Conference Agenda

Biodiversity-oriented urban management and planning require information on the drivers of wildlife composition and ecosystem function within cities. Urban landscapes impose environmental gradients along which species may be filtered away, or respond by showing adaptive variation in functional trait values. Such trait variation may be due to phenotypic plasticity, or a consequence of microevolution leading to local adaptation. We investigated three possible plant responses to urban environmental gradients: extinction, plasticity and adaptation. We assessed whether three individual functional traits, two population performance traits, as well as species frequency, responded to gradients in mowing frequency, soil fertility and structure, temperature, and compactness of the built-up matrix, among four herbaceous plant species in the city of Strasbourg. Using a common garden experiment, we tested whether the observed trait variation was hereditary. Each species displayed a different set of the 3 expected responses. Urban management and planning therefore impact on the evolutionary capabilities of plants in cities. In the case of management this was highlighted by the detected trends in species’ traits and frequency in response to mowing. The consequences of urban planning were evidenced by compactness of the built-up matrix most often eliciting plastic and adaptive responses.

Through the Biodiversity Plan, Paris aims to enhance the city's natural environment. The Labbé law (2017) prohibiting phytosanitary products in public spaces and the adoption of sustainable practices in green areas foster the growth of spontaneous flora in Paris. The city's ecological connectivity is improved with "Les Chemins de la nature," a network of ecological reservoirs and corridors, facilitating seed dispersal and promoting genetic connectivity within species.

To evaluate the effectiveness of these policies, we focus on the genetic diversity and the population genetic structure of Geum urbanum (wood avens), a common autogamous and epizoochorous species in Paris. Analyzing the polymorphism of 10 microsatellite loci across 650 individuals from 30 stations, we consider the following hypotheses:

1. The high urban density limits gene flow, increasing genetic differentiation between populations while restricting intra-population genetic diversity.

2. Dispersal relies mainly on humans and domestic animals, fostering extensive gene flow across Paris and enhancing within-population genetic diversity with weak or no population genetic structure.

3. Ecological connectivity restoration limits dispersal primarily by spatial distance, resulting in an isolation by distance genetic pattern.

This study aimed to investigate the floristic features of urban habitats in 24 cities in Serbia. Seven 1-ha plots were selected in every city and each selected plot represents a different habitat type. In each plot, spontaneously growing vascular plant species were recorded to determine species composition, species richness and diversity, taxonomic, horological, and ecological structure, indicator values, and presence of alien species. A total of 647 taxa were recorded in the study area, of which 172 were alien species. The taxonomic spectrum of urban flora in Serbia is dominated by representatives of the families Asteraceae and Poaceae, while the range of the spectrum is dominated by Eurasian and Adventive areal types. The flora of urban habitats in Serbia is hemicryptyphite-therophytic, moderately thermophilic, moderately heliophilic, mesophilic to moderately xerophilic, neutrophilic to moderately calciphilic, moderately nitrophilic, and moderately continental. The habitat types studied are characterized by significantly different floristic features. Differences between floras of cities are less pronounced and mostly consistent with the climate and geographical affiliation of the city, indicating that local features have the greatest influence on the flora of urban habitats in Serbia, while the influence of climatic parameters and the degree of urbanization is much less pronounced.

Urbanization and agricultural intensification effects can be well studied in small settlements within contrasting landscape settings. In our study, we carried out botanical surveys in 64 villages around 16 cities in the Carpathian Basin in 2022. We sampled the spontaneous vegetation of village centres and edges embedded in semi-natural vs. agricultural landscapes, located close to vs. far from cities. We found 455 plant species, including ten protected and 128 alien species in 1152 coenological quadrats (1m2). We found that landscape composition and within-village position were the most important factors shaping spontaneous vegetation. The richness of grassland species, and the relative cover of natives was higher, whereas alien cover was lower in villages in semi-natural than in agricultural landscapes. Edges had a higher richness of grassland related species but also a higher richness of short-lived species and aliens than the centres. From the conservation viewpoint, the vegetation was the most favourable in village edges within semi-natural landscapes as they hold a high native and perennial herb richness, and the highest cover of species characteristic to broadleaved forests. We found the lowest plant biodiversity in villages surrounded by agricultural land and in village centres, where greening measures would be the most important.

In the dynamic social-ecological context of urban gardens, plant communities consist of a diverse mix of species ranging from ornamentals to food crops, wild varieties, and natives. Yet, the degree to which urban gardens can support native plants across a local management and a landscape urbanization gradient remains unclear. Thus, challenges in native plant conservation are understudied and opportunities are underutilized. We conducted plant surveys in 31 urban community gardens in Berlin and Munich, Germany. We examined the diversity of native species present, which species may be of conservation concern, and how local and landscape-scale urbanization may predict such occurrences. We also investigated the relationship between cultivated and native plant species. We discovered a diversity of plant species including native endangered species, regardless of urbanization context. This implies that all community gardens, irrespective of their urban environments, can foster plant diversity alongside food production. Yet, at the local garden-scale, there remains opportunity to enhance plant habitats in gardens. In this talk, we discuss which species were found, underscoring the unique nature of community gardens as urban ecosystems of diverse flora. As the urban agriculture movement thrives, botanical investigations provide insight into how gardens can harmonize plant conservation and food production.

Grassland biodiversity is endangered in Europe. Urban areas can provide opportunities for the conservation of grasslands as they provide considerable amounts of open habitats with underexplored biodiversity potential. We are asking: how to increase plant biodiversity in urban grasslands?

While urban grasslands can be highly species-rich and host rare grassland species, they can also be limited by processes such as eutrophication and fragmentation. It is still poorly understood how different kinds of grasslands contribute to biodiversity conservation in the highly variable mosaic of open habitats in cities. Even though cities have attempted to create more biodiverse habitats, e.g., by reducing management intensity in lawns, or by establishing new grasslands by sowing seed mixtures, we need to better understand the outcomes of these actions.

We sampled vegetation from 200 urban grasslands in the Helsinki capital region, Finland. We explore how plants with different traits assemble into communities as a function of local and landscape-scale factors, producing communities with varying levels of biodiversity and trait compositions. The results help us understand the relative roles of different kinds of urban grasslands, environmental conditions, and biodiversity actions for conserving grassland biodiversity.