Threshold Reaction of Soil Arthropods to Simulative Nitrogen Deposition in Urban Green Spaces

Sustained nitrogen (N) deposition has a wide-ranging impact on terrestrial ecosystems. However, still little attention has been paid to responses of urban soil fauna to the increasing N deposition. To clarify such effects on the soil properties and soil fauna in typical urban lawns (featuring Cynodon dactylon vegetation), a control experiment was conducted for 1 year, in which NH4NO3 was added as the external nitrogen source with four treatments of N addition: N0 (i.e., only water), N1 (50 kg N ha–1 yr–1), N2 (100 kg N ha–1 yr–1), N3 (150 kg N ha–1 yr–1). Results showed that N additions influence soil faunal communities in the urban lawns soil. The relative abundance of Oribatida increased with the N treatment level, partially replacing the more sensitive Collembola. Significant differences in the Shannon-Wiener and Margalef indices (p < 0.01) supported this statement. Although higher doses of N addition showed adverse effects on soil fauna communities, low N inputs increased the soil fauna diversity and richness, especially at 5–10 cm depth. A threshold effect appears to exist low nitrogen addition (<25 kg N ha–1) did not affect negatively pedofauna structure and composition, while in the range from these values up to 50 kg N ha–1, the composition of the soil fauna underwent major changes confirmed by the decline of biodiversity indices. These changes are accompanied by the decreased pH values with increasing N inputs.

Significance of Urban Vegetation on Lawns Regarding the Risk of Fire

Urban green infrastructure significantly influences the functioning of a city and the comfort of its residents. Lawns are an essential element of public greenery. They represent a live component, and if they are lacking, of low quality, or neglected, this will cause major problems in the urban environment. The vegetation structure of urban grassy areas changes under the influence of different management methods used for their maintenance. The main goal of this study was to evaluate the species diversity of urban lawns and to determine the influence of this vegetation on factors based on the representation of the species found. Three sites with urban lawns were chosen in a built-up city area where different types of vegetation management were applied: Typical management, in which grassy areas are mowed twice a year; intensive management, in which lawns are mowed several times a year and the biomass is removed; and extensive management, in which lawns are mowed irregularly, once a year at most, and the biomass is left unevenly on the site. Extensive management and unkempt urban grassy areas represent a high risk of fire due to the presence of plant species that produce great amounts of biomass. Combined with dry and warm weather, the dead biomass can lead to outbreaks of fire. Extensive management of urban grassy areas brings some benefits, such as lower maintenance costs and increased biodiversity and bioretention. On the other hand, intensive management reduces the risk of fire and the biodiversity of the plant community. Attention should be paid to the composition of vegetative species and their functions that could threaten the safety of residents, with the risk of fire being one of them. However, the vegetation biomass of grassy areas affected by management practices is only a precondition for the risk of fire because weather and drought occurrence play important roles as well.

Partial mowing of urban lawns supports higher abundances and diversities of insects

Within the citizen science project “Flowering meadows for Saxonian butterflies”, more than 640 meadows are partially and at maximum three times annually mowed in order to change urban lawns into habitats for insects. In 2019, insect diversity was evaluated using the 100 sweep net technique during five visits at nine butterfly meadows (BM) and nine intensively mowed lawns (IML). The mean arthropod biomass of these five visits per site is significantly higher on BM compared to IML. All adult individuals of Apidae, Coleoptera, Heteroptera, Orthoptera, Papilionoidea as well as Asilidae and Syrphidae have been identified morphologically, revealing 260 species from all study sites. The mean number of species per visit is significantly higher on BM compared to IML. 90 species are recorded as larva and the mean number of species per visit is significantly higher on BM compared to IML. 42 species are recorded as larva as well as adult. The records of larvae provide evidence for reproduction on the meadows. Implications for insect conservation Our results clearly demonstrate that a reduced mowing frequency together with an always partial mowing of the area support higher biomass, abundances and diversities of insects as well as reproduction of insects on urban lawns. Therefore, reduced mowing frequency together with partial mowing is recommended for urban lawns as well as meadows in the countryside and conservation areas to foster insect diversity.

Sedum pallidum (Crassulaceae) – alien species of the flora of plain part of Ukraine

Objective – to study the current distribution of Sedum pallidum in Ukraine, to analyze its state in the alien flora of Ukraine. Material and methods. The studies were conducted in 2008–2019 in the plain part of Ukraine and in the Mountain Crimea. Literature information, several national herbarium collections and other sources were analyzed. Special attention was paid to the delimitation of synantropic locations of S. pallidum from cultural ones. Results. S. pallidum is a sub-euxine species, which range occupies the Mountain Crimea. It is widely cultivated throughout Ukraine and is prone to naturalization, thanks to its vegetative and generative reproduction. In general, about 30 synantropic locations of S. pallidum have been recorded, mainly in the Middle Prydniprovia and Western Ukraine. Urban lawns and roadsides on light substrates are favorable ecological niches for S. pallidum. Соnclusions. S. pallidum is the alien species in the flora of the plain part of Ukraine and ergasiophyte in its origin. A potential secondary synanthropic range of this species occupies the whole country except the Carpathian highlands. It has been established that S. pallidum in the culture of the Forest-Steppe is a perennial herb. Two races identified in its composition (var. pallidum and var. bithynicum) are probably ecads, and have no systematic importance. In the culture, S. pallidum is characterized by successful vegetative and generative reproduction, which contributes to its naturalization. S. pallidum is often confused with other species of the genus, what does not contribute to its study in adventive floras. A key for S. pallidum determination has been proposed.

Lawns in Cities: From a Globalised Urban Green Space Phenomenon to Sustainable Nature-Based Solutions

This opinion paper discusses urban lawns, the most common part of open green spaces and urban green infrastructures. It highlights both the ecosystem services and also disservices provided by urban lawns based on the authors’ experience of working within interdisciplinary research projects on lawns in different cities of Europe (Germany, Sweden and Russia), New Zealand (Christchurch), USA (Syracuse, NY) and Australia (Perth). It complements this experience with a detailed literature review based on the most recent studies of different biophysical, social, planning and design aspects of lawns. We also used an international workshop as an important part of the research methodology. We argue that although lawns of Europe and the United States of America are now relatively well studied, other parts of the world still underestimate the importance of researching lawns as a complex ecological and social phenomenon. One of the core objectives of this paper is to share a paradigm of nature-based solutions in the context of lawns, which can be an important step towards finding resilient sustainable alternatives for urban green spaces in the time of growing urbanisation, increased urban land use competition, various user demands and related societal challenges of the urban environment. We hypothesise that these solutions may be found in urban ecosystems and various local native plant communities that are rich in species and able to withstand harsh conditions such as heavy trampling and droughts. To support the theoretical hypothesis of the relevance of nature-based solutions for lawns we also suggest and discuss the concept of two natures—different approaches to the vision of urban nature, including the understanding and appreciation of lawns. This will help to increase the awareness of existing local ecological approaches as well as an importance of introducing innovative landscape architecture practices. This article suggests that there is a potential for future transdisciplinary international research that might aid our understanding of lawns in different climatic and socio-cultural conditions as well as develop locally adapted (to environmental conditions, social needs and management policies) and accepted nature-based solutions.

FLORA OF LAWNS IN THE CITY OF UFA

The paper presents a study in the flora of lawns in Ufa. The lawn flora is represented by 192 species belonging to 31 families. Based on coenotic and ecological characteristics, four ecological coenotic groups of species were singled out that were described in the lawn designated areas. The ecological coenotic groups were analysed for life form spectra, hemeroby, species activity. Among the plant communities of typical low-trampled and well-maintained urban lawns (the ecological coenotic group of Festuca pratensis) Poaceae, Asteraceae, Fabaceae, Rosaceae, Apiaceae families were the leading ones, where hemicryptophytes and oligo-meso-αeuhemerobes dominated. The lawns subjected to significant anthropogenic impact (trampling, salinization) (the ecological coenotic group of Taraxacum officinale) had a large number of species that belonged to the «ruderal» Polygonaceae, Asteraceae, Fabaceae, Brassicaceae, Lamiaceae families, where hemicryptophytes and meso-euhemerobes dominated. Ruderal species of Asteraceae, Poaceae, Amaranthaceae, Lamiaceae, Malvaceae, Polygonaceae families prevailed, with a large share of ruderal and semi-ruderal annual and biennial plants, β-eupolyhemerobes, in the lawn designated areas where gramineous plant community did not develop after soil disturbance (the ecological coenotic group of Chenopodium album). Ruderal species of Poaceae, Chenopodiaceae, Polygonaceae families with a large portion of ruderal annual and biennial β-eupolyhemerobes also dominated in humid and waterlogged lawn areas. The ecological ecoenotic groups of Taraxacum officinale, Chenopodium album and Bidens tripartita had a large number of neophyte species. The lawn areas with the ecological coenotic groups of Taraxacum officinale, Chenopodium album and Bidens tripartite were found as most colonized with ruderal plants. A number of measures are required to build dense grass covering: reconstruction and heavy maintenance of lawns combined with sowing quality lawn grass mixtures, regular mowing practices to reduce the number of ruderal hemytherophytes and therophytes, timely plant nutrition and watering.