432 research outputs found

    Classification and mapping of the woody vegetation of Gonarezhou National Park, Zimbabwe

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    Within the framework of the Great Limpopo Transfrontier Conservation Area (GLTFCA), the purpose of this study was to produce a classification of the woody vegetation of the Gonarezhou National Park, Zimbabwe, and a map of its potential distribution. Cover-abundance data of woody species were collected in 330 georeferenced relevés across the Park. These data were used to produce two matrices: the first one using the cover-abundance values as collected in five height layers and the second one based on merging the layers into a single cover value for each species. Automatic classifications were produced for both matrices to determine the optimal number of vegetation types. The two classification approaches both produced 14 types belonging to three macro-groups: mopane, miombo and alluvial woodlands. The results of the two classifications were compared looking at the constant, dominant and diagnostic species of each type. The classification based on separate layers was considered more effective and retained. A high-resolution map of the potential distribution of vegetation types for the whole study area was produced using Random Forest. In the model, the relationship between bioclimatic and topographic variables, known to be correlated to vegetation types, and the classified relevés was used. Identified vegetation types were compared with those of other national parks within the GLTFCA, and an evaluation of the main threats and pressures was conducted. Conservation implications: Vegetation classification and mapping are useful tools for multiple purposes including: surveying and monitoring plant and animal populations, communities and their habitats, and development of management and conservation strategies. Filling the knowledge gap for the Gonarezhou National Park provides a basis for standardised and homogeneous vegetation classification and mapping for the entire Great Limpopo Transfrontier Conservation Area

    Alien plant invasions in Mediterranean habitats: an assessment for Sicily

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    Levels of plant invasions in different habitat types were assessed in several regional studies, but few of them were from the Mediterranean. Here we compare the levels of vascular plant invasion across habitats and plant communities of Sicily. We used a large dataset of plant species presences/ absences in vegetation plots to analyze the invasion patterns across habitats considering biogeography, life form and phenology of alien plants. Vegetation plots were classified based on the EUNIS classification of European habitats. The invasiveness of each species was expressed in terms of its absolute and percentage frequency. Representation of different life forms and phenological patterns was compared between alien and native species. The fidelity of alien species to individual habitats was calculated using the phi coefficient. Our analysis shows that annual and woody species are the most represented life forms in the alien flora of Sicily and that alien species tend to have a longer flowering period than the native species. The investigated habitats differed strongly in their level of invasion by alien species, ranging from 0 to 15.6% of aliens of all species recorded. Most of the habitats were colonized by very few alien species or completely lacked them, except for sandy coasts, naturally-disturbed riverbeds, and synanthropic habitats. It must be noted, however, that the number of alien species occurring in a given habitat does not relate to the severity of the impact of invasion in that habitat. Some habitats are invaded by few (or single) species, which attain a high cover, transforming the whole ecosystem. The habitat-based approach proved to be suitable for evaluating the habitat specificity and frequency of alien species at a regional scale, improving the capacity for risk assessment in different ecological contexts

    Il Museo Orto Botanico di Roma dal medioevo a oggi. Caratteristiche, funzioni e prospettive

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    The history of the Botanical Garden of Rome has been documented since the Middle Ages, the period to which date back the first records relating to the papal Botanical Gardens that were planted in the Vatican grounds in order to grow and study plants of particular interest for medicine and food. In 1660, Alessandro VII entrusted the care of the papal Botanical Gardens to the University of Rome, which were moved from the Vatican to the Gianicolo area of Rome. After being relocated at various times over the years, in 1883 the Botanical Gardens were planted in the gardens of Villa Corsini, and became famous when Queen Christina of Sweden was resident in the 1600s and as a result of work carried out by Ferdinando Fuga the following century. The Botanical Garden of Rome covers a surface area of approximately 12 hectares, where thousands of plant species are cultivated and laid out according to various scientific criteria in the field of taxonomy, ecology, biogeography, and conservation. The most important collections comprise palms, conifers, roses, bamboo, medicinal plants and succulents. Of great interest are also the Japanese Garden, Rock Garden, the historical greenhouses (Serra Corsini, Serra Francese and Serra Monumentale) and the Tropical Greenhouse. There are many centuries-old trees including four oriental planes and a cork oak. Compared to the Garden that existed in the Middle Ages and later centuries, today's Botanical Garden of Rome has noticeably expanded its functions and is ready to face the stimulating challenges that lie ahead, challenges related to scientific research in support of conservation and sustainable use of plant biodiversity

    Phytosociology and taxonomic notes on some endemic-rich associations of the Naples Gulf

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    The Gulf of Naples is an important centre of endemism, well known from the floristic point of view, but much less from the phytosociological one. In this paper we investigated the non-forest vegetation focusing on communities rich in endemics. We described two communities as new: Eryngio amethystini-Santolinetum neapolitanae for the garrigues on limestone, Globulario neapolitanae-Loniceretum stabianae for the vegetation on dolomitic rocks, both from the Lattari mountains, and we extend the area of Crithmo maritimi-Limonietum cumani for the vegetation on volcanic rocks and rarely on limestones along the coast, which was known for a few localities. The syntaxonomical position and the phytogeographical context of these communities are discussed. A few taxonomic notes are added on rare or interesting species retrieved in the course of the enquiry

    How to improve the distribution maps of habitat types at national scale

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    Annex I habitat types are a key factor for biodiversity conservation in Europe and distribution maps are essential for assessing their conservation status. We aim to increase the responsiveness to habitat knowledge needs and to propose the use of data collected at local scale for assessing a key indicator such as the Area of Occupancy (AOO) of habitats. In this paper, starting from the 4th Report of Habitats Directive data, we present a multi-source approach that allows national habitat distribution maps to be refined and their AOO estimated, by combining certified available information on habitat maps and vegetation databases. For the first time a comprehensive up-to-date knowledge on habitat distribution at national scale is now available; our approach will be an essential tool for the implementation of the Habitats Directive and to achieve the goals of EU biodiversity strategy in Italy

    Temporal changes of vascular plant diversity in response to tree dieback in a mediterranean lowland forest

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    Palo Laziale wood is a small biotope of about 129 ha situated along the north coast of Rome. It is one of the last remaining patches of an ancient lowland floodplain forest that once covered the coastal area of the Lazio region. It contains several habitats and species of high conservation interest which has been included in the Natura2000 network. The forest suffered an impressive dieback event in 2003, coinciding with a particularly hot and dry summer. In the framework of an ecological restoration project (LIFE PRIMED LIFE17 NAT/GR/000511), a preliminary assessment of the biotic and abiotic components of the ecosystem was carried out, including a floristic analysis. This analysis was compared with that conducted in 1990 to assess whether there was any change in the species composition also following the forest dieback. Comparisons between biological forms, chorotypes and the Ellenberg indicators were also made in the analysis. The total flora of the site increased from 462 to 490 species. Moreover, there has been a turnover of species with the disappearance of some grassland and halophytic species and the appearance of allochthonous/ruderal and freshwater habitat species. Despite this, the flora remained unchanged in ecological terms, demonstrating a certain resilience of the plant species, confirming this approach to identify declining processes and support ecosystem-based restoration actions elsewhere

    Open Source Tools Applied to Text Data Recovery in Big Data Environments

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    As the volume of data on the web continue to increase, it is getting more challenging for the search mechanism to find with a high precision rate what the users want to find. As a solution to improve these results, the development of a recommender engine, based on the content of the documents, would prove itself very useful. In this context, this research has the objective to show how the current search and indexing tools could be improved with recommendation, Machine Learning and textual analysis algorithms. The idea behind these project would be to, based on the content of the documents recovered in the search, find similar documents using most of the Open Source technology we have available right now

    Investigating the effect of selective logging on tree biodiversity and structure of the tropical forests of Papua New Guinea

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    Abstract: Unsustainable exploitation of tropical forest resources is raising worldwide concern. In Papua New Guinea (PNG) timber harvesting has been identified as a major contributor to deforestation and forest degradation but its impact on biodiversity is still poorly understood. In this study we investigated the effect of selective logging on tree taxonomic composition, structure and diversity of PNG forests. We used data from 101 one-hectare permanent sample plots (PSPs) belonging to two vegetation types: low altitude forests on plains and fans (type P) and low altitude forests on uplands (type H). We used multivariate techniques to test for significant differences in species composition between plots of different vegetation types and disturbance regimes, identifying the tree taxa to which these differences could be ascribed. ANOVA was used to test for differences between logged-over and unlogged forest PSPs with respect to biodiversity (richness, Shannon's diversity, Pielou's evenness) and stand structure (stem density, basal area - BA). Temporal trends of forest features were analyzed using linear regression. Significant differences in taxonomic composition were found between logged-over and unlogged plots of the H type (p = 0.04). No differences were found in richness, diversity and evenness between logged-over and unlogged forest plots, while stem density was higher in the latter (421 ± 153 stems ha-1). Greater BA was found in unlogged forests (30.28 ± 4.45 m2 ha-1) of the H type when compared to the logged-over stands (15.52 ± 4.04 m2 ha-1). We detected positive trends in richness (0.55 ± 0.19 taxa ha-1 yr-1) and diversity after logging. Furthermore, H type forest exhibited positive trends in stem density (9 ± 1 stems ha-1 yr-1) and BA (0.42 ± 0.06 m2 ha-1 yr-1) with elapsed time since harvesting. Our analysis highlights some significant effects of logging activities on biodiversity and structure of PNG forests. Additionally, forests exhibited a significant recovery with respect to richness, diversity and stand structure. These preliminary results will be compared with data collected by the forthcoming National Forest Inventory in order to assess and monitor the effects of human activities and ecological factors on PNG forest biodiversity and develop appropriate conservation measures and sustainable management strategies

    A comparative framework for broad-scale plot-based vegetation classification

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    Aims: Classification of vegetation is an essential tool to describe, understand, predict and manage biodiversity. Given the multiplicity of approaches to classify vegetation, it is important to develop international consensus around a set of general guidelines and purpose-specific standard protocols. Before these goals can be achieved, however, it is necessary to identify and understand the different choices that are made during the process of classifying vegetation. This paper presents a framework to facilitate comparisons between broad-scale plot-based classification approaches. Results: Our framework is based on the distinction of four structural elements (plot record, vegetation type, consistent classification section and classification system) and two procedural elements (classification protocol and classification approach). For each element we describe essential properties that can be used for comparisons. We also review alternative choices regarding critical decisions of classification approaches; with a special focus on the procedures used to define vegetation types from plot records. We illustrate our comparative framework by applying it to different broad-scale classification approaches. Conclusions: Our framework will be useful for understanding and comparing plot-based vegetation classification approaches, as well as for integrating classification systems and their sections. We present a comparison framework for vegetation classification that distinguishes four structural elements (plot record, vegetation type, consistent classification section and classification system) and two procedural elements (classification protocol and classification approach). The framework will be useful for understanding and comparing plot-based vegetation classification approaches, as well as for integrating classification systems and their sections. © 2015 International Association for Vegetation Science

    Phytosociological overview of the Fagus and Corylus forests in Albania

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    Aim: The aim of this study is to analyze the mesophilous forests of Albania including Fagus sylvatica and submontane Corylus avellana forests. Mesophilous Albanian forests are poorly known and were not included in the recent syntaxonomic revisions at the European scale. Study area: Albania. Methods: We used a dataset of 284 published and unpublished relevés. They were classified using the Ward's minimum variance. NMDS ordination was conducted, with over-laying of climatic and geological variables, to analyze the ecological gradients along which these forests develop and segregate. Random Forest was used to define the potential distribution of the identified forest groups in Albania. Results: The study identified seven groups of forests in Albania: Corylus avellana forests, Ostrya carpinifolia-Fagus sylvatica forests, lower montane mesophytic Fagus sylvatica forests, middle montane mesophytic Fagus sylvatica forests, middle montane basiphytic Fagus sylvatica forests, upper montane basiphytic Fagus sylvatica forests, upper montane acidophytic Fagus sylvatica forests. These can be grouped into four main types: Corylus avellana and Ostrya carpinifolia-Fagus sylvatica forests, thermo-basiphytic Fagus sylvatica forest, meso-basiphytic Fagus sylvatica forest and acidophytic Fagus sylvatica forests. This scheme corresponds to the ecological classification recently proposed in a European revision for Fagus sylvatica forests Conclusion: Our study supports an ecological classification of mesophilous forests of Albania at the level of suballiance. Analysis is still preliminary at the level of association, but it shows a high diversity of forest types. Taxonomic reference: Euro+Med PlantBase (http://ww2.bgbm.org/EuroPlusMed/) [accessed 25 Novemeber 2019]. Syntaxonomic references: Mucina et al. (2016) for alliances, orders and classes; Willner et al. (2017) for suballiances
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