Human impacts on soil

The hidden threat: Environmental toxins and their effects on gut microbiota

The human gut microbiota (GM), which consists of a complex and diverse ecosystem of bacteria, plays a vital role in overall wellness. However, the delicate balance of this intricate system is being compromised by the widespread presence of environmental toxins. The intricate connection between contaminants in the environment and human well-being has garnered significant attention in recent times. Although many environmental pollutants and their toxicity have been identified and studied in laboratory settings and animal models, there is insufficient data concerning their relevance to human physiology. Consequently, research on the toxicity of environmental toxins in GM has gained prominence in recent years. Various factors, such as air pollution, chemicals, heavy metals, and pesticides, have a detrimental impact on the composition and functioning of the GM. This comprehensive review aims to comprehend the toxic effects of numerous environmental pollutants, including antibiotics, endocrine-disrupting chemicals, heavy metals, and pesticides, on GM by examining recent research findings. The current analysis concludes that different types of environmental toxins can lead to GM dysbiosis and have various potential adverse effects on the well-being of animals. We investigate the alterations to the GM composition induced by contaminants and their impact on overall well-being, providing a fresh perspective on research related to pollutant exposure.

Connectivity approach in urban protected area management based on soil and vegetation chemical status

The quality and vitality of cities largely depend on the design, management, and maintenance of green areas, including urban protected areas (UPAs), since they provide multiple benefits for the city. Due to urbanization and higher anthropogenic pressure, green areas are decreasing which directly affects natural habitats and biodiversity. This study aims to assess soil and vegetation chemical status in UPAs in the city of Belgrade, Serbia, and to understand how their distance from pollution hotspots affects soil and vegetation quality. Additionally, this paper considers the inclusion of soil and vegetation conditions in the urban protected areas management as a basis for introducing a connectivity approach to expand green infrastructure throughout the city. Chemical properties, the content of nutrients (C, N, P, and K), and microelements (Cr, Co, Ni, Cu, Zn, As, Cd, Sn, Pb, Zr, U, and Th) in soil and conifer needles were analyzed. Results showed that the distance of pollution hotspots does not affect nutrient and microelements concentrations in soil, i.e., they do not vary significantly between sites and do not exceed remediation intervention values. However, the microelements status of vegetation is affected since Cr, Cu, Zn, Sn, and Pb are higher in needles from trees from the city center. The state of soil and plant composition supports the establishment of a network of green corridors and should become a part of management strategies, thus helping biodiversity protection, climate change mitigation, and human well-being in the cities.

Do adaptive policy adjustments deliver ecosystem-agriculture-economy co-benefits in land degradation neutrality efforts? Evidence from southeast coast of China

Ecosystem restoration projects (ERPs) facilitate land degradation neutrality (LDN). However, the response dynamics and interactions of sectors within ecosystem-agriculture-economy nexus (EAEN) have not been sufficiently explored, which constrains the coordinated efficacy of LDN efforts. To bridge the knowledge gaps, the present study selected a land restoration hotspot in southeastern China as a case to investigate the simultaneous responses of the EAEN sectors to ERPs from a novel social-ecological system (SES)-based LDN perspective. Various biophysical models and Manne-Kendall trend test as well as multi-source spatially explicit data and socioeconomic statistics were applied to quantify the co-evolution of natural and socioeconomic indicators. ERPs converting cropland to woodland and grassland promoted vegetation restoration, reduced soil erosion, and enhanced carbon sequestration. However, cropland loss initially resulted in a decline in grain productivity. Policy adjustments and improvements in ecosystem restoration efforts and agricultural production conditions improved food security and increased agricultural production capacity. Effective policymaking and favorable resident engagement accelerated the transformation from a grain-production-based agriculture to diversified industries and, by extension, economic output, income, and population. The success of socioeconomic development under the SES framework for LDN demonstrated that this strategy could achieve the desired environmental, agricultural, and economic targets. EAEN under the SES conceptual framework provides an inclusive, comprehensive LDN perspective and improves ERP efficacy. The findings of the present work might be applicable to other land restoration areas challenged by the complex interactions among multidimensional factors. Comparably successful implementation of these ERPs could be realized if individual environmental and socioeconomic conditions are thoroughly considered during the formulation of coordinated development policies.

Soil erosion in diverse agroecological regions of India: a comprehensive review of USLE-based modelling

Soil erosion caused by water refers to the removal of topsoil by rainfall and runoff. Proper selection of an assessment method is crucial for quantifying the spatial variance of soil erosion. The Universal Soil Loss Equation (USLE) and its revised version (RUSLE) are widely used for modelling soil erosion. This study aimed to evaluate the effectiveness of the USLE-based soil erosion modelling in different agroecological regions of India, identify potential issues, and provide suggestions for future applications. The review revealed that little attention has been given to estimate soil erosion in high-priority land degradation regions of India. Additionally, many studies failed to thoroughly verify the authenticity of stated soil loss rates in their research regions either by overestimating or underestimating at least one of the five soil loss parameters. Furthermore, flaws in the application of methods to calculate these parameters leading to erroneous values were identified and suggestions for improvement were made. The USLE-based soil erosion modelling is an effective tool for quantifying soil erosion risk, but researchers should put emphasis on thoroughly verifying the methodologies adopted, unit conversions, and data availability for the estimation of soil loss parameters to improve the accuracy of their final results. This paper provides valuable insights to assist researchers in implementing USLE-based erosion models in diverse agroecological regions in India and elsewhere. However, for effective soil conservation and sustainable agriculture, further research is necessary to develop efficient techniques for using USLE-based soil erosion modelling to achieve a comprehensive understanding of erosion risk across different agroecological regions.

Application of the Adaptive Cycle and Panarchy in La Marjaleria Social-Ecological System: Reflections for Operability

The adaptive cycle and panarchy are recognised tools for resilience assessment prior to establishing new management approaches aligned with Anthropocene needs. This study used the adaptive cycle and panarchy to assess the dynamics of the social-ecological system (SES) of La Marjaleria, Spain, which experienced increasing human pressure and environmental degradation in recent decades, and developed the ‘adaptive curve’ as a novel graphical representation of system change in the presentation of the results. Based on a literature review of historical changes in La Marjaleria, a SES analysis was performed using the adaptive cycle and panarchy, following the Resilience Alliance’s Practitioners Guide. The assessment offered new insights into the social and ecological dynamics of La Marjaleria through identification of causes and consequences from a complex systems perspective. Previous land-use management in the area has generated tensions between different stakeholders and reduced environmental resilience. The systems thinking approach highlighted the complexity of change processes, offering the possibility of new routes for dialogue and understanding. The ‘adaptive curve’ developed as a method of illustrating interactions across scales in this study could be useful for synthesising the results of a panarchy analysis and supporting their interpretation, offering relevant departure points for future planning and decision-making.

Forest Resources Management and Sustainability: The Specific Case of European Union Countries

Forest land provides several environmental services and goods with significant implications for different socioeconomic and environmental dimensions. Forestry and its management are determinant activities for sustainable development, specifically in the current context of urgent mitigation of climate change. In this perspective, one objective of this research was to survey the main insights from the literature about the forest and management dimensions put together, highlighting the contributions of these activities to mitigate climate change. Another objective was to explore indicators related to forest management (land, employment, output, and net emissions) in order to obtain a forest sustainability index through factor analysis. As main insights from this study, we can quote that the literature survey pinpoints the most relevant factors framing forest management: soil characteristics, ecology, ecosystems, biodiversity, deforestation, climate change, socioeconomic frameworks, local knowledge, public policies, institutional context, and new technologies. Forest indicators reveal a strong relationship between forest land, employment and output, and a weaker relation with net emissions. We concluded that there is a need for stakeholders to explore and improve the interlinkage with climate change impact, specifically with regard to improving the relationships of forestry greenhouse gas emissions impacts with forest size and output.

Loess Plateau: from degradation to restoration

United Nations established 2021-2030 as the decade for ecosystem restoration and "prevent, halt and reverse the degradation of ecosystems worldwide". Ecosystem and land degradation are a global phenomenon. As a consequence of land degradation, in the late 1990s, the "Grain for Green Program" (GFGP) was established in Loess Plateau (China). It converted slope farmlands to forest or grassland over the, resulting in a visible "greening" trend. Other effects of GFGP on soil properties, land production, hydrological conditions, ecosystem services, and policy implications are the topics of this Special Issue. This Special Issue includes 17 contributions that cover recent research carried out in Loess Plateau in the mentioned topics at different spatial and temporal scales. The collection of papers presented in this Special Issue discusses critical issues in vegetation restoration and sustainable land management in the region. This Special Issue will contribute to United Nations strategy for ecosystems restoration.

Unraveling Latent Aspects of Urban Expansion: Desertification Risk Reveals More

Urban expansion results in socioeconomic transformations with relevant impacts for peri-urban soils, leading to environmental concerns about land degradation and increased desertification risk in ecologically fragile districts. Spatial planning can help achieve sustainable land-use patterns and identify alternative locations for settlements and infrastructure. However, it is sometimes unable to comprehend and manage complex processes in metropolitan developments, fueling unregulated and mainly dispersed urban expansion on land with less stringent building constraints. Using the Mediterranean cities of Barcelona and Rome as examples of intense urbanization and ecological fragility, the present study investigated whether land use planning in these cities is (directly or indirectly) oriented towards conservation of soil quality and mitigation of desertification risk. Empirical results obtained using composite, geo-referenced indices of soil quality (SQI) and sensitivity to land desertification (SDI), integrated with high-resolution land zoning maps, indicated that land devoted to natural and semi-natural uses has lower soil quality in both contexts. The highest values of SDI, indicating high sensitivity to desertification, were observed in fringe areas with medium-high population density and settlement expansion. These findings reveal processes of land take involving buildable soils, sometimes of high quality, and surrounding landscapes in both cities. Overall, the results in this study can help inform land use planers and policymakers for conservation of high-quality soils, especially under weak (or partial) regulatory constraints.

GIS-Based Site Selection for Check Dams in Watersheds: Considering Geomorphometric and Topo-Hydrological Factors

Check dams are widely used watershed management measures for reducing flood peak discharge and sediment transport, and increasing lag time and groundwater recharge throughout the world. However, identifying the best suitable sites for check dams within the stream networks of various watersheds remains challenging. This study aimed to develop an open-source software with user-friendly interface for screening the stream network possibilities and identifying and guiding the selection of suitable sites for check dams within watersheds. In this developed site selection software (SSS), multi-criteria decision analysis (MCDA) was integrated into geographic information systems (GIS), which allowed for numerous spatial data of the multiple criteria to be relatively simply and visually processed. Different geomorphometric and topo-hydrological factors were considered and accounted for to enhance the SSS identification of the best locations for check dams. The factors included topographic wetness index (TWI), terrain ruggedness index (TRI), topographic position index (TPI), sediment transport index (STI), stream power index (SPI), slope, drainage density (DD), and stream order (SO). The site identification performance of the SSS was assessed using the receiver operating characteristic (ROC) curve method, with results for the case study example of the Poldokhtar watershed in Iran showing excellent performance and identifying 327 potential sites for efficient check dam construction in this watershed. The SSS tool is not site-specific but is rather general, adaptive, and comprehensive, such that it can and should be further applied and tested across different watersheds and parts of the world.

Soil erosion modelling: The new challenges as the result of policy developments in Europe

New challenges and policy developments after 2015 (among others, the Common Agricultural Policy (CAP), Sustainable Development Goals (SDGs)) are opportunities for soil scientists and soil erosion modellers to respond with more accurate assessments and solutions as to how to reduce soil erosion and furthermore, how to reach Zero Net Land Degradation targets by 2030. This special issue includes papers concerning the use of fallout for estimating soil erosion, new wind erosion modelling techniques, the importance of extreme events (forest fires, intense rainfall) in accelerating soil erosion, management practices to reduce soil erosion in vineyards, the impact of wildfires in erosion, updated methods for estimating soil erodibility, comparisons between sediment distribution models, the application of the WaTEM/SEDEM model in Europe, a review of the G2 model and a proposal for a land degradation modelling approach. New data produced from field surveys such as LUCAS topsoil and the increasing availability of remote sensing data may facilitate the work of erosion modellers. Finally, better integration with other soil related disciplines (soil carbon, biodiversity, compaction and contamination) and Earth Systems modelling is the way forward for a new generation of erosion process models.