Trend Of Erosion Research Articles

Tracking Changing Evidence of Water Erosion in Ordos Plateau, China Using the Google Earth Engine

Ordos Plateau is one of the primary sources of sediment in the Yellow River, and changes in regional soil erosion directly affect the ecological status of the lower reaches of the Yellow River. Many recent studies have been published using remote sensing (RS) and geographic information systems (GIS) to evaluate soil erosion. In this study, much satellite remote sensing data in the Google Earth Engine (GEE) can better track soil erosion protection, which is significant in guiding the ecological protection and restoration of the Ordos Plateau and the Yellow River basin. In this study, we used GEE to observe the changes in soil erosion in the Ordos area from 2013 to 2021. The Theil–Sen procedure and Mann–Kendall significance test methods were used to evaluate the trend of land erosion in the Ordos area from 2013 to 2021. Based on GEE, the RUSLE is applied to evaluate soil erosion and analyze the changing trend. As a result, (1) we found that the annual change of soil and water loss in the Ordos Plateau showed three stages: 2013–2015, 2016–2018, and 2018–2021. After 2018, soil loss decreased from 14 × 1017 Mg in 2018 to 4 × 1017 Mg in 2021, which indicates that the environmental restoration project started in 2018 has achieved encouraging results. (2) The results showed that 40.9% of the regional soil erosion trend showed a significant decline, and 45.7% of the regional soil erosion trend showed a slight decline. Only 13.3% of the regional soil erosion is on the rise. (3) The test results of different land use types show that 87.3% of soil erosion occurs in bare and cultivated land. Because the terrain of Ordos is relatively flat, 95.39–96.17% of soil erosion occurs in areas with a slope of 0 to 5. (4) The reliability of the RUSLE model based on the GEE platform is proved by regression model verification of observation data and model prediction results. (5) GEE’s cloud-based features can provide data and scripts to users in developing countries which lack sufficient observation data or the necessary computing resources to develop these data. The results show that GEE has robust analysis and processing ability, can analyze a large amount of data, and can provide efficient digital products for soil erosion research.

Democratic backsliding in the Philippines: Are voters becoming illiberal?

Democratic backsliding by incumbents is one of the most prevalent forms of backsliding in recent global trends of democratic erosion. Understanding the attitude of voters toward backsliding incumbents is crucial because popular support is the basis of legitimacy for these incumbents. This article studies voter attitudes in the Philippines, where democracy was subverted by the incumbent president, Rodrigo Duterte, who served from 2016 to 2022. Specifically, we examine the validity of the claim that Filipino voters are acquiring a “taste for illiberal rule” made by some scholars. First, we analyzed the survey data regarding the support for various types of political systems, where part of the data comes from our originally commissioned survey at the Social Weather Stations. Second, we explored Pulse Asia's longitudinal survey data on martial-rule support. Our investigation of these survey data did not find substantive support for the “taste for illiberal rule” proposition. Further, we argue that Filipino voters are contingent supporters of illiberal politics while supporting the procedural principles of democracy at the baseline.

Combining remote sensing analysis with machine learning to evaluate short-term coastal evolution trend in the shoreline of Venice

With increasing storminess and incessant sea-level rise, coastal erosion is becoming a primary issue along many littorals in the world. To cope with present and future climate change scenarios, it is important to map the shoreline position over years and assess the coastal erosion trends to select the best risk management solutions and guarantee a sustainable management of communities, structures, and ecosystems. However, this objective is particularly challenging on gentle-sloping sandy coasts, where also small sea-level changes trigger significant morphological evolutions.This study presents a multidisciplinary study combining satellite images with Machine Learning and GIS-based spatial tools to analyze short-term shoreline evolution trends and detect erosion hot-spots on the Venice coast over the period 2015–2019. Firstly, advanced image preprocessing, which is not frequently adopted in coastal erosion studies, was performed on satellite images downloaded within the same tidal range. Secondly, different Machine Learning classification methods were tested to accurately define shoreline position by recognizing the land-sea interface in each image. Finally, the application of the Digital Shoreline Analysis System tool was performed to evaluate and visualize coastal changes over the years.Overall, the case study littoral reveals to be stable or mainly subjected to accretion. This is probably due to the high presence of coastal protection structures that stabilize the beaches, enhancing deposition processes. In detail, with respect to the total length of the considered shoreline (about 83 km), 5 % of the coast is eroding, 36 % is stable, 52 % is accreting and 7 % is not evaluable. Despite a significant coastal erosion risk was not recognized within this region, well-delimited erosion hot-spots were mapped in correspondence of Caorle, Jesolo and Cavallino-Treporti municipalities. These areas deserve higher attention for territorial planning and prioritization of adaptation measures, facing climate change scenarios and sea-level rise emergencies in the context of Integrated Coastal Zone Management.

Sediment Transport Equivalent Waves for Estimating Annually Averaged Sedimentation and Erosion Trends in Sandy Coastal Areas

In this paper, a simple approach to determine representative offshore wave characteristics for estimating the annually averaged sedimentation and erosion trends in sandy coastal areas is presented. Given the offshore wave climate, the proposed approach breaks down the climate into fixed 22.5-degree bins and based on the sediment transport potential it determines the equivalent wave characteristics for each bin, i.e., a significant wave height, a peak period, a mean wave direction, and a corresponding frequency of occurrence. The approach is validated in idealized cases of uniformly sloping beaches with the presence of a breakwater, for various sediment diameters, sea bottom slopes, and different offshore wave characteristics. The performance of the proposed approach is evaluated against the full climate, returning good results. Furthermore, the proposed approach is applied in a real-life challenge, in the coastal area of Therma in the Island of Samothraki in Greece, where the presence of a fishing shelter has led to sedimentation and erosion problems. The performance of the proposed approach is very satisfactory, given the complexity of the problem. The generic nature of the proposed methodological approach allows it to be applied in numerous sandy coastal regions to estimate the sedimentation and erosion trends, reducing the amount of input parameters and thus requiring significantly less computational efforts.

Spatiotemporal patterns and drivers of soil erosion in Yunnan, Southwest China: RULSE assessments for recent 30 years and future predictions based on CMIP6

Soil erosion is a critical driving force of regional-scale ecosystem dynamics. Quantifying soil erosion and its responses to climate and land cover changes comprise an important part of regional ecological security assessment. Taking account of rainfall and vegetation cover changes in Yunnan Province, Southwest China, from 1986 to 2015, this study explored the spatiotemporal patterns of soil erosion intensity in Yunnan over this 30-year period, using the Revised Universal Soil Loss Equation. Sensitivity analyses were performed to evaluate the roles of rainfall (R) and vegetation cover (C) changes in soil erosion. Based on the climate model CMIP6, the carbon emission socio-economic sharing scenarios SSP126 and SSP585 were compared, using a random forest model, to predict soil erosion risk in Yunnan in different future periods. The results indicated the following: (1) During 1986–2015, soil erosion was detected in 33.55% of the land area of Yunnan, among which the areas of slight, moderate, severe, very severe, and extremely severe erosion accounted for 19.55%, 7.64%, 3.23%, 2.08%, and 1.04%, respectively; the 30-year mean annual soil erosion modulus over Yunnan was 1289.72 t km−2 a−1. (2) The area percentage change of five soil erosion intensity levels consistently showed a generally declining trend of soil erosion during the 30-year period. Comparing 1995–2006 vs. 1986–1995 and 2006–2015 vs. 1996–2005, area percentages were 1.56% and 2.4% for intensively reduced, respectively, and correspondingly 16.65% and 22.12% for reduced, 68.11% and 71.15% for no significant change, 12.79% and 4.02% for enhanced, and 0.08% and 0.03% for intensively enhanced. (3) Factor C was a more sensitive driver than R for soil erosion in this period. (4) Under the SSP126 and SSP585 scenarios, soil erosion risk was predicted to rise in the 21st century; and the provincial average soil erosion risk was larger for the SSP585 than the SSP126 scenario. Compared with the average of the 30-year period, predicted soil erosion in the SSP585 and SSP126 scenarios in 2100 would increase in western and southern Yunnan, while the SSP585 scenario predicted more severe soil erosion in southern and southwestern regions than SSP126. Our historical assessments and future forecasts suggest vegetation protection in karst areas and restoration in southern Yunnan will be critical for future soil erosion control and regional ecological security in Yunnan.

Dynamic Modelling of Water and Wind Erosion in Australia over the Past Two Decades

Soil erosion caused by water and wind is a complicated natural process that has been accelerated by human activity. It results in increasing areas of land degradation, which further threaten the productive potential of landscapes. Consistent and continuous erosion monitoring will help identify the location, magnitude, and trends of soil erosion. This information can then be used to evaluate the impact of land management practices and inform programs that aim to improve soil conditions. In this study, we applied the Revised Universal Soil Loss Equation (RUSLE) and the Revised Wind Erosion Equation (RWEQ) to simulate water and wind erosion dynamics. With the emerging earth observation big data, we estimated the monthly and annual water erosion (with a resolution of 90 m) and wind erosion (at 1 km) from 2001 to 2020. We evaluated the performance of three gridded precipitation products (SILO, GPM, and TRMM) for monthly rainfall erosivity estimation using ground-based rainfall. For model validation, water erosion products were compared with existing products and wind erosion results were verified with observations. The datasets we developed are particularly useful for identifying finer-scale erosion dynamics, where more sustainable land management practices should be encouraged.

Assessment of the vulnerability of zemmouri bay to coastal erosion, diachronic study between 1957 and 2017

The analysis and understanding of coastline variability and coastal erosion trends, and accretion are essential to scientists and local decision-makers to guide shoreline management regulations and decisions. This study focuses on detecting and analyzing historical changes in the Zemmouri (Central Algeria) shoreline position between 1957 and 2017. We collected all the necessary data related to the Zemmouri bay to achieve our objective, such as satellite images, aerial photos, and topographical surveys carried out by the DGPS, all between 1957 and 2017 DSAS calculation tool. Diachronic analysis of aerial photographs and satellite images of Zemmouri Bay revealed that only 39% of sandy beaches are eroding while 3% have some stability. The maximum erosion at Mazer East beach is -1.25m/year. The maximum accretion rate of +1.40m/year at Blue Waves beach, mainly due to the implantation of breakwaters at this beach which created tombolos favoring sand accumulation and beach widening.

Evidence and Implications of Hydrological and Climatic Change in the Reno and Lamone River Basins and Related Coastal Areas (Emilia-Romagna, Northern Italy) over the Last Century

Climate change and human activities have consequences on coastal areas as they affect hydrological processes in the related river basins. The riverine sediment supply to the beaches of the Emilia-Romagna coast, a highly urbanized area with high economic and naturalistic value, has been heavily impacted by human activities throughout the catchment, reducing solid transport to the coast and increasing the threat of coastal erosion and flooding. Despite the introduction of safeguard policies in the early 1980s and the consequent stoppage of such activities, the expected return in solid transport has not yet been reflected at the coast. To better understand the various processes acting at the river basin scale, we utilized empirical mode decomposition to analyze the variability in different parameters (river discharge, rainfall, air temperature, and sea level) from the headwaters to the coast of the Reno and Lamone rivers over the last century. The anthropogenic footprint, linked to the large-scale dimming/brightening phenomenon, is visible in the long-term trends. Moreover, natural signals with variable periodicity are evident and partially correlated with two major climate modes (North Atlantic Oscillation and Atlantic Multidecadal Oscillation). The coupled interactions among these processes, combined with the changes in land use and evapotranspiration during the last century, have resulted in the prolonged scarcity of river sediment supply and a long-term trend of erosion of the coastal area.

Theoretical Model and Solution of Dynamic Evolution in Initial Stage of Lacustrine Delta

Sediment is carried by flows into lake during the formation of lacustrine deltas. The subsequent movement of sediment-laden flow is maintained by the initial momentum at the early stage of delta growth. A theoretical model of the plane jet boundary layer in the initial stage of a lacustrine delta, including the consideration of gravity action on the slope and bottom friction, was established according to characteristics of this process, and a similarity solution method was used to solve the model. A coefficient ε was introduced that describes the characteristics of sediment-laden flow spreading along a straight line and its value is given. The theoretical expression of morphological characteristics of the initial stage was derived based on the general mathematical model of river bed evolution, and the erosion and deposition patterns were quantitatively analyzed. It was verified through experimental data that the theoretical model can be solved accurately and, can satisfactorily describe the trend in erosion and deposition and morphological characteristics of the initial stage of a delta.

Regional Potential Wind Erosion Simulation Using Different Models in the Agro-Pastoral Ecotone of Northern China.

Wind erosion is crucial for assessing regional ecosystem services and sustainable development. The Agro-Pastoral Ecotone of northern China (APEC) is a typical region undergoing wind erosion and soil degradation. In this study, the National Wind Erosion Survey Model of China, the Integrated Wind Erosion Modeling System, and the regional versions of the Revised Wind Erosion Equation and Wind Erosion Prediction System were used to evaluate the regional potential wind erosion of the APEC during 2000 and 2012. The results showed that the potential wind erosion predicted by National Wind Erosion Survey Model of China (NWESMC), Revised Wind Erosion Equation (RWEQ), Wind Erosion Prediction System (WEPS), and Integrated Wind Erosion Modeling System (IWEMS) were significantly related to the observed wind erosion collected from published literature, but the observed data were generally smaller than the predicted values. The average potential wind erosions were 12.58, 25.87, 52.63, and 58.72 t hm−2 a−1 for NWESMC, RWEQ, WEPS, and IWEMS, respectively, while the spatial pattern and temporal trend of annual potential wind erosion were similar for different wind erosion models. Wind speed, soil moisture, and vegetation coverage were the dominant factors affecting regional wind erosion estimation. These results highlight that it is necessary to comprehensively calibrate and validate the selected wind erosion models. A long-term standard wind erosion monitoring network is urgently required. This study can serve as a useful reference for improving wind erosion models.

Adapting the WEPP Hillslope Model and the TLS Technology to Predict Unpaved Road Soil Erosion.

Unpaved road erosion have been recognized as important sediment sources in a watershed. To evaluate where and when road erosion occurs, the soil loss along road segments should be precisely predicted with process-based erosion models. Methods: The hillslope version of the Water Erosion Prediction Project (WEPP) was used to estimate soil loss from 20 typical road segments in the red soil region of South China. Terrestrial laser scanning (TLS)-measured soil losses were used to validate the model simulations. The results showed that the WEPP model could reasonably predict the total soil loss in relatively short (less than 100 m) and gentle (slope gradient lower than 10%) road segments. In contrast, soil loss would be underestimated for long or steep road segments. Detailed outputs along roads revealed that most of the peak soil loss rates were underestimated. It might due to the linear critical shear stress theory in the WEPP model. Additionally, the lack of upstream flow was found to be connected to the relatively low model efficiency. Nevertheless, the WEPP simulation could accurately fit erosion trend and predict the peak soil loss positions along road segments. Conclusions: The WEPP model could be adopted to evaluate the erosion risk of unpaved roads in the red soil region of South China.

Spatio-temporal analysis of shoreline changes and erosion risk assessment along Jerba island (Tunisia) based on remote-sensing data and geospatial tools

Jerba, the largest island in North Africa, is among the most exposed islands to the combined effects of climate change and human activities in the Mediterranean. The eastern coast of Jerba island has long been subject to intense tourist development due to its attractive natural potential. The main issue addressed in this study concerns the evolutionary trends of Jerba shoreline and the assessment of coastal erosion risk. This work focuses on the historical study of the shoreline positions based on satellite data processing. The use of geographic information system (GIS) and the Digital Shoreline Analysis System (DSAS) geostatistical calculation tool allowed for the identification of erosion and accretion rates and the description of evolutionary trends across 32 years covering three periods (1989–1999, 1999–2009, and 2009–2021). The results show an overall erosion trend (89% of the coastline). The statistics revealed that the study area, with the exception of the sandy spit, has experienced an intense and alarming level of erosion between 1989 and 1999, with an end point rate (EPR) equal to −4.12 m/year. This net rate continued to be negative in the period between 1999 and 2009, with an EPR of −0.5 m/year. Between 2009 and 2021, the net rate of shoreline change is marked by slight accretion, at an average of +1.4 m/year. The overall long-term trend shows the shoreline is eroding, with an average linear regression rate of −1.38 m/year for the whole period. This trend is due to a combination of the cumulative effects of sea-level rise and anthropogenic actions. Therefore, sustainable management strategies need to be implemented urgently by coastal managers to restore the sectors that are susceptible to further erosion.

Dynamic Evolution and Quantitative Attribution of Soil Erosion Based on Slope Units: A Case Study of a Karst Plateau-Gorge Area in SW China

Exploring the dynamics of soil erosion and identifying its driving mechanisms is key to understanding soil erosion processes, particularly in karst areas. In this study, the RUSLE model, optimized on the basis of rocky desertification factors, was used to estimate soil erosion in a karst plateau gorge area in SW China. The spatial and temporal dynamics of soil erosion in the region over the past 20 years were analyzed on the basis of slope units, while the relationship between soil erosion and elevation, slope, fractional vegetation cover (FVC), karst rocky desertification (KRD), rainfall, and land use cover/change (LUCC) was identified quantitatively by the geographical detector on the basis of spatial heterogeneity. The results showed that: (1) The no erosion area decreased from 2000 to 2020, with the highest proportion of light to medium erosion and an increasing trend of soil erosion. (2) Soil erosion conversion mainly occurred between no erosion, slight erosion, and light erosion. (3) The hotspots of erosion occurred in high slope–low elevation and high slope–high elevation units, while the coldspots of erosion occurred in low slope–low elevation units. (4) Soil erosion was positively correlated with FVC and slope, and negatively correlated with KRD. (5) The dominant factor of soil erosion changed from KRD-slope to LUCC-slope and finally to elevation-slope, while the q value of rainfall-elevation had the most significant increase throughout the study period. This study will help to advance the goal of sustainable development of soil and water conservation in karst areas.

Investigation of human-induced land use dynamics in a representative catchment on the Chota Nagpur Plateau, India: A spatiotemporal application of soil erosion modeling with connectivity index studies

The soil erosion and sediment yield on the Chota Nagpur Plateau, India have been greatly affected over the years by ever increasing anthropogenic influences and associated land-use/land-cover (LULC) changes. This study coupled a CA-Markov model with the Geospatial Interface for Water Erosion Prediction Project (GeoWEPP) model along with sediment connectivity index (IC) to estimate the decadal-scale soil erosion and sediment yield changes in a representative catchment of Chota Nagpur Plateau for 2001–2040 period. This LULC- Erosion-IC modeling approach in the Konar catchment has revealed (i) concerning patterns of conversions of bare lands and grasslands to agricultural fields and (ii) dominance of the new agricultural lands in the areas with higher connectivity. Results indicated that around 11 % and 13 % of the total catchment area undergoing agriculture will be in the highly erodible and highly connected category respectively by 2040. The corresponding mean erosion rates showed a significant increase for agricultural lands [from 26 to 35 T/Ha/Y], built up areas [from 43 to 48 T/Ha/Y], and bare lands [from 30 to 36 T/Ha/Y] during the time period of 2001 to 2040. The evaluation of mean connectivity values showed future expansions of forests (through agro-forestry, i.e. ∼2400 ha) with low connectivity by 2040. A strong linkage between increased future sediment yield and changing LULC patterns (around +6 % and +8 % of the built up area and agricultural lands and −5% and −9% of bare lands and grasslands respectively) can be observed by 2040. These changes are directly attributed to the sediment yield in the region with approximately 59 % and 97 % increase during 2001–2020 and 2020–2040 periods respectively. This study provided a good understanding of general trends in erosion and sediment yield in the Chota Nagpur Plateau and the influence of ongoing efforts in agro-forestry components and land use change dynamics.

Heavy Metal Content and Pollution Assessment in Typical Check Dam Sediment in a Watershed of Loess Plateau, China

To understand historical trends and assess the ecological risk associated with heavy metal pollution, the concentration of eight species of heavy metals (vanadium (V), chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), zinc (Zn), copper (Cu), and arsenic (As)) in typical silt dam sediments on the Loess Plateau were analyzed. The radionuclide 137Cs was used to quantify rates of erosion, deposition, and heavy metal contamination in the soils of a watershed that supplies a check dam. The sediment record revealed three time periods distinguished by trends in erosion and pollutant accumulation (1960–1967, 1968–1981, and 1985–1991). Heavy metal concentrations were highest but exhibited significant fluctuation in the first two periods (1960–1967 and 1968–1981). From 1985 to 1991, heavy metal pollution showed a downward trend and tended to be stable. The potential risks of heavy metals in silt dam sediments were explored by applying the geo-accumulation index and the potential ecological risk index. The results indicated medium risk associated with Cu and As accumulation, especially in 1963, 1971, and 1986 when the assessed values increased significantly from previous levels. Agricultural practices and high rates of slope erosion may be responsible for the enrichment of As and Cu in soil and the accompanying increase in risk. Land use optimization and the careful use of fertilizers could be used to control or intercept heavy metal pollutants in dammed lands. The results provide the basis for evaluating the current status and ecological risk of heavy metal contamination in dam sediments and for predicting possible heavy metal pollution in the future.

Historical morphological changes (1956-2017) and future trends at the mouth of the Ebro River delta (NE Spain)

The present work focuses on the recent morphological changes recorded in the Ebro River delta, by using aerial photographs in the last six decades and by analyzing changes in the main constitutive features through geomorphological maps. Geomorphological maps of the years 1956 and 2017 are here presented. The results obtained give very valuable clues about the recent trends of the river delta mouth, which can be used to predict future coastal changes to be expected in the following decades. In this sense, by analysing changes in the surface by means of the geomorphological maps together with a shoreline analysis, a differential behavior has been described at both sides of the river mouth: the left side, El Garxal wetland, shows an accretionary trend with rates reaching +40 m/year, while the right side, San Antonio Island, shows erosive trends of more than -20 m/year. This last side also presents a surface reduction of more than 50 ha in the last 60 years. These results suggest that, approximately by the year 2050, the emerged San Antonio Island may disappear if shoreline retreat trends are maintained, making El Garxal exposed to easterly storms, the main erosive dynamic processes in this zone and, therefore changing the entire configuration of the Ebro River delta mouth in the upcoming years. Despite possible solutions have been described in recent works, they may not contribute to a total recovery of the most natural part of the Ebro Delta. Urgent management plans are required to attempting to slow or reverse these trends, otherwise one of the most valuable ecosystems of the delta could disappear.

Storm Surges Versus Shore Erosion: 21 Years (2000–2020) of Observations on the Świna Gate Sandbar (Southern Baltic Coast)

Abstract Based on observations spanning 21 years (2000–2020), the article studies the effects of storm surges on the shore of the Świna Gate Sandbar in the southern part of the Pomeranian Bay (southern Baltic Sea). Impacts of selected maximum storm surges in each year were assessed with respect to morphological data collected on the beach and the foredune. The data included parameters of beach-dune erosion as measured along a beach transect before and after each surge. Differences and trends in the shore erosion were related to the sea level (SL), duration of a storm surge [highest storm sea level (HSL) > 1 m], wind-wave sector and wave run-up. The relationships were explored using a simple correlation analysis. The most serious erosion was observed during the heaviest surges [HSL > 1.3 m above the mean sea level (AMSL)], with a wave run-up higher than 3.2 m AMSL. Such surges occurred at about 2-year intervals. The average SL during a surge was 1.2 m AMSL, with a run-up of 2.6 m AMSL. The beach and the lower part of the shore, below that level, were eroded each year. The heaviest surges resulted in an average 5.2 m and 7.0 m dune retreat on the high-beach-accumulative shore and on the low-beach-erosive shore, respectively. The dune was not eroded when the beach height exceeded the wave run-up. The heaviest surges eroded away 12–14 m3 of the beach sand volume. The shore erosion was found to be related to the storm surge duration, the maximum SL, the run-up and the beach height prior to the surge.

A Field Study for the Effects of Grass Cover, Rainfall Intensity and Slope Length on Soil Erosion in the Loess Plateau, China

Slope length is an important topographic factor for controlling soil erosion. There exists limited knowledge of the interactions of slope length, vegetation restoration, and rainfall intensity on soil erosion. This study investigated the impact of the slope length on soil erosion for different grass coverages and different rainfall intensities via simulated rainfall experiments. The experiments included five rainfall intensity treatments (1, 1.5, 2, 2.5, and 3 mm min−1), four grass cover treatments (0%, 30%, 60%, and 90%), and five slope length treatments (2, 4, 6, 8, and 10 m). The change process of soil loss was significantly different (p < 0.05) for different slope lengths. The trend of soil loss changing with slope length is: under a grass cover of 0 or 30%, the soil erosion increased exponentially with increasing slope length. However, under a grass cover of 60%, the soil erosion rate peaked at a slope length of 8 m, and under a grass cover of 90%, the soil erosion rate peaked at a slope length of 6 m. At rainfall intensities of 1.5–2 mm min−1, the overall soil erosion amount was small. The soil loss increased drastically with slope length when the rainfall intensity exceeded 2 mm min−1. Compared with a slope length of 2 m, longer slope lengths increased the erosion rate by 225–930% under different grass coverages treatments. Regression analysis showed that grass cover and rainfall intensity change the trend of erosion with slope length, and the negative effect of slope length on erosion is strengthened with the increase of grass cover, while this negative effect gradually weakens with the increase of rainfall intensity.

Democratic Erosion in Comparative Contexts: Evidence from Egypt, Indonesia, Iran, and Pakistan

This article examines the state of democracy in the comparative contexts of Egypt, Indonesia, Iran, and Pakistan. Employing Larry Diamond’s regime categorization, the article identifies specific characteristics of the systems of governance in these countries and investigates their democratic conditions. This article makes two arguments using data from Freedom House and World Justice Project (WJP) and triangulating them with scholarly studies on relevant contexts. First, all four countries have suffered from a democracy deficit for an extended period and continue to face the same predicament. Second, there has been a disturbing trend of erosion in their democratic qualities during the 2010–2020 period. The article concludes that none of these countries is a politically closed authoritarian system. Nor is any of them a liberal democracy. Instead, all these countries bear the hallmarks of hybrid regimes, except Indonesia that turned out to be an electoral democracy.

Identifying Shoreline Changes in Tanjung Burung Forest Reserve and its Impact on Mangrove Stands Using Geospatial Technique

The Forestry Department of Peninsular Malaysia (FDPM) has received reports of coastal erosion and the death of mangrove trees in some parts of Tanjung Burung Forest Reserve, in the Kinta/Manjung area. This forest reserve especially on the southern part serves as a natural protector to Pantai Remis – an economically important coastal town in that area. To investigate the shoreline changes and its impact on mangrove stands, eight scenes of Landsat and SPOT-6 images from 1988 to 2020 were used. Shoreline extraction was performed using the classification technique and reclassify function, while statistics of shoreline change rate were measured using Digital Shoreline Analysis System (DSAS) tool. Normalized Different Vegetation Index (NDVI) analysis was also conducted to assess the condition of mangrove stands in the study area. Shoreline changes in the study area showed an erosion trend of up to 733.33 m with rate of change from -3.01 m/y to -23.43 m/y. This indicates many areas are experiencing critical erosion according to National Coastal Erosion Study (NCES) 2015. The results of this study can provide an overview of the current coastal erosion as well as an input for the authorities in taking appropriate necessary measures to protect this forest reserve.