Panayotis Dimopoulos
University of Patras
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Featured researches published by Panayotis Dimopoulos.
Landscape Ecology | 2013
Valeria Tomaselli; Panayotis Dimopoulos; Carmela Marangi; Athanasios S. Kallimanis; Maria Adamo; Cristina Tarantino; Maria Panitsa; Massimo Terzi; Giuseppe Veronico; Francesco P. Lovergine; Harini Nagendra; Richard Lucas; Paola Mairota; C.A. Mücher; Palma Blonda
Periodic monitoring of biodiversity changes at a landscape scale constitutes a key issue for conservation managers. Earth observation (EO) data offer a potential solution, through direct or indirect mapping of species or habitats. Most national and international programs rely on the use of land cover (LC) and/or land use (LU) classification systems. Yet, these are not as clearly relatable to biodiversity in comparison to habitat classifications, and provide less scope for monitoring. While a conversion from LC/LU classification to habitat classification can be of great utility, differences in definitions and criteria have so far limited the establishment of a unified approach for such translation between these two classification systems. Focusing on five Mediterranean NATURA 2000 sites, this paper considers the scope for three of the most commonly used global LC/LU taxonomies—CORINE Land Cover, the Food and Agricultural Organisation (FAO) land cover classification system (LCCS) and the International Geosphere-Biosphere Programme to be translated to habitat taxonomies. Through both quantitative and expert knowledge based qualitative analysis of selected taxonomies, FAO-LCCS turns out to be the best candidate to cope with the complexity of habitat description and provides a framework for EO and in situ data integration for habitat mapping, reducing uncertainties and class overlaps and bridging the gap between LC/LU and habitats domains for landscape monitoring—a major issue for conservation. This study also highlights the need to modify the FAO-LCCS hierarchical class description process to permit the addition of attributes based on class-specific expert knowledge to select multi-temporal (seasonal) EO data and improve classification. An application of LC/LU to habitat mapping is provided for a coastal Natura 2000 site with high classification accuracy as a result.
Flora | 1994
Maria Panitsa; Panayotis Dimopoulos; Gregoris Iatrou; Dimitris Tzanoudakis
Summary Enousses is an islets group situated eastwards of Chios island (E. Aegean, Greece), which remained quite unexplored floristically. Based on our herborizations, 270 taxa belonging to 51 families and 204 genera of spermatophytes are listed for the flora of this area. The flora of the area is analysed and the plant species recognized are classified into 9 chorological groups and 5 life form types. The results of this analysis confirm the Mediterranean character of the flora since the Mediterranean elements and the therophytes are predominant in the area. The vegetation of all islets is characterized by the dominance of phryganic communities, and the three “vegetation zones” distinguished (littoral, sublittoral and interior ones) are described. Geological history, geography, microecological differences, random events and human activities seem to be the most important factors related to the diversity of the flora and vegetation observed in our area. Special attention has been given to human interference, since in the bigger islets of the group -which are used for agriculture, grazing etc. - high percentages of Therophytes and Leguminous species have been observed (indexes of disturbance). On the contrary, in the smaller ones, which are not affected by human activities (i.e. Vatopoula), these indexes show deviate values. For this reason, the importance of the small islets ecosystems in floristic and ecological studies in the Aegean area is pointed out.
European Journal of Radiology | 1998
Michael D. Melekos; Pandora N. Kosti; Ioannis E. Zarakovitis; Panayotis Dimopoulos
Milk of calcium renal cysts contain a colloidal suspension of calcium crystals. By routine radiography and sonography in supine position this rare condition may be misinterpreted as renal lithiasis for which an unnecessary surgical intervention may be performed as it happened in our two cases that are presented here. Postoperatively, the characteristic finding of half-moon contour on upright abdominal plain views was lacking in one case, but in both cases computed tomography revealed the typical calcific suspension layering. However, upright plain views and computed tomography are not routinely performed in patients in whom a renal stone has initially been considered. This entity should be considered in the differential diagnosis of renal paracalyceal calcifications of obscured origin.
Willdenowia | 2016
Panayotis Dimopoulos; Thomas Raus; Erwin Bergmeier; Theophanis Constantinidis; Gregoris Iatrou; Stella Kokkini; Arne Strid; Dimitrios Tzanoudakis
Abstract: Supplementary information on taxonomy, nomenclature, distribution within Greece, total range, life form and ecological traits of vascular plants known to occur in Greece is presented and the revised data are quantitatively analysed. Floristic discrepancies between Vascular plants of Greece: An annotated checklist (Dimopoulos & al. 2013) and relevant influential datasets (Flora europaea, Med-Checklist, Euro+Med PlantBase, etc.) are explained and clarified. An additional quantity of synonyms and misapplied names used in previous Greek floristic literature is presented. Taxonomic and floristic novelties published after 31 October 2013 are not considered. Citation: Dimopoulos P., Raus Th., Bergmeier E., Constantinidis Th., Iatrou G., Kokkini S., Strid A. & Tzanoudakis D. 2016: Vascular plants of Greece: An annotated checklist. Supplement. — Willdenowia 46: 301–347. doi: http://dx.doi.org/10.3372/wi.46.46303 Version of record first published online on 26 October 2016 ahead of inclusion in December 2016 issue.
Scientific Reports | 2017
Athanasios S. Kallimanis; Maria Panitsa; Panayotis Dimopoulos
EU biodiversity conservation policy is based on the Habitats Directive (92/43/EC), which aims that habitat types and species of Community interest should reach ‘favourable conservation status’. To this end, Member States are obliged to perform periodic assessment of species and habitat conservation status through biodiversity monitoring, which, in almost all cases, was performed by experts implementing standardized field protocols. Here, we examine the quality of data collected in the field by non-experts (citizen scientists) for the conservation status assessment of habitat types, and specifically for the criteria ‘typical species’, ‘specific structures and functions’, and ‘pressures and threats’. This task is complicated and demands different types of field data. We visited two Natura 2000 sites and investigated four habitat types (two in each site) with non-experts and compared their data to the data collected by experts for accuracy, completeness and spatial arrangement. The majority of the non-expert data were accurate (i.e. non-experts recorded information they observed in the field), but they were incomplete (i.e. non-experts detected less information than the experts). Also, non-experts chose their sampling locations closer to the edge of the habitat, i.e. in more marginal conditions and thus in potentially more degraded conditions, than experts.
Scientific Reports | 2016
Elpida Karadimou; Athanasios S. Kallimanis; Ioannis Tsiripidis; Panayotis Dimopoulos
The relationship between species richness and area is one of the few well-established laws in ecology, and one might expect a similar relationship with functional diversity (FD). However, only a few studies investigate the relationship between trait-based FD and area, the Functional Diversity - Area Relationship (FDAR). To examine FDAR, we constructed the species accumulation curve and the corresponding FD curve. We used plant diversity data from nested plots (1–128 m2), recorded on the Volcanic islands of Santorini Archipelagos, Greece. Six multidimensional FD indices were calculated using 26 traits. We identified a typology of FDARs depending on the facet of FD analyzed: (A) strongly positive for indices quantifying the range of functional traits in the community, (B) negative correlation for indices quantifying the evenness in the distribution of abundance in the trait space, (C) no clear pattern for indices reflecting the functional similarity of species and (D) idiosyncratic patterns with area for functional divergence. As area increases, the range of traits observed in the community increases, but the abundance of traits does not increase proportionally and some traits become dominant, implying a reliance on some functions that may be located in either the center or the periphery of the trait space.
Plant Biosystems | 2017
Valeria Tomaselli; Maria Adamo; Giuseppe Veronico; Saverio Sciandrello; Cristina Tarantino; Panayotis Dimopoulos; P. Medagli; Harini Nagendra; Palma Blonda
Abstract Habitats are effective indicators of biodiversity. Remote sensing data and techniques are of great utility for their long-term monitoring. Habitat maps can be derived from land cover (LC) maps through rules obtained from expert knowledge and integrated with in situ data. Spatial (vegetation pattern) and temporal (phenology and water seasonality) relationships were explored and documented to infer reliable rules for LC (according to the Food and Agricultural Organization Land Cover Classification System (FAO-LCCS) taxonomy) to habitat (Annex I to the 92/43 EEC Directive and EUNIS) class translation. A coastal site in southern Italy was considered as study site for the definition and validation of such rules. Phenological data of the plant communities were collected on the basis of vegetation plots randomly distributed within the study site. Water seasonality was extracted from periodical observation of the water surface. Vegetation pattern was analyzed by means of vegetation survey along transects. The potentiality of rules, based on this specific expert knowledge, was tested in an experimental setting for habitat mapping. The overall accuracy of the habitat map was 75.1%. Such a result supports the usefulness of prior expert knowledge for habitat mapping from LCCS classes and disambiguation on one-to-many relations between LC/LU and habitat types.
Journal of Biological Research-thessaloniki | 2014
Eleni Iliadou; Athanasios S. Kallimanis; Panayotis Dimopoulos; Maria Panitsa
BackgroundGreece has two island archipelagos, the Aegean and the Ionian, which host a rich array of plants and wildlife, particularly endemic and threatened plant species. Despite the long history of island biogeographic studies in the Aegean, similar studies in the Ionian remain limited, with the two island archipelagos rarely being compared.ResultsThe Aegean and Ionian archipelagos share many features, especially regarding total plant diversity, but exhibit different patterns of endemism. For instance, when considering similarly sized islands, those in the Ionian host as many as, if not more, species compared to the Aegean. In contrast, the Ionian Islands are poor in endemics (particularly narrow range endemics, such as single island or regional endemics) and threatened taxa, compared to the Aegean Islands. In the Ionian, endemics only persist on the largest islands, and form a very small proportion of the species pool, compared to the Aegean archipelago.ConclusionsThe lack of endemism might be attributed to the more recent separation of the Ionian Islands from the mainland and the shorter distance separating them from the mainland. In addition, the Ionian Islands receive higher levels of precipitation and are typically covered by denser and higher vegetation than the Aegean Islands. These conditions favour greater total species richness, but tend to lead to higher numbers of common species compared to threatened and endemic taxa. This study demonstrates that both isolation and precipitation serve as biodiversity drivers, influencing plant species diversity and endemism patterns, of the two Greek archipelagos.
Folia Geobotanica Et Phytotaxonomica | 1996
Panayotis Dimopoulos; Theodoros Georgiadis; Karle Sykora
The montane coniferous forests and their degraded syntaxa included either in theQuercetalia ilicis or in theQuercetalia pubescenti-petraeae of the Meso- up to the Mountain-Mediterranean vegetation belts of Mount Killini, have been studied using the Braun-Blanquet method with 69 phytosociological relevés. The application of classification and ordination methods resulted in the recognition of seven forest and two scrub plant communities. These communities could be arranged along an altitudinal gradient. Their syntaxonomy and structure are described and the present horizontal and vertical arrangement of the coniferous syntaxa is mapped. From these syntaxa, 3 new associations and 1 new subassociation are described. The main factors influencing the differences in floristic composition, are altitude and human impact resulting in degradation of the coniferous forest associations. In addition, differences in soil parameters like pH, the presence of organic matter and nutrients appear to be important. Information on the site characteristics, structure and syndynamical position of the communities is given.
Rendiconti Lincei-scienze Fisiche E Naturali | 2018
Ioannis Tsiripidis; Fotios Xystrakis; Athanasios S. Kallimanis; Maria Panitsa; Panayotis Dimopoulos
Monitoring of habitat types conservation status is an essential task in the frame of the European policy for biodiversity conservation. The parameters to be assessed for the purposes of habitat types’ conservation status assessment are described in several European documents, but the methodology for their determination has not yet been standardized or optimized. This study presents methods for the assessment of the actual status and the future prospects of structure and functions of habitat types. Specifically, it presents a bottom–up approach for the assessment of these two parameters at different spatial scales. In the proposed method, conservation status assessment is based on a classification of habitat types to subtypes, with the latter representing the basic monitoring entities. The conservation status is assessed by recording: (i) the presence/absence of specific indicators of structure and functions per habitat type, and (ii) the presence/absence, abundance, and vitality of the typical species of the habitat subtypes. The typical species are determined objectively using algorithms and fidelity coefficient values. The conservation status and future prospects of structure and functions (including the typical species) are estimated quantitatively with the help of numerical methods and algorithms, but their assignment to conservation status classes is based on thresholds defined by experts. Assessments are made at the local scale, but can be upscaled to coarser ones (up to the national level). The proposed methods have been applied in Greece and were effective both in terms of results obtained and costs needed.