Sophie Lokatis’s research while affiliated with Freie Universität Berlin and other places

Urban rewilding, which promotes the development and transformation of urban greenspaces (UGS) into wilder forms, has garnered public support and offers numerous benefits-from enhancing human well-being and providing wildlife habitats to bolstering urban resilience against climate change. However, many UGS remain highly manicured. Research suggests that public expectations, safety concerns, conflicts with heritage preservation goals, and perceived disservices (e.g., allergenic pollen or unwanted wildlife) are among the barriers to adopting wilder designs; however, it remains unclear which factors hinder UGS rewilding the most. To investigate this, the study conducted semi-structured interviews with 26 experts involved in UGS management, including members of administrative bodies and conservation NGOs in Germany, to identify perceived benefits, challenges, and recommended measures for implementing wilder UGS. The interviews revealed that both groups viewed urban parks as focal points for rewilding, listing wildlife habitats, the human-nature connection, and aesthetic value as key benefits. However, a persisting demand for orderliness and conflicts with the recreational functionality of UGS emerged as predominant hurdles across all interviews. Conservation experts additionally highlighted challenges such as financial constraints, limited personnel, and rigid bureaucratic processes, while administrative experts emphasized safety, heritage preservation, and the risk of attracting unwanted wildlife. Regarding rewilding measures, both groups advocated for ecological interventions like creating wildflower meadows and allowing natural growth. Conservationists additionally recommended social measures to foster public acceptance, including educational signage, lighthouse projects, and features like early-blooming plants or designated mowing strips. To further advance urban rewilding, this study recommends that administrations and conservationists (1) create room for exchange to combat hurdles together, (2) target diverse UGS, including informal areas and cemeteries, (3) emphasize the climate resilience of wilder UGS, (4) address biases toward orderliness through social measures, and (5) reassess budgetary frameworks to enable broader rewilding. Finally, future studies should explore how to integrate rewilding efforts with recreational, cultural heritage, and safety objectives.

Municipal authorities around the world have come to recognize the importance of making conservation and restoration a priority. Multiple urban restoration programs now foster insects and other pollinators through planting and sowing flowering plants, many of them within residential areas. But residents are not only walking next to pollinators visiting flowering sidewalk grass verges, they are also walking on top of them, nesting in the cracks and interstices of urban pavements. Combining morphological and molecular monitoring schemes, we conducted a survey of urban pavements at twelve locations across Berlin and found that pavements can foster a surprising number and quantity of soil dwelling insects—in particular wild bees and wasps. Pavements located within 200 m to an insect-friendly flower garden were covered with significantly more nests of wild bees and solitary wasps, and showed higher species richness of these groups, while the degree of sealed surfaces in the surrounding had no effect per se. This underlines the positive impact that insect-friendly gardens can have for pollinators and other insects, even in highly sealed areas. Also, it shows the potential of cobbled pavements as valuable nesting sites in highly sealed urban areas. We provide a list of 55 species of ground-nesting Hymenoptera found in Berlin pavements, including 28 species of wild bees and 22 apoid wasps. In our study, the molecular approach only detected three Hymenoptera species and did not yield comparable results to classical monitoring. Nonetheless, using eDNA methods might be a promising tool for further studying soil nesting insects in the future, and to gain insights into the web of life in urban pavements.

Wildlife in cities divides people, with some animals bringing positive benefits and others causing conflict, for example due to property damage. Urban wildlife professionals from municipal administration, nature conservation, and hunting associations have a crucial role in shaping human‐wildlife relationships in cities and fostering conflict‐free coexistence. While many studies on urban wildlife have focused on the views of citizens, few have investigated the perspectives of experts to date. To address this knowledge gap, we interviewed 36 urban wildlife professionals giving guidance in the context of urban wildlife management, either in one of the four largest German cities by population (Berlin, Hamburg, Munich and Cologne) or at the national level. Red foxes, wild boars, raccoons, stone martens and Eurasian beavers were the five mammal species most frequently highlighted in interviews to cause human‐wildlife conflicts. The interviewees saw wild boars and raccoons as the most controversial urban wild mammals but emphasized the need to create refuges for beavers and better inform the public about foxes. Management in terms of public outreach, urban planning and population control, as well as establishing official contact points and stricter fines of activities violating regulations were highlighted as important elements of a toolkit to manage urban wildlife conflicts. Read the free Plain Language Summary for this article on the Journal blog.

With the exponential increase in scientific publications, new conceptual and technological tools are needed to help scientists, students, managers and policy-makers to navigate and digest current scientific knowledge. Hi Knowledge is an initiative to synthesise and visualise scientific knowledge, with an initial focus on invasion biology that is currently expanding to include urban ecology, restoration ecology and freshwater ecology. In a workshop on 5-6 June 2023 in Berlin, Germany, we discussed and tested a collection of new open tools related to this initiative in order to publish, curate, explore and synthesise concepts and results in ecology. Three main themes were discussed during in-person breakout group sessions: (1) building and using open tools for knowledge curation, exploration and synthesis; (2) making open knowledge searchable and machine friendly by improving modelling and annotation of scientific knowledge; and (3) extending beyond the field of invasion biology. We report on the discussions of all twelve sessions pertaining to these themes. A main underlying goal of our workshop was to build a community of scientists involved in openly co-designing and using these tools. Overall, the participants were enthusiastic about the usefulness of these tools and discussions gravitated around improving them and finding strategies to scale-up participation by the community. Follow-up user tests and publications are planned for individual tools and topics.

In the last 10 years, the interest in nature‐based solutions and ecosystem services like pollination has increased profoundly and with it the need to gather knowledge about wild bees and apoid wasp community dynamics, especially in urban ecosystems. Research on how the urban environment impacts the conditions of nesting sites is relatively scarce. Recent observations in the Brussels‐Capital Region (BCR; Belgium) show that urban pavements can provide alternative nesting opportunities for ground‐nesting Hymenoptera, such as wild bees and apoid wasps. Here, using a citizen science approach, we investigated the richness of ground‐nesting species living under urban pavements, as well as their preferences for sidewalk characteristics. A total of 22 species belonging to 10 families of wild bees, digger wasps and their associated cleptoparasites were identified at 89 sites in the BCR (Belgium). Sandstone setts or concrete slabs, with an unbound joint size of around 10 mm, were found to be the best suitable urban pavements for the ground‐nesting species. The soil texture under the pavement contained mainly sandy particles. We propose management guidelines to support bee and wasp species nesting under urban pavement in highly urbanised areas. Our observations pave the way for further research in the field of urban ecology and highlight the potential of multifunctional pavement designs that promote not only climate adaptation but also biodiversity.

Urban ecology is a rapidly growing research field that has to keep pace with the pressing need to tackle the sustainability crisis. As an inherently multidisciplinary field with close ties to practitioners and administrators, research synthesis and knowledge transfer between those different stakeholders is crucial. Knowledge maps can enhance knowledge transfer and provide orientation to researchers as well as practitioners. A promising option for developing such knowledge maps is to create hypothesis networks, which structure existing hypotheses and aggregate them according to topics and research aims. Combining expert knowledge with information from the literature, we here identify 62 research hypotheses used in urban ecology and link them in such a network. Our network clusters hypotheses into four distinct themes: (i) Urban species traits & evolution, (ii) Urban biotic communities, (iii) Urban habitats and (iv) Urban ecosystems. We discuss the potentials and limitations of this approach. All information is openly provided as part of an extendable Wikidata project, and we invite researchers, practitioners and others interested in urban ecology to contribute additional hypotheses, as well as comment and add to the existing ones. The hypothesis network and Wikidata project form a first step towards a knowledge base for urban ecology, which can be expanded and curated to benefit both practitioners and researchers.

Urbanization is restructuring ecosystems at an unprecedented pace, with complex and profound consequences for life on Earth. One of the hypothesized trajectories of urban ecosystems and species communities is biotic homogenization, possibly leading to very similar species assemblages in cities across the globe. Urbanization can, however, also have the opposite effect: biotic diversification, with cities, at least at the local scale, becoming biologically more diverse, mainly as a consequence of high species introduction rates and habitat diversification. Applying the hierarchy‐of‐hypotheses approach, we systematically map and structure the comprehensive body of literature on the urban biotic homogenization (UBH) hypothesis, comprising 225 individual studies (i.e., tests of the hypothesis) retrieved from 145 publications. The UBH hypothesis is studied at multiple levels with a multitude of approaches and underlying assumptions. We show that UBH is generally used with two very different connotations: about half of the studies investigated a potential increase in community similarity across cities, whereas the other half investigated biotic homogenization within cities, the latter being supported more frequently. We also found strong research biases: (1) a taxonomic bias towards birds and plants, (2) a bias towards small and medium distances (<5000 km) in comparisons across cities, (3) a dominance of studies substituting space for time versus true temporal studies, (4) a strong focus on terrestrial versus aquatic systems, (5) more extraurban (including periurban) areas than natural or rural ecosystems for comparison to urban systems, (6) a bias towards taxonomic versus functional, phylogenetic, and temporal homogenization, and (7) more studies undertaken in Europe and North America than in other continents. The overall level of empirical support for the UBH hypothesis was mixed, with 55% of the studies reporting supporting evidence. Results significantly differed when a natural/nature reserve, an extraurban, or rural/agricultural area served as reference to infer biotic homogenization, with homogenization being detected least frequently when urban systems were compared to agricultural, i.e., other anthropogenically influenced, study sites. We provide an evidence map and a bibliographic network and identify key references on UBH with the goal to enhance accessibility and orientation for future research on this topic.

Urbanization is an important driver of global insect decline. Yet, recent studies have demonstrated the potential of greenspaces in cities to promote biodiversity conservation. One of many factors negatively affecting arthropods in urban areas are unsuitable habitats, as non-woody greenspaces predominantly consist of manicured lawns. Maintenance practices such as high mowing frequencies, can have direct and indirect negative impacts on the local flora and fauna. The present study examines the effects of different mowing regimes on arthropod abundance and diversity by conducting meta-analyses of studies assessing the effect of mowing on arthropod abundance (46 datasets) and taxa richness (23 datasets) in urban environments. Due to a geographical bias in the literature, only data from the temperate, northern hemisphere are analyzed. While our meta-analysis on arthropod abundance showed a medium positive effect (effect size: g = 0.54) of reduced mowing, the cumulative effect of reduced mowing on arthropod taxa richness was large (g = 1.25). Grouping the studies not only resulted in lower heterogeneity, but also showed that manicured lawns disproportionately favor the abundance of “pest” species as well as ground-dwelling arthropods. There was also a significantly higher abundance of winged insects on sites with reduced mowing as compared to arthropods without wings. Overall, the findings of the present meta-analysis strongly support the notion that a reduction in mowing frequencies in urban greenspaces benefits insect biodiversity.