Plant sciences for the Anthropocene: What can we learn from research in urban areas?

et al., 2019) . This requires more interdisciplinarity between ecologists and social and cultural scientists. Third, a managerial approach to nature conservation that intends to reach specific targets through planned interventions based on disciplinary scientific evidence from the biological sciences is a too narrow vision for the healing of our relationships with nature in our time of biodiversity loss and overexploitation of the planet. We need to develop new bonds with nature and work toward a new ethic and culture of stewardship for nature (e.g., Krasny & Tidball, 2015). This will require hybrid thinking at the intersections of ecology, social and cultural sciences, planning and design, social, cultural and artistic practice, ethics religion, and civil society.


| INTRODUC TI ON
There is no doubt, we live on a planet dominated by one keystone species-Homo sapiens. The biomass of humans and their livestock make up c. 95% of all mammals and birds on the planet (Bar-On, Phillips, & Milo, 2018). Almost the whole Earth, with the exception of unproductive areas such as deserts and high latitudes, is intensively used by humans resulting in novel and human-dominated biomes-so-called anthromes (Ellis, 2015).
Evidently, the major conceptual challenge for ecology in the 21th century is to understand a natural world in which most ecological processes and patterns are shaped by humans (Ellis, 2015;Kueffer, 2017). Framing the role of humans in nature as an external factor that disturbs from the outside the self-organization of ecosystems has become anachronistic (Krasny & Tidball, 2015;Kueffer, 2015). The Anthropocene is not the culmination of modernity resulting in the ultimate emancipation of humans from nature. Rather it is the end of modernity-the moment when we realize that we have to find a new place in the web of life that, however, is now fundamentally different from pre-modern times.
Although urban areas cover only a few percent of the planet's surface, more than half of the human population is urban, and the vast majority of resources and energy (and with this indirectly land) is used by urban populations (IRP, 2018;WBGU, 2016).
Urban areas are thus paradigmatic places for an ecology of the Anthropocene and for a transformation of society toward a sustainable future. They are pivotal nodes of the global ecosystem, and it is in cities where the majority of humans and influential decision-makers experience nature and other species. Cities can be rich in biodiversity (e.g., Ossola & Niemelä, 2017), and they are hotspots of rapid evolution and the formation of new biodiversity (Schilthuizen, 2019). Not surprisingly, urban ecology is a fast-growing research field (e.g., Alberti, 2008;Forman, 2014;Gaston, 2010;Hall & Balogh, 2019;Krasny & Tidball, 2015;Marzluff et al., 2008;Ossola & Niemelä, 2017;Pickett, Cadenasso, & McGrath, 2013), and nature-based solutions increasingly influence the design of materials, buildings, infrastructures, and cities (e.g., Myers, 2018;Roggema, 2020;WBGU, 2016).
Urban ecology transgresses biology and integrates concepts from systems science, geosciences, social and cultural sciences, and urban planning and design among others. However, there is surprisingly little feedback of such interdisciplinary urban research on the discipline of ecology. Basic ecology largely still aims to investigate the generality of ecological laws in non-anthropogenic nature thereby neglecting interdependences of ecosystems with technological, social, and cultural systems.
Such a resistance to conceptual innovations from 'applied' research that already addresses the emerging phenomena of the Anthropocene is widespread in ecology, and it can, for instance, also be observed at the intersections of ecology with invasion science (Kueffer, 2017;Vaz et al., 2017). While geographers, cultural and social scientists working on the ecology of globalized floras and faunas integrate insights from ecology and evolutionary biology, invasion biology still largely ignores the social and cultural factors that drive and explain invasion dynamics (Kueffer, 2017;Vaz et al., 2017). This Virtual Issue featuring articles published in Plants, People, Planet highlights the great diversity of botanical research in urban settings. In three sections, I will explore how the compiled research contributes to three questions that arguably must be at the core of ecology in the Anthropocene: • Ecological Novelty: How can we understand and manage rapidly changing novel ecological systems that differ fundamentally from those that were formed through long-term ecoevolutionary processes?
• Socioecological Systems: How can we better understand and embrace the role of humans as embedded ecological actors of socioecological systems?
• Biophilia in the Anthropocene: How can we strengthen new bonds between humans and nature in the Anthropocene?
Articles featured in the Virtual Issue are denoted by citations set in bold type, click on the citation to read the paper and the Virtual Issue.

| ECOLOG IC AL NOVELT Y: UNDER S TANDING AND MANAG ING NOVEL ECO LO G IE S
At present, many ecological processes and patterns change at once and threat factors such as climate change, pollution, or biological invasions interact. Addressing threat factors individually will therefore often not work or can worsen the situation-for instance, when an invasive species is being eradicated that controlled another invasive species (e.g., Bergstrom et al., 2009).

| SOCIOECOLOG IC AL SYS TEMS: HUMAN AG EN C Y S HAPE S URBAN B I OD IVER S IT Y
Research in invasion biology and plant health has over the past decades increasingly recognized how important it is to understand human preferences and behaviors to be able to predict and manage future species distributions in the Anthropocene. One example of such re- increase performance (e.g., learning), promote social life, and remove pollution. Urban biodiversity and ecosystem health sustain human well-being, while human stewardship sustains urban biodiversity and ecosystem health (e.g., Krasny & Tidball, 2015).

| B I OPHILIA IN THE ANTHROP O CENE: ENG AG ING WITH URBAN NATURE
The different ways through which people engage with nature are thus central to ecology in the Anthropocene. One of the most important human relationships with nature has for millennia been agriculture.
With a growing interest in urban agriculture and gardening, food production has moved to cities. However, it has remained unclear whether urban agriculture is merely a fad or can indeed substantially contribute to food production.  (Kueffer, 2017;Marchese, 2015;Sanders, 2019). Ultimately, ecology is tightly linked with broader societal issues such as sustainability and environmental justice (e.g., Agyeman & Evans, 2003;Krasny & Tidball, 2015).

| CON CLUS IONS
The papers brought together in this Virtual Issue show how rich plant research in urban areas has become. They point out some of the main pillars of an emerging paradigm of an ecology of the Anthropocene or-in the words of the mission statement of Plants, People, Planet-of how to "put plant focused research firmly in the context of its wider relevance to people, society and the planet". These are three key insights for an ecology of the Anthropocene that I gained from this collection of papers: First, theoretical insights and new analytical and methodological developments from basic research must be integrated with field and applied research and with participatory processes such as citizen science to understand ecological novelty. The separations of basic from applied ecology, laboratory from field research, and science from application might have become anachronistic. Future ecology will be hybrid and bridge between different research cultures and types of experts. Third, a managerial approach to nature conservation that intends to reach specific targets through planned interventions based on disciplinary scientific evidence from the biological sciences is a too narrow vision for the healing of our relationships with nature in our time of biodiversity loss and overexploitation of the planet. We need to develop new bonds with nature and work toward a new ethic and culture of stewardship for nature (e.g., Krasny & Tidball, 2015). This will require hybrid thinking at the intersections of ecology, social and cultural sciences, planning and design, social, cultural and artistic practice, ethics and religion, and civil society.