Dynamics of the species diversity and composition of the ruderal vegetation of Slovak and Czech cities

This study reports the results of the evaluation of changes in the species diversity and composition of ruderal vegetation of three Slovak and one Czech city over the time. The dataset of 1489 relevés from five ruderal syntaxa from the cities Bratislava, Malacky, Trnava and Brno was used. Data were from two different time periods, the older dataset from the years 1960–1982, the more recent dataset from the years 2005–2016. The statistical analysis revealed the decrease of Shannon–Wiener diversity index of all (native + alien) species in the majority of classes of ruderal vegetation of cities. The analysis of the changes in the Pielou's measure of species evenness showed that in some of the classes and cities, the species evenness remained unchanged, in the other ones it decreased. The percentage of native species in the ruderal vegetation did not change over the time, but the percentage of invasive alien species in the majority of syntaxa and cities increased significantly. In total, 38 invasive taxa were recorded in the ruderal vegetation of cities. Most of them are neophytes, therophytes and belong to the family Asteraceae. The majority of invasive taxa were recorded in both time periods. Some of the invasive species, e.g. Fallopia japonica and Juncus tenuis were recorded only in the more recent time period. Our results contribute to the knowledge about biological invasions in the cities

Effects of invasive plant species on species diversity: implications on ruderal vegetation in Bratislava City, Slovakia, Central Europe

Invasive species pose one of the most serious global environmental threats. Our study aimed to examine the correlation between the proportion of invasive alien taxa and species diversity of ruderal vegetation in the urban ecosystem of Bratislava, located in Central Europe. Ruderal habitats serve as the means of spread of invasive species to seminatural and natural habitats. Twenty-six invasive taxa were recorded among the ruderal vegetation of Bratislava. The majority of the recorded invasive species were neophytes, which came from North America and represent the Asteraceae family. Half of them were introduced accidentally, whereas the remaining species were introduced deliberately. Correlation and regression analyses showed that the proportion of invasive taxa has a negative effect on the species diversity of all the analyzed syntaxa in the ruderal vegetation of Bratislava

Comparison of the differences in the composition of ruderal flora between conventional tram tracks and managed green tram tracks in the urban ecosystem of the city of Bratislava

Green infrastructure (GI) brings many benefits to urban ecosystems (e.g. better air and water quality) and it presents a helpful tool in the effort to reduce the consequences of climate change. Green tram tracks can be considered to be a part of GI. The presented study is focused on the comparison of the frequency of ruderal plant species, as well as species composition when comparing conventional tram tracks with green tram tracks (with planted succulents and ornamental plants) in Bratislava, Slovakia, Central Europe. This comparison also provides an insight into the changes of the flora of tram tracks over time, as we compare the results of the older research (from the years 2014–2019) with recent research on green tram tracks, which were built in Bratislava in 2020. The data were analysed by cluster analysis, Sign test and Wilcoxon two-sample test in the R 3.5.1. The results revealed significant differences in the composition of flora between conventional tram tracks and green tram tracks. In particular, the total number of species has decreased over time, as green tram tracks host fewer spontaneously growing taxa than conventional ones. The frequency of occurrence of archaeophytes and neophytes has decreased on the strict rail yard (covered by planted succulents) while on the tracksides (covered by non-succulent ornamental plants) it has increased. Green tram tracks deliver positive features to ecosystems, but may also have negative aspects because they present a pool of alien, potentially invasive plants. &nbsp

Návrh na manažment biotopov vybraných taxónov z rodu Ophrys L. (Orchidaceae) na Devínskej Kobyle (Bratislava)

Many valuable and threatened taxons of the family Orchidaceae, including the representatives of genus Ophrys, are disappearing from semi-natural grasslands because of the advancing secondary succession. Conservation and restoration of calcareous grasslands rich in species at the Devínska Kobyla Mt. requires appropriate interventions after the traditional forms of management will be finished. Bromus erectus is the dominant species at the Devínska Kobyla Mt., hence it is necessary to choose adequate intervention aim of which would be the reduced dominance of this species. Restoration of extensive sheep grazing in this calcareous grassland is not realistic. This is the reason why it is proposed to mow every year or at least every two years (and remove the mown mass) the growths where the taxons of genus Ophrys occur. The best moment for mowing is after maturation of the Orchid Genus Ophrys seeds. With regard to the phenologic cycles of the species concerned, the following mowing terms are proposed: end of June for the locality with occurrence of Early Spider Orchid (Ophrys sphegodes), July for localities with occurrence of Late Spider Orchid (O. holosericea) and Fly Orchid (O. insectifera). The locality with Bee Orchid (Ophrys apifera) does not require mowing due to shallow soil (Lithosol) and vegetation that is close to Poo badensis-Festucetum pallentis association. If mowing cannot be used on the particular dates, it is proposed to mow the growths with the dominating species Bromus erectus in October. The study presents the example how the number of flowering Early Spider Orchid (Ophrys sphegodes) individuals increased after the locality was mown by the employees of the State Nature Conservation in autumn 2004. Their number more than quadrupled in 2005

Dynamics of the species diversity and composition of the ruderal vegetation of Slovak and Czech cities

This study reports the results of the evaluation of changes in the species diversity and composition of ruderal vegetation of three Slovak and one Czech city over the time. The dataset of 1489 relevés from five ruderal syntaxa from the cities Bratislava, Malacky, Trnava and Brno was used. Data were from two different time periods, the older dataset from the years 1960–1982, the more recent dataset from the years 2005–2016. The statistical analysis revealed the decrease of Shannon–Wiener diversity index of all (native + alien) species in the majority of classes of ruderal vegetation of cities. The analysis of the changes in the Pielou’s measure of species evenness showed that in some of the classes and cities, the species evenness remained unchanged, in the other ones it decreased. The percentage of native species in the ruderal vegetation did not change over the time, but the percentage of invasive alien species in the majority of syntaxa and cities increased significantly. In total, 38 invasive taxa were recorded in the ruderal vegetation of cities. Most of them are neophytes, therophytes and belong to the family Asteraceae. The majority of invasive taxa were recorded in both time periods. Some of the invasive species, e.g. Fallopia japonica and Juncus tenuis were recorded only in the more recent time period. Our results contribute to the knowledge about biological invasions in the cities

Changes in presence of alien species in the ruderal vegetation of a representative ecosystem in a major city over 30 years: a case study from Bratislava

The study is focused on evaluating changes in the presence of alien species in ruderal vegetation. Two datasets comprising phytosociological relevés of ruderal communities during two time periods within the Bratislava City (in southwestern Slovakia) were analyzed. The old dataset consisted of 387 relevés recorded in the years 1975–1982, and the more recent dataset consisted of 308 relevés from the years 2011–2014. The relevés from both time periods were assigned to phytosociological classes via the same procedure – numerical classification (hierarchical clustering) using HIERCLUS software. The average values of the percentage number and percentage cover of the archaeophytes and neophytes as groups in the earlier and more recent relevés of each class were compared by the main effects ANOVA analysis in the STATISTICA 7.0 software. The proportion of each taxon of archaeophytes and neophytes in both datasets was also calculated. The invasive status, origin, and life forms of alien species in both datasets were compared. In total, both datasets comprised 120 archaeophytes and 71 neophytes. The old dataset contained more archeaophytes than the more recent dataset. On the contrary, the more recent dataset contained more neophytes than the old dataset. In the years 2011–2014, more invasive neophytes were recorded than in the past. The results revealed a statistically significant decrease in the average percentage number of archaeophytes in the classes Stellarietea mediae, Artemisietea vulgaris, and Galio-Urticetea, and a decrease in the average percentage cover of archaeophytes in the class Artemisietea vulgaris, compared to the past. On the contrary, a statistically significant increase in the average percentage number and cover of neophytes in the classes Artemisietea vulgaris and Galio-Urticetea was recorded. Some rare species of archaeophytes were only recorded 30 years ago (e.g., Kickxia elatine, Silene gallica). Furthermore, several species of neophytes (including some invasive taxa, e.g., Fallopia japonica, Helianthus tuberosus, Juncus tenuis) occur only currently in the ruderal vegetation of Bratislava

Changes in presence of alien species in the ruderal vegetation of a representative ecosystem in a major city over 30 years: a case study from Bratislava

The study is focused on evaluating changes in the presence of alien species in ruderal vegetation. Two datasets comprising phytosociological relevés of ruderal communities during two time periods within the Bratislava City (in southwestern Slovakia) were analyzed. The old dataset consisted of 387 relevés recorded in the years 1975–1982, and the more recent dataset consisted of 308 relevés from the years 2011–2014. The relevés from both time periods were assigned to phytosociological classes via the same procedure – numerical classification (hierarchical clustering) using HIERCLUS software. The average values of the percentage number and percentage cover of the archaeophytes and neophytes as groups in the earlier and more recent relevés of each class were compared by the main effects ANOVA analysis in the STATISTICA 7.0 software. The proportion of each taxon of archaeophytes and neophytes in both datasets was also calculated. The invasive status, origin, and life forms of alien species in both datasets were compared. In total, both datasets comprised 120 archaeophytes and 71 neophytes. The old dataset contained more archeaophytes than the more recent dataset. On the contrary, the more recent dataset contained more neophytes than the old dataset. In the years 2011–2014, more invasive neophytes were recorded than in the past. The results revealed a statistically significant decrease in the average percentage number of archaeophytes in the classes Stellarietea mediae, Artemisietea vulgaris, and Galio-Urticetea, and a decrease in the average percentage cover of archaeophytes in the class Artemisietea vulgaris, compared to the past. On the contrary, a statistically significant increase in the average percentage number and cover of neophytes in the classes Artemisietea vulgaris and Galio-Urticetea was recorded. Some rare species of archaeophytes were only recorded 30 years ago (e.g., Kickxia elatine, Silene gallica). Furthermore, several species of neophytes (including some invasive taxa, e.g., Fallopia japonica, Helianthus tuberosus, Juncus tenuis) occur only currently in the ruderal vegetation of Bratislava

Changes in the Diversity of Dry Calcareous Grasslands After Abandonment of Traditional Management in Devínska Kobyla National Nature Reserve (Southwestern Slovakia, Central Europe)

This study is focused on the evaluation of the values of the diversity indices of semi-natural dry calcareous grasslands of the Festuco-Brometea class in the area of Devínska Kobyla National Nature Reserve 50 years after abandonment of traditional management (grazing and mowing). The values of the species richness, the Shannon–Wiener index of diversity, the Simpson index, and Pielou’s measure of species evenness in the communities in the old and recent data, and the values of the environmental variables based on the Ellenberg indicator values of species were analyzed. For most of these analyses, we used Kruskal–Wallis in R 3.5.1. Compared to the past, we have recorded a significant lower values of the species richness, biodiversity, and species evenness in some communities. In some communities, no significant changes were recorded. Only in one community—Poo badensis-Festucetum pallentis, the higher values of Shannon–Wiener index was recorded compared to the past. The analysis of the Ellenberg indicator values revealed a statistically significant higher Ellenberg indicator values for moisture and nutrients and lower values for light in more recent period compared to the old period. The recorded results could be caused by the changes in the management after the year 1965, after abandonment of grazing and the gradual overgrowing by woody species took place in the area. The frequency of occurrence of some woody species (e.g., Populus alba, P. nigra, and Robinia pseudoacacia) in some communities increased compared to the past