Current agricultural practices in Europe are increasingly aggravating societal and environmental safety concerns. This creates social and regulatory pressures on farmers, which can lead to declining material and social status of farmers, farmer discontent, and anti -regulation protests. These tensions are rooted in conflicting value systems for agricultural development, which can range from productivist pathways (i.e. valuing production above all else) to increasing multifunctionality pathways (i.e. valuing agriculture for its contribution to multiple economic, environmental and societal needs). It is largely unknown to what degree individual farms and agricultural landscapes are transitioning towards increasing productivism or multifunctionality in practice. Here, we mapped landscape changes and interviewed farmers (n = 274) to examine the diversity of agricultural development pathways in 17 study sites across Europe over the last 20 years (2000 -2020). We also assessed the associations between the development pathways and farmers ' perceptions of socio-economic outcomes, namely job satisfaction, societal valuation, and economic performance. Farm -level development was largely aligned with productivist pathways, while landscape -level changes aligned more closely with an increasing multifunctionality pathway. Farmers on pathways of increasing multifunctionality did not perceive improved outcomes on livelihood indicators as compared to productivist farmers. Furthermore, farms on increasing multifunctionality pathways were concentrated in sites with very high management intensities that face strong pressure from environmental regulations, as well as low -intensity, mountainous sites, where opportunities for intensification are limited. These results suggest that current pathways that increase multifunctionality arise mostly by necessity. Successful agricultural transformation will therefore require policy to create enabling environments that provide socioeconomic benefits for farmers to increase multifunctionality, and a civil society and market conditions that value sustainable agriculture.

Farming in Europe has been the scene of several important socio-economic and environmental developments and crises throughout the last century. Therefore, an understanding of the historical driving forces of farm change helps identifying potentials for navigating future pathways of agricultural development. However, long-term driving forces have so far been studied, e.g. in anecdotal local case studies or in systematic literature reviews, which often lack context dependency. In this study, we bridged local and continental scales by conducting 123 oral history interviews (OHIs) with elderly farmers across 13 study sites in 10 European countries. We applied a driving forces framework to systematically analyse the OHIs. We find that the most prevalent driving forces were the introduction of new technologies, developments in agricultural markets that pushed farmers for farm size enlargement and technological optimisation, agricultural policies, but also cultural aspects such as cooperation and intergenerational arrangements. However, we find considerable heterogeneity in the specific influence of individual driving forces across the study sites, implying that generic assumptions about the dynamics and impacts of European agricultural change drivers hold limited explanatory power on the local scale. Our results suggest that site-specific factors and their historical development will need to be considered when addressing the future of agriculture in Europe in a scientific or policy context.

Sustainability challenges in socio-environmental systems (SES) are inherently multiscale, with global-level changes emerging from socio-environmental processes that operate across different spatial, temporal, and organisational scales. Models of SES therefore need to incorporate multiple scales, which requires sound methodologies for transferring information between scales. Due to the increasing global connectivity of SES, upscaling – increasing the extent or decreasing the resolution of a modelling study – is becoming progressively more important. However, upscaling in SES models has received less attention than in other fields (e.g., ecology or hydrology) and therefore remains a pressing challenge. To advance the understanding of upscaling in SES, we take three steps. First, we review existing upscaling approaches in SES as well as other disciplines. Second, we identify four main challenges that are particularly relevant to upscaling in SES: 1) heterogeneity, 2) interactions, 3) learning and adaptation, and 4) emergent phenomena. Third, we present an approach that facilitates the transfer of existing upscaling methods to SES, using two good practice examples from ecology. To describe and compare these methods, we propose a scheme of five general upscaling strategies. This scheme builds upon and unifies existing schemes and provides a standardised way to classify and represent existing as well as new upscaling methods. We demonstrate how the scheme can help to transparently present upscaling methods and uncover scaling assumptions, as well as to identify limits for the transfer of upscaling methods. We finish by pointing out research avenues on upscaling in SES to address the identified upscaling challenges.

The propagation of full-depth lock-exchange bottom gravity currents past a submerged array of circular cylinders is investigated using laboratory experiments and large eddy simulations. Firstly, to investigate the front velocity of gravity currents across the whole range of array density $\unicode[STIX]{x1D719}$ (i.e. the volume fraction of solids), the array is densified from a flat bed ( $\unicode[STIX]{x1D719}=0$ ) towards a solid slab ( $\unicode[STIX]{x1D719}=1$ ) under a particular submergence ratio $H/h$ , where $H$ is the flow depth and $h$ is the array height. The time-averaged front velocity in the slumping phase of the gravity current is found to first decrease and then increase with increasing $\unicode[STIX]{x1D719}$ . Next, a new geometrical framework consisting of a streamwise array density $\unicode[STIX]{x1D707}_{x}=d/s_{x}$ and a spanwise array density $\unicode[STIX]{x1D707}_{y}=d/s_{y}$ is proposed to account for organized but non-equidistant arrays ( $\unicode[STIX]{x1D707}_{x}\neq \unicode[STIX]{x1D707}_{y}$ ), where $s_{x}$ and $s_{y}$ are the streamwise and spanwise cylinder spacings, respectively, and $d$ is the cylinder diameter. It is argued that this two-dimensional parameter space can provide a more quantitative and unambiguous description of the current–array interaction compared with the array density given by $\unicode[STIX]{x1D719}=(\unicode[STIX]{x03C0}/4)\unicode[STIX]{x1D707}_{x}\unicode[STIX]{x1D707}_{y}$ . Both in-line and staggered arrays are investigated. Four dynamically different flow regimes are identified: (i) through-flow propagating in the array interior subject to individual cylinder wakes ( $\unicode[STIX]{x1D707}_{x}$ : small for in-line array and arbitrary for staggered array; $\unicode[STIX]{x1D707}_{y}$ : small); (ii) over-flow propagating on the top of the array subject to vertical convective instability ( $\unicode[STIX]{x1D707}_{x}$ : large; $\unicode[STIX]{x1D707}_{y}$ : large); (iii) plunging-flow climbing sparse close-to-impermeable rows of cylinders with minor streamwise intrusion ( $\unicode[STIX]{x1D707}_{x}$ : small; $\unicode[STIX]{x1D707}_{y}$ : large); and (iv) skimming-flow channelized by an in-line array into several subcurrents with strong wake sheltering ( $\unicode[STIX]{x1D707}_{x}$ : large; $\unicode[STIX]{x1D707}_{y}$ : small). The most remarkable difference between in-line and staggered arrays is the non-existence of skimming-flow in the latter due to the flow interruption by the offset rows. Our analysis reveals that as $\unicode[STIX]{x1D719}$ increases, the change of flow regime from through-flow towards over- or skimming-flow is responsible for increasing the gravity current front velocity.

The Front Condition for Gravity Currents Propagating over Rough Boundaries Roger Nokes 1 , Claudia Cenedese 2 , Megan Ball 1 and Tim Williams 1 . Department of Civil and Natural Resources Engineering, University of Canterbury roger.nokes@canterbury.ac.nz Woods Hole Oceanographic Institution Abstract Gravity currents – fluid flows generated by horizontal density gradients – are ubiquitous in the environment. An area of increasing interest in this general field is the interaction of gravity currents with boundary roughness, where that roughness may be of the scale of the current itself. This paper describes an experimental study investigating the impact of varying boundary roughness densities on the flow structure and propagation speed of a gravity current. The gravity currents exhibit two primary flow regimes, a “flow through” regime where the current is enmeshed in the roughness elements, and an “overriding” regime where the current is forced to flow almost entirely over the roughness elements. As the flow transitions from the first to the second of these regimes through increasing roughness density there is the possibility that the Froude number of the current will actually increase. Introduction Gravity currents are a well-known, and well-researched, environmental fluid flow caused by horizontal density gradients. Simpson (1997) provides an excellent overview of the dynamics of these currents and their appearance in natural settings. However much of the work to date has focused on currents propagating along smooth boundaries. Boundaries that incorporate roughness elements that are of a significant height compared to the current itself, while geophysically important, have received little attention. Nepf and her collaborators have made significant contributions to understanding fluid flow through canopies of various types. Zhang and Nepf (2011) explore the dynamics of a surface gravity current propagating through a suspended canopy comprising an array of circular cylinders using an experimental PIV system. The focus is to understand the exchange flow through the canopy. Nepf (2012) provides an overview of research in the area of flow through aquatic canopies. This paper describes part of a larger investigation into the dynamics of currents encountering large roughness fields, focusing on the impact of the roughness on the flow structure and current propagation speed. Methodology Flume Experiments were conducted in 6.2m long, 0.5m high and 0.25m wide flat-bottomed flume as illustrated in figure 1. A conventional lock exchange configuration was VIII th Int. Symp. On Stratified Flows, San Diego, USA, Aug. 29 – Sept. 1, 2016