3b: Urban ecology and evolution

3b:     Urban ecology and evolution

Conveners:     Wouter van der Vegt (Vrije Universiteit Amsterdam)

                       Roy Remme (Leiden University)

                       Tim Claerhout (Naturalis)

1. Improving urban air quality with smart green Infrastructure designs

Nemi Dorst, Barbara Gravendeel, Arjen Speksnijder, Letty de Weger, Marcel Polling, Leon van Leeuwen, Martijn van de Velde, Dominique de Boer, Joris Meurs, Luc van Driel, Fons Verbeek and Lu Cao, Naturalis Biodiversity Centre 

Temperatures in cities are rising due to global warming. Urban green infrastructure offers cooling but also poses health risks if not appropriately designed. Pollen of allergenic species cause hay fever and rows of trees concentrate fine dust. I investigate which designs of urban green increase shade and biodiversity but reduce airborne allergenic pollen and fine dust concentrations. Vegetation, pollen and fine dust were monitored biweekly at ten localities in Leiden over two years before and after redesign of public green. Aerial pollen was captured using a handheld sniffer and identified and quantified with DNA metabarcoding and AI. Fine dust was measured using a particle counter. Results are used to calibrate hay fever forecast and air quality models operating at street level. Annually, an estimated 10% of allergenic airborne pollen is produced by private gardens. Designs of public green containing less gras fields and more scattered non-allergenic herbs and trees increase air quality.

2. From co-dying to co-habitation: Bringing One Health to urban rat ecology

Tuomas Aivelo, Leiden University

Humans are notorious spreaders of pathogens and parasites across the globe to a number of other species. These diseases, so called anthroponoses, pose increasing risk to the other species, especially synanthropic species that closely associate with humans. Indeed, urban rats have a long and documented history in acquiring major pathogenic agents, such as plague bacteria, from humans. I have studied human-rat interactions and pathogen and parasite spread in Helsinki, Finland, for six years. The data suggests that pathogens, such as Campylobacter jejuni, are spread from humans to rats. Additionally, I posit that human persecution of rats facilitate urban disease spread through immunological and ecological phenomena. I will bring together our findings in the framework of One Health and suggest ways how our cities could be healthier environments for rats and other synanthropic species.

3. Noise pollution as a major disturbance of avian predation in Amsterdam

Joscha Beninde, Vrije Universiteit Amsterdam

Global species observations from citizen science platforms provide unprecedented biodiversity data and hold great promise for developing data-driven metrics to quantify species’ responses to environmental changes. Species’ population ecological responses to urbanization can be consistent across spatial and temporal scales. Yet, city-specific factors such as landscape configuration or local biotic interactions also profoundly influence species and may cause shifts in species’ urban affinity. Here, I present a novel metric to measure affinity to urban landscapes and apply it to ecological niche predictions of 1,023 species in Southern California. This demonstrates the stability of species’ urban affinity through time and space. Simultaneously, this metric is also sensitive to rapid changes in urban affinity and detected urban declines in the Western Black Widow spiders due to competition with an introduced congeneric species. In conclusion, this metric provides a versatile and data-driven tool for studying urban biodiversity trends.

4. Densely vegetated facade gardens in highly urbanised environments as hotspot for urban insects, regardless of native plants

Joeri Morpurgo, Margot Huurdeman, Gerard Oostermeijer and Roy Remme, Leiden University

Urban green spaces, often private, shrink as cities densify, with facade gardens (~1.5m²) representing the smallest green spaces.  From the land-sparing v. land-sharing debate, the sparing perspective  considers façade gardens benefits to biodiversity to be minimal due to their small size and spread. In contrast, the sharing perspective argues that façade gardens could be beneficial to insects by acting as stepping stone, providing shelter and food availability. However, evidence assessing facade gardens capacity to enhance biodiversity is lacking. Therefore, we studied of 65 gardens across Amsterdam and The Hague investigating how facade gardens design benefits biodiversity. Results indicate that facade gardens are biodiversity hotspots, with 154 insect and 235 plant species found. Results also show that plant coverage and species richness were most important, while factors like plant nativeness. These results provide evidence that even in dense urban settings, façade gardens with dense vegetation provide substantial benefits to insect biodiversity.

5. Legacy of stress: How heat and drought affect fungal communities associated with tree roots in cities

Annemiek van Dijke, Vincent Merckx, Martijn Bezemer, Giovanni Bortolami, Frederic Lens and Sofia Gomes, Leiden University

Heat waves, characterized by high temperatures and drought, impact trees and their associated fungal communities, particularly in cities. How these communities adapt to environmental stressors, such as heat and drought is still understudied. Heat and drought stress may leave a lasting legacy within fungal communities, influencing their future activity and resilience. This study explores the relationship between physiological stress experienced by urban trees and the responses of their root-associated fungal communities to heat and drought stress. To investigate these dynamics, we first quantified the water stress experienced by urban trees and assessed corresponding changes in their root-associated fungal communities. We then examined how soil fungal communities responded to induced heat and drought stress through soil respiration. By applying these stressors to fungal communities collected in an urban gradient of heat exposure, we aimed to define the legacy effect on fungal communities and understand its implications for microbial function under stress.