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AbstractSoil legacies play an important role for the creation of priority effects. However, we still poorly understand to what extent the metabolome found in the soil solution of a plant community is conditioned by its species composition and whether soil chemical legacies affect subsequent species during assembly. To test these hypotheses, we collected soil solutions from forb or grass communities and evaluated how the metabolome of these soil solutions affected the growth, biomass allocation and functional traits of a forb (Dianthus deltoides) and a grass species (Festuca rubra). Results showed that the metabolomes found in the soil solutions of forb and grass communities differed in composition and chemical diversity. While soil chemical legacies did not have any effect onF.rubra, root foraging byD.deltoidesdecreased when plants received the soil solution from a grass or a forb community. Structural equation modelling showed that reduced soil exploration byD.deltoidesarose via either a root growth‐dependent pathway (forb metabolome) or a root trait‐dependent pathway (grass metabolome). Reduced root foraging was not connected to a decrease in total N uptake. Our findings reveal that soil chemical legacies can create belowground priority effects by affecting root foraging in later arriving plants.

This paper reviews recent literature concerning a wide range of processes through which climate change could potentially impact global-scale agricultural productivity, and presents projections of changes in relevant meteorological, hydrological and plant physiological quantities from a climate model ensemble to illustrate key areas of uncertainty. Few global-scale assessments have been carried out, and these are limited in their ability to capture the uncertainty in climate projections, and omit potentially important aspects such as extreme events and changes in pests and diseases. There is a lack of clarity on how climate change impacts on drought are best quantified from an agricultural perspective, with different metrics giving very different impressions of future risk. The dependence of some regional agriculture on remote rainfall, snowmelt and glaciers adds to the complexity. Indirect impacts via sea-level rise, storms and diseases have not been quantified. Perhaps most seriously, there is high uncertainty in the extent to which the direct effects of CO 2 rise on plant physiology will interact with climate change in affecting productivity. At present, the aggregate impacts of climate change on global-scale agricultural productivity cannot be reliably quantified.

Accurate modelling of agricultural management impacts on greenhouse gas emissions and the cycling of carbon and nitrogen is complicated due to interactions between various processes and the disturbance caused by field management. In this study, a process-based model, the Soil-Plant-Atmosphere Continuum System (SPACSYS), was used to simulate the effects of different fertilisation regimes on crop yields, the dynamics of soil organic carbon (SOC) and total nitrogen (SN) stocks from 1990 to 2010, and soil CO2 (2007-2010) and N2O (2007-2008) emissions based on a long-term fertilisation experiment with a winter-wheat (Triticum Aestivum L.) and summer-maize (Zea mays L.) intercropping system in Eutric Cambisol (FAO) soil in southern China. Three fertilisation treatments were 1) unfertilised (Control), 2) chemical nitrogen, phosphorus and potassium (NPK), and 3) NPK plus pig manure (NPKM). Statistical analyses indicated that the SPACSYS model can reasonably simulate the yields of wheat and maize, the evolution of SOC and SN stocks and soil CO2 and N2O emissions. The simulations showed that the NPKM treatment had the highest values of crop yields, SOC and SN stocks, and soil CO2 and N2O emissions were the lowest from the Control treatment. Furthermore, the simulated results showed that manure amendment along with chemical fertiliser applications led to both C (1017 ± 470 kg C ha(-1) yr(-1)) and N gains (91.7 ± 15.1 kg N ha(-1) yr(-1)) in the plant-soil system, while the Control treatment caused a slight loss in C and N. In conclusion, the SPACSYS model can accurately simulate the processes of C and N as affected by various fertilisation treatments in the red soil. Furthermore, application of chemical fertilisers plus manure could be a suitable management for ensuring crop yield and sustaining soil fertility in the red soil region, but the ratio of chemical fertilisers to manure should be optimized to reduce C and N losses to the environment.

Oil palm plantations have expanded rapidly in recent decades, and are causing substantial impacts on tropical habitats and biodiversity. However, owing to its long lifespan (25-30 years), oil palm forms a much more varied and structurally-complex habitat than many other crops. This can include abundant understory vegetation and also epiphytes on palm trunks. However, the diversity of this plantation vegetation has been poorly studied, and there has been little consideration of the impacts of common plantation vegetation management practices on plant communities. We conducted a long-term vegetation management experiment that forms part of the Biodiversity and Ecosystem Function in Tropical Agriculture (BEFTA) Programme in Riau, Indonesia. We manipulated herbicide and manual cutting regimes within mature oil palm plantations to create three different understory complexity treatments (Reduced, Normal, and Enhanced vegetation) across replicated sets of plots. Plant communities were surveyed before and after experimental understory vegetation treatments began in three different microhabitats: within the middle of the plantation block (core), on the road edge (edge) and on oil palm trunks (trunk). Part of the sampling was also conducted during a drought event. We recorded 120 plant species, which comprised a mixture of native, non-native, ‘beneficial’, and ‘problem’ species. We found substantial variation in plant communities between edge, core, and trunk microhabitats, indicating high levels of heterogeneity within the plantation. There were significant effects of varying understory treatment within both core and edge microhabitats, but no spillover of impacts into the trunk microhabitat. We also observed substantial impacts of drought on plant communities, with declines in either biomass, percentage cover, or richness seen across core, edge, and trunk microhabitats during low-rainfall periods. Our findings highlight the diversity of plant communities that can be supported within oil palm plantations, and the substantial impacts that management decisions, and also drought, can have on them. Given the role that diverse plant communities can have in supporting species in other groups, this is likely to have a significant impact on the wider plantation biodiversity. We suggest that plantation management strategies give greater consideration to within-plantation understory plant communities and choose more wildlife-friendly options where possible.

Microalgae are considered to be a potential alternative to terrestrial crops for bio-energy production due to their relatively high productivity per unit area of land. In this work we examined the amount of dissolved organic matter exuded by algal cells cultured in photobioreactors, to examine whether a significant fraction of the photoassimilated biomass could potentially be lost from the harvestable biomass. We found that the mean maximum amount of dissolved organic carbon (DOC) released measured 6.4% and 17.3% of the total organic carbon in cultures of Chlorellavulgaris and Dunaliella tertiolecta, respectively. This DOM in turn supported a significant growth of bacterial biomass, representing a further loss of the algal assimilated carbon. The release of these levels of DOC indicates that a significant fraction of the photosynthetically fixed organic matter could be lost into the surrounding water, suggesting that the actual biomass yield per hectare for industrial purposes could be somewhat less than expected. A simple and inexpensive optical technique, based on chromophoric dissolved organic matter (CDOM) measurements, to monitor such losses in commercial PBRs is discussed.

As the effects of global climate change become more apparent, animal species will become increasingly affected by extreme climate and its effect on the environment. There is a pressing need to understand animal physiological and behavioural responses to climatic stressors. We used the reactive scope model as a framework to investigate the influence of drought conditions on vervet monkey ( Chlorocebus pygerythrus ) behaviour, physiological stress and survival across 2.5 years in South Africa. Data were collected on climatic, environmental and behavioural variables and physiological stress via faecal glucocorticoid metabolites (fGCMs). There was a meaningful interaction between water availability and resource abundance: when food availability was high but standing water was unavailable, fGCM concentrations were higher compared to when food was abundant and water was available. Vervet monkeys adapted their behaviour during a drought period by spending a greater proportion of time resting at the expense of feeding, moving and social behaviour. As food availability decreased, vervet mortality increased. Peak mortality occurred when food availability was at its lowest and there was no standing water. A survival analysis revealed that higher fGCM concentrations were associated with an increased probability of mortality. Our results suggest that with continued climate change, the increasing prevalence of drought will negatively affect vervet abundance and distribution in our population. Our study contributes to knowledge of the limits and scope of behavioural and physiological plasticity among vervet monkeys in the face of rapid environmental change.

Ressourcen stellen die Basis für eine erfolgreiche industrielle und technologische Entwicklung dar und somit auch für den Wohlstand heutiger und zukünftiger Generationen. Mit steigender Ressourcennutzung nehmen auch die (physische und sozio-ökonomische) Verfügbarkeit abiotischer und biotischer Ressourcen, die Umweltverschmutzung und die sozialen Auswirkungen durch den Abbau und Nutzung der Ressourcen zu. Um den Erfolg implementierter Strategien (und deren Maßnahmen) hinsichtlich ihres Beitrags zu einem effizienten und nachhaltigen Umgang mit Ressourcen zu bewerten, bedarf es an entsprechenden Bewertungsmethoden. Diese Dissertation stellt vier Methoden bereit um die Bewertung abiotischer und biotischer Ressourcennutzung im Kontext der Nachhaltigkeit auf Produkt- und regionaler Ebene in konsistenter Weise zu bewerten. Die Methode zur Bewertung abiotischer Ressourcen auf Produktebene betrachtet insgesamt 21 relevante Aspekte und stellt Indikatoren zur Quantifizierung bereit. Für die Bewertung der sozio-ökonomischen Einschränkungen von Lieferketten ist eine neuer Ansatz entwickelt, der geopolitische, politische und regulative Aspekte berücksichtigt. Des Weiteren sind Screening-Indikatoren verfügbar, die die gesellschaftliche Akzeptanz der Ressourcennutzung adressieren. Um die Verfügbarkeit terrestrischer biotischer Ressourcen in Produktsystemen zu bewerten, wurde eine umfassende Methode mit 25 Indikatoren erstellt. Des Weiteren wird ein Ansatz vorgestellt, der es ermöglicht eine konsistente Zusammenführung und somit auch Bewertung verschiedener Ressourcentypen zu ermöglichen. Er findet bei der Zusammenführung der entwickelten Methoden zur Bewertung abiotischer und biotischer Ressourcen Anwendung. Da die Nutzung von Ressourcen auch auf Macro-Ebene betrachtet werden muss, wurde eine Methode zur Bewertung abiotischer Ressourcen auf regionaler Ebene entwickelt, die 25 Indikatoren für die Bewertung der Kritikalität (Verfügbarkeit von Ressourcen und Vulnerabilität der Region) und der gesellschaftlichen Akzeptanz zur Verfügung stellt. Verschiedene Fallstudien wurden durchgeführt um die Anwendbarkeit der entwickelten Methoden aufzuzeigen und zu verdeutlichen, warum eine umfassende Bewertung der Ressourcennutzung notwendig ist. Die Fallstudien umfassen u.a. die Bewertung eines Smartphones, Pkw-Herstellung und Biokraftstoffe. Die Anwendbarkeit der Methoden wird zudem erhöht, indem Indikatorwerte für 36 Metalle und 4 fossile Rohstoffe zur Verfügung gestellt werden. Die Bewertung der Nutzung abiotischer und biotischer Ressourcen auf Produkt- und regionaler Ebene wird mit dieser Dissertation signifikant verbessert, indem vier wissenschaftliche Methoden zur robusten und umfassenden Bewertung aller drei Nachhaltigkeitsdimensionen bereitgestellt werden. Resources are the basis for a thriving industrial and technological development and therefore for prosperity of present and future generations. With increasing resource use, challenges with regard to (physical and socio-economic) availability of abiotic and biotic resources and raw materials, pollution of the environment as well as social impacts associated with resource extraction and use arise. To evaluate the success of strategies managing resource use more efficiently and sustainably methodologies are required to comprehensively assess resource use and related impacts. This thesis provides four methodologies to improve the assessment of abiotic and biotic resource use in the context of sustainability on product and regional level. For the method to assess abiotic resources use on product level overall 21 aspects are considered as relevant and indicator for quantification are provided. In order to determine socio-economic supply chain restrictions a new approach is developed, considering geopolitical, political and regulatory aspects affecting resource extraction and use. Further, screening indicators are established to evaluate the societal acceptance of resources with regard to compliance with social and environmental standards. To assess the availability of terrestrial biotic resources in product systems a comprehensive methodology is established, which includes 25 indicators. Further, an approach is proposed to combine assessment methodologies in a consistent way. This approach is applied to the developed method of this thesis leading to a combined methodology. The use of resources also has to be considered on macro-economic. Thus, a methodology is developed providing 25 indicators for the two dimensions criticality, consisting of the sub-dimensions (physical and socio-economic) availability and vulnerability, as well as societal acceptance. Several case studies are carried out to demonstrate the applicability of the developed methods and to confirm the need for a comprehensive assess of resource use on micro and macro level, e.g. case studies for smart phones and cars, for biofuels produced from rapeseed and soybean. The applicability of the methodologies is further enhanced by providing indicator results for 36 metals and four fossil raw materials. The assessment of abiotic and biotic resource use on product and regional level is improved significantly by establishing four scientifically robust yet applicable methodologies, which consider multiple aspects of resource use in all three sustainability dimensions.