The Tertiary relict tree Zelkova abelicea (Ulmaceae): distribution, population structure and conservation status on Crete

Relict species provide a unique opportunity to understand past and recent biogeographical and evolutionary processes. Zelkova abelicea (Ulmaceae), which is endemic to the island of Crete (Greece), is one of the most prominent Tertiary relict trees of the Mediterranean region. We collected distribution, threat and population structure data by reviewing literature and herbaria and through field surveys at 14 study plots throughout the range of the species. The present distribution of Z. abelicea is extremely fragmented. Although the total estimated number of individuals is relatively high, the populations are dominated by dwarf, severely browsed, non-flowering individuals. The population structure is asymmetric. At most, 5% of a plot's trees are large and fruit-bearing. The asymmetric structure is particularly pronounced in isolated and small populations. Based on its limited geographical range, the fragmented spatial pattern, and data on distribution and population structure, our study confirms that Z. abelicea is a threatened species (IUCN category Endangered). Our research aim is to promote the development of new approaches for the improvement of conservation strategies for Tertiary relict trees characterized by major local disjunction

Free behind bars: Effects of browsing exclusion on the growth and regeneration of Zelkova abelicea

Abstract Caprine overbrowsing is a main threat to trees of pastoral mountain woodlands in the Mediterranean region of Europe. In this study, we assess the impact of browsing exclusion on the growth and regeneration of the endangered Zelkova abelicea, a Paleogene relict tree endemic to Crete (Greece). Shoot elongation, height growth and natural regeneration were monitored during two to five years in 31 fenced plots across the distribution range of the species. We found that in the absence of browsing pressure, Z. abelicea produces shoots on average two times longer than when browsed, therefore clearly demonstrating the negative impact of current browsing pressure on the growth performance of the species. Shoot elongation and height growth were maximal in most plots during the first two years following fencing, after which growth rates decreased. The proportion of trees that reached a height considered out of reach of caprine browsing had more than doubled already after four years, although this was dependent on initial tree height. Shoot elongation and height growth were positively correlated with tree height, and smaller trees took more time to reach a specific height. Seedlings were only found in three fenced plots as well as in two control browsed areas during a single year and only in western Crete. This underlines the possible strong and concerning impact of climatic factors on seed formation as well as on seedling growth and survival, although site specificities such as stand structure and micro-topography should also be considered. Our findings have important implications for conservation actions, as they can help choose which stands and which individuals to fence in priority for efficient long-term conservation

Species delimitation in the East Asian species of the relict tree genus Zelkova (Ulmaceae): A complex history of diversification and admixture among species

Zelkova species, trees of the elm family (Ulmaceae), are part of the Cenozoic relict flora. In western Eurasia, the genus comprises three species that are restricted to disjunct areas (Z. sicula on Sicily, Z. abelicea on Crete and Z. carpinifolia in Transcaucasia). The situation is different in East Asia, where three species (Z. serrata, Z. schneideriana and Z. sinica) have at least partly overlapping distributions. The phylogenetic and phylogeographic status of these East Asian species is still not well understood, mainly since all previous studies used almost exclusively plant material collected in botanical gardens and were based on very small numbers of individuals. Our study is the first based on 33 natural populations covering all important areas with Zelkova species in the Sino-Japanese Floristic Region. Chloroplast and microsatellite markers were used, and Bayesian analyses were run for both types of markers. East Asian Zelkova species cluster into two groups that partially overlap when comparing the two types of markers. For chloroplast markers, the two groups coincide with all Japanese, some Korean and northern Chinese Z. serrata in one group and all other individuals in the other group, regardless of whether they are attributed to Z. serrata, Z. sinica or Z. schneideriana from Korea, mainland China and Taiwan. At the nuclear level, however, the clustering clearly groups all the Z. serrata individuals together, regardless of whether they are from Japan, Korea or China, and the two other species in a second group. This complex genetic pattern in East Asian Zelkova species is most likely due to a combination of ancient diversification and speciation events and more recent hybridization during the last glacial/interglacial retractions and recolonizations. One of the surprising results of our study concerns the populations from Taiwan, which are genetically similar to Z. schneideriana. Thus, their assignation to a separate taxon (Z. tarokoensis) or to a variety of Z. serrata (Z. serrata var. tarokoensis), as currently reported in all local and national floras, might be in need of revision. Furthermore, our results indicate that the East Asian species are more closely related to Z. carpinifolia than to any other Western European species. Haplotypes of Z. sicula and Z. abelicea (Mediterranean region) as well as those of Z. sinica and Z. schneideriana (East Asia) seem to have diversified more recently. The most ancient haplotypes are found among the western Eurasian Z. carpinifolia and the East Asian Z. serrata. This result is in agreement with the carpinifolia and serrata-like morphotypes commonly found in the fossil record

Integrated forest management to prevent wildfires under Mediterranean environments

This review presents a multidisciplinary framework for integrating the ecological, regulatory, procedural and technical aspects of forest management for fi res prevention under Mediterranean environments. The aims are to: i) provide a foreground of wildfi re scenario; ii) illustrate the theoretical background of forest fuel management; iii) describe the available fuel management techniques and mechanical operations for fi re prevention in forest and wildland-urban interfaces, with exemplifi cation of case-studies; iv)allocate fi re prevention activities under the hierarchy of forest planning. The review is conceived as an outline commentary discussion targeted to professionals, technicians and government personnel involved in forestry and environmental management

Overcoming sexual sterility in conservation of endangered species: the prominent role of biotechnology in the multiplication of Zelkova sicula (Ulmaceae), a relict tree at the brink of extinction

Biotechnology provides valuable tools to support conservation of plant species, especially in case of threatened taxa or when dealing with seed unavailability, low viability or sterility. However, plant cell culture methods have often to face problems associated with tissue recalcitrance to in vitro systems. Recalcitrance can be related to a variety of triggering factors, involving many efforts and manipulations within one or more of the micropropagation stages before obtaining successful results. An in vitro propagation protocol was developed for Zelkova sicula, a very rare and endangered relict tree, endemic to Sicily (Southern Italy). The species revealed extremely recalcitrant to in vitro culture approaches, but after many trials throughout a number of years an effective micropropagation protocol was completed. The rooting rate was about 84% of the treated explants, 8% of which were successfully acclimatized outdoor and reintroduced in the wild within a comprehensive conservation project. The technique allowed to overcome the problems of sexual sterility of this species, hence contributing concretely to contrast the problems connected with its conservation. However, additional efforts need to be carried out in order to refine the acclimatization step and further improve the whole process effectiveness

Influence of ivy (Hedera helix L.) on the growth of downy oak (Quercus pubescens s.l.) in the Monte Carcaci Nature Reserve (central-western Sicily)

Lianas are commonly considered to be harmful to forest tree species and forest dynamics. They can compete with other ligneous species, with negative influences on forest tree regeneration, growth and/or fecundity. However, few studies also report that the climbing ivy can have a cooperative action, with beneficial effects on hosting trees. In the last decades, in an aged coppice in the Monte Carcaci Nature Reserve (central-western Sicily, Italy), a luxuriant development of ivy (Hedera helix L.) has been observed, leading to detrimental effects on the hosting downy oaks (Quercus pubescens s. l.), which in many cases showed evidences of decline. An investigation focusing on epigeal biomass and tree-ring analysis was carried out in order to contribute at elucidating the nature of interaction between ivy and host oaks. Results suggested that an initial phase of positive influence of ivy on the growth of oaks was followed by a second phase of active competition, with the progressive reduction of host tree vitality. According to that, the continuous monitoring of forest ecosystem evolution is advised in order to better understand the role of lianas in forest dynamics and to define subsequent forest management guidelines.Les lianes sont communément considérées comme des espèces nuisibles aux arbres forestiers et aux processus dynamiques des forêts. En effet, elles peuvent entrer en compétition avec d’autres espèces ligneuses et avoir des influences négatives sur la régénération des arbres, leur croissance voire leur fécondité. Toutefois, quelques études rapportent que le lierre peut avoir aussi une action de coopération avec des effets positifs sur les espèces hôtes. Au cours des dernières décennies, dans un taillis âgé dans la Réserve Naturelle de Monte Carcaci (Sicile centro-occidentale, Italie), un fort développement du lierre (Hedera helix L.) a été observé au détriment des chênes blancs (Quercus pubescens s. l.) hôtes, lesquels montraient parfois des symptômes évidents de dépérissement. Une analyse de la biomasse aérienne et des cernes de croissance a donc été effectuée dans le but de clarifier la nature des interactions entre le lierre et les chênes hôtes. Les résultats ont montré que, après une phase d’influence positive du lierre sur la croissance des chênes, une phase de compétition active s’établit, se matérialisant par la réduction progressive de la vitalité des arbres porteurs. Sur cette base, un suivi de l’évolution forestière serait souhaitable afin de mieux comprendre le rôle des lianes au sein de l’écosystème et de définir les lignes guide les plus appropriés de l’aménagement forestier futur.Garfì Giuseppe, Ficarrotta Salvina. Influence of ivy (Hedera helix L.) on the growth of downy oak (Quercus pubescens s.l.) in the Monte Carcaci Nature Reserve (central-western Sicily). In: Ecologia mediterranea, tome 29 n°1, 2003. pp. 5-14

Analyse comparée de l'évolution de la régénération de Quercus suber et Quercus pubescens après élimination du pâturage en forêt de Pisano (Sicile sud-orientale)

Several studies carried out in north-west Mediterranean areas showed the role of Quercus deciduous species as pioneer woody species in secondary succession processes in abandoned areas. The aim of this paper is to verify this phenomenon in a Quercus suber open woodland in Monti Iblei (South-East Sicily, Italy) where grazing is still present. A diachronic approach was used to study the patterns and growth rate of young individuals (seedlings and saplings) of a deciduous oak (Q . pubescens) and a sclerophyllous oak (Q. suber) in presence or absence of grazing. Q. pubescens is frequent in all the stands, but no one individual reaches the canopy layer. In absence of grazing Q. pubescens growth rate is higher than the Q. suber one, thus showing a strong competitive capacity. These results confirm the main role of Q. pubescens in dynamical processes of this region.Plusieurs travaux effectués dans le nord-ouest de la Méditerranée ont montré la potentialité des chênes caducifoliés à coloniser les espaces abandonnés par l’homme. Les auteurs proposent de vérifier cette tendance dans les Monti Iblei (Sicile sud-orientale) où les perturbations anthropiques, notamment le pâturage, sont encore présentes. Une étude diachronique a été effectuée, visant à analyser les patrons de la distribution spatiale et de la vitesse de croissance de la régénération de Quercus pubescens et de Q. suber en condition de présence ou d’absence de pâturage. Q. pubescens est absent de la strate arborescente, alors qu’il se régénère bien. En absence de pâturage, Q. pubescens montre une vitesse de croissance et donc un pouvoir compétitif plus importants que Q. suber. Si on compare ces résultats aux données déjà disponibles pour la végétation du bassin occidental de la Méditerranée, ceux-ci confirment le rôle important des chênes caducifoliés au sein des processus dynamiques de cette région.Di Pasquale Gaetano, Garfì Giuseppe. Analyse comparée de l'évolution de la régénération de Quercus suber et Quercus pubescens après élimination du pâturage en forêt de Pisano (Sicile sud-orientale). In: Ecologia mediterranea, tome 24 n°1, 1998. pp. 15-25

Phenology and growth of Quercus ilex L. in different environmental conditions in Sicily (Italy)

Phenology and growth of Quercus ilex L. in four different sites in Sicily were analysed over a period of two years, with the aims to contribute at the knowledge of ecology and adaptive plasticity of this species. The following aspects were considered : i) sprouting, ii) flowering, iii) fruiting, iv) shoot growth, v) leaf longevity, vi) leaf area. The results showed a variability among the four investigated sites. A precocity for most of the phenological phases, a higher growth and a polycyclic growth were observed only at Mt Pellegrino, the most “oceanic” and hottest site among the investigated ones. Indeed, such features are likely further enhanced by the climatic peculiarities of that site, such as the high atmospheric moisture and the mild autumn. According to our data, Quercus ilex globally exhibits a notable adaptive ability to different environments. In the same time, its response at Mt Pellegrino is consistent with the assumption that this species originated in a tropical-type climate.Pendant deux ans, la phénologie et la croissance du chêne vert (Quercus ilex L.) ont été étudiées dans quatre localités de Sicile, dans le but de contribuer à la connaissance de l’écologie et de la plasticité adaptative de cette espèce. Les aspects suivants ont été considérés : le débourrement, la floraison, la fructification, la croissance des pousses, le turn-over des feuilles, et la surface foliaire. Les résultats ont montré une certaine variabilité des réponses parmi les quatre populations étudiées. Une précocité pour la plupart des phases phénologiques, un taux de croissance plus marqué et une croissance polycyclique ont été observés seulement au Mt. Pellegrino, site le plus “océanique” et le plus chaud parmi ceux étudiés. En outre, ces caractères sont vraisemblablement encore plus prononcés en raison d’autres particularités climatiques de ce site, telles que l’humidité atmosphérique très élevée et les automnes doux. D’après nos résultats, le chêne vert montre une capacité adaptative notable face à des environnements très différents. La réponse du chêne vert dans la population du Mt. Pellegrino est assez cohérente avec l’hypothèse d’une origine de l’espèce au sein d’un climat de type tropical.La Mantia Tommaso, Cullotta Sebastiano, Garfì Giuseppe. Phenology and growth of Quercus ilex L. in different environmental conditions in Sicily (Italy). In: Ecologia mediterranea, tome 29 n°1, 2003. pp. 15-25

An Updated Checklist of the Sicilian Native Edible Plants: Preserving the Traditional Ecological Knowledge of Century-Old Agro-Pastoral Landscapes

The traditional use of native wild food plants (NWFP) may represent a valuable supplementary food source for the present and future generations. In Sicily, the use of wild plants in the human diet dates back to very ancient times and still plays an important role in some rural communities. Moreover, in this regard, the natural and cultural inheritance of this island is wealthy and diversified for several reasons. First, Sicily hosts a rich vascular flora, with 3,000 native and 350 endemic plants. Second, due to its central position in the Mediterranean, the island has acted as a veritable melting pot for the ethnobotanical knowledge of the rural communities of the entire basin. We reviewed all the available literature and, starting from such omnicomprehensive checklist, partially improved thanks to the data issuing from recent field investigations, we critically revised the whole species list, basing our review on field data issuing from interviews and on our expert knowledge. As a result, we provide a substantially updated list of 292 NWFP growing on the island. Further 34 species, reported as NWFP on previous papers were discarded because they are not native to Sicily, while 45 species were listed separately because their identity, occurrence and local use as food is doubtful and needs to be further investigated. Moreover, we tried to shed light on the ecology (growth form and preferential habitat) of the Sicilian NWFP, with special focus on crop wild relatives (CWR). Our preliminary ecological analyses point out that a high percentage of these plants are linked with the so-called ‘cultural’ landscapes, patchy semi-natural environments rich in ecotones, leading to the conclusion that the maintenance of century-old agro-pastoral practices may represent an effective way to preserve the local heritage of edible plants. Our study allowed to identify as much as 102 taxa of agronomic interest which could be tested as novel crops in order to face ongoing global changes and to comply with sustainable agriculture policies. Among them, 39 taxa show promising traits in terms of tolerance to one or more environmental stress factors, while 55 more are considered CWR and/or can be easily cultivated and/or show high productivity/yield potential