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EDITORIAL article

Front. Sustain. Cities, 06 October 2022
Sec. Innovation and Governance
This article is part of the Research Topic Social Movements and Sustainable Urban Commons Governance View all 8 articles

Editorial: Social movements and sustainable urban commons governance

  • 1Department of Political Sociology, Friedrich Schiller University Jena, Jena, Germany
  • 2Maastricht Sustainability Institute, School of Business and Economics, Maastricht University, Maastricht, Netherlands

Urban commons have recently received considerable attention as new institution of collective action (Dellenbaugh et al., 2015), social innovation (Bianchi, 2020) as product and incubator of social movements (De Angelis, 2017; Colding et al., 2021). Critical urban scholars embrace urban commons as an alternative to neoliberal urban housing strategies (Lamarca, 2015; Bruun, 2016; Nonini, 2017), infrastructure provisioning (McFarlane and Desai, 2016) or the production of public space (Shareable, 2018). More recently, scholars have started to explore the contribution of urban food commons (Morrow, 2019) and urban green commons (Barthels et al., 2022) to urban sustainability. However, beyond scholarly interest in such episodes, we lack an understanding of how urban commons are sustained over longer periods of time, and how this process is shaped by their governance embedded within multiple and multi-facetted relations to the state, their urban surroundings and translocal networks with social movements.

The idea of sustainability is inherent in the concept of the commons, since it implies an institutionalized process, a community that takes responsibility and a shared resource, all of which are oriented toward their reproduction over time. Research in the line of Ostrom has primarily focused on the internal organization of commons governance, famously summarized by Ostrom in the eight principles of commons governance (Ostrom, 1990). Originally, the concept was coined by Ostrom to study the governance of natural resources in rural settings where communities would self-organize to guarantee the self-sustainability of the local community, but she eventually broadened the concept of the commons to include intangible and social resources (Hess and Ostrom, 2007).

“Urban commons” refers to resources and services that are essential for the exercise of fundamental rights in cities (e.g., housing, health, water, energy, transportation, education, etc.) and that are governed collectively in a way that transcends the clear-cut public-private distinction (Kip et al., 2015). Urban contexts display a number of traits that pose a challenge to sustainable urban commons governance: a larger array of actors and a high degree of mobility of people and things, the experience of anonymity and socio-cultural heterogeneity, as well as the social production of space with its overlapping and sometime contested uses (Kip et al., 2015). Reflecting on Ostrom's Design Principles in the light of an urban situation, Foster and Iaione (2020) have extended these ideas to a contemporary urban context.

Scholars from a Marxist perspective broadened the perspective on commons governance by conceptualizing the commons as a system that regulates itself autonomously, yet in ongoing exchange with its environment, often broadly conceived of as “the state,” on the one side, and “the market,” on the other (Caffentzis and Federici, 2014; Kratzwald, 2015; De Angelis, 2017). While a real-existing interdependence has been acknowledged, research from this perspective has tended to emphasize the antagonistic character of the commons with state and markets, and the risk of co-optation through buying into state support (but see also Volont and Smets, 2022).

More recently, several critical scholars have taken an alternative perspective on the state, by conceptualizing its potential role as “enabling state” as Michel Bauwens and collaborators (Bauwens and Niaros, 2017; Bauwens et al., 2022) have coined it. Developing this idea further into a political-strategic concept, scholars have proposed notions of “public-commons-partnerships” (Milburn and Russell, 2018, 2019), “public-civic partnerships” (Horvat, 2019) or “public-community-partnerships” (Chaves-Avila and Gallego-Bono, 2020) to reflect on how public administration and state regulation could indeed enable commons initiatives, while at the same time, holding commons also accountable to the broader, public interest.

Studies along these lines have also studied and interacted with practical examples, such as water remunicipalization in Naples and elsewhere (Mattei, 2013; Carrozza and Fantini, 2016; Popartan et al., 2020; Turri, 2022); civic assets management programs in Barcelona (Pera and Bianchi, 2021); BIP/ZIP urban regeneration programs in Lisbon (Patti, 2017); community land trusts in England (Thompson, 2018) and elsewhere (Bunce, 2018). New Municipalism has been studied as an emergent political program around the idea of expanding such public-commons-partnerships as a governance paradigm for the city (Thompson, 2021). The contributions to this edited collection demonstrate that within these strategies there is a positive engagement with the law, however, mixed with a careful and ambivalent relationship about its danger to depoliticize ongoing struggles.

Recent debates about the urban commons, have also promoted a more differentiated idea about the commons' environmental context, namely the urban conditions in their socio-spatial and physical dimensions. Such studies (Stavrides, 2014, 2016; Dellenbaugh et al., 2015; Borch and Kornberger, 2016) have taken into consideration how urban conditions affect the emergence and reproduction of urban commons. Kip et al. (2015) emphasize three urban challenges to the commons: the need for constant boundary negotiation of a fluid community, particularly when the community understands itself as open and inclusive; the need for a democratic institutional regulation between multiple urban commons and the complex relationships among a diversity of identities, mobilities, needs, and abilities that commoners bring in; and conflicts arising around the use and meaning of the shared resources based on a difference in interest or perspective. Just how such challenges and opportunities within the environments become an aspect of urban commons governance warrant clarification and empirical scrutiny.

These recent developments in the literature suggest that the relational embedment warrants further study and conceptualization. Specifically, the complex relations of urban commons begs the question what kind of embedded governance is needed to ensure their sustainability. This edited collection brings together seven contributions addressing the questions of sustainable urban commons governance. All contributions are empirically grounded in case studies. Amacher et al. compare the legal appropriations of territorialized commons in Berlin and Santiago de Chile; taking the example of the German “Mietshäuser Syndikat,” Hölzl studies the translocal mobilization of housing commons; Müller and Köpper examine the complex dynamics leading to sustainably governed commons in Europe, comparing three cases in Germany, the Netherlands, and France; Smets and Volont look at processes of institutionalizing non-institutionalization in the case of Savings and Credit Associations as a form of financial commoning in India and the Netherlands; Zielke et al. reflect on lessons learnt form a failed transdisciplinary project with urban commons in Liverpool, England; Cermeño et al. study knowledge practices of urban commons initiatives in the three German cities Kassel, Stuttgart and Berlin; finally, Iaione et al. look at participatory governance of culture and cultural heritage in Naples. Taken together, these contributions provide a broad understanding of how the embedded governance of urban commons in Europe, and even beyond, can contribute to their sustainment.

Based on the seven contributions to this edited collection, we argue here that we need a broadening of our perspective from the internal governance of commons toward an understanding of its governance as embedded within broader governance processes. This embeddedness is contingent, frictious, and contested and highlights the relational character of the internal governance and its interaction with other societal domains and institutional processes outside of the commons. The perspective of frictious and contested embeddedness fosters analytical sensibility for the complex interplay between urban commons governance and processes in the socio-institutional and physical context. On the one hand, it raises attention to important enabling factors and conditions of the urban environment for urban commons, and on the other hand, to the contributions of urban commons to their environment. We contend that critical assessments of the achievements and pitfalls of urban commons need to take into account the multiple and multi-facetted embedments of urban commons and their dynamic interactions

The contributions to this collection highlight and study three key relations that urban commons develop toward their “outside”: (1) the political-administrative state apparatus; (2) the geographic surrounding or the neighborhood; and (3) the social movements that have given rise to commons initiatives and their embodiments in translocal networks of initiatives with similar or complementary interests and outlooks. It is with actors in these three spheres that urban commons develop significant relations in terms of instrumental coordination, strategic contestation, identity construction, or communicative exchanges. These relations are by no means unilateral, as the contributions to this edited collection demonstrate. In the following part, we summarize the key finding of the seven contributions to this edited article collection on how urban commons governance is embedded within these (larger) processes of the state apparatuses, the urban surroundings and movements.

Relations with political administrations and the law

The contributions by Amacher et al., Iaione et al., and Müller and Köpper put specific emphasis on the relations between urban commons initiatives, on the one hand, and political administrations and the law (as a strategic resource), on the other. In particular, Müller and Köpper find that the support from (local) authorities plays a crucial role for the continuity of urban commons. Iaione et al. equally stress the importance of local authorities as enabler of urban commons initiatives and point to the institutional and legal diversity necessary for nurturing the partnerships behind urban commons. Their case studies in Naples draw on the resolutions on the urban commons of the City of Naples and show how the mechanism of “Civic Uses” regulations preserves the public ownership of cultural heritage sites by granting communities a non-exclusive right of use to self-manage these spaces and to benefit economically from them. Yet, the authors also observe signs of possible capture of the community actor by private and public partners.

The strategic use of law to initiate and sustain urban commons is also examined in the contribution of Amacher et al. Their research finds that legal instruments, by setting in place inhibitions for the commodification and privatization of the appropriated land, can play an important role in mediating and facilitating the relationship between urban commons and social movements. Based on case studies of ExRotaprint in Berlin and Conjunto Maestranza in Santiago de Chile, the authors discuss the use of the law and point out both the ability to politicize the question of urban land use and ownership and the associated risk that using the law may render the issue for experts only. In spite of innovative new approaches to the law for transformative purposes, the authors conclude that legal tools do not replace activist engagements and self-organization of the commoners.

The latter is even more relevant, since not only the law, but also local authorities may operate against urban commons initiatives. And even when supporting them, they might do so for very different reasons. In the face of gentrification dynamics, Müller and Köpper (p. 17), therefore, warn that “(v)ery often urban politics use urban commons as a flagship for innovative urban development and consequently instrumentalise them without necessarily supporting them.” The decisive criteria of political and legal support are whether civic use rights are protected in the long-term and whether substantive financing is provided to reduce the pressure for commodification within the initiatives.

Local relations with the urban surroundings

Territorial relations with the urban neighborhoods surrounding the commons initiatives are scrutinized in three contributions. Bracketing the challenge of gentrification, Müller and Köpper find that urban commons can contribute to sustainable governance, insofar as they achieve a permanent impact on the quality, use or regulation of the built environment, in the immediate neighborhood or even the whole city. This impact may last even when the commons itself may disappear at some point. Based on their research, they also claim that urban commons are more likely to be sustainable when they are easily accessible spaces (both on a physical and an organizational level) engaging with the urban environment that allow new commoners to participate. However, at the same time, their research also suggests certain limits to growth as commons are more resilient when striking the right balance between the scale of the spatial resource and the size of the community.

Similarly, the piece by Smets and Volont highlights the significance of (implicitly local) relationships of trust as a counterweight to institutional arrangements mediated by given rules. As the authors demonstrate, the success of the growing movement of Savings and Credit Associations over the past decade worldwide has not led to the growth of these associations in size, but rather in number across different localities.

Starting from the observation of pre-existing spatial inequalities, Hölzl points to the powerful conditions that construe localities and that cannot be unmade by a place-making commons model alone. Likewise, research insights by Zielke et al. render the authors skeptical about the potential positive contribution of urban commons to their direct urban environment. They consider the aspect of class and socio-spatial inequalities as a “thorny issue” for any commoning effort. To the extent that these social cleavages are not acknowledged and addressed, commoning is criticized as a post-political approach that ultimately reproduces inequality.

Translocal relations with movements and networks of solidarity

Local and translocal networks of urban commons intersect in important and sometimes mutually reinforcing ways, as the contributions by Cermeño et al. and Hölzl emphasize in their relational analyses. From such perspective, this edited collection also shows that translocal exchanges, networks and movements are important conditions for urban commons. Amacher et al., for example, observe a dialectic between commons initiatives and broader social movement dynamics that can be mutually beneficial. While, on the one hand, the appropriated territory can be a material and symbolic resource for the movement, the movement plays an important role as a source of motivation for commoners' engagements.

Hölzl research finds that it is a rather small groups of activists that are crucial drivers of the diffusion of urban commoning approaches. The author points out an inherent middle-class bias within these knowledge transfers, at least within Europe. Müller and Köpper's case studies from the Northern European context confirms the suspicion that organizers often have a high level of education and count with the time and financial resources available to commit to such initiatives. The class-bias in view of sustaining commons is also illustrated by the relative privilege of engaging in voluntary labor and committing to a “project in life” as Cermeño et al. observe in the housing commons they studied.

Open and direct meetings remain key instruments for commons learning and the strengthening of networks of solidarity, as Hölzl finds. A special role is played by what she calls “translocal support and solidarity networks” among activists and commoners such as the German “Mietshäuser Syndikat” (“rent houses union”) as a facilitator of urban development elsewhere, for example by providing financial guarantees for loans. Both contributions by Hölzl and Müller and Köpper argue that translocal networking promotes knowledge transfer and an impact of urban commons initiatives beyond their locality.

Discussion and conclusion

Urban commons inevitably consider their relations with state apparatuses, urban surroundings and movements within their governance. It is for this reason that we propose to speak of a governance that is embedded within external relations which may be, supportive, but also frictious or even contested. Based on our analysis of the contributions to this edited collection, we identify three ideal-type oppositions characterizing the relationality of urban commons.

First, urban commons relations with political administrations and the law may be collaborative and enhancing or obstructive, if not repressive. Second, with regard to the urban surrounding, urban commons may contribute to a revitalization of neighborhoods but they may also deepen inequalities and conflicts over space. Third, urban commons can develop relations with social movement actors and other commons initiatives in a way that, one the one side, may foster the circulation and expansion of struggles, or on the other side, may be characterized by exclusiveness and enclosure of a resource.

To be sure, by taking these oppositions as ideal types we do not only take into account that any situation finds itself somewhere on a continuum between these opposites, but also that it is shaped by the complexities and ambiguities that these relations entail. The details in which these relations are negotiated and dealt with can make all the difference for the development and sustainability of urban commons—whether they are repressed, co-opted or, indeed, publicly supported; and whether they close themselves off vis-à-vis their surrounding or other commons initiatives, or rather thrive off networks of mutual support.

If these challenges are not met, urban commons either dissolve or transform into exclusive clubs. Their connections to movements and solidarity networks that gave rise to them gets cut off and the possibility of mutually beneficial interactions with their surrounding neighborhoods becomes undermined. Several papers in this special issue present innovative, yet never unambiguous, practices of urban commons initiatives in relating to the state apparatus and the law, the surrounding neighborhoods and movement actors. The authors highlight the challenge yet also the promise of how urban commons initiatives can become transformative agents within the city and beyond. Future research therefore would do well to continue this path and pay close empirical attention to the way in which urban commons governance is embedded in relations to state apparatuses, urban surroundings and movement actors, and balances the tensions resulting from this multi-facetted relationality.

Author contributions

MK and CS have contributed equally to the conceptualization, writing, revision, and editing of the manuscript. Both authors approved the submitted version.

Funding

MK acknowledges support through the Collaborative Research Centre-Structural Change of Property funded by the Deutsche Forschungsgemeinschaft (DFG) – SFB TRR 294/1-424638267.

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher's note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

References

Barthels, S., Colding, J., Hiswåls, A., Thalén, P., and Turunen, P. (2022). Urban green commons for socially sustainable cities and communities. Nord. Soc. Work Res. 12, 310–322. doi: 10.1080/2156857X.2021.1947876

CrossRef Full Text | Google Scholar

Bauwens, M., Kranjc, R., and Ramos, J. (2022). “Commons economies in action: Mutualizing urban provisioning systems,” in Sacred Civics: Building Seven Generation Cities, eds J. Engle, J. Agyeman, and T. Chung-Tiam-Fook (London: Routledge), 213–225.

Google Scholar

Bauwens, M., and Niaros, V. (2017). Changing Societies Through Urban Commons Transitions. P2P Foundation. Available online at: https://pl.boell.org/sites/default/files/changing_societies_through_urban_commons_transitions.pdf (accessed September 24, 2022).

Google Scholar

Bianchi, I. (2020). “Urban commons. Between collaborative pacts and neoliberal governmentality,” in Society and the City. The Dark Sides of Social Innovation, eds Borelli, G., and Busacca, M., (Milan: Mimesis International).

Borch, C., and Kornberger, M (eds)., (2016). Urban Commons: Rethinking the City. First Issued in Paperback. London; New York, NY: Routledge, Taylor & Francis Group.

Bruun, M. H. (2016). “Communities and the commons. Open access and community ownership of the urban commons,” in Urban Commons: Rethinking the City. First Issued in Paperback, eds Borch, C., and Kornberger, M., (London; New York, NY: Routledge, Taylor & Francis Group).

Google Scholar

Bunce, S. (2018). “Alternatives to gentrification: Exploring urban community land trusts and urban ecovillage practices,” in Handbook of Gentrification Studies, edsL. Lees, and M. Philipps, (Cheltenham: Edward Elgar Publishing), 413–427.

Google Scholar

Caffentzis, G., and Federici, S. (2014). Commons against and beyond capitalism. Community Dev. J. 49 (Suppl. 1), i92–i105. doi: 10.1093/cdj/bsu006

CrossRef Full Text | Google Scholar

Carrozza, C., and Fantini, E. (2016). The Italian water movement and the politics of the commons. Water Alternat. 9, 99–119.

Google Scholar

Chaves-Avila, R., and Gallego-Bono, J. R. (2020). Transformative policies for the social and solidarity economy: the new generation of public policies fostering the social economy in order to achieve sustainable development goals. The European and Spanish cases. Sustainability 12, 4059. doi: 10.3390/su12104059

CrossRef Full Text | Google Scholar

Colding, J., Barthel, S., Ljung, R., Eriksson, F., and Sjöberg, S. (2021). Urban commons and collective action to address climate change. Soc. Inclus. 10, 103–114. doi: 10.17645/si.v10i1.4862

CrossRef Full Text | Google Scholar

De Angelis, M. (2017). Omnia Sunt Communia: On the Commons and the Transformation to Postcapitalism. London: Zed Books. doi: 10.5040/9781350221611

CrossRef Full Text | Google Scholar

Dellenbaugh, M., Kip, M., Bieniok, M., Müller, A., and Schwegmann, M, (eds). (2015). Urban Commons: Moving Beyond State and Market. Gütersloh; Basel: Bauverlag; Birkhäuser.

Google Scholar

Foster, S., and Iaione, C. (2020). “Ostrom in the City. Design principles and practices for the urban commons,” in Routledge Handbook of the Study of the Commons, eds B. Hudson, J. D. Rosenbloom, and D. H., Cole (London; New York, NY: Routledge, Taylor & Francis Group). doi: 10.4324/9781315162782-19

CrossRef Full Text | Google Scholar

Hess, C., and Ostrom, E. (2007). Understanding Knowledge as a Commons: From Theory to Practice. Boston, MA: MIT Press. doi: 10.7551/mitpress/6980.001.0001

CrossRef Full Text | Google Scholar

Horvat, V. (2019). Real Democracy in Your Town. Public-Civic Partnerships in Action. Luxemburg; Brussels: Green European Foundation; Institut Za Politicku Ekologiju. Available online at: https://gef.eu/wp-content/uploads/2019/02/GEF-Public-Civic-partnerships-print.pdf (accessed May 30, 2022).

Google Scholar

Kip, M., Bieniok, M., Dellenbaugh, M., Müller, A. K., and Schwegmann, M,. (eds). (2015). “Seizing the (every)day: welcome to the urban commons!” in Urban Commons: Moving Beyond State and Market (Gütersloh; Basel: Bauverlag; Birkhäuser), 7–25. doi: 10.1515/9783038214953-001

CrossRef Full Text | Google Scholar

Kratzwald, B. (2015). “Urban commons-dissident practices in emancipatory spaces,” in Urban Commons: Moving Beyond State and Market. ed M. Dellenbaugh, (Gütersloh; Basel: Bauverlag; Birkhäuser). doi: 10.1515/9783038214953-002

CrossRef Full Text | Google Scholar

Lamarca, M. G. (2015). “Insurgent acts of being-in-common and housing in spain: making urban commons?” in Urban Commons, ed A. K. Müller, (De Gruyter), 165–177. doi: 10.1515/9783038214953-011

CrossRef Full Text | Google Scholar

Mattei, U. (2013). Protecting the commons: water, culture, and nature: the commons movement in the italian struggle against neoliberal governance. South Atlant. Q. 112, 366–376. doi: 10.1215/00382876-2020244

CrossRef Full Text | Google Scholar

McFarlane, C., and Desai, R. (2016). “The urban metabolic commons. Rights, civil society and subaltern struggle,” in Releasing the Commons: Rethinking the Futures of the Commons, eds A. Amin, and P. Howell, (London; New York, NY: Routledge), 145–160. doi: 10.4324/9781315673172-9

CrossRef Full Text | Google Scholar

Milburn, K., and Russell, B. (2019). Public-common partnerships: building new circuits of collective ownership. Common Wealth, 27. Available online at: https://www.common-wealth.co.uk/reports/public-common-partnerships-building-new-circuits-of-collective-ownership

Google Scholar

Milburn, K., and Russell, B. T. (2018). What can an institution do? Towards public-common partnerships and a new common-sense. Renewal J. Soc. Democ. 26, 45–55.

Google Scholar

Morrow, O. (2019). Community self-organizing and the urban food commons in Berlin and New York. Sustainability 11, 3641. doi: 10.3390/su11133641

CrossRef Full Text | Google Scholar

Nonini, D. (2017). Theorizing the urban housing commons. Focaal 2017, 23–38. doi: 10.3167/fcl.2017.790103

CrossRef Full Text | Google Scholar

Ostrom, E. (1990). Governing the Commons: The Evolution of Institutions for Collective Action. Cambridge: Cambridge University Press. doi: 10.1017/CBO9780511807763

PubMed Abstract | CrossRef Full Text | Google Scholar

Patti, D. (2017). BIP/ZIP—Promoting Partnerships in Sensitive Urban Areas. Cooperative City. Available online at: https://cooperativecity.org/2017/05/07/bipzip/ (accessed May 30, 2022).

Google Scholar

Pera, M., and Bianchi, I. (2021). Governmentality, the local state, and the commons: an analysis of civic management facilities in Barcelona. Soc. Inclus. 10, 115–125. doi: 10.17645/si.v10i1.4732

CrossRef Full Text | Google Scholar

Popartan, L. A., Ungureanu, C., Velicu, I., Amores, M. J., and Poch, M. (2020). Splitting urban waters: the politicisation of water in Barcelona between populism and anti-populism. Antipode 52, 1413–1433. doi: 10.1111/anti.12630

CrossRef Full Text | Google Scholar

Shareable (2018). Sharing Cities: Activating the Urban Commons. Shareable. Available online at: https://www.shareable.net/sharing-cities/ (accessed May 30, 2022).

Google Scholar

Stavrides, S. (2014). Emerging common spaces as a challenge to the city of crisis. City 18, 546–550. doi: 10.1080/13604813.2014.939476

CrossRef Full Text | Google Scholar

Stavrides, S. (2016). Common Space: The City as Commons. London: Zed Books. doi: 10.5040/9781350219267

CrossRef Full Text | Google Scholar

Thompson, M. (2018). From co-ops to community land trusts: tracing the historical evolution and policy mobilities of collaborative housing movements. Hous. Theory Soc. 37, 82–100. doi: 10.1080/14036096.2018.1517822

CrossRef Full Text | Google Scholar

Thompson, M. (2021). What's so new about new municipalism? Prog. Hum. Geogr. 45, 317–342. doi: 10.1177/0309132520909480

CrossRef Full Text | Google Scholar

Turri, V. M. (2022). Understanding European drinking water services remunicipalisation: a state of literature analysis. Cities 120, 103437. doi: 10.1016/j.cities.2021.103437

CrossRef Full Text | Google Scholar

Volont, L., and Smets, P. (2022). The politics and aesthetics of the urban commons: navigating the gaze of the city, the state, the market. Soc. Inclus. 10, 84–90. doi: 10.17645/si.v10i1.5392

CrossRef Full Text | Google Scholar

Keywords: urban commons, social movements, sustainability, embedded governance, solidarity networks

Citation: Kip M and Scholl C (2022) Editorial: Social movements and sustainable urban commons governance. Front. Sustain. Cities 4:967874. doi: 10.3389/frsc.2022.967874

Received: 13 June 2022; Accepted: 08 August 2022;
Published: 06 October 2022.

Edited and reviewed by: Masaru Yarime, Hong Kong University of Science and Technology, Hong Kong SAR, China

Copyright © 2022 Kip and Scholl. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Markus Kip, markus.kip@uni-jena.de; Christian Scholl, christian.scholl@maastrichtuniversity.nl

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.