Challenges in trade-off governance of ecosystem services: Evidence from the Loess Plateau in China

Trade-offs of ecosystem services (ESs) are valuable for decision-making when integrating growth, the achievement of human well-being, and the maintenance of ecosystem functions. Incorporating trade-offs of ESs into land-use decisions has become a major challenge for regional environmental governance, and a deeper understanding of the complex interaction patterns between ESs is a prerequisite for achieving sustainable management of social and ecological systems. This study analyzed the spatial and temporal dynamics and trade-off changes in eight ESs on the Loess Plateau during 2000–2015 using multi-source data and integrated explicit assessment methods, with the following results: 1) Grain production was widely distributed, raw material provision and net primary productivity (NPP) showed northwest to southeast stepwise growth, carbon sequestration and soil conservation were concentrated in high vegetation coverage areas in the southeast, oxygen production was similarly distributed to raw material provision, and recreational and cultural services were centered in urbanized areas. 2) There were significant synergies among raw material provision, oxygen production and NPP, with trade-offs existing mainly between water conservation and NPP, oxygen production, and raw material provision, all of which had consistently increasing correlation coefficients. 3) The number of trade-off service pairs increased, and the intensity of trade-offs strengthened where the pairs between grain production and oxygen production, recreation, and NPP changed from synergy to trade-off. It is recommended that the long-term impacts of urban land expansion, slope afforestation, and climatic factors such as precipitation and temperature on water conservation and other services be assessed in an integrated manner in ecosystem management and that appropriate, scientific response strategies be developed. This study provides theoretical and decision-making references for regulating the complex trade-offs of ESs in ecologically fragile regions worldwide

Simulation of the Key Ecosystem Services Changes in China’s Loess Plateau under Various Shared Socioeconomic Pathways Scenarios

Understanding future ecosystem services (ESs) is crucial for optimizing ecosystems and devising sustainable development strategies. This study used China’s Loess Plateau as a case study to investigate key ESs from 2020 to 2100. It accomplished this by coupling the Patch-Generating Land Use Simulation and the Integrated Valuation of Ecosystem Services and Trade-offs models under 3 shared socioeconomic pathways (SSP119, SSP245, and SSP585 scenarios). The results showed the following: (a) The generated land use exhibits strong performance, with an overall accuracy of 0.92. Among projected future land-use and land-cover changes, forests are expected to increase by 31.3% and 29.1% on the Loess Plateau under the SSP119 and SSP245 scenarios, respectively. (b) Between 2020 and 2100, soil conservation (SC) is projected to increase by 127.1% and 8.34%, carbon storage (CS) is projected to increase by 39.8% and 8.1%, while water yield (WY) is expected to decrease by 0.5% and 39.4% under the SSP119 and SSP245 scenarios, respectively. (c) The SSP245 scenario demonstrates the most substantial growth synergy area across the entire Loess Plateau. In this scenario, synergy areas related to SC&CS, CS&WY, and SC&WY are projected to increase by 39.1% and 20.6% while decreasing by 21.1%. These findings identified the most suitable scenario for enhancing ESs and optimizing trade-off relationships throughout the Loess Plateau. The research framework presented here can be applied to other vulnerable ecological regions worldwide

Decoupling Land Use Intensity and Ecological Risk: Insights from Heilongjiang Province of the Chinese Mollisol Region

Global land use changes and human activities have escalated regional ecological risk, yet studies on the decoupling relationship between land use intensity (LUI) and ecological risk (ERI) remain limited. This study explored the decoupling relationship between LUI and ERI from 1990 to 2020 in Heilongjiang Province and analyzed the primary driving factors of the ERI using a decoupling model and an optimal parameter geographic detector (OPGD). The results indicate significant land use changes, particularly the conversion of woodland and grassland into farmland, resulting in a net increase of 18,055.96 km2 in farmland area. The LUI in Heilongjiang Province increased by 6.43 between 1990 and 2020. The ERI exhibited a significant upward trend from 1990 to 2020, with the average index rising from 0.097 in 1990 to 0.132 in 2020. The proportion of moderate- and higher-ecological-risk areas increased by 10.6%. A decoupling analysis indicated that most regions experienced expansionary negative decoupling between the LUI and ERI, in which the ERI escalated at a faster rate than the LUI. Furthermore, the DEM and NDVI demonstrated the highest explanatory power for the ERI, both exceeding 30%, and the synergistic interaction between the DEM and NDVI amplified spatial heterogeneity by altering microclimatic conditions. This study provides crucial insights for land management and ecological conservation policies in Heilongjiang

High-Performance NiO/TiO2/ZnO Photovoltaic UV Detector

The ultraviolet (UV) photodetector has found many applications, ranging from optical communication to environmental monitoring. There has been much research interest in the development of metal oxide-based UV photodetectors. In this work, a nano-interlayer was introduced in a metal oxide-based heterojunction UV photodetector to enhance the rectification characteristics and therefore the device performance. The device, which consists of nickel oxide (NiO) and zinc oxide (ZnO) sandwiching an ultrathin dielectric layer of titanium dioxide (TiO2), was prepared by radio frequency magnetron sputtering (RFMS). After annealing, the NiO/TiO2/ZnO UV photodetector exhibited a rectification ratio of 104 under UV irradiation of 365 nm at zero bias. The device also demonstrated a high responsivity of 291 A/W and a detectivity of 6.9 × 1011 Jones at +2 V bias. Such a device structure provides a promising future for metal oxide-based heterojunction UV photodetectors in a wide range of applications.</jats:p

Medical versus surgical abortion methods for pregnancy in China: A cost-minimization analysis

Background: Both medical and surgical abortions are popular in developing countries. However, the monetary costs of these two methods have not been compared. Methods: 430 women seeking abortions were recruited in 2008. Either a medical or surgical method was used for the abortion. We adopted the perspective of a third-party payer. Cost-minimization analysis was used based on all charges for the overall procedures in an out-patient clinic in Guangzhou, China. Results: 219 subjects (51%) chose a medical method (mifepristone and misoprostol), whereas 211 subjects (49%) chose a surgical method. The efficacy in the surgical group was significantly higher than in the medical group (100 vs. 90%, p < 0.001). Surgical abortion incurred much more costs than medical abortion on average after initial treatment. When the subsequent costs were accumulated within the 2-week follow-up, the mean total cost in the medical group increased significantly due to failure of abortion and persistent bleeding. Patients undergoing medical abortion eventually incurred equivalent expenses compared to patients undergoing surgical abortion (p = 0.42). Conclusions: There was no difference in the mean final costs between the two abortion methods. Complications of persistent bleeding and failure to abort (requiring surgical intervention) in the medical treatment group increased the final mean total cost substantially. © 2011 S. Karger AG, Basel.link_to_OA_fulltex

Transparent dual-band ultraviolet photodetector based on graphene/p-GaN/AlGaN heterojunction

Versatile applications have driven a desire for dual-band detection that enables seeing objects in multiple wavebands through a single photodetector. In this paper, a concept of using graphene/p-GaN Schottky heterojunction on top of a regular AlGaN-based p-i-n mesa photodiode is reported for achieving solar-/visible-blind dual-band (275 nm and 365 nm) ultraviolet photodetector with high performance. The highly transparent graphene in the front side and the polished sapphire substrate at the back side allows both top illumination and back illumination for the dual band detection. A system limit dark current of 1×10−9 A/cm2 at a negative bias voltage up to -10 V has been achieved, while the maximum detectivity obtained from the detection wavebands of interests at 275 nm and 365 nm are ∼ 9.0 ×1012 cm·Hz1/2/W at -7.5 V and ∼8.0 × 1011 cm·Hz1/2/W at +10 V, respectively. Interestingly, this new type of photodetector is dual-functional, capable of working as either photodiode or photoconductor, when switched by simply adjusting the regimes of bias voltage applied on the devices. By selecting proper bias, the device operation mode would switch between a high-speed photodiode and a high-gain photoconductor. The device exhibits a minimum rise time of ∼210 µs when working as a photodiode and a maximum responsivity of 300 A/W at 6 μW/cm2 when working as a photoconductor. This dual band and multi-functional design would greatly extend the utility of detectors based on nitrides.</jats:p