Connectivity assessment and prioritization of urban grasslands as a helpful tool for effective management of urban ecosystem services

Abstract

Urban grasslands are usually managed as short-cut lawns and have limited biodiversity. Urban grasslands with low-intensity management are species rich and can perform numerous ecosystem services, but they are not accepted by citizens everywhere. Further, increasing and/or maintaining a relatively high level of plant species richness in an urban environment is limited by restricted plant dispersal. In this study, we examined the connectivity of urban grasslands and prioritized the grassland patches with regard to their role in connectivity in an urban landscape. We used high-resolution data from a land use system to map grassland patches in Wrocław city, Silesia, southwest Poland, Central Europe, and applied a graph theory approach to assess their connectivity and prioritization. We next constructed a model for several dispersal distance thresholds (2, 20, 44, 100, and 1000 m), reflecting plants with differing dispersal potential. Our results revealed low connectivity of urban grassland patches, especially for plants with low dispersal ability (2–20 m). The priority of patches was correlated with their area for all dispersal distance thresholds. Most of the large patches important to overall connectivity were located in urban peripheries, while in the city center, connectivity was more restricted and grassland area per capita was the lowest. The presence of a river created a corridor, allowing plants to migrate along watercourse, but it also created a barrier dividing the system. The results suggest that increasing the plant species richness in urban grasslands in the city center requires seed addition.

The Role of Brownfields and Their Revitalisation for the Functional Connectivity of the Urban Tree System in a Regrowing City

“…These four classes with a minimum patch area of 0.1 ha, representing habitats for breeding birds [63], have been used for performing FCA using Graphab (Figure 2). Graphab is a tool for modelling ecological networks based on graph theory that focuses on the behavioural interactions of a targeted species for functional connectivity calculation [64].…”

How to successfully improve the biodiversity of city grasslands?

“…To deliver ecosystem services, UG need to have a high diversity of plant species and to be properly managed [ 13 ]. However, UG are usually species poor, and the spontaneous species migration that can increase biodiversity is very limited in cities ([ [14] , [15] , [16] ], however, see [ 17 ]). Therefore, the modern UG should be established and/or managed with the goal of having high biodiversity and including cover with native, local-origin species typical of grasslands with a high fraction of flowering plants that can provide food for pollinators [ [18] , [19] , [20] , [21] ].…”

Patterns and determinants of plant, butterfly and beetle diversity reveal optimal city grassland management and green urban planning

“…Therefore, diversity of green spaces present within urban landscapes is essential, of which grasslands represent important ecosystems for many species (du Toit et al, 2020;Dylewski et al, 2019;Mollashahi et al, 2020). Though grasslands are among the most highly studied habitat types in terms of their biodiversity and conservation value in natural and agricultural landscapes (e.g., Dengler et al, 2014), this is not the case in urban areas (Öckinger et al, 2009;Fischer et al, 2013;du Toit et al, 2020).…”