Plant Sociology 52 (1) 2015

pag. 3-8: Contribution to the knowledge of the edaphoxerophilous communities of the Samana Peninsula (Dominican Republic)

E. Cano1, A. Cano-Ortiz2, A. Veloz31Departamento Biología Animal, Vegetal y Ecología. Botánica. Universidad de Jaén. Paraje las Lagunillas s/n, ES-3071 Jaén, España.

2Departamento Sostenibilidad Interra. Ingeniería y Recursos SL. Plaza España, 317,5 ES-27004 Salamanca, España.

3Jardín Botánico Rafael Ma. Moscoso de Santo Domingo. República Dominicana.

doi: 10.7338/pls2015521/01

The Samana Peninsula belongs to the biogeographical North Sector of the Caribbean-Atlantic Subprovince (Hispaniola Province, Caribbean-Mesoamerican Region). In the past the Peninsula was separated from the rest of Hispaniola but today it is joined by a small strip of land made up of Quaternary sediments in the Gran Estero. Rainfall records are as high as 2,339 mm. The Io value is 7.3 (i.e., humid ombrotype) and Ti/Tic values are 741/675. These conditions give rise to an infratropical thermotype. The Samana Peninsula forms a geomorphological unit dominated by karstic materials, limestones, schists and marls. Despite the heavy rainfall rates, the presence of escarpments (farallones) gives rise to an edaphoxerophilous community. Species such as Pilosocereus polygonusZamia debilisAgave antillarumEugenia samanensisBursera simarubaCapparis fexuosa, Ficus velutina, Opuntia dellinii, Comocladia dodonaea, Stigmaphyllum emarginatum are not infrequent in this plant community. This edaphoxerophilous community is rich in endemic species and is dominated by Coccotrinax gracilis, Agave antillarum, Leptocereus weingartianus and, to a lesser extent, by Eugenia samanensis. The presence in the peninsula of 134 endemic species justifies considering this a biogeographical territory (A4) within the North Sector (Cano et al., 2010).

pag. 9-18: Vegetation outlines of two active rock glaciers with contrasting lithology

D. Tampucci1, G. Boffa1, F. Mangili1, M. Gobbi2, M. Caccianiga11Department of Biosciences, University of Milano, Via Celoria 26, I-20133 Milano, Italy.

2Department of Invertebrate Zoology and Hydrobiology, MUSE – Museo delle Scienze, Corso del Lavoro e della Scienza 3, I-38123 Trento, Italy.

doi: 10.7338/pls2015521/02

Rock glaciers are periglacial landforms consisting of coarse debris with interstitial ice or ice core, characterized by creeping due to ice deformation. These landforms are drawing the attention of plant ecologist as harsh habitats and potential refugia in the global change context. Our aim was to describe the vegetation outlines of two active rock glaciers of the Ortles-Cevedale Massif (Central Italian Alps) on different substrates (silicate and carbonate) and compare them with the neighboring stable slopes and scree slopes. Two hypotheses were tested: 1) rock glaciers differ from the surrounding landforms for the presence of cold-adapted plant communities; 2) rock glacier plant communities indicate similar microclimatic conditions in spite of the contrasting lithology. Data were collected by phytosociological method performing 80 relevés of 25 m². Plant communities were compared by a cluster analysis based on the presence/absence species matrix and species relative frequencies for each landform were calculated. The cluster analysis separated first for all the two sites; afterwards, the landforms were differently discerned each other depending on the site. Despite the remarkable floristic differences due to the substrate, the vegetation of both rock glaciers suggest a general adjustment to cold-moist microclimate and long-lasting snow cover, differentiating more or less evidently from the adjacent scree slopes and enhancing the survival of nival entities at the elevation of alpine grasslands.

pag. 19-40: The edge communities of Asphodelus macrocarpus subsp. macrocarpus: the different ecological aspects and a new case study in the central Apennines

M. Allegrezza1, E. Biondi1, S. Ballelli2, G. Tesei1, C. Ottaviani1

1Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Via Brecce Bianche, I-60131 Ancona, Italy.

2School of Biosciences and Veterinary Medicine, University of Camerino, Via Pontoni 5, I-62032 Camerino (MC), Italy

doi: 10.7338/pls2015521/03

This article begins with an extended presentation of the logical process that led to the definition of the orderAsphodeletalia macrocarpiBiondi & Allegrezza 2014, highlighting the various aspects that justified this. The new analysis conducted in other areas of the central Apennines that were analysed with the present study allows the more precise description of the syntaxonomy of the lower hierarchical levels. This describes the new allianceThalictro aquilegiifolii-Asphodelion macrocarpithat groups the communities withAsphodelus macrocarpusin the lower supratemperate thermotype of the central Apennines, a vicariant of the allianceCyano triumfettii-Asphodelion macrocarpithat is typical of the upper supratemperate thermotype. Three new associations of the new alliance are recognized, according to the geomorphological characteristics and the dynamic context and landscape:Leontodo cichoracei-Asphodeletum macrocarpi,Trifolio ochroleuci-Asphodeletum macrocarpiandSenecio apennini-Asphodeletum macrocarpi. The statistical comparison between the associations published, at European level in whichA. macrocarpusorAsphodelus albushave been used in the epithet of the association, has provided a biogeographical overview at the European level and a critical syntaxonomic re vision of theApennine phytocoenoses, for some of which the correction of the nomenclature was necessary according to the most recent taxonomic acquisitions.
Based on the analysis performed, the syntaxonomic scheme of the orderAsphodeletalia macrocarpifor the central-southern Apennines is proposed, which is currently recognized in three alliances:Cyano triumfettii-Asphodelion macrocarpi,Thalictro aquilegiifolii-Asphodelion macrocarpiandHyperico calabricae-Asphodelion macrocarpi. The indications of the environmental characteristics and preferential dynamic relationships of each of the syntaxa considered contribute to the present state of knowledge, with both the definition and clarification of the ecological range and landscape of the orderAsphodeletalia macrocarpi, to complete the main landscape units described for the central-southern Apennines.

pag. 41-64: Diachronic analysis of variations induced on the flora and vegetation of river ecosystems by actions taken to reduce the risk of flooding. Case study of the River Chienti (central Adriatic, Italy)

M. A. Crisanti, F. Taffetani

Department of Agricultural, Food and Environmental Sciences, Marche Polytechnic University, Via Brecce Bianche, I-60131 Ancona, Italy

doi: 10.7338/pls2015521/04

We present here a diachronic comparison of the flora and vegetation of a stretch of River Chienti, in central Marche (Italy). We assess the impact of mechanical cleaning of the river on its ecological structure and biodiversity. The first survey was carried out in 1993, and then repeated in the same areas and with the same methodology in 2005, following heavy and repeated hydraulic maintenance of River Chienti. This process included excavation of gravel from the river bed and its accumulation on the river banks, with the objective to broaden and deepen the flow channel. In some places that were under strong anthropic influence and subjected to continuous erosion, this process was accompanied by work on the protection of the river banks using various materials, to reduce the risk of flooding. In connection with this, it should be noted that the mouth of River Chienti has been defined as an area at very high hydro-geological risk according to the Specific Basin Plan (Piano Stralcio di Bacino) for the Hydrogeological Assets of the Basins of Regional Importance (PAI), as approved by Resolution N° 116 of the Regional Council, of 21 January, 2004. This work has resulted in the disappearance of lateral branches of the river that had still or slow-flowing water, and mechanical removal of the vegetation of the river bed, and in some instances, also of the river banks. These actions have removed the wet flats at the sides of the main channel, which represented favourable habitats for the establishment of different types of helophytic and hydrophytic plant communities according to the main ecological gradients. These actions that were designed to secure the river banks have led to an upheaval in the vegetation of the alluvial terraces closest to the water course, with profound alterations to the structure of the communities that had developed in the area, resulting in some cases in their disappearance. The floristic comparison shows the loss of 95 (69.34%) entities in 2005 in comparison to those surveyed in 1993. The floristic entities that have been lost in the area are mainly those related to helophytic and marsh environments, such as Zannichellia palustrisNasturtium officinale and Glyceria notata. On the other hand, particularly invasive exotic entities have appeared, such as Robinia pseudoacaciaAmorpha fruticosaArundo donaxCuscuta scandens subsp. cesatianaPaspalum /distichum and Helianthus tuberosus, along with species from the fields or from the surrounding marshy areas, such as Helianthus annuus, Brassica nigra, Rumex crispus and Tripleurospermum inodorum. Analysis of the vegetation has shown a decrease in the plant communities both of the river bed and the river banks, which have been reduced from 15 (in 1993) down to 10 (in 2005). The following associations have disappeared: Zanichellietum palustris, Nasturtietum officinalis, Helosciadetum nodiflori, Bolboschoenetum maritimi, Glycerietum plicatae, Typhaetum latifoliae, Sparganietum erecti, Saponario-Artemisietum verlotorum, Ranunculetum repentis, Aro italici-Alnetum glutinosae and Salicetum incano-purpureae. The vegetational types that have disappeared can be attributed to the classes Potametea pectinati, Phragmito australis-Magnocaricetea elatae, Agrostietea stoloniferae, Alnetea glutinosae and Salicetea purpureae. The class that has suffered the greatest number of losses is Phragmito australis-Magnocaricetea elatae. Many of the communities that are no longer found have high ecological value, such as Zanichellietum palustris, Nasturtietum officinalis, Helosciadetum nodiflori, Bolboschoenetum maritimi and Glycerietum plicate.