We report on the fabrication of ridge waveguides in KTiOPO
nonlinear optical crystals through carbon ion irradiation followed by precise diamond blade dicing. The diced side-walls have low roughness, ...which allows for low propagation loss of ~1dB/cm in fabricated of ridges. The waveguide property investigation has been performed at 1064 nm as well as 532 nm, showing good guidance at both TE and TM polarizations. Based on type II phase matching configuration, efficient second harmonic generation of green light at room temperature has been realized. High conversion efficiencies of ~1.12%W
and ~12.4% have been obtained for frequency doubling under the pump of continuous-wave (CW) and pulsed fundamental waves at 1064 nm, respectively.
Agricultural intensification has stimulated the economy in the Guayas River basin in Ecuador, but also affected several ecosystems. The increased use of pesticides poses a serious threat to the ...freshwater ecosystem, which urgently calls for an improved knowledge about the impact of pesticide practices in this study area. Several studies have shown that models can be appropriate tools to simulate pesticide dynamics in order to obtain this knowledge. This study tested the suitability of the Soil and Water Assessment Tool (SWAT) to simulate the dynamics of two different pesticides in the data scarce Guayas River basin. First, we set up, calibrated and validated the model using the streamflow data. Subsequently, we set up the model for the simulation of the selected pesticides (i.e., pendimethalin and fenpropimorph). While the hydrology was represented soundly by the model considering the data scare conditions, the simulation of the pesticides should be taken with care due to uncertainties behind essential drivers, e.g., application rates. Among the insights obtained from the pesticide simulations are the identification of critical zones for prioritisation, the dominant areas of pesticide sources and the impact of the different land uses. SWAT has been evaluated to be a suitable tool to investigate the impact of pesticide use under data scarcity in the Guayas River basin. The strengths of SWAT are its semi-distributed structure, availability of extensive online documentation, internal pesticide databases and user support while the limitations are high data requirements, time-intensive model development and challenging streamflow calibration. The results can also be helpful to design future water quality monitoring strategies. However, for future studies, we highly recommend extended monitoring of pesticide concentrations and sediment loads. Moreover, to substantially improve the model performance, the availability of better input data is needed such as higher resolution soil maps, more accurate pesticide application rate and actual land management programs. Provided that key suggestions for further improvement are considered, the model is valuable for applications in river ecosystem management of the Guayas River basin.
Multifunctional landscapes are used and shaped by a range of different stakeholders. The high number of diverging values, interests or demands in such landscapes can lead to conflicts that impact ...sustainability goals. In this study, our aim was to include stakeholders' valuations of ecosystem services in multifunctionality assessments and thereby to identify different and possibly contradictory perspectives on landscape multifunctionality. Two European cultural landscapes, the Vereinigte Mulde (Germany) and the Kromme Rijn (The Netherlands), were used as case studies. Spatially explicit indicators of eleven ecosystem services were assessed and weighted according to their survey-based perceived importance for different stakeholder groups. While some significant differences between the groups were apparent, the results also revealed that all stakeholder groups acknowledge the importance of multiple ecosystem services. Stakeholder-specific multifunctionality hotspots occurred mainly in forests or grasslands and largely overlapped between the groups. Our study therefore clearly shows that the diversity of ecosystem services must be preserved in order to preserve the values that cultural landscapes offer to a wide range of people. While local solutions must be sought to resolve local land use conflicts over the use of ecosystem services, we conclude that multifunctionality can be declared a common goal.
Optimal land use allocation with the intention of ecosystem services provision and biodiversity conservation is one of the key challenges in agricultural management. Optimization techniques have been ...especially prevalent for solving land use problems; however, there is no guideline supporting the selection of an appropriate method. To enhance the applicability of optimization techniques for real-world case studies, this study provides an overview of optimization methods used for targeting land use decisions in agricultural areas. We explore their relative abilities for the integration of stakeholders and the identification of ecosystem service trade-offs since these are especially pertinent to land use planners. Finally, we provide recommendations for the use of the different optimization methods. For example, scalarization methods (e.g., reference point methods, tabu search) are particularly useful for a priori or interactive stakeholder integration; whereas Pareto-based approaches (e.g., evolutionary algorithms) are appropriate for trade-off analyses and a posteriori stakeholder involvement.
•We present a review of optimization techniques for land use allocation problems.•The review also considers constraint handling for the different methods.•A structured guideline for selecting appropriate optimization methods is proposed.•This guideline includes the moment of stakeholder integration and trade-off analysis.
•We study methodological gaps of linking global and sub-global research on land management.•Synthesis of sub-global projects requires embedding results in global scenarios.•For identification of ...trade-offs in land management, scenario analysis has limitations.•Exploratory modelling, namely optimization of land use pattern, supports quantifying functional trade-offs.•Combining scenario analysis and exploratory modelling at sub-global and global scale offers new opportunities for land system science.
Research on mitigating land use conflicts is characterized by a variety of projects from the global to various sub-global scales. These projects are aiming at disentangling feedbacks within changing socio-environmental systems to identify strategies for sustainable resource use. Our review shows that any global analysis benefits from systematic synthesis of sub-global research from various scales, while sub-global investigations require embedding in global scenarios. There is an urgent need for improved methods to identify trade-offs at all scales as scenario analysis frequently results in a discrete set of options. We argue that the use of optimization algorithms including Pareto-frontiers combined with scenario analysis can provide efficient options for sustainable land use from global to sub-global scales.
Functional traits offer promising avenues to investigate how community composition and diversity define ecosystem functioning and service delivery. In recent years, many empirical studies on the ...importance of functional traits for ecosystem service provisioning have been undertaken, but a general understanding and synthesis of results is lacking for many ecosystems.
Here we focus on temperate grasslands and present a systematic literature review synthesizing how plant functional traits are interrelated with ecosystem services.
Based on 108 studies, we identified a core set of 40 functional traits and 11 ecosystem services. Several of these traits were only linked to one, while 75% of traits were linked to two or more ecosystem services.
We found that trait‐specific constraints can lead to both synergies and trade‐offs in the supply of multiple ecosystem services. For instance, synergies between biomass production and climate regulation can be achieved by changing morphometric root traits such as increasing root diameter, tissue density or shoot to root ratio. On the other hand, supporting fast‐growing exploitative species characterized by high specific leaf area and nitrogen content typically leads to trade‐offs between fodder quality and water purification.
Synthesis and applications. By applying network analysis, we found five groups of ecosystem services sharing common functional traits. Within and among these groups, we identified trade‐offs among traits as well as among services and found options for synergies. These can be particularly useful in landscape planning, and when management aims focus on maintaining multifunctionality of ecosystems and maximizing corresponding ecosystem service delivery.
By applying network analysis, we found five groups of ecosystem services sharing common functional traits. Within and among these groups, we identified trade‐offs among traits as well as among services and found options for synergies. These can be particularly useful in landscape planning, and when management aims focus on maintaining multifunctionality of ecosystems and maximizing corresponding ecosystem service delivery.
•101 studies were identified that assess multifunctionality using quantitative methods.•On average, studies investigated eight ecosystem functions and services.•Studies covered biophysical and ...integrated socio-ecological assessments.•84% of the studies aggregated multifunctionality into a single metric.•The results elucidate different conceptualizations of multifunctionality.
The capacity of a landscape or ecosystem to provide multiple socio-economic and ecological benefits to society is referred to as multifunctionality. While this topic is receiving growing attention in politics and research, the concept continues to lack implementation partly due to varying conceptualizations and assessments of multifunctionality. To analyze how multifunctionality is conceptualized, characterized and quantified in scientific publications, we reviewed 101 studies that used quantitative methods to assess landscape or ecosystem multifunctionality. On average, 7.9 ± 4.7 ecosystem functions and services were considered, covering Provisioning (19%), Regulating (30%), Cultural (16%) and Supporting (35%) service categories. The studies ranged from micro-scale experiments to global analyses. Different methods were used to aggregate multifunctionality into a single metric (e.g. the number of ecosystem functions and services above a certain threshold, the average value of ecosystem functions and services, the sum of ecosystem functions and services). The interpretation of multifunctionality and the way it is operationalized varied largely among the studies: 42 studies assessed ecological and socio-economic variables in equal shares and often integrated stakeholders (33%). 59 studies focused on ecological variables only and did not include stakeholders except for one study (1.7%). Based on these findings, we discuss the implications of the conceptual and methodological ambiguity within multifunctionality assessments. We present the strengths and limitations of current approaches and provide recommendations for future multifunctionality assessments.
Alternative land management practices such as conservation or no-tillage, contour farming, terraces, and buffer strips are increasingly used to reduce nonpoint source and water pollution resulting ...from agricultural activities. Models are useful tools to investigate effects of such management practice alternatives on the watershed level. However, there is a lack of knowledge about the sensitivity of such models to parameters used to represent these conservation practices. Knowledge about the sensitivity to these parameters would help models better simulate the effects of land management. Hence, this paper presents in the first step a sensitivity analysis for conservation management parameters (specifically tillage depth, mechanical soil mixing efficiency, biological soil mixing efficiency, curve number, Manning's roughness coefficient for overland flow, USLE support practice factor, and filter strip width) in the Soil and Water Assessment Tool (SWAT). With this analysis we aimed to improve model parameterisation and calibration efficiency. In contrast to less sensitive parameters such as tillage depth and mixing efficiency we parameterised sensitive parameters such as curve number values in detail.
In the second step the analysis consisted of varying management practices (conventional tillage, conservation tillage, and no-tillage) for different crops (spring barley, winter barley, and sugar beet) and varying operation dates. Results showed that the model is very sensitive to applied crop rotations and in some cases even to small variations of management practices. But the different settings do not have the same sensitivity. Duration of vegetation period and soil cover over time was most sensitive followed by soil cover characteristics of applied crops.
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