Forest vegetation diversity of Slivenska Mountain (eastern Stara planina, Bulgaria)

This study deals with the diversity of forest vegetation in the Slivenska Mountain (Eastern Stara planina) and presents a contemporary classification scheme for the identified syntaxa. A total of 137 relevés were collected and analyzed using specialized software (JUICE 7.0 and PC-ORD Version 4). As a result, forest vegetation is classified into 10 associations, 3 subassociations, 4 variants and 5 communities They belong to 7 alliances, 5 orders and 3 classes: Carpino-Fagetea sylvaticae, Quercetea pubescentis and Alno glutinosae-Populetea albae. The recorded 18 distinguished vegetation groups show a relatively high diversity of forest plant communities of the study area

Amorpha fruticosa invasibility of different habitats in lower Danube

Abstract. Danube River plays a role of major corridor for plant invasions. Downstream is expected to be more strongly affected by such invasions. There were scarce data about alien plants dispersion by habitats in Bulgarian part of Danube. Sampling sites were selected on the river banks and on several islands and Amorpha fruticosa cover together with number of alien plants were sampled. Four habitat types were recognized. Most affected by indigo bush were poplar plantations while natural forests due to their closed structure and biodiversity remain less influenced

Drivers of plant diversity in Bulgarian dry grasslands vary across spatial scales and functional-taxonomic groups

Questions: Studying dry grasslands in a previously unexplored region, we asked: (a) which environmental factors drive the diversity patterns in vegetation; (b) are taxonomic groups (vascular plants, bryophytes, lichens) and functional vascular plant groups differently affected; and (c) how is fine-grain beta diversity affected by environmental drivers? Location: Northwestern and Central Bulgaria. Methods: We sampled environmental data and vascular plant, terricolous bryophyte and lichen species in 97 10-m2 plots and 15 nested-plot series with seven grain sizes (0.0001–100 m2) of ten grassland sites within the two regions. We used species richness as measure of alpha-diversity and the z-value of the power-law species–area relationship as measure of beta-diversity. We analysed effects of landscape, topographic, soil and land-use variables on the species richness of the different taxonomic and functional groups. We applied generalised linear models (GLMs) or, in the presence of spatial autocorrelation, generalised linear mixed-effect models (GLMMs) in a multi-model inference framework. Results: The main factors affecting total and vascular plant species richness in 10-m2 plots were soil pH (unimodal) and inclination (negative). Species richness of bryophytes was positively affected by rock cover, sand proportion and negatively by inclination. Inclination and litter cover were also negative predictors of lichen species richness. Elevation negatively affected phanerophyte and therophyte richness, but positively that of cryptophytes. A major part of unexplained variance in species richness was associated with the grassland site. The z-values for total richness showed a positive relationship with elevation and inclination. Conclusions: Environmental factors shaping richness patterns strongly differed among taxonomic groups, functional vascular plant groups and spatial scales. The disparities between our and previous findings suggest that many drivers of biodiversity cannot be generalised but rather depend on the regional context. The large unexplained variance at the site level calls for considering more site-related factors such as land-use history

GrassPlot - a database of multi-scale plant diversity in Palaearctic grasslands

GrassPlot is a collaborative vegetation-plot database organised by the Eurasian Dry Grassland Group (EDGG) and listed in the Global Index of Vegetation-Plot Databases (GIVD ID EU-00-003). GrassPlot collects plot records (releves) from grasslands and other open habitats of the Palaearctic biogeographic realm. It focuses on precisely delimited plots of eight standard grain sizes (0.0001; 0.001;... 1,000 m(2)) and on nested-plot series with at least four different grain sizes. The usage of GrassPlot is regulated through Bylaws that intend to balance the interests of data contributors and data users. The current version (v. 1.00) contains data for approximately 170,000 plots of different sizes and 2,800 nested-plot series. The key components are richness data and metadata. However, most included datasets also encompass compositional data. About 14,000 plots have near-complete records of terricolous bryophytes and lichens in addition to vascular plants. At present, GrassPlot contains data from 36 countries throughout the Palaearctic, spread across elevational gradients and major grassland types. GrassPlot with its multi-scale and multi-taxon focus complements the larger international vegetationplot databases, such as the European Vegetation Archive (EVA) and the global database " sPlot". Its main aim is to facilitate studies on the scale-and taxon-dependency of biodiversity patterns and drivers along macroecological gradients. GrassPlot is a dynamic database and will expand through new data collection coordinated by the elected Governing Board. We invite researchers with suitable data to join GrassPlot. Researchers with project ideas addressable with GrassPlot data are welcome to submit proposals to the Governing Board

Auswirkungen der Viehdichte auf Sommerweiden im Balkan während der landwirtschaftlichen Transformationen zwischen 1947 und 2012

The historical transition from the Bulgarian Kingdom through the Soviet period to the present state of Bulgaria has affected humans and their land use preferences, leading to repeated transformations of the vegetation. We analysed the proportional change of vegetation types in the Tsentralen Balkan National Park in Bulgaria using aerial imagery over the last 65 years and object based image segmentation. Segments were classified into three land cover classes (vegetation types): shrubland, grassland, and shrub-grassland mosaic. In order to interpret the observed proportional changes of these vegetation types we collated livestock numbers over the same period. The shrub-grassland mosaic constantly decreased over the first 20 years, whereas shrublands and grasslands both increased. During the period 1969–1989, the trend continued and areas covered by the shrub-grassland mosaic decreased by 82%, while shrublands increased by 56% and grasslands increased by 18%. The species rich shrub-grassland mosaics were most affected by the land use changes. The overall land cover diversity pattern reduced to two classes. The period with the least changes was 1989–2012, when changes in landscape cover stabilized after the area was designated a National Park. Livestock numbers varied throughout the study period due to the transformation processes. This probably also affected the change in the vegetation patterns analyzed, as few other drivers are known from the Stara Planina Mts. The aerial imagery time series was helpful to reconstruct the changes in the vegetation of the study area, however, extending the time series would allow for a better correlation with livestock numbers.Einleitung: Das Grasland des Balkans stellt als Sommerweidegebiet seit Jahrhunderten eine wichtige Grundlage für die Wanderweidewirtschaft dar (MARINOV 1961). Seit der Zeit des bulgarischen Königreichs über die Sowjetzeit bis heute hat sich die Nutzung des Graslands des Balkans wiederholt geändert. In den letzten 65 Jahren wechselten im Gebiet v. a. ökonomische Krisen und Aufschwünge einander ab (BEROV 1974, DARDZHONOV 1994). Diese führten in den Sommerweidegebieten zu unterschiedlichen Vieh- insbesondere Schafsdichten. Als im Stara Planina-Gebiet im Jahr 1989 der Tsentralen Balkan National Park eingerichtet wurde, nahm die Schafsdichte zuerst stark ab und später dann, ab 2007, wieder etwas zu. Heute herrscht im Gebiet eher Über- als Unterbeweidung. Diese Veränderungen der Landnutzung bewirkten auch Veränderungen der Vegetation, die jedoch für das Gebiet bisher kaum dokumentiert wurden. Das Ziel dieser Studie war es, die Anteile von drei auf Luftbildern erkennbaren Vegetationstypen – Strauchsteppe, Grassteppe und Strauch-Grassteppe-Mosaik – über einen Zeitraum von 65 Jahren zu quantifizieren und die Ergebnisse in Beziehung zur Schafsdichte zu interpretieren. Methoden: Wir analysierten Flächenänderungen der Strauchsteppe, Grassteppe und Strauch-Grassteppe-Mosaike im Tsentralen Balkan National Park mithilfe von Luftbildern aus den Jahren 1947, 1969, 1989 und 2012 mittels objektbasierter Luftbildsegmentierung (OBIA). Die Anteile der Vegetationstypen wurden mithilfe eines post-hoc Kartenvergleichs in einem Geographischen Informationssystem analysiert. Die Entwicklungsverläufe der drei Vegetationstypen wurden jeweils einzeln untersucht und aus zwei verschiedenen Blickwinkeln interpretiert: erstens der Entwicklungsverlauf ausgehend von einem Vegetationstyp und zweitens hinführend zu einem Vegetationstyp. Um die Veränderungen zu interpretieren, wurden für die gleichen Zeiträume die Schafsdichten anhand von lokalen Berichten ermittelt und diese visuell mit den sich ergebenden Trends aus der Bildanalyse verglichen. Ergebnisse: Zwischen 1947 und 1969 hatte das Strauch-Grassteppe-Mosaik kontinuierlich ab- und sowohl die Strauch- als auch die Grassteppe kontinuierlich zugenommen. Dieser Trend setzte sich in der Periode 1969–89 fort, wobei das artenreiche Strauch-Grassteppe-Mosaik insgesamt am stärksten von den Landnutzungsänderungen betroffen war. Während schließlich nur noch 18 % der ursprünglichen Fläche des Strauch-Grassteppe-Mosaiks vorhanden waren, hatten die Strauchsteppe in diesem Zeitraum um 56% und die Grassteppe um 18 % zugenommen (Tab. 1). Die Zahl der Schafe im Untersuchungsgebiet schwankte zwischen 1947 und 1989 um die 140.000 Tiere. Im Zeitraum von 1989–2012, nach der Errichtung des National Parks, nahm die Schafsdichte dann von über 180.000 Tieren auf ca. 40.000 Tiere stark ab (Abb. 2). Die Entwicklungsverläufe der Vegetationstypen (Abb. 4) zeigten, dass das Strauch-Grassteppe-Mosaik häufiger in Gras- als in Strauchsteppe umgewandelt wurde. Dies geschah vor allem in der Periode 1947–1969. Ein geringer Anteil der Grassteppe entwickelte sich ab 1989 wieder zu Strauch-Grassteppe-Mosaik wohingegen Strauchsteppe nie in Strauch-Grassteppe-Mosaik überführt wurde. Diskussion: Zwei gegensätzliche Trends ließen sich beobachten: In den Jahren bis 1989 nahmen sowohl die Strauch- als auch die Grassteppe auf Kosten des Strauch-Grassteppen-Mosaiks zu. Diese Veränderung ging einher mit steigenden Viehzahlen aber auch neuen viehwirtschaftlichen Praktiken, die in dieser Zeit im Gebiet getestet wurden, z. B. mikrobielle Futterzusätze, widerstandsfähigere Schafsrassen, mechanisierte Kollektivwirtschaft etc. (ILIEVA et al. 1997). Im Zeitraum von 1989 bis 2012, nach Gründung des Nationalparks, zeigte die Strauch- und die Grassteppe die geringsten Veränderungen der Flächenanteile. Das artenreiche Strauch-Grassteppe-Mosaik nahm in dieser Zeit leicht zu, ohne jedoch seinen ursprünglichen Anteil auch nur annährend zu erreichen. Zunahmen von Patch-Mosaik-Strukturen durch extensive Beweidungen wurden bereits aus anderen Gebieten beschrieben (z. B. LEDERBOGEN et al. 2004, VASSILEV et al. 2011). Dem Nationalpark kann extensive Beweidung daher als Managementmethode empfohlen werden, um Strauch-Grassteppe-Mosaike zu fördern. Schlussfolgerungen: Anhand einer Luftbildserie konnten Landschaftsveränderungen über einen Zeitraum von 65 Jahren rekonstruiert werden. Anhand von drei Vegetationstypen – Grassteppe, Strauchsteppe und Strauch-Grassteppe-Mosaik – konnte gezeigt werden, dass die Landschaftsveränderungen vor allem auf Kosten des Strauch-Grassteppe-Mosaiks verliefen. Erst ab der Errichtung des Nationalparks im Jahre 1989 konnte sich dieser artenreiche Vegetationstyp (aus Grassteppen) wieder regenerieren. Obwohl nur visuell/korrelativ festgestellt, stellt die saisonale Beweidung durch Schafe im Stara Planina-Gebirge einen wichtigen Faktor für die Vegetation dar. Es sollten weitere Untersuchungen zur Entwicklung der Vegetation in Abhängigkeit von der Viehdichte im Stara Planina-Gebirge folgen

Razred Festuco-Brometea v zahodni Bolgariji s posebnim ozirom na zvezo Cirsio-Brachypodion pinnati

A total of 546 relevés collected in western Bulgaria and referred to Festuco-Brometea were classified into the alliances Festucion valesiacae, Saturejion montanae, Cirsio-Brachypodion pinnati and Chrysopogono-Danthonion calycinae. All relevés assigned to alliance Cirsio-Brachypodion pinnati were further classified towards lower level which resulted in the description of a new association – Hieracio pilosellae-Festucetum dalmaticae and two new subassociations added to ass. Galio lovcense-Artemisietum chamaemelifoliae. Both associations were ecologically well differentiated on the basis of soil parameters (pH and humus content) as well as some additional factors (exposition, land use, etc.).V zahodni Bolgariji smo naredili 546 vegetacijskih popisov, ki jih uvrščamo v razred Festuco-Brometea in dalje v zveze Festucion valesiacae, Saturejion montanae, Cirsio-Brachypodion pinnati in Chrysopogono-Danthonion calycinae. Vse popise, ki smo jih uvrstili v zvezo Cirsio-Brachypodion pinnati smo členili na nižje sintaksonomske enote. Opisali smo novo asociacijo – Hieracio pilosellae-Festucetum dalmaticae in dodali dve novi subasociaciji k asociaciji Galio lovcense-Artemisietum chamaemelifoliae. Obe asociaciji sta ekološko jasno ločeni na podlagi talnih parametrov (pH in vsebnost humusa) in nekaterih dodatnih dejavnikov (ekspozicija, raba tal, itd.)

Dry grasslands of NW Bulgarian mountains: first insights into diversity, ecology and syntaxonomy

We present the data of the 3rdresearch expedition of the European Dry Grasslands Group (EDGG), which was conducted in 2011 in two contrasting areas in NW Bulgarian mountains. The aim was to collect plot data for comparing Bulgarian dry grasslands with those of other parts of Europe in terms of syntaxonomy and biodiversity. We sampled 15 nested-plot series (0.0001–100 m²) and 68 normal plots(10 m²) covering the full variety of dry grassland types occurring in the Vratsa area (Balkan Mts.) and the Koprivshtitsa area (Sredna Gora Mt.). In the plots all vascular plants, terricolous non-vascular plants and a set of soil and other environmental parameters were determined. By applying modified TWIN-SPAN, we distinguished 10 floristically well characterised vegetation types at the association level. After comparison with the regional and European literature, we propose to place them within three classes and five orders: Festuco-Brometea with the orders Stipo pulcherrimae-Festucetalia pallentis (xerophilous dry grasslands of base-rich rocks; alliance Saturejion montanae), Brachypodietalia pinnate (meso-xeric, basiphilous grasslands; alliances Cirsio-Brachypodion pinnate and Chyrsopogono grylli-Danthonion calycinae),Calluno-Ulicetea with the order Nardetalia stricae (lowland to montane Nardus swards; alliance Violion caninae), and Koelerio-Corynephoretea with the orders Sedo-Scleranthetalia (open communities of skeleton-rich, acidic soils; alliance unclear) and Trifolioarvensis-Festucetalia ovinae(closed, meso-xeric, acidophilous grasslands; alliance Armerio rumelicae-Potentillion). The Violion caninae with the association Festuco rubrae-Genistelletum sagittalisis reported from Bulgaria for the first time, while the two occurring Koelerio-Corynephoretea communities are described as new associations (Cetrario aculeatae-Plantaginetum radicatae, Plantagini radicatae-Agrostietum capillaris). According to DCA the main floristic gradient was largely determined by soil conditions, differentiating the Festuco-Brometea communities on soils with high pH and high humus content from the Koelerio-Corynephoretea communities on acidic, humus-poor soils, while the Calluno-Ulicetea stands are the connecting link. At 10 m² Festuco-Brometea and Calluno-Ulicetea stands were richer in species across all investigated taxa and in vascular plants than Koelerio-Corynephoretea stands; the latter were richest in lichen species, while bryophyte richness did not differ significantly among syntaxa. Among the Bulgarian classes, the species-area relationships tended to be steepest in the Festuco-Brometea (i.e. highest beta diversity), but both alpha and beta diversity clearly fell behind the Festuco-Brometea communities in the Transylvanian Plateau, Romania, located less than 500 km north of the study region. Overall, our study contributes to a more adequate placement of the Bulgarian dry grasslands in the European syntaxonomic system and provides valuable data for large-scale analyses of biodiversity pattern

Trockenrasen in den Gebirgen Nordwest-Bulgariens : erste Einblicke in Diversität, Ökologie und Syntaxonomie

We present the data of the 3rd research expedition of the European Dry Grasslands Group (EDGG), which was conducted in 2011 in two contrasting areas in NW Bulgarian mountains. The aim was to collect plot data for comparing Bulgarian dry grasslands with those of other parts of Europe in terms of syntaxonomy and biodiversity. We sampled 15 nested-plot series (0.0001–100 m²) and 68 normal plots (10 m²) covering the full variety of dry grassland types occurring in the Vratsa area (Balkan Mts.) and the Koprivshtitsa area (Sredna Gora Mt.). In the plots all vascular plants, terricolous non-vascular plants and a set of soil and other environmental parameters were determined. By applying modified TWIN-SPAN, we distinguished 10 floristically well characterised vegetation types at the association level. After comparison with the regional and European literature, we propose to place them within three classes and five orders: Festuco-Brometea with the orders Stipo pulcherrimae-Festucetalia pallentis (xerophilous dry grasslands of base-rich rocks; alliance Saturejion montanae), Brachypodietalia pinnati (meso-xeric, basiphilous grasslands; alliances Cirsio-Brachypodion pinnati and Chyrsopogono grylli-Danthonion calycinae), Calluno-Ulicetea with the order Nardetalia stricae (lowland to montane Nar-dus swards; alliance Violion caninae), and Koelerio-Corynephoretea with the orders Sedo-Scleranthetalia (open communities of skeleton-rich, acidic soils; alliance unclear) and Trifolio arvensis-Festucetalia ovinae (closed, meso-xeric, acidophilous grasslands; alliance Armerio rumelicae-Potentillion). The Violion caninae with the association Festuco rubrae-Genistelletum sagittalis is reported from Bulgaria for the first time, while the two occurring Koelerio-Corynephoretea communities are described as new associations (Cetrario aculeatae-Plantaginetum radicatae, Plantagini radicatae-Agrostietum capillaris). According to DCA the main floristic gradient was largely determined by soil conditions, differentiating the Festuco-Brometea communities on soils with high pH and high humus content from the Koelerio-Corynephoretea communities on acidic, humus-poor soils, while the Calluno-Ulicetea stands are the connecting link. At 10 m2 Festuco-Brometea and Calluno-Ulicetea stands were richer in species across all investigated taxa and in vascular plants than Koelerio-Corynephoretea stands; the latter were richest in lichen species, while bryophyte richness did not differ significantly among syntaxa. Among the Bulgarian classes, the species-area relationships tended to be steepest in the Festuco-Brometea (i.e. highest beta diversity), but both alpha and beta diversity clearly fell behind the Festuco-Brometea communities in the Transylvanian Plateau, Romania, located less than 500 km north of the study region. Overall, our study contributes to a more adequate placement of the Bulgarian dry grasslands in the European syntaxonomic system and provides valuable data for large-scale analyses of biodiversity patterns.Die Balkanhalbinsel ist innerhalb Europas überdurchschnittlich reich an Pflanzenarten und Endemiten, während zugleich halbnatürliche Grasländer von hohem Naturschutzwert dort noch großflächig erhalten sind. Bulgarien hinkt, was die pflanzensoziologische Inventarisierng angeht, den meisten anderen europäischen Ländern hinterher, da dort bis zum Fall des Eisernen Vorhangs die wenigen Vegetationskundler nahezu ausschließlich der russischen Schule folgten. Seither wurden zahlreiche pflanzensoziologische Studien durchgeführt, was zu einer besonders in den Graslandklassen gut mit Aufnahmen bestückten nationalen Vegetationsdatenbank führte (Apostolova et al. 2012). Allerdings fehlten bislang überregionale Analysen, die auf die Eingliederung der bulgarischen Einheiten in ein europaweites syntaxonomisches System abzielten. Europäische Trockenrasen sind ein besonders inte-ressantes Studienobjekt für Biodiversitätsanalysen, unter anderem, da sie auf Flächengrößen unter 100 m2 die globalen Rekorde im Pflanzenartenreichtum halten (Dengler 2005, 2012, Wilson et al. 2012). Zum Verständnis der Diversitätsmuster in paläarktischen Trockenrasen und der sie steuernden Faktoren sowie als Beitrag zu einer konsistenten supranationalen Klassifikation derselben führt die European Dry Grassland Group (http://www.edgg.org) seit 2009 jährliche Forschungsexpeditionen in noch unzureichend erforschte Regionen durch, um dort Grundlagendaten mit einer standardisierten Erfassungsmethode zu erheben (vgl. Dengler et al. 2012). Die vierte derartige Expedition führte im Sommer 2012 nach Westbulgarien mit den folgenden Hauptzielen: (1) Abgrenzung der vorkommenden Typen von Trockenrasen und Ermittlung ihrer Kennarten mit statistischen Methoden; (2) Einordnung dieser Einheiten in das europäische syntaxonomische System; (3) Grundverständnis der ökologischen Faktoren, die zur Differenzierung der Einheiten führen; (4) Dokumentation der Diversitätsmuster von Gefäßpflanzen, Moosen und Flechten auf verschiedenen räumlichen Skalenebenen