylostei-Querceto cerridis sigmetum is found on the arenaceous-peliticous substrata. The flood plain series of the oldest alluvial terraces corresponds to the Rubio peregrinae-Carpineto betuli, while in more recent ones the edaphous-hygrophilous series of the Symph...

Phytosociological survey of Northern California dunes

ABSTRACT The vegetation of sandy coasts of California between Point Arena and Morro Bay, was investigated. Near the tide line, was annual vegetation of the Cakile maritima community. Dunal vegetation included the new Abronio latifoliae-Ambrosietea chamissonis class with the new Ambrosietalia chamissonis order and the new Ambrosion chamissonis alliance (proposed). Foredune vegetation included the two new Abronio latifoliae-Elymetum mollis and Atriplici leucophyllae-Abronietum maritimae associations, with the new Polygono paronychiae-Artemisietum pycnocephalae and Erigero glauci-Abronietum latifoliae associations on more stabilised surfaces. In some localities, Ammophila arenaria var. australis occurs within a Lupino variicoloris-Ammophiletum australis association, which colonises the whole dune ecosystem. In the flat areas characterised by grit and affected by frequent sea ingression is an association characterised by Juncus lesueurii and Distichlis spicata (Junco lesueurii-Distichletum spicatae). In the hollows among inland dunes, affected by stagnation, thick meadows develop which contain two new associations: Stachydo rigidae-Iridetum douglasianae developing on flat areas with a stronger stagnation and Achilleo millefoliae-Elymetum pacifici.

Geosynphytosociological analysis of the plant landscape of an area with high geomorphology variability on the central Italian Adriatic coast

Abstract This study of the plant landscape of a sub-coastal hilly area in southern Marche, Italy, has allowed the proposal of two main models that are highly correlated with the geomorphological and bioclimate variations of the area. This study area is very complex from a geological point of view. The synphytosociological analysis reveals the changes that occur locally within each lithological unit. This confirms the strong correlation between vegetation series and lithological characteristics of the substrate, and also the high value and quality of such plant communities as bioindicators.

A palm fossil closely related to Chamaerops humilis L. from the Lower Miocene of Sardinia

Abstract This paper deals with the anatomical and histological study of a silicified specimen of a palm consisting of a part of the trunk surrounded by roots. The sample comes from the Lower Miocene of North West Sardinia. The comparison with fossil species and exsting species leads to the conclusion that the specimen belongs to a new fossil species closely related to Chamaerops humilis L., widespread throughout the Mediterranean area. Paleo-environmental considerations confirm the presence in Sardinia, in the epoch in question, of formations of Mediterranean forest corresponding in part to forest existing in North Africa today.

Population characteristics of Juniperus oxycedrus L. and their importance to vegetation dynamics

Abstract The paper deals with some preliminary data on the characteristics of a population of Red Juniper growing on abbandoned farmlands and xeric pasture in the central Apennines. The distribution of the older specimens is random as a result of the external origin of the seeds; all other specimens are distributed in groups due to the autochthonous origin of the seeds. The inexistence of hypogeous connections between the individuals was verified, thus confirming that asexual reproduction is of little importance in the growth of the population. The description of the population by age and by sex was made using a pyramid diagram. The diagram shows the four phases of the development of the population: colonization, stabilization, propagation and regression. While the males are more numerous, the females predominate in the older age class and are characteristic of the colonization and stabilization phases of the population. In conclusion the study demonstrates how after 39 years of the development of the pop...

A contribution to the knowledge of «Betula aetnensis» Rafin. through an anatomic and morphometric study of its wood

Abstract This research has its own main propose to describe Betula aetnensis wood comparing it to Betula pendula one. The most significant anatomic character found in Betula aetnensis, even if at a low rate, regards vessels with simple perforation and at the same time, others with scalariform perforation. In comparison with Betula pendula, the decrease in the number of bars is remarkable in scalariform perforation. The morphometric test stressed lower average values as to cross and longitudinal dimensions both in vessels and in fibres. The trend curves of these characters related to age nearly steady for the two species are well correlated. For the first time simple perforation vessels in the wood of a species within the genus Betula is tested out. This feature, together with the decrease in the number of bars for scalariform perforations and the decrease in length for vessel elements and fibres, shows a more advanced evolution in Betula aetnensis in relation to B. pendula.