Mitja Kaligarič

Recent vegetation history of the North Adriatic grasslands: expansion and decay of an anthropogenic habitat.

A summary pollen diagram and old cartographic materials were used to reconstruct the recent vegetation history and trends of temporal dynamics of the North Adriatic Karst grasslands. Before the Roman period some evidence about grassland vegetation exists from Neolithic settlements, but deforestation, detectable on the landscape level because of pollen, started 2500-2000 years BP. A large-scale anthropogenically-driven process of clearance started in the Roman period as is reflected in the increasing pollen of grasses (Poaceae) and other herbaceous species (Apiaceae). The presence of pioneer trees (Quercus, Ostrya), juniper and grasses during 1000-400 years BP suggests that cycling processes of cultivation (strong grazing pressure), abandonment and re-cultivation were present. A 250-year-old map shows a peak of probable deforestation, where grasslands have 3.2 times larger surface area than on a recent land-use map in a 665.8 km2 large pilot area. More than 60% of grasslands changed into forest since then. On a sub-plot area of 626 ha (1% of the pilot area), where habitat mappings were performed, only 12.8% were still grasslands without tall herb invasions or scrub encroachments. Another 27.1% were grasslands with early signs of reforestation. The traditionally open landscape of the North Adriatic Karst was able to recover to forest due to almost total abandonment and sufficient mesic climate conditions.

Dry calcareous grasslands from two neighboring biogeographic regions: relationship between plant traits and rarity

European dry grasslands formed of the Festuco-Brometea type are among the most diverse plant communities within agricultural landscapes. We examined floristic composition, functional trait structure and threatened species occurrence in grasslands of this type from in two distinct biogeographic regions, Dinaric (NW Balkan) and the Central European. In the Central European region this type of grassland is threatened by a decline in traditional extensive management. We tested, if differences in the level of threat between regions are matched by differences in community-weighted means for resource use strategy traits and occurrence of Red List (threatened) species. We then tested if threatened species differed in their traits from other species and if threatened species richness was related to CWM for resource use strategy traits. The communities from the Central European region had significantly higher SLA and lower LDMC, which perhaps reflects an increase in intensive agriculture promoting fast-growing species. Threatened species occurrence did not differ significantly between regions, but threatened species richness was significantly negatively correlated with CWM for height and SLA. This may suggest that threatened species are less likely to occur in high productivity communities where light competition is intense. This study provides initial evidence that changes in CWM for resource use strategy traits may provide a useful means for predicting threatened species loss in dry grassland ecosystems.

Grassland succession is mediated by umbelliferous colonizers showing allelopathic potential

Abstract Two Umbelliferous tall herbs – Laserpitium siler and Grafia golaka tend to form monodominant stands in the montane belt of the North Adriatic Karst after grassland abandonment. The germination and development of shade-tolerant species of further successional stages could be facilitated by favorable climatic conditions, measured in the canopy, but colonization by woody species was not perceived, except for Pinus sylvestris and Pinus nigra, which are not common trees in the area. The vegetation history of the site shows rather slow reforestation after abandonment and almost exclusively with pine woodland. All organs of both Umbelliferous species showed high allelopathic potential, measured as significantly inhibited germination and early development of test plants in bioassays. Under similar treatments, the germination rate of P. sylvestris was reduced, but further development of seedlings was stable. One possible explanation for the relative persistence of Umbelliferous monodominant stands is the strong allelopathic potential of both umbellifers. They act as “succession retardants”, and only pinus is able to colonize these stands successfully; the explanation for that is based on the presence of the same essential oils (limonene, pinene) in both Pinus and L. siler.

Assessing community assembly along a successional gradient in the North Adriatic Karst with functional and phylogenetic distances.

Recently, two approaches to account for ecological differences in community composition have been developed: one based on trait differences (functional diversity) and another based on evolutionary history (phylogenetic diversity). Combining them allows an integrated view of processes structuring communities. The North Adriatic Karst is covered by species-rich grasslands, but land abandonment has resulted in replacement by woodlands. This creates a successional gradient along which environmental conditions may change, and different community assembly rules may apply. We sampled 56 plant communities in the Karst and used functional-phylogenetic distances to assess assembly along a successional gradient, from grasslands to shrublands and woodlands. We found 146 species, for which we measured functional traits and built a phylogenetic tree. The three successional stages were floristically different, with grasslands having species that are typical of harsher soil conditions and woodlands with species preferring milder soil conditions. All communities had higher functional than phylogenetic distances, implying that closely related species tended to be phenotypically dissimilar. When more importance was given to functional distances, most grasslands and some shrublands were underdispersed; when more importance was given to phylogenetic distances, only one grassland was underdispersed and one woodland was overdispersed. Combining functional and phylogenetic distances provided us with better estimates of ecological differences in a successional gradient, where environmental filters seem to be the dominant force in early stages and competitive exclusion becomes more important in later stages. Taking into account that sucessional stages are assembled by different rules is essential to predicting their behaviour under future environmental scenarios.

Political Systems Affect Mobile and Sessile Species Diversity - A Legacy from the Post-WWII Period

Political ideologies, policies and economy affect land use which in turn may affect biodiversity patterns and future conservation targets. However, few studies have investigated biodiversity in landscapes with similar physical properties but governed by different political systems. Here we investigate land use and biodiversity patterns, and number and composition of birds and plants, in the borderland of Austria, Slovenia and Hungary. It is a physically uniform landscape but managed differently during the last 70 years as a consequence of the political “map” of Europe after World War I and II. We used a historical map from 1910 and satellite data to delineate land use within three 10-kilometre transects starting from the point where the three countries meet. There was a clear difference between countries detectable in current biodiversity patterns, which relates to land use history. Mobile species richness was associated with current land use whereas diversity of sessile species was more associated with past land use. Heterogeneous landscapes were positively and forest cover was negatively correlated to bird species richness. Our results provide insights into why landscape history is important to understand present and future biodiversity patterns, which is crucial for designing policies and conservation strategies across the world.

Germination characteristics of Salicornia patula Duval-Jouve, S. emerici Duval-Jouve, and S. veneta Pign. et Lausi and their occurrence in Croatia

Abstract - According to recent molecular analyses of Salicornia, we revised the annual glassworts from the Croatian coast, classified until now only as Salicornia europaea. Two species, a diploid Salicornia patula and a tetraploid S. emerici were recognized. They can be easily distinguished by floral characters, but not only by their habitus, which varies extremely according to environmental factors. Both species differ also in seed morphology. Salicornia patula has dimorphic seeds, with larger central seeds reaching high germination rates. Germination patterns helped to explain the habitat preferences. The species rarely co-occur, however. The rare S. patula occupies drier habitats, on coastal mudflats or sands that are irregularly inundated. It occurs within the assoc. Suaedo maritimae-Salicornietum patulae. Salicornia emerici occupies the lowest coastal mudflats, regularly inundated, where nutrient-rich conditions prevail, and forms an almost monotypical assoc. Salicornietum emerici. Due to the synonymy of S. veneta with S. emerici, we exclude the occurrence of S. veneta in Croatia as an independent taxon.

Germination and survival of endangered Pulsatilla grandis (ranunculaceae) after artificial seeding, as affected by various disturbances

Pulsatilla grandis is a rare and endangered species in Central Europe. A field experiment was set up to test the effects of disturbances on its germination and survival rates after artificial seeding. Disturbances were simulated by the following treatments: burning, hoeing, and removal of vegetation. The germination percentage decreased rapidly with time, to only 2% in 2-year-old fruits. The germination rate of fresh fruits was the highest in hoed plots (29.2 ± 12.9%), followed by removedvegetation plots (21.8 ± 17.3%) and burned plots (1.8 ± 2.2%). No germination was observed in control plots. The survival rate of seedlings was monitored over the next 5 years. In the year following the treatment, all the seedlings survived in the burned plots; in the hoed and in removed-vegetation plots, survival rates were 38.5 ± 2 and 55 ± 27%, respectively. Approximately half of them were alive after 5 years. Grassland vegetation in burned quadrates recovered very quickly, whereas in other disturbed plots the numbers ...

Potential Impacts of Climate Change on Protected Habitats

This chapter deals with several potential effects of climate change, addressed to Natura 2000 habitats from the following categories: woodlands, grasslands, brushwoods, rocky habitats, coastal and dune habitats, surface water habitats, peat bogs and moorlands. For these categories seven impact classes were identified: seasonal impact, sea level rise, hydrology, soil, extreme events, CO2 concentration, cumulative effects that change the quality of environmental conditions. The chapter provides information and examples regarding the actual and anticipated types of impacts on Natura 2000 habitats and underlines some trends which can be predicted for the future.

Habitat Changes Caused by Sea Level Rise, Driven by Climate Change in the Northern Adriatic Coastal Wetlands, Slovenia

The constantly increasing anthropogenic pressure on coastal habitats is additionally intensified by climate change effects. Sea level rise is a major threat to the two most important coastal wetlands in Slovenian seacoast, Secovlje Salina (Secoveljske soline) and Skocjan Inlet (Skocjanski zatok). Different methods from field vegetation mapping, field geodetic measurements, LIDAR scanning to spatial statistics were used to study effects of rising sea levels. They revealed that the spatial distribution of habitat types follows the micro-elevations. Therefore a habitat transition model could be developed for Secovlje Salina (Secoveljske soline) and Skocjan Inlet (Skocjanski zatok). Different scenarios of sea level rise where analysed. The prediction model demonstrated to which degree, how and where coastal habitats will shift to each other and decrease their surfaces in total.

High potential of sub-Mediterranean dry grasslands for sheep epizoochory

Abstract There is a general decline of grasslands across Europe due to habitat loss and degradation. Ensuring plant dispersal thus becomes a key process for preserving grassland patches in all scales. We examined diaspore dispersal by sheep epizoochory in the pastures of the North Adriatic Karst (NW Slovenia) and determined the qualitative and quantitative features of diaspores in fur. We recorded 25,650 diaspores of 141 plant taxa (with 107 taxa and 23,350 diaspores determined to species level), using three different methods: (i) the “whole-coat method”, (ii) the “part-of-thecoat method” and (iii) a “seedling emergence method”. A comparison of these techniques revealed that the “wholecoat method” provided the highest number of diaspores and plant species. All diaspores were clustered into five emergent groups based on seven functional traits (diaspore weight, length, width, height, volume, specific weight and the diaspore surface structure). Our research revealed that sheep represent an important dispersal vector, since about half of the plant species recorded in the pastures were found as diaspores in fur. This study contributes to knowledge about the modes of seed dispersal in seminatural grasslands. Taking into account that livestock play a key role in vegetation dynamics, understanding their effects on seed dispersal is essential for conservation and restoration of these species-rich grassland communities.