Soil seed banks, plant diversity and grazing in deciduous oak forests of Greece

The role of grazing as a management practice, which could favor the conservation of high biodiversity levels in forest ecosystems, but also the regeneration of the herb layer, has not been studied in detail. Within the present doctoral thesis the following questions where investigated: • The composition of the above-ground vegetation under different grazing regimes • The composition and the abundance of the soil seed bank. • Comparison of the soil seed bank with the above-ground vegetation. • Assessment of the usefulness of the soil seed bank in restoration. • Monitoring of the above-ground vegetation changes, in time, focusing on the herb layer of the overgrazed forests. The study area is covered by extensive sub-Mediterranean mixed deciduous oak forests near Konitsa (Epirus), which undergo long-term overgrazing. The forests cover flysch and belong to the South Balkan association Verbasco glabrati-Quercetum frainetto. The soil seed bank of the study area is persistent and the seeds density reaches the levels of 2000 seeds/m². The long-term overgrazing and especially the wild boar grazing caused the qualitative and quantitative degradation of the soil seed bank. In the persistent soil seed bank 28 taxa were recorded, from which the dominant woody taxa and many typical forest taxa of the above-ground vegetation were absent. The long-term overgrazing reduced: a) the species richness (a-diversity) and b-diversity of the soil seed bank and of the above-ground vegetation, b) the similarity between the above-ground vegetation and the soil seed bank and c) the species richness and the seed density of the non-ruderal species, and especially the typical forest herbs, as well as of the animal-dispersed species. Monitoring the changes in the above-ground vegetation revealed that the continuously overgrazed forests are poorer in species while the sites under succession and the undisturbed sites are richer. The temporal turnover of species did not differ significantly between the successional and the sporadically grazed plots and was low in the overgrazed plots. The disturbance caused by overgrazing reduced plant diversity in time. By comparing of the spatial turnover with the temporal turnover of species the space for time substitution was found to be applicable in the studied ecosystem. The dissimilarity in species composition increases as the distance between two observations increases similarly to the case of distance decay. The studied forests have an 'ecological memory' which reflects grazing history. The relation between the above-ground vegetation and the soil seed bank is poor and the potential for restoration of the soil seed bank is limited. The persistent herb seed bank would be insufficient to restore the overgrazed forests after cessation of grazing; consequently, it should be used combined with other methods. The sporadically grazed forests maintain their structure, good regenerative ability and high plant diversity.Ο ρόλος της βόσκησης ως διαχειριστική πρακτική, που μπορεί να ευνοεί τη διατήρηση υψηλών επιπέδων βιοποικιλότητας σε δασικά οικοσυστήματα, αλλά και την αναγέννηση του ποώδους ορόφου δεν έχει μελετηθεί διεξοδικά. Στην παρούσα διδακτορική διατριβή ερευνήθηκαν τα ακόλουθα: • Η σύνθεση της υπέργειας βλάστησης υπό διαφορετικά καθεστώτα βόσκησης. • Η σύνθεση και η αφθονία της εδαφικής τράπεζας σπερμάτων. • Σύγκριση της εδαφικής τράπεζας σπερμάτων με την υπέργεια βλάστηση. • Αξιολόγηση της χρησιμότητας της εδαφικής τράπεζας σπερμάτων στην αποκατάσταση. • Παρακολούθηση των μεταβολών της υπέργειας βλάστησης, στο χρόνο, που υπόκεινται σε μεταβαλλόμενο καθεστώς υπερβόσκησης, δίνοντας βάρος στον ποώδη όροφο. Η περιοχή μελέτης αποτελείται από εκτεταμένα υπο-Μεσογειακά μικτά δάση φυλλοβόλων δρυών κοντά στην Κόνιτσα (Ήπειρος), που υφίστανται μακροχρόνια υπερβόσκηση. Τα δάση εδράζονται σε φλύσχη και εντάσσονται στη φυτοκοινωνική ένωση των Νότιων Βαλκανίων Verbasco glabrati-Quercetum frainetto. Η εδαφική τράπεζα των δασών της περιοχής μελέτης είναι μόνιμη και η πυκνότητα των σπερμάτων είναι της τάξης των 2000 σπερμάτων/m² . Η μακροχρόνια υπερβόσκηση και ειδικά η βόσκηση από αγριόχοιρους επέφερε την ποιοτική και ποσοτική υποβάθμιση της εδαφικής τράπεζας σπερμάτων. Στη μόνιμη εδαφική τράπεζα σπερμάτων καταγράφτηκαν 28 taxa, από τα οποία απουσιάζουν τα κυρίαρχα ξυλώδη taxa και πολλά δασικά είδη της υπέργειας βλάστησης. Με την επίδραση της μακροχρόνιας υπερβόσκησης μειώνεται: α) ο πλούτος ειδών (α-ποικιλότητα) και η β-ποικιλότητα της τράπεζας σπερμάτων και της υπέργειας βλάστησης, β) η ομοιότητα μεταξύ υπέργειας βλάστησης και εδαφικής τράπεζας σπερμάτων και γ) ο πλούτος ειδών και η πυκνότητα σπερμάτων των μη διαταραχόφιλων ειδών και ειδικά των τυπικών δασικών ποών, καθώς και των ζωόχωρων ειδών. Από την παρακολούθηση των μεταβολών της υπέργειας βλάστησης προέκυψε ότι, οι διαρκώς υπερβοσκημένες περιοχές είναι οι φτωχότερες σε είδη, ενώ οι περιοχές υπό διαδοχή και οι μη διαταραγμένες περιοχές είναι οι πλουσιότερες. Η χρονική μεταβολή των ειδών δε διέφερε σημαντικά μεταξύ των περιοχών της διαδοχής και των μη διαταραγμένων περιοχών και στις υπερβοσκημένες επιφάνειες ήταν μικρή. Η υπερβόσκηση ως διαταραχή μείωσε τη φυτική ποικιλότητα και διαχρονικά. Από τη σύγκριση της χωρικής με τη χρονική μεταβολή των ειδών προέκυψε ότι στο συγκεκριμένο οικοσύστημα εφαρμόζεται η υποκατάστατη του χώρου από το χρόνο. Η ανομοιότητα στη σύνθεση των ειδών αυξάνεται όσο αυξάνεται η απόσταση μεταξύ δύο παρατηρήσεων, όπως και στην περίπτωση της μείωσης της ομοιότητας με την απόσταση. Τα ερευνούμενα δάση διαθέτουν «οικολογική μνήμη» που αντανακλά το ιστορικό βόσκησης. Η σχέση της εδαφικής τράπεζας σπερμάτων με την υπέργεια βλάστηση είναι φτωχή και η δυναμική της τράπεζας σπερμάτων για αποκατάσταση είναι περιορισμένη. Μετά τη διακοπή της βόσκησης, η μόνιμη ποώδης τράπεζα σπερμάτων δε θα είναι επαρκής για αποκατάσταση του ποώδους ορόφου, επομένως πρέπει να χρησιμοποιηθούν και άλλες μέθοδοι συμπληρωματικά. Τα σποραδικά βοσκημένα δάση διατηρούν καλή κατάσταση στη δομή τους, καλή αναγεννητική ικανότητα και υψηλή φυτική ποικιλότητα

Topsoil Seed Bank as Feeding Ground for Farmland Birds: A Comparative Assessment in Agricultural Habitats

The topsoil seed bank was studied in four types of agricultural bird habitats: fields with cereals, maize, clover and tilled fields of a Mediterranean plain to determine the potentially richest habitat based on food supply for the wintering farmland birds. The diversity and abundance of topsoil seeds differed between seasons but did not differ significantly between habitats. The cereal habitat was the richest in food supply for the overwintering of farmland birds. The topsoil seed bank was dominated by Chenopodium album, Polygonum aviculare and Amaranthus retroflexus. The findings of this study provide insight for low-intensity management of higher-elevation mount agricultural areas of southern Mediterranean by preserving seed-rich habitats for farmland avifauna

Topsoil seed bank as feeding ground for farmland birds: A comparative assessment in agricultural habitats

The topsoil seed bank was studied in four types of agricultural bird habitats: fields with cereals, maize, clover and tilled fields of a Mediterranean plain to determine the potentially richest habitat based on food supply for the wintering farmland birds. The diversity and abundance of topsoil seeds differed between seasons but did not differ significantly between habitats. The cereal habitat was the richest in food supply for the overwintering of farmland birds. The topsoil seed bank was dominated by Chenopodium album, Polygonum aviculare and Amaranthus retroflexus. The findings of this study provide insight for low-intensity management of higher-elevation mount agricultural areas of southern Mediterranean by preserving seed-rich habitats for farmland avifauna. © 2021 by the authors. Licensee MDPI, Basel, Switzerland

Spatial analysis of orchids diversity unveils hot-spots: The case of Zante Island, Greece

The current study aims to analyze the ecological niche and mapping the distribution of species belonging to Orchidaceae family, in Zante Island and to determine hotspots at sites of high species richness. 967 observations were recorded into 110 tracks in 2015 and 120 tracks in 2016, where 47orchid species were identified belonging to 9 genera. Using Maxent, the ecological niche of each species was analyzed and habitat suitability map was created using 12 environmental parameters. The suitability maps were transformed into a binary format according to the threshold “10th percentile training presence” and the transformed maps used to compute hot-spot regions by applying the SMD toolbox using the software ArcGIS.Zante Island is characterized by remarkably high orchid species richness since the synthetic model indicates presence of at least 10 species for the 53.2% of the island area. Topography, geology and landscape openness are determining factors for orchids’ diversity conservation. Altitude is the determining factor of differentiation in species distribution. Hydro-lithology was the following most significant interpreting parameter. The mapping analysis of species abundance units revealed that 12.5% of the island surface could be characterized as hotspots of high value for the conservation of orchid diversity

Digital Progression and Economic Growth: Analyzing the Impact of ICT Advancements on the GDP of European Union Countries

This research thoroughly examines the dynamic relationship between the European Union’s economic growth and rapid advancements in Information and Communication Technology (ICT). Specifically, it assesses how certain ICT indicators are associated with significant economic growth. Utilizing an extensive dataset from the Digital Economy and Society Index 2022 (DESI), the Statistical Office of the European Union (EUROSTAT), and the Organisation for Economic Co-operation and Development (OECD), this study encompasses data from all 27 European Union member states. Employing structural equation modelling, our analysis illustrates the positive correlation between ICT development and the Gross Domestic Product (GDP) index. Our findings highlight the critical role of swiftly evolving technological landscapes, emphasizing the growing influence of new Artificial Intelligence (AI) technologies in business sectors. Furthermore, this study showcases the need to enhance human capital and expedite the growth of e-government technologies. These advancements are pivotal in strengthening the infrastructure supporting citizens and public enterprises across European countries, thereby contributing to their economic vitality

How does plant species composition change from year to year? A case study from the herbaceous layer of a submediterranean oak woodland

Over millions of years there is a long-term increase in species richness, accompanied by substantial turnover in species composition. However, little is known about species temporal turnover over shorter, ecologically relevant time periods, such as years. In the present study, we examine the inter-annual temporal turnover in species composition in 100 m2 plots of the herbaceous layer in a submediterranean oak woodland over six years. We found that approximately half of the accumulated number of species over the six years is accommodated as temporal turnover. We also found that species temporal turnover in undisturbed control plots was not significantly different from that in plots where vegetation was recovering naturally without assistance, i.e., plots undergoing ecological succession. Only in the most disturbed (continuously overgrazed) plots temporal turnover was low to non-existent. We therefore suggest that diversity estimates based on a single year of observations may seriously underestimate species richness or the detrimental effects of disturbance, at least at the 100 m2 scale. Furthermore, we found that, with the exception of the heavily grazed plots, short-lived species (annuals and biennials) did not display significantly greater temporal turnover than long-lived (perennial) species. Our analysis also supports that the space for time substitution applies in the patterns of species turnover. Spatial species turnover was comparable to temporal turnover. Species that are observed in many plots are also present in many years, and vice versa. Also, the similarity in species composition decreased as the time period between observations increased, as is the case with distance decay. Overall we conclude that the patterns of species turnover in time resemble those in space, and thus temporal turnover makes an important contribution to total biodiversity that should not be ignored

Seed bank composition and above-ground vegetation in response to grazing in sub-Mediterranean oak forests (NW Greece)

We investigate the persistent soil seed bank composition and its relation to the above-ground flora of grazed and non-grazed sub-Mediterranean deciduous oak forests of NW Greece. Twenty-eight taxa were recorded in the soil seed bank and 83 taxa (70 taxa in plots of seed bank sampling) in the above-ground vegetation. The dominant tree species and many woodland species found in the above-ground vegetation were absent from the soil seed bank. Similarity between the soil seed bank and the above-ground vegetation decreased with grazing, and grazing led to a decrease of species richness in above-ground vegetation and soil seed bank. Beta diversity of vegetation among grazed and among non-grazed plots did not differ, but was significantly higher between grazed and non-grazed areas. Beta diversity of the soil seed bank declined with grazing. When applying classification tree and logistic regression analyses, non-grazed forest sites are clearly differentiated by the presence of Phillyrea latifolia, Euphorbia amygdaloides and Brachypodium sylvaticum. PCA ordination of above-ground species composition reflected a gradient from sites grazed by ruminants to non-grazed sites, but no clear structure was detected in the seed bank. © 2008 Springer Science+Business Media B.V

Seed bank composition and above-ground vegetation in response to grazing in sub-Mediterranean oak forests (NW Greece)

We investigate the persistent soil seed bank composition and its relation to the above-ground flora of grazed and non-grazed sub-Mediterranean deciduous oak forests of NW Greece. Twenty-eight taxa were recorded in the soil seed bank and 83 taxa (70 taxa in plots of seed bank sampling) in the above-ground vegetation. The dominant tree species and many woodland species found in the above-ground vegetation were absent from the soil seed bank. Similarity between the soil seed bank and the above-ground vegetation decreased with grazing, and grazing led to a decrease of species richness in above-ground vegetation and soil seed bank. Beta diversity of vegetation among grazed and among non-grazed plots did not differ, but was significantly higher between grazed and non-grazed areas. Beta diversity of the soil seed bank declined with grazing. When applying classification tree and logistic regression analyses, non-grazed forest sites are clearly differentiated by the presence of Phillyrea latifolia, Euphorbia amygdaloides and Brachypodium sylvaticum. PCA ordination of above-ground species composition reflected a gradient from sites grazed by ruminants to non-grazed sites, but no clear structure was detected in the seed bank. © 2008 Springer Science+Business Media B.V

Seed bank composition and above-ground vegetation in response to grazing in sub-Mediterranean oak forests (NW Greece)

We investigate the persistent soil seed bank composition and its relation to the above-ground flora of grazed and non-grazed sub-Mediterranean deciduous oak forests of NW Greece. Twenty-eight taxa were recorded in the soil seed bank and 83 taxa (70 taxa in plots of seed bank sampling) in the above-ground vegetation. The dominant tree species and many woodland species found in the above-ground vegetation were absent from the soil seed bank. Similarity between the soil seed bank and the above-ground vegetation decreased with grazing, and grazing led to a decrease of species richness in above-ground vegetation and soil seed bank. Beta diversity of vegetation among grazed and among non-grazed plots did not differ, but was significantly higher between grazed and non-grazed areas. Beta diversity of the soil seed bank declined with grazing. When applying classification tree and logistic regression analyses, non-grazed forest sites are clearly differentiated by the presence of Phillyrea latifolia, Euphorbia amygdaloides and Brachypodium sylvaticum. PCA ordination of above-ground species composition reflected a gradient from sites grazed by ruminants to non-grazed sites, but no clear structure was detected in the seed bank. © 2008 Springer Science+Business Media B.V

The use of wind energy for passive cooling applications in western Greece

The use of a small wind turbine for the power supply of a radiative passive cooling system for indoor cooling or pre-cooling, even in areas with rather poor wind potential, was investigated in the present study. The passive cooling system was a lightweight aluminium nocturnal radiator, painted with an appropriate white paint and was established on the roof of the Department of Environmental and Natural Resources Management in Agrinio, in western Greece. The metallic radiator was used for indoor space cooling or pre-cooling, by providing cooled air to a specific thermal zone of the building of the Department. The limited energy demands of the system as well as the lighting demands of that specific thermal zone of the building were satisfied by a small wind turbine, placed on the roof of the building. Furthermore, the financial benefits of the system were investigated by a cost analysis, which gave excellent results and demonstrated that, even in areas with rather poor wind potential, there is the possibility of using wind power for domestic use in applications concerning indoor air conditioning. Finally, a neural network approach was used for modelling the energy consumption of a residential building in the area of western Greece using various wind energy and other climatic parameters. © 2009 Earthscan