Supramediterranean Belt Research Articles

Hymenochaete ametzii sp. nov. (Hymenochaetales, Basidiomycota), an endangered bark-dwelling species inhabiting old Quercus pyrenaica trees from the Iberian Peninsula

Bark-dwelling fungi represent a group of ecologically highly specialized organisms. This study deals with an undescribed species of Hymenochaete characterized by specifically inhabiting the bark of Pyrenean oak (Quercus pyrenaica), and producing effuse-reflexed basidiomata and mainly globose to subglobose basidiospores. Maximum Likelihood and Bayesian analyses of the nuclear ITS-LSU regions revealed that the sequences of H. ametzii form a monophyletic group with a low intraspecific variation and substantially different from closest taxa, further supporting its recognition as a species. The seven localities H. ametzii is known from are old forests with a long ecological continuity, containing large old Q. pyrenaica trees, and are located in the supramediterranean belt of the Mediterranean biogeographical region. Based on habitat availability and field counts of colonized trees, the global population of H. ametzii is estimated at 8,670 mature individuals. Considering that the traditional use of old Q. pyrenaica stands ceased several decades ago in the Iberian Peninsula, with a consequent decline in habitat quality and availability, it is concluded that H. ametzii is Endangered (EN) according to the IUCN criteria.

Holocene vegetation and fire dynamics in the supra-Mediterranean belt of the Gredos Range (central Iberian Peninsula)

High-resolution pollen, macrofossil and charcoal data, combined with multivariate analysis, were used to reconstruct Holocene vegetation and fire dynamics at Manaderos. The studied mire is located in a highly valued location in the supra-Mediterranean belt of the Gredos Range (central Iberian Peninsula). The record started at 1260 calendar years (cal yrs) BP, according to eight radiocarbon dates, with the occurrence of an open Quercus pyrenaica forest and Pinus nigra stands. The palynological data show a dramatic change ∼380 cal yrs BP, when the oak forest was progressively replaced by a maritime pine one. The interpretation of this record is related to an increase in agricultural and livestock activities and changes in the role of fire, thus Pyrenean oak canopy was consumed by fires providing openings for Pinus pinaster, better adapted to fire. The results are compared with other sequences from the Spanish Central System in order to better understand the past dynamics of the main forest constituents and to provide a critical view of the role of fire, anthropic dynamics and climatic events.

The dialectic between deciduous and coniferous forests in central Iberia: A palaeoenvironmental perspective during the late Holocene in the Gredos range

Pollen analyses supported by fifteen AMS 14C dates from Fuente de la Leche (1382 m) and Fuente del Pino Blanco (1343 m) peat sequences, in the Gredos range (central Spain), are used to reconstruct the late Holocene vegetation history in this mountain region. These results are compared with other sequences from the Spanish Central System in order to better understand the past dynamics of the main forest constituents and to provide a critical view of the dialectic between conifers and deciduous forests. The vegetation record at Fuente de la Leche starts at 3000 cal yr BP, with the occurrence of rather closed forests composed of Pinus sylvestris and Betula. Pinus sylvestris was the dominant pollen taxa for almost the entire period. However, during the last 850 years, Pinus sylvestris forests were progressively replaced by Quercus pyrenaica woodlands and grasslands, as a result of a high pastoral pressure, until forming mixed woodlands ∼400 years ago. The interpretation of Fuente del Pino Blanco record is that dramatic changes started about 265 years ago. Prior to this date, an open canopy woodland included species (Alnus glutinosa, Quercus pyrenaica) whose distributions no longer exist in the studied area. We suggest that the increase in agricultural (rye and other cereals) and livestock activities forced a change in the role of fire in the supramediterranean belt of the Gredos range, thus Pyrenean oak canopy was consumed by fires, providing openings for Pinus pinaster and broom communities better adapted to fire.

Different parts of the same plants. Charcoals and seeds from Cova de les Cendres (Alicante, Spain)

The analysis of archaeobotanical macroremains from Cova de les Cendres (Teulada-Moraira, Alicante, Spain) allows a better understanding of the dynamic of the vegetation during the Upper Palaeolithic in the region. The anthracological sequence shows that Pinus type nigra/sylvestris dominates in the area during the Upper Palaeolithic, while more open formations of Juniperus and Fabaceae spread in Upper Solutrean and Early-Middle Magdalenian. The carpological analysis that has been carried out in the Middle Magdalenian level has brought to light different species of Juniperus (J. sabina, J. communis and J. oxycedrus). This information indicates that during the period, Cova de les Cendres had similar bioclimatic conditions to those currently prevailing in the Iberian summits of the supramediterranean belt. New 14C dates obtained from Juniperus sabina and Buglossoides cf. arvensis seeds as well as from charcoal fragments of Ephedra sp., presented in this paper, prove the existence of steppe landscapes during the Late Glacial.

Floristic Analyses of the Corsican Flora: Biogeographical Origin and Endemism

JEANMONOD, D., Y. NACIRI, A. SCHLUSSEL & J. GAMISANS (20 15). Floristic analyses of the Corsican flora : biogeographical origin and endemism. Candollea 70 : 21-41. In English. English and French abstracts. DOI : http://dx.doi.org/10.15553/c2015v701a3 This article discusses various aspects of the biogeographical origin and endemism of the Corsican flora based on data retrieved from “Flora Corsica” project. It focuses on species richness, taxonomy, life forms, taxa abundance, distribution in vegetation belts, habitats and substrate types. The results are compared to other geographic regions, particularly Mediterranean ones. These data show that in Corsica the species of Mediterranean origin are slightly more numerous than those of Holarctic origin. It is surprising that the Holarctic elements start to dominate at low altitude in the supramediterranean belt. The endemic flora (12.7 %) shows distribution patterns often distinct from those of the non-endemic native flora, particularly regarding taxonomy, biological types and altitudinal distributions. The rates of hemicryptophytes and chamaephytes are for instance higher for the former compared to the latter while it is the reverse for therophytes. These rates are quite similar to those recorded in Sardinia, but rather different from those of other Mediterranean islands. More unexpected is the abundance pattern of endemic species which is quite similar to that of non-endemic ones. However, strictly endemic Corsican species are generally rarer than subendemics. The number of endemic species increases from the coast to the montane belt and then decreases in the upper belts. The percentage of endemic species, meanwhile, regularly increases from the thermomediterranean belt to the alpine one where it reachs a maximum of 43.1 %. The endemic flora also shows a wider altitudinal spectrum than other native species. The distribution of endemic species in the different Corsican habitats is slightly different from the one recorded for the indigeneous taxa. Endemics are however preferentially found in rocky habitats, but without any preference for a particular substrate. In the endemic flora, the Mediterranean origin is predominant but this trend is more marked in subendemics. The strict Corsican endemics have a mostly Holarctic origin and are more often found at high altitudes. These results shed light on the specificity of the Corsican endemic flora and should help the management of endemic species. Resume

Morphological and ecological comparison of populations of Juniperus turbinata Guss. and J. phoenicea L. from the Mediterranean region

The aim of the present study was the biometrical comparison and ecological analysis of six populations of Juniperus phoenicea complex from the western part of the species' geographic range, each represented by about 30 individuals. This is the first study to include the Sicilian population of J. turbinata sensu stricto. Seven features of the cones and seeds, two of the shoots and leaves and eight ratios were used to describe the individuals and populations which were then compared using statistical methods. Four of the analysed populations (representatives of J. turbinata s.s.) are closely related to each other. The two other populations representing J. phoenicea s.s. appear to be much more variable but on the whole the two taxa treated at a species level seem to be quite distinct from each other. It was also noted that there are two quite different ecologies of these species: the first is typical of the thermomediterranean belt which is only found at high altitudes in the mountains of north Africa, and the second circumscribed to the meso- or supramediterranean belt of western Spain, France and northwestern Italy. In many parts of its coastal distribution, Juniperus turbinata is endangered due to the construction of summer resorts and therefore actions to protect this species are needed.

English

The study of Quercus pyrenaica forests in eastern areas of the Iberian Peninsula has differentiated a set of relevés from the Sierra de Espadán (Castellón). They are located in subhumid sites in the upper mesomediterranean to low supramediterranean belt, in the Valenciano-Tarraconense Mountains. A new forest Minuartio valentinae-Quercetum pyrenaicae is therefore described here, together with its main seral communities.

Holocene vegetation and fire dynamics in the supra‐mediterranean belt of the Nebrodi Mountains (Sicily, Italy)

AbstractHigh‐resolution pollen, macrofossil and charcoal data, combined with accelerator mass spectrometry 14C dating and multivariate analysis, were used to reconstruct Holocene vegetation and fire dynamics at Urio Quattrocchi, a small lake in the supra‐mediterranean belt in the Nebrodi Mountains of Sicily (Italy). The data suggest that after 10 000 cal a BP increasing moisture availability supported closed forests with deciduous (Quercus cerris, Fagus sylvatica and Fraxinus spp.) and evergreen (Quercus ilex) species. Species‐rich closed forest persisted until 6850 cal a BP, when Neolithic activities caused a forest decline and affected plant diversity. Secondary forest with abundant Ilex aquifolium recovered between 6650 and 6000 cal a BP, indicating moist conditions. From 5000 cal a BP, agriculture and pastoralism led to the currently fragmented landscape with sparse deciduous forests (Quercus cerris). The study suggests that evergreen broadleaved species were more important at elevations above 1000 m a.s.l. before ca. 5000 cal a BP than subsequently, which might reflect less human impact or warmer‐than‐today climatic conditions between 10 000 and 5000 cal a BP. Despite land use since Neolithic times, deciduous supra‐mediterranean forests were never completely displaced from the Nebrodi Mountains, because of favourable moist conditions that persisted throughout the Holocene. Reconstructed vegetation dynamics document the absence of any pronounced mid‐ or late‐Holocene ‘aridification’ trend at the site, an issue which is controversially debated in Italy and the Mediterranean region. Copyright © 2012 John Wiley & Sons, Ltd.

The Tamaricetalia order in the Western Mediterranean region

Tamaricetalia (Nerio oleandri-Tamaricetea) is the order that groups the tamarisk, oleander and chaste tree scrubby communities of river beds, creeks and temporary pools with occasional running water from the Mediterranean region. Several communities growing in the inframediterranean to the supramediterranean belt with arid to dry ombroclimate from the Mediterranean region (Western Mediterranean, North African Mediterranean and Canarian-Madeira subprovinces) have been studied. The available relevés were arranged in a synthetic table and subjected to a correspondence analysis (DCA). Five alliances: Tamaricion africanae, Tamaricion boveano-canariensis, Rubo ulmifolii-Nerion oleandri, Rubo sancti-Nerion oleandri and Flueggeion tinctoriae were distinguished. In agreement with Izco, Fernández and Molina, the syntaxonomical position of Imperato-Eranthion has been debated.

Relationships among soil characteristics, plant macronutrients, and cardenolide accumulation in natural populations of Digitalis obscura

AbstractIn the present study, we have investigated relationships among several soil parameters (pH, organic matter, total carbonate, macronutrients, electrical conductivity, cation‐exchange capacity) and macronutrient and cardenolide contents in leaves of wild Digitalis obscura plants. Young and mature leaves and soil samples were collected in ten different areas, corresponding to three Mediterranean bioclimatic belts (thermo‐, meso‐, and supramediterranean belts). Soil and leaf macronutrient (N, P, K, Ca, and Mg) contents and leaf cardenolide contents were determined. Bioclimatic conditions influenced the development of D. obscura, biomass being lowest in plant populations of the supramediterranean belt, but they did not exert any relevant effect on the contents of macronutrients in soils and plants. Magnesium (total and EDTA‐extracted) was the only soil macronutrient significantly correlated with its content in the plant. Cardenolide contents were negatively correlated with the N, P, and K contents in young leaves, whereas such correlations were highly significant and positive for Mg.

Sclerophora peronella new to the Iberian Peninsula

An interesting calicioid lichen has been collected as a consequence of the study that our research group is developing in the Iberian meridional beech forests. One of these is the forest Natural Reserve “Chaparral de Montejo” (Madrid Province), which represents one of the southern biogeographic limits of Fagus sylvatica in the Iberian Peninsula. The geological substratum is Silurian clayey slate. It is located in the Supramediterranean belt of central Spain. Sclerophora peronella has been found for the first time in the Iberian Peninsula and for the third time in southern Europe. The previous records in S Europe are from Calabria (Italy) by Puntillo (1992) and from Corse (France) by Vězda (Lich. Sel. Exs. 828).

Lichenized species of Omphalina (Tricholomataceae) in the Iberian Peninsula

Abstract:A taxonomic revision of the lichenized species of the genus Omphalina in the Iberian Peninsula is presented, based upon fungal and lichen herbarium material, as well as on fresh collections. Relevant morphological and ecological features are discussed and a diagnostic key is provided. Four lichenized species, O. ericetorum, O. hudsoniana, O. meridionalis and O. velutina, are recognized. A squamulose vegetative thallus (Coriscium -type) is present only in O. hudsoniana, while the other three species form a thallus of hyphal globules (Botrydina -type). Anatomical features of the vegetative thallus cannot be used to distinguish between these last three species. Whilst O. hudsoniana is known only from the montane belt of the Eurosiberian Region and O. meridionalis seems to be restricted to the Mediterranean Region, living in more or less humid sites of the Supramediterranean belt, the other two species, O. ericetorum and O. velutina, are widespread.

Ecology of cryptogamic epiphytes and their communities in deciduous forests in mediterranean Spain

A distribution of the epiphytic bryophyte and lichen vegetation of deciduous forests from the centre and north of the supramediterranean belt from the Spanish Iberian Peninsula was established using numerical (PCA, CCA) and traditional floristic characteristics. Four groups have been established in relation to several syntaxa. Derived by numerical classification, possible successional trends between the groups with respect to changes in moisture, light and diameter of the trees are described. Nevertheless, patterns with succession in epiphytic communities are very complex to establish.

La zone némorale xérotherme sud-européenne

Abstract The South-European nemoral region. - The objective of this paper is to present a checklist and a biogeographical arrangement of the main vegetation types on the whole submediterranean zone (and supramediterranean belt in the mountains) of the European southern nemoral region. This revision has been made possible by the recent publication of a number of synthetic vegetation maps. It is suggested that this cartographic information may facilitate the design of an ecological study of this zone, particularly of its parameters.