Agricultural intensification with modern plant breeding focuses on few high-yielding crops and varieties. The loss of traditional crop species and variety diversity contributes to the current decline of provisioning, regulating, and cultural ecosystem services, as reported in the Millennium Ecosystem Assessment. Access to local and adapted varieties is pivotal for resilient agroecosystems, in particular under current global change. We reviewed the scientific literature to understand the role of different crop varieties for ecosystem services, comparing the performance and perception of traditional landraces versus modern varieties and ask the following questions: 1. Do landraces and modern varieties differ in terms of provisioning and regulating ecosystem services? 2. When and why do farmers prefer cultural ecosystem services of landraces over high-yielding varieties? Based on 41 publications, our results document that modern varieties are preferred over landraces because of their typically higher provisioning services such as crop yield. However, landraces often guarantee higher provisioning services under non-optimal farming conditions. Landraces can show high resilience under harsh environmental conditions and are a trusted source achieving stable crop yield (e.g., under droughts stress). Regulating services such as resistance against pests and diseases appear to often become lost during breeding for high-yielding, modern varieties. Furthermore, small-scale farmers typically prefer local landraces due to regional cultural features such as family traditions and cooking characteristics for special dishes. In conclusion, both landraces and modern varieties have merit depending on the farmers' priorities and the social-ecological context. In any case, maintaining and restoring the huge diversity of landrace varieties is necessary for sustaining current and future needs.

Relational values are values of desirable relationships between people and nature and among people (through nature). We report on the approach to capture relational values of nature's contributions to people in the regional assessment for Europe and Central Asia of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). We present a framework considering indicators along four relational value dimensions about people's relationships with nature: security and sovereignty; health; equity and justice; and heritage, social identity and stewardship. The framework has been operationalized for three nature's contributions to people (NCP): regulation of freshwater quality and quantity, food and feed, and physical and psychological experiences derived from nature. We identify ways to empirically assess relational values of nature's contributions to people at regional and continental scales with social-ecological indicators and proxies, ranging from biophysical indicators to indicators that intersect socioeconomic with biophysical data. We conclude that many of the identified indicators can be considered as useful proxies of relational values in a quantitative way. The analysis shows that relational values are essential to consider at the science-policy interface as they are an important set of values that people hold about nature and that go beyond instrumental relations.

Commons approaches in the seed sector are multi-faceted: They span from traditional seed systems, i.e. seed sharing networks, to recent anti-enclosure movements that resist intellectual property rights on varieties, like organic breeding initiatives. This paper derives a conceptualization of 'Seed Commons' at the local and regional level, based on a comprehensive transdisciplinary research process that integrates diverse types of knowledge, both from practitioners (German and Philippine seed initiatives, companies and NGOs), and the scientific community. As a result, we identify four core criteria that characterize diverse Seed Commons arrangements at local and regional scales: (1) collective responsibility, (2) protection from private enclosure, (3) collective, polycentric management, and (4) sharing of formal and practical knowledge. Discussing these Seed Commons criteria in the context of different Commons approaches, we find that Seed Commons transcend the distinction between traditional (natural resource) Commons and New Commons approaches, by integrating biophysical, informational and cultural elements in their collective governance. Reaching beyond resource characteristics, the Seed Commons criteria reflect practices of Commoning, which aim to fulfill social functions such as farmer empowerment and food sovereignty.

Transdisciplinary research is intriguing and challenging. Early-career researchers in particular, who lack experience and are still working on their disciplinary standing, struggle with difficulties and uncertainties. We offer insights into the challenges faced and solutions found by seven transdisciplinary junior research groups.While transdisciplinarity offers a way to tackle complex social-ecological challenges, transdisciplinary research is a challenging task in itself. The integration of research methods across academic disciplines, the collaboration between researchers and practitioners, and the need to balance societal and disciplinary academic impacts pose many difficulties even to experienced applied scientists and even more so to early-career researchers. Young scholars face particular problems, given their lack of longer-term experience and their still fragile position within academia. Drawing on existing literature, an early-career researcher workshop, and our own experience as junior research group leaders, we discuss specific challenges and respective solution strategies of transdisciplinary research within the context of sustainability.

We argue that economicsas the scientific method of analysing trade-offs-can be helpful (and may even be indispensable) for assessing the tradeoffs between intergenerational and intragenerational justice. Economic analysis can delineate the "opportunity set" of politics with respect to the two normative objectives of interand intragenerational justice, i.e. it can describe which outcomes are feasible in achieving the two objectives in a given context, and which are not. It can distinguish efficient from inefficient uses of instruments of justice. It can identify the "opportunity cost" of attaining one justice to a higher degree, in terms of less achievement of the other. We find that, under very general conditions, (1) efficiency in the use of instruments of justice implies that there is rivalry between the two justices and the opportunity cost of either justice is positive; (2) negative opportunity costs of achieving one justice exist if there is facilitation between the two justices, which can only happen if instruments of justice are used inefficiently; (3) opportunity costs of achieving one justice are zero if the two justices are independent of each other, which is the case in the interior of the opportunity set where instruments of justice are used inefficiently.