In contrast to molecular gases, granular gases are characterized by inelastic collisions and require therefore permanent driving to maintain a constant kinetic energy. The kinetic theory of granular ...gases describes how the average velocity of the particles decreases after the driving is shut off. Moreover, it predicts that the rescaled particle velocity distribution will approach a stationary state with overpopulated high-velocity tails as compared to the Maxwell-Boltzmann distribution. While this fundamental theoretical result was reproduced by numerical simulations, an experimental confirmation is still missing. Using a microgravity experiment that allows the spatially homogeneous excitation of spheres via magnetic fields, we confirm the theoretically predicted exponential decay of the tails of the velocity distribution.
Abstract
Crop production is a crucial ecosystem service that requires a combination of natural and anthropogenic contributions to high and stable yields, which is a coproduction process. We analysed ...this coproduction based on nationally aggregated data for 15 major crops for 67 countries and the European Union with data for four time steps (2000, 2006, 2010, 2014). We found strong increases in fertilizer use, net capital stock and manure use intensity for lower-middle-income countries and stagnation or decrease of these for high-income countries. We used a multiple linear regression model predicting yield to distinguish the effect of anthropogenic contributions (crop-specific fertilizer use intensity, net capital stock intensity, manure use intensity) and natural contributions (crop-specific agricultural suitability, including soil characteristics, topography and climate). We found that in particular fertilizer use intensity, manure use intensity and agricultural suitability explained variation in yields to a considerable degree (R
2
= 0.62).
Recognizing culture, and diverse sources of knowledge, can improve assessments
A major challenge today and into the future is to maintain or enhance beneficial contributions of nature to a good ...quality of life for all people. This is among the key motivations of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), a joint global effort by governments, academia, and civil society to assess and promote knowledge of Earth's biodiversity and ecosystems and their contribution to human societies in order to inform policy formulation. One of the more recent key elements of the IPBES conceptual framework (
1
) is the notion of nature's contributions to people (NCP), which builds on the ecosystem service concept popularized by the Millennium Ecosystem Assessment (MA) (
2
). But as we detail below, NCP as defined and put into practice in IPBES differs from earlier work in several important ways. First, the NCP approach recognizes the central and pervasive role that culture plays in defining all links between people and nature. Second, use of NCP elevates, emphasizes, and operationalizes the role of indigenous and local knowledge in understanding nature's contribution to people.
Leibniz said “Naturam cognosci per analogiam”: nature is understood by making analogies. This statement describes a seminal epistemological principle. But one has to be aware of its limitations: ...quantum mechanics for example at some point had to push Bohr’s model of the atom aside to make progress. This article claims that the physics of granular packings has to move beyond the analogy of frictionless spheres, towards local models of contact formation.
We describe and reflect on seven recurring critiques of the concept of ecosystem services and respective counter‐arguments. First, the concept is criticized for being anthropocentric, whereas others ...argue that it goes beyond instrumental values. Second, some argue that the concept promotes an exploitative human–nature relationship, whereas others state that it reconnects society to ecosystems, emphasizing humanity's dependence on nature. Third, concerns exist that the concept may conflict with biodiversity conservation objectives, whereas others emphasize complementarity. Fourth, the concept is questioned because of its supposed focus on economic valuation, whereas others argue that ecosystem services science includes many values. Fifth, the concept is criticized for promoting commodification of nature, whereas others point out that most ecosystem services are not connected to market‐based instruments. Sixth, vagueness of definitions and classifications are stated to be a weakness, whereas others argue that vagueness enhances transdisciplinary collaboration. Seventh, some criticize the normative nature of the concept, implying that all outcomes of ecosystem processes are desirable. The normative nature is indeed typical for the concept, but should not be problematic when acknowledged. By disentangling and contrasting different arguments we hope to contribute to a more structured debate between opponents and proponents of the ecosystem services concept.
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•Increasing number of ecosystem services indicators generated, but impact questioned.•Credibility, salience and legitimacy (CSL) are crucial for informing decision making.•In ...addition, feasibility (F) criteria ensure continued assessment and use of indicators.•Sixteen selection criteria synthesized from practical experience and the literature.•A checklist to develop effective ecosystem service indicators.
Decision makers are increasingly interested in information from ecosystem services (ES) assessments. Scientists have for long recognised the importance of selecting appropriate indicators. Yet, while the amount and variety of indicators developed by scientists seems to increase continuously, the extent to which the indicators truly inform decision makers is often unknown and questioned. In this viewpoint paper, we reflect and provide guidance on how to develop appropriate ES indicators for informing decision making, building on scientific literature and practical experience collected from researchers involved in seven case studies. We synthesized 16 criteria for ES indicator selection and organized them according to the widely used categories of credibility, salience, legitimacy (CSL). We propose to consider additional criteria related to feasibility (F), as CSL criteria alone often seem to produce indicators which are unachievable in practice. Considering CSLF together requires a combination of scientific knowledge, communication skills, policy and governance insights and on-field experience. In conclusion, we present a checklist to evaluate CSLF of your ES indicators. This checklist helps to detect and mitigate critical shortcomings in an early phase of the development process, and aids the development of effective indicators to inform actual policy decisions.
Stabilizing agricultural production is fundamental to food security. At the national level, increasing the effective diversity of cultivated crops has been found to increase temporal production ...stability, i.e., the year-to-year stability of total caloric production of all crops combined. Here, we specifically investigated these effects at the regional level for the European Union and tested the effect of crop diversity in relation to agricultural inputs, soil properties, climate instability, and time on caloric, protein, and fat stability, as we hypothesized that the effect of diversity is context dependent. We further investigated these relationships for specific countries. We found that greater crop diversity was consistently associated with an increase in production stability, particularly in regions with large areas equipped for irrigation and low soil type diversity. For instance, in Spain and Italy, crop diversity showed the strongest positive effect among all predictors, while on the European level, the stabilizing effect of nitrogen use was substantially higher. In Germany, the crop diversity-stability relationship was weak, suggesting that crops react similarly to climatic, economic, and political factors or are grown in the same periods. With this study, we substantiate previous findings that crop diversity stabilizes agricultural caloric production and extend these with regard to protein and fat. The results elucidate the key drivers that enhance production stability for different European countries and regions, which is of key importance for a comparably productive agricultural region like Europe.
•We argue that ecosystem services need to be refocused towards sustainability.•Sustainability aims at justice within ecological limits over the long term.•We explore seven sustainability strategies ...and relate them to ecosystem services.•We emphasize intra-, intergenerational, procedural and interspecies distribution.•Sufficiency, efficiency and persistence are strategies to handle ecological limits.
Ecosystem services and sustainability have become prominent concepts in international policy and research agendas. However, a common conceptual ground between these concepts is currently underdeveloped. In particular, a vision is missing on how to align ecosystem services with overarching sustainability goals. Originally, the ecosystem service concept focused on sustaining human well-being through biodiversity conservation. Nevertheless, studies within the field also consider appropriation beyond carrying capacities, and natural resource management that involves environmentally damaging inputs as ecosystem service provision. This brings the ecosystem service concept into conflict with the core goal of sustainability, i.e. achieving justice within ecological limits over the long term. Here, we link the ecosystem service concept to sustainability outcomes operationalized in terms of justice. Our framing positions sustainability as an overarching goal which can be achieved through seven key strategies: equitable (1) intergenerational and (2) intragenerational distribution, (3) interspecies distribution, (4) fair procedures, recognition and participation, (5) sufficiency, (6) efficiency, and (7) persistence. Applying these strategies has the potential to re-focus the ecosystem service concept towards the normative goal of sustainability. We identify research needs for each strategy and further discuss questions regarding operationalization of the strategies.
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