Nikolay Velev

The Balkan wet grassland vegetation: a prerequisite to better understanding of European habitat diversity

The knowledge of broad-scale floristic variation in wet grasslands, which are endangered throughout Europe, is still limited and some regions have remained unexplored so far. In addition, hitherto published phytosociological studies were concentrated at the national level and therefore national vegetation classifications are not consistent with each other. In order to overcome these shortcomings of traditional phytosociology, we gathered original data from Bulgaria and analysed them together with the data from Central Europe. We further analysed major compositional gradients within Bulgarian wet grasslands and changes in species richness along them. We sampled 164 wet grassland vegetation plots throughout Bulgaria. We further prepared a restricted data set of wet grasslands from Central-European phytosociological databases. Both data sets were merged and classified by modified TWINSPAN. Four distinct vegetation types were differentiated. Even if they correspond with traditional alliances, which are primarily drawn as geographically defined units in Western and Central Europe (sub-Mediterranean Trifolion resupinati, sub-continental Deschampsion cespitosae and Molinion caeruleae and sub-oceanic Calthion palustris), they all occur in Bulgaria. When more precise classification was applied, two types of sub-Mediterranean wet grasslands and one high-altitude type of Calthion grasslands were detected solely in Bulgaria. DCA analysis showed that altitude is a dominant gradient controlling variation in Balkan wet grasslands. The second DCA axis was interpreted as the gradient of nutrient availability. Species richness shows skewed-unimodal trends along both major gradients, with the highest species richness in intermittently wet nutrient-limited grasslands. Tukey post-hoc test of altitudinal differences amongst vegetation types is significant for all pairs of clusters, suggesting that altitudinal differentiation is responsible for co-occurrence of nearly all European types of wet grasslands in Bulgaria. Our results suggest that (1) climate is an important factor for the diversity of wet grasslands; (2) Balkan vegetation of middle altitudes matches with that of Central Europe, whereas that of the lowest altitudes corresponds rather to the sub-Mediterranean region and high mountains are specific; (3) upward shift of Central-European vegetation types in southern Europe, so often described in forest vegetation is also evident for grassland vegetation and (4) the high diversity of Balkan vegetation is determined by a diverse relief enabling confluence of habitats possessing different climatic conditions.

A review of Potentillo ternatae-Nardion strictae alliance.

A Review of Potentillo Ternatae — Nardion Strictae Alliance A classification of the Nardus stricta dominated communities in the Balkan Range is presented. Two associations are identified: Nardetum strictae and Campanulo alpinae — Nardetum strictae nom. nov. The alliance Potentillo ternatae — Nardion strictae is typified and some comments on its distribution range and syntaxonomical affiliation to the higher units are presented. A synopsis is included of all available associations referred to Potentillo ternatae — Nardion strictae. Pregled zveze Potentillo ternatae - Nardion strictae V članku je predstavljena klasifikacija združb z dominantno vrsto Nardus stricta na Balkanu. Prikazali smo dve asociaciji: Nardetum strictae and Campanulo alpinae - Nardetum strictae nom. nov. Zvezo Potentillo ternatae - Nardion strictae smo tipizirali in predstavili njeno razširjenost in sintaksonomsko uvrstitev v višje enote. Prikazan je sinopsis vseh opisanih asociacij, ki jih uvrščamo v zvezo Potentillo ternatae - Nardion strictae.

The insecure future of Bulgarian refugial mires: economic progress versus Natura 2000

Bulgarian mires acted as refugia during the dry phases of ice ages and contain a high number of rare and disjunct species. In this study we ranked all known mire and spring complexes in Bulgaria according to the occurrence of rare and threatened plant and mollusc species. This analysis shows a conspicuous concentration of rare species at several sites, and no correspondence between the importance of individual mires for biodiversity and their legal protection. Of the 10 mire complexes of highest priority only one is effectively protected. The remaining unprotected mires have either been destroyed or are threatened by ongoing development. Destruction of mire habitats proceeds faster than the approval of Natura 2000 sites. There is a possibility that unique Bulgarian mires will be lost before the Natura 2000 system begins to perform its role. Only effective and timely protection of the mire remnants, together with appropriate management, will ensure the future of these unique habitats.

Management Regimes within Syntaxa of Semi-Natural Grasslands in West Bulgaria

Abstract This study focuses on mesic and xeric grasslands of mostly secondary origin, and that are influenced by human activity. Mesic grasslands are traditionally used for hay-making, and xeric ones for pastures. Over the last 20 years, livestock farming in Bulgaria has significantly declined so that less grass is needed. Many types of grasslands are no longer used and lots of abandoned fields can be found nowadays in Bulgaria. The analyses in this study are based on 868 releves collected on xeric and mesic grasslands according to the methodological approach of Braun- Blanquet. As a result, five alliances within two classes are recognized: the class Festuco-Brometea, represented by three alliances, namely Cirsio-Brachypodion pinnati, Chrysopogono-Danthonion calycinae and Festucion valesiacae, and the class Molinio-Arrhenatheretea, represented by two alliances, namely Arrhenatherion elatioris and Cynosurion cristati. The majority of the managed grasslands are situated in close proximity to settlements. Most of the abandoned areas (30%) are found within Cirsio-Brachypodion alliance. These grasslands are characterized by the highest values of total cover of vegetation. They are located in the most distant and least accessible areas. If use is not resumed, all the abandoned grasslands will be under threat of extinction in the near future. At the same time, many arable lands have been abandoned and turned into grasslands by the processes of secondary succession. Izvleček V raziskavi smo se osredotočili na mezična in kserična travišča večinoma sekundarnega nastanka, ki so pod vplivom človekovih aktivnosti. Mezična travišča se tradicionalno uporabljajo za seno, kserična pa kot pašniki. V Bolgariji je živinoreja v zadnjih 20 letih močno upadla in je potreba po krmi manjša. S številnimi tipi travišč ne gospodarijo več in danes je v Bolgariji moč najti številne opuščene površine. V analizi smo zbrali 868 vegetacijskih popisov kseričnih in mezičnih travišč, narejenih z Braun-Blanquetovo metodo. Uvrstili smo jih v pet zvez in dva razreda: razred Festuco-Brometea, ki ga predstavljajo tri zveze Cirsio-Brachypodion pinnati, Chrysopogono- Danthonion calycinae in Festucion valesiacae in razred Molinio-Arrhenatheretea z dvema zvezama Arrhenatherion elatioris in Cynosurion cristati. Večina vzdrževanih travišč se nahaja v bližini naselij. Večino opuščenih površin (30%) uvrščamo v zvezo Cirsio-Brachypodion in za te travnike je značilno, da imajo največjo skupno pokrovno vrednost in se nahajajo v najbolj oddaljenih, težko dostopnih območjih. Če jih ne bomo ponovno začeli uporabljati, bodo v bližnji prihodnosti izginili. Obenem se opuščajo tudi številne obdelovalne površine, ki se spreminjajo v travnike v procesu sekundarne sukcesije.