Topographic Factors Research Articles

Influence of Terrain on MODIS and GLASS Leaf Area Index (LAI) Products in Qinling Mountains Forests

Leaf Area Index (LAI), as a pivotal parameter in characterizing the structural properties of vegetation ecosystems, holds significant importance in assessing the carbon sink function. Given the availability of multiple long-term LAI products, validating these LAI products with consideration of topographic factors is a prerequisite for enhancing the quality of LAI products in mountainous areas. Therefore, this study aims to evaluate the performance of MODIS LAI and GLASS LAI products from 2001 to 2021 by comparing and validating them with ground-measured LAI data, focusing on the spatio-temporal and topographic aspects in the Qinling Mountains. The results show that the GLASS LAI product is a better choice for estimating LAI in the Qinling Mountains. The GLASS LAI product has better completeness and generally higher values compared to the MODIS LAI product. The time-series curve of the GLASS LAI product is more continuous and smoother than the MODIS LAI product. Both products, however, face challenges in quantifying LAI values of evergreen vegetation during winter. The MODIS and GLASS LAI products exhibit differences between sunny and shady slopes, with mean LAI values peaking on sunny slopes and reaching their lowest on shady slopes. When the slope ranges from 0 to 10°, the mean values of GLASS LAI product show a higher increasing trend compared to the MODIS LAI product. At elevations between 1450 and 2450 m, the mean LAI values of the GLASS LAI product are higher than the MODIS LAI product, primarily in the southern Qinling Mountains. Compared to ground-measured LAI data, the GLASS LAI product (R² = 0.33, RMSE = 1.62, MAE = 0.61) shows a stronger correlation and higher accuracy than the MODIS LAI product (R² = 0.24, RMSE = 1.61, MAE = 0.68).

Study on the Driving Factors of the Spatiotemporal Pattern in Forest Lightning Fires and 3D Fire Simulation Based on Cellular Automata

Lightning-induced forest fires frequently inflict substantial damage on forest ecosystems, with the Daxing’anling region in northern China recognized as a high-incidence region for such phenomena. To elucidate the occurrence patterns of forest fires caused by lightning and to prevent such fires, this study employs a multifaceted approach, including statistical analysis, kernel density estimation, and spatial autocorrelation analysis, to conduct a comprehensive examination of the spatiotemporal distribution patterns of lightning-induced forest fires in the Greater Khingan Mountains region from 2016–2020. Additionally, the geographical detector method is utilized to assess the explanatory power of three main factors: climate, topography, and fuel characteristics associated with these fires, encompassing both univariate and interaction detections. Furthermore, a mixed-methods approach is adopted, integrating the Zhengfei Wang model with a three-dimensional cellular automaton to simulate the spread of lightning-induced forest fire events, which is further validated through rigorous quantitative verification. The principal findings are as follows: (1) Spatiotemporal Distribution of Lightning-Induced Forest Fires: Interannual variability reveals pronounced fluctuations in the incidence of lightning-induced forest fires. The monthly concentration of incidents is most significant in May, July, and August, demonstrating an upward trajectory. In terms of temporal distribution, fire occurrences are predominantly concentrated between 1:00 PM and 5:00 PM, conforming to a normal distribution pattern. Spatially, higher incidences of fires are observed in the western and northwestern regions, while the eastern and southeastern areas exhibit reduced rates. At the township level, significant spatial autocorrelation indicates that Xing’an Town represents a prominent hotspot (p = 0.001), whereas Oupu Town is identified as a significant cold spot (p = 0.05). (2) Determinants of the Spatiotemporal Distribution of Lightning-Induced Forest Fires: The spatiotemporal distribution of lightning-induced forest fires is influenced by a multitude of factors. Univariate analysis reveals that the explanatory power of these factors varies significantly, with climatic factors exerting the most substantial influence, followed by topographic and fuel characteristics. Interaction factor analysis indicates that the interactive effects of climatic variables are notably more pronounced than those of fuel and topographical factors. (3) Three-Dimensional Cellular Automaton Fire Simulation Based on the Zhengfei Wang Model: This investigation integrates the fire spread principles from the Zhengfei Wang model into a three-dimensional cellular automaton framework to simulate the dynamic behavior of lightning-induced forest fires. Through quantitative validation against empirical fire events, the model demonstrates an accuracy rate of 83.54% in forecasting the affected fire zones.

Geochronology and ice‐flow modelling of the Late Quaternary glaciers on Mt. Soğanlı, Türkiye

ABSTRACTUnderstanding Earth's climate history through the chronology and reconstruction of palaeoglaciers is a central topic of palaeoclimatology. Examining the remnants of past glaciations preserved in isolated alpine environments provides insight into critical palaeoclimatic conditions. Accurate dating techniques, such as terrestrial cosmogenic nuclides, are crucial for understanding the timing of these changes. The Anatolian Peninsula, characterized by diverse topographical and climatic factors, witnessed the presence of glaciers during the Late Pleistocene, shaping its alpine landscape significantly. While mountain ranges such as the Taurus and Pontic favoured glacier development due to their elevation and lower temperatures, isolated mountains such as Mount Soğanlı in the interior hinterland also supported significant palaeoglaciers. Despite previous studies on Anatolia's glaciers, numerical dating of glacial deposits on Mount Soğanlı has remained elusive until now, hindering precise palaeoclimatic interpretations. This study employs cosmogenic 36Cl surface exposure dating and physical‐based ice‐flow modelling using an open‐source framework, Parallel Ice Sheet Model (PISM), to determine the timing of glaciations and to reconstruct past glacier extents on Mount Soğanlı. The results reveal glacier retreat ages of 48.3 ± 13.4 and 18.3 ± 4.4 ka based on two well‐preserved moraines. Additionally, palaeoclimate simulations matched with the field observations indicate considerably colder conditions (6.65–8.15°C colder than today) necessary to sustain glaciers on Mount Soğanlı, when precipitation amounts were the same as today. These findings contribute to a better understanding of Anatolia's palaeoclimatic fluctuations and align with similar studies in neighbouring regions, enhancing our knowledge of past climate dynamics of the Eastern Mediterranean and the Middle East.

Agricultural legacy shapes plant diversity patterns in mountain grasslands of Maramureș and Bukovina: A cross‐border perspective (Ukraine, Romania)

Abstract We investigated farming practices and grassland plant diversity patterns in the historical regions of Maramureș and Bukovina, located in the central Eastern Carpathians of Romania and Ukraine. We explored the influence of social and historical factors on recent grassland plant diversity, including changes and modifications in land use and grassland management practices. We used stratified random sampling to select 48 grassland parcels in eight villages on the Ukrainian‐Romanian borderlands. We identified the factors that affect the composition and diversity of grassland vascular plants and bryophytes at multiple spatial scales and compared the frequency and timing of historical and recent grassland management practices to distinguish between preserved and modified agricultural traditions. In most of the grassland parcels studied (83% in Romania and 78% in Ukraine), traditional land use persisted. Local plant species richness was primarily influenced by management practices, outweighing the impact of topography and soil factors. Regular mowing at appropriate intensity increased the richness of vascular plants, while grazing promoted the richness of bryophyte species. Modifications to farming systems, observed in all studied villages, were mainly due to declining population and livestock numbers. Although the timing of spring and autumn grazing in hay meadows still adhered to tradition, mowing schedules shifted earlier, especially for the first cut of two‐cut hay meadows. Traditional corralling, fertilization and hayseed application have become rare or discontinued in certain villages, while controlled burning has increased. Past use of mineral fertilizers in Ukrainian villages during the Soviet era influenced the recent diversity and composition of vascular plant species, favouring nutrient‐demanding species. Social factors and agricultural policies indirectly affect biodiversity in semi‐natural grasslands, leaving a tangible footprint even in the most remote areas of the Carpathian Mountains. We provide basic recommendations to preserve the remarkable biodiversity of the region. Read the free Plain Language Summary for this article on the Journal blog.

Infiltration Characteristics and Hydrodynamic Parameters in Response to Topographic Factors in Bare Soil Surfaces, Laboratory Experiments Based on Cropland Fields of Purple Soil in Southwest China

Topography is an important factor that impacts the hydrological processes on sloping farmlands. Yet, few studies have reported the combined influences of slope gradient and slope position on infiltration characteristics and hydrodynamic parameters on sloping croplands in purple soil regions, an important area for agricultural productivity in Southwest China. Here, laboratory-simulated rainfall experiments were conducted in a steel trough (5 m long, 2 m wide, and 0.45 m deep), and rainfall lasted for 1 h at a rate of 90 mm h−1 to examine the variations in the infiltration rates and hydrodynamic parameters under varying slope gradients (i.e., 3°, 6°, 10°, 15°, 21°, and 27°) and slope positions (i.e., upper, middle, and lower), and explore the relationships between the infiltration rate and the soil detachment rate. The results showed that the infiltration rate decreased gradually with duration rainfall and ultimately approached a steady state in the six slope treatments. Cumulative infiltration ranged from 15.54 to 39.32 mm during rainfall, and gradually reduced with the increase of slope gradient. The Horton’s model outperforms other models for predicting the infiltration rate with an R2 value of 0.86. Factors such as Darcy–Weisbach friction, flow shear force, Manning friction coefficient, unit energy, and runoff depth varied in the following order: upper slope > middle slope > lower slope, whilst the Reynolds number and Froude number gradually increased along the slope transect from the upper to lower slope positions. A significant linear function was fitted between the soil detachment rate and the infiltration rate at the gentle slopes (3°, 6°, 10°), whereas an exponential relationship was observed at the steep slopes (15°, 21°, and 27°). Observation also suggested that 15° was the critical slope gradient of sediment detachment, infiltration characteristics, and hydrodynamic parameters. Our results provide theoretical insight for developing models that predict the impacts of topographic factors on hydrological characteristic and soil erosion in hilly agricultural landscapes of purple soil fields.

Revitalisation Design of North Coastal Border in Lemahwungkuk Sub-District with Urban Design Element Analysis

Cirebon is one of the cities in West Java province. The city is located in the lowlands on the north coast of Java. The low topography factor is closely related to urban problems, such as slums in the Lemahwungkuk sub-district of Cirebon City. This research aims to solve urban problems because, according to the Mayor's Regulation No. 663/Kep.421-DPRKP/2021, Lemahwungkuk sub-district includes Cangkol coastal and Kesunean coastal areas among the eleven slum locations in Cirebon city. In addition, there is a plan to revitalize the coastal border area. The method used in this research is qualitative, using urban design analysis and site analysis. The data sources were obtained through interviews with 20 informants and mapping using ArcGIS 10.8 software. The concept of an environmental approach with an orientation towards the community in the design of the revitalization of the north coast area in Lemahwungkuk District emphasizes the physical environment, infrastructure, economy, socio-culture, disaster, and collaboration between the government and the community. The results of this revitalization design can also be a recommendation for development in Cirebon, West Java. In addition, it recommends conservation and tourism activities on the north coast of Cirebon, West Java. Efforts to overcome the phenomenon of urban sprawl at the research site by changing the pattern of settlements and building layout to improve the quality of the community environment and increase public space and green open space for conservation, tourism, and aesthetic functions of the region.

Land Subsidence Detection Using SBAS- and Stacking-InSAR with Zonal Statistics and Topographic Correlations in Lakhra Coal Mines, Pakistan

The adverse combination of excessive mining practices and the resulting land subsidence is a significant obstacle to the sustainable growth and stability of regions associated with mining activities. The Lakhra coal mines, which contain some of Pakistan’s largest coal deposits, have been overlooked in land subsidence monitoring, indicating a considerable oversight in the region. Subsidence in mining areas can be spotted early when using Interferometric Synthetic Aperture Radar (InSAR), which can precisely monitor ground changes over time. This study is the first to employ the Small Baseline Subset (SBAS)-InSAR and stacking-InSAR techniques to identify land subsidence at the Lakhra coal mines. This research offers critical insights into subsidence mechanisms in the study area, which has never been previously investigated for ground deformation monitoring, by utilizing 150 Sentinel-1A (ascending) images obtained between January 2018 and September 2023. A total of 102 deformation spots were identified using SBAS-InSAR, while stacking-InSAR detected 73 deformation locations. The most extensive cumulative subsidence in the Lakhra coal mine was −114 mm, according to SBAS-InSAR, with a standard deviation of 6.63 mm. In comparison, a subsidence rate of −19 mm/year was reported using stacking-InSAR with a standard deviation of 1.17 mm/year. The rangeland covered 88.8% of the total area and exhibited the most significant deformation values, as determined by stacking and SBAS-InSAR techniques. Linear regression showed that there was not a strong correlation between subsidence and topographic factors. As detected by optical remote sensing data, the subsidence locations were near or above the mines in the research area, indicating that widespread mining in Lakhra coal mines was the cause of subsidence. Our findings suggest that SAR interferometric time series analysis is helpful for proactively identifying and controlling subsidence difficulties in mining regions by closely monitoring activities, hence reducing negative consequences on operations and the environment.

Tropical forest cover, oil palm plantations, and precipitation drive flooding events in Aceh, Indonesia, and hit the poorest people hardest.

Tropical forest loss and degradation in watersheds disrupt essential ecosystem services that regulate water flow, often causing devastating floods that impact agricultural productivity and impoverish downstream communities. Despite its importance, evaluations of the interconnectedness between the depletion of hydrological services and flooding lack an evidence-base in the Global South and, therefore, have little influence on policy dialogue. In this study, we focus on the forest-rich province of Aceh, Indonesia, using local and national newspaper articles to compile information on flood events between 2011 and 2018. We explored spatio-temporal flood patterns with a combination of climatic, topographic, and environmental factors. We compiled 2,029 reported flood events in mainland Aceh located in 20 of the 21 districts/cities, with a disproportionately high occurrence (71%) in four districts. The trend of flood events exhibited an increasing pattern between 2011 and 2018. Over this period, floods displaced ~158,000 people and damaged ~24,500 houses and ~11,500 ha of agricultural land. Our generalized linear mixed-effect model found that reported flood events were more likely to occur in areas with lower tree cover, more oil palm plantations, and higher precipitation. Areas with a lower human population density and higher poverty rates were found to be most susceptible to flooding events. Our findings highlight the critical link between forest preservation and flood prevention, and the irreplaceable role that forests play in ensuring the well-being of local communities, especially those affected by poverty. Our study underscores the importance of considering these interconnected factors in future land use and economic development plans and policies.

Quantitative analysis of the contribution of moisture recycling to precipitation in the cold region

This study quantitatively analyzed the contribution rate of recycled moisture to precipitation in the basin based on the Craig-Gordon model and the three-end-member mixing model through selecting 456 precipitation sample data collected from six sampling points in the source region of the Yellow River from September 2019 to August 2021. The results showed that: the contribution rate of moisture recycling to precipitation during the growing season is 40 %, and the total contribution to local moisture recycling is equivalent to 41 mm of precipitation. The contribution rate of evaporation and transpiration has obvious seasonal variation characteristics, showing a trend of decreasing first and then increasing in the source region of the Yellow River. Spatially, the contribution rate of evaporation and transpiration showed an increasing trend from south to north. It is assumed that all the precipitation generated by moisture recycling produces runoff, and the water yield is about 51 × 108 m3, which is 25 % of the total annual average runoff. In addition, the proportion of local moisture recirculation is mainly related to altitude, topography, vegetation coverage, and meteorological factors. Moisture recirculation is one of the important sources of precipitation in the source region of the Yellow River.

Once Common, Long in Decline: Dynamics of Traditional Orchards in a Central European Landscape

Traditional orchards are distinctive features of cultural landscapes in Central Europe. Despite their high level of ecological importance, they are in decline, and comprehensive spatial data over broad extents, which could enable a trend analysis, are lacking. We analysed traditional orchard maps from 1952 to 1967 and a map from 2010, generated via aerial image interpretation, for the state of Hesse (ca. 21,115 km2), which has the second largest share of traditional orchards in Germany. We aimed to (1) quantify long-term orchard dynamics, (2) compare orchard characteristics in terms of topographical, ecological, and socioeconomic factors, and (3) identify key drivers of orchard loss. We found that the number and area of orchards have clearly decreased across Hesse, with varying local and regional patterns. Further, historically old orchards tended to have a larger area, higher shape complexity, and were located closer to settlements, highways, and neighbouring orchards. In contrast, newly established orchards were often found at higher elevations and on steeper slopes. Finally, the three historical orchard hotspots also experienced the most notable losses driven by different factors, namely the expansion of Artificial Surfaces, Residential Buildings, and Agricultural Land. We highlight the importance of such multitemporal spatial data for a wide range of ecological applications, and we encourage the use of novel technologies to support geospatial analyses in the future.

A modified Soil and Water Assessment Tool Plus (M-SWAT+) model for sediment yield estimation

ABSTRACT The Soil and Water Assessment Tool Plus (SWAT+) model depends on the Modified Universal Soil Loss Equation (MUSLE), which in turn depends on the peak runoff rate for the estimation of soil loss from a catchment. The SWAT+ model generates a random number for each day in the process of peak runoff rate estimation from the catchment. On the other hand, the model provides calibration parameters like the peak rate adjustment factor for sediment routing in the tributary channels and main channels. There is uncertainty that how likely the SWAT+ model estimates the actual peak runoff rates. An improved MUSLE does not depend on the peak runoff rate, and, therefore, it minimizes uncertainty related to the peak runoff rate when estimating soil loss from the catchment in the SWAT+ environment. On the other hand, the effect of the topographic factor of the MUSLE or improved MUSLE on soil erosion and sediment transport is not explicitly explained. Therefore, we modify the source code of the SWAT+ model for sediment yield estimation by replacing the improved MUSLE and the best-fitted equations of the topographic factor in the source code. The modified SWAT+ model showed better performance than the original SWAT+ model.

Analysis of short- and long-term controls on the variability of event-based runoff coefficient

Study regionThis study focuses on the Ohio Region, which spans 11 states in the eastern United States. Study focusRunoff coefficients are crucial in hydrology, indicating the relationship between rainfall and runoff. Understanding their controls and variability is essential for water resource assessment, management strategies, and land use planning. This research examines factors influencing runoff coefficients and their trends in the Ohio region using data from the North American Land Data Assimilation System phase-2 (NLDAS-2) Mosaic Land Surface Model, covering 2000–2020. The analysis considers short-term controls, such as climatic features (rainfall intensity, amount, and duration), hydrological factors (antecedent soil moisture, drainage density, and curve number), topographic factors (drainage area, land use, slope, elevation), and watershed shape. Additionally, the study investigates trends in runoff coefficients and their long-term controls, including climatic factors and land use changes. New hydrological insights for the regionThe findings indicate that runoff coefficients increase with antecedent soil moisture and rainfall intensity. Higher elevations show lower runoff coefficients due to forested land use. Larger watersheds have lower runoff coefficients at low rainfall intensity but higher ones when intensity is high. Long-term trends reveal soil moisture as the primary control, with land cover changes as a secondary factor. This research deepens understanding of runoff coefficient dynamics and controls in the Ohio region. Future studies could explore the impacts of urbanization, reservoirs, evapotranspiration, and snowmelt on runoff coefficients.

Estimation and Spatial Distribution of Individual Tree Aboveground Biomass in a Chinese Fir Plantation in the Dabieshan Mountains of Western Anhui, China

Understanding aboveground biomass (AGB) and its spatial distribution is key to evaluating the productivity and carbon sink effect of forest ecosystems. In this study, a 123-year-old Chinese fir forest in the Dabieshan Mountains of western Anhui Province was used as the research subject. Using AGB data calculated from field measurements of individual Chinese fir trees (diameter at breast height [DBH] and height) and spectral vegetation indices derived from unmanned aerial vehicle (UAV) remote sensing images, a random forest regression model was developed to predict individual tree AGB. This model was then used to estimate the AGB of individual Chinese fir trees. Combined with digital elevation model (DEM) data, the effects of topographic factors on the spatial distribution of AGB were analyzed. We found that remote sensing spectral vegetation indices obtained by UAVs can be used to predict the AGB of individual Chinese fir trees, with the normalized difference vegetation index (NDVI) and the optimized soil-adjusted vegetation index (OSAVI) being two important predictors. The estimated AGB of individual Chinese fir trees was 339.34 Mg·ha−1 with a coefficient of variation of 23.21%. At the local scale, under the influence of elevation, slope, and aspect, the AGB of individual Chinese fir trees showed a distribution pattern of decreasing from the middle to the northwest and southeast along the northeast-southwest trend. The effect of elevation on AGB was influenced by slope and aspect; AGB on steep slopes was higher than on gentle slopes, and the impact of slope on AGB was influenced by aspect. Additionally, AGB on north-facing slopes was higher than on south-facing slopes. Our results suggest that local environmental factors such as elevation, slope, and aspect should be considered in future Chinese fir plantation management and carbon sink assessments in the Dabieshan Mountains of western Anhui, China.

Assessing habitat suitability for aoudad (Ammotragus lervia) reintroduction in southeastern morocco to promote ecotourism

The objective of this study is to address the complex task of identifying optimal locations for reintroducing Ammotragus lervia in a semi-arid area in the Eastern High Atlas of Morocco, considering three topographical factors. The study assesses the effectiveness of a commonly used machine learning classifier (MLC) in mapping potential areas for introducing these species, which is crucial for promoting and enhancing local biodiversity. To begin with, an extensive inventory of 88 remaining sites where these Barbary sheep still living was conducted, and precise measurements of three topographical parameters were collected at each site. Subsequently, a machine learning algorithm called Bagging was employed to develop a predictive model. The predictive model demonstrated a high level of performance, as evidenced by an area under the curve (AUC) value of 0.929. Bagging effectively identified favorable areas, encompassing around 13.8 % of the study region, which were predominantly located in the western part. These areas were characterized by mountainous terrain, shorter slopes, and higher altitudes. The research findings provide valuable guidance to decision-makers, offering a roadmap to reintroduce these species for enhancing the local biodiversity in the region.

Spatiotemporal variation and GeoDetector analysis of NDVI at the northern foothills of the Yinshan Mountains in Inner Mongolia over the past 40 years

The study of spatiotemporal variation and driving forces of the normalized difference vegetation index (NDVI) is conducive to regional ecosystem protection and natural resource management. Based on the 1982–2022 GIMMS NDVI data and 26 influencing variables, by using the Theil-Sen median slope analysis, Mann-Kendall (M-K) test method and GeoDetector model, we analyzed the spatial and temporal characteristics of vegetation cover and the driving factors of its spatial differentiation in the northern foothills of the Yinshan Mountains in Inner Mongolia. The NDVI showed a significantly increasing trend during 1982–2022, with a growth rate of 0.0091 per decade. It is further predicted that future change in NDVI will continue the 1982–2022 trend, and sustainable improvement will dominate in the future; however, 17.69% of vegetation will degrade, that is, NDVI will degrade instead of improvement.. The spatial distribution of the NDVI in the northern foothills of the study area was generally characterized by high in the east and low in the west. Annual precipitation (Pre), evapotranspiration (Evp), relative humidity (Rhu) and sunshine hours (Ssd) had > 70% explanatory power (73.5, 79.9, 79.0, and 74.9%, respectively). The explanatory power of edaphic factors was > 30%, whereas anthropogenic and topographic factors had little influence on the spatial variation of NDVI, with an explanatory power of < 30%. Thus, climatic factors were the dominant factors influencing the spatial variability of NDVI in the study area. The results of the interaction detector analysis showed nonlinear strengthening for any two factors, and the interaction between Rhu and barometric pressure had the highest explanatory power. There were optimal ranges or characteristics of each factor that promoted vegetation growth. This study investigated the differences in the explanatory power of different factors on the NDVI and the optimal range of individual factors to promote vegetation growth, which can provide a basis for the development of vegetation resource management programs.

Modeling of the spatial distribution of species of interest in agriculture for their conservation: case of Punica granatum L.

Abstract Modeling the spatial distribution of species is an important step in biodiversity conservation. The models used can be helpful in predicting the impacts of climate change on the geographical distribution of species and in identifying areas where they are most likely to occur. The purpose of this work was to model the spatial distribution of the pomegranate species (Punica granatum L.) in Morocco according to the principle of maximum entropy (Maxent). This modelling method is widely used in ecology and biogeography because of its ability to work with datasets, and to produce accurate predictions of species distribution. Based on agro-ecological data such as topographical factors and climatic variables and focusing on regions where pomegranate cultivation is significant, these data can be collected at different spatial and temporal scales. They are typically integrated into Geographic Information Systems (GIS) for utilization within the simulation model. The resulting model depicts the potential spatial distribution of pomegranate cultivation throughout Morocco. The model obtained agrees perfectly with the actual distribution of the species in different regions of the country, especially since it is known for its hardiness and its adaptation to variable environmental conditions. Thus, the modeling showed that other geographical areas present favorable conditions for the development of pomegranate cropping. The determination of spatial distribution constitutes a first step to predict possible evolution of the pomegranate cropping according to climate change. The importance of this process for biodiversity conservation lies in several aspects, such as the identification of areas at risk, conservation planning, and the assessment of impacts on ecosystems.

Spatial Analysis of Chronic Kidney Disease of Unknown Aetiology (CKDu) Prevalence in Badulupura Village, Sri Lanka

This study investigated spatial patterns of chronic kidney disease of unknown aetiology (CKDu) patients in Badulupura village. The analysis utilized published locational data for all households, including households affected by CKDu, and all wells used by CKDu-affected patients (CPA wells). The study employed Average Nearest Neighbour (ANN) and Hot Spot Analysis (Getis-Ord Gi*) tools to assess the spatial clustering of CKDu households and CPA wells. The study also explored the impact of topographical factors such as elevation, slope, and distance to watershed boundaries on the spatial distribution of CKDu patients. The ANN analysis revealed a dispersed pattern for all wells, and a random distribution for all households. However, both CKDu households and CPI wells exhibited a clustered pattern, suggesting a location-specific cause for the spatial distribution of the disease. Additionally, overlaying CKDu-affected households on the digital elevation model revealed a concentration of CKDu hot spots in high-elevation areas, while cold spots were observed in low-elevation regions. Furthermore, the t-test was employed to investigate the significance of elevation, slope, and distance to the watershed boundaries in relation to CKDu distribution. The results indicated a significant (p&lt;0.05) prevalence of CKDu in high-elevation areas, while no significant association was found with slope or distance to watershed boundaries. The study revealed the presence of localized CKDu hot spots and cold spots within a small geographical area, highlighting the importance of considering topographical factors and conducting comprehensive hydrogeological and geological studies to gain valuable insights into the spatial distribution of CKDu.

PERTURBATION IN MEANDER BEHAVIOUR OF A SUBTROPICAL RIVER IN INDIA UNDER VARIABLE NATURAL AND ANTHROPOGENIC CONTROLS

Meander morphology is perturbed worldwide by human interventions to a certain extent in the Anthropocene. To this end, the present study aims to investigate the meander behaviour, including its deformations, of the Kopai River, a subtropical river in India in the last 50 years (1970-2020). A total of 394 loops (134 loops each in 1970 and 1995 and 126 loops in 2020) were selected for the four river reaches – the upper, middle-upper, middle-lower, and lower reaches. The meandering behaviour was assessed using Mueller’s sinuosity index (SI), meander form index, meander shape index, and radius/wavelength ratio. The study found a higher meandering tendency in the lower and upper reaches controlled by fluvial hydraulics, and topographic factors. However, the middle reaches were comparatively stable. The meander loops along the middle reaches regular meander is the dominant meander type, however, more than 50% of meander loops for the lower reaches were intense meander types. Positive extensions were the predominant type of meander deformation in all the reaches. However, few negative extensions are found in the middle-upper and lower reaches, while irregular changes and cut-offs were only found in the lower reach. Thus, the upper and lower reaches exhibited more natural controls dotted with regular meander progression. The middle reaches characterized by higher Bouguer anomaly and steep basement gradient led to channel confinement. Besides, profuse sand mining and the brick kiln industries are perturbing the meander beahviour through human channel straightening, dwarfing the meander evolution in the middle reaches.

GIS and remote sensing-based wildlife habitat suitability analysis for mountain nyala (Tragelaphus buxtoni) species mapping at Bale Mountains National Park, Ethiopia

Ethiopia's Bale Mountains National Park protects the continent's largest remaining alpine environments. This park was first suggested in 1973 to safeguard its great biodiversity, including the endangered Mountain Nyala (Tragelaphus buxtoni) and Red Foxes. Despite these conservation measures, the lack of infrastructure and the enormous area projected have resulted in significant wildlife habitat fragmentation. The purpose of this study is to analyse the habitat appropriateness of the Mountain Nyala in Bale Mountains National Park using GIS and remote sensing technologies in order to inform conservation efforts and assist park managers in making decisions. To identify potential habitats for the Mountain Nyala, the study employed GIS spatial analyst techniques such as the Digital Elevation Model (DEM) and Landsat 9 (OLI/TIRS) data, as well as key environmental factors such as vegetation types, soil types, topographic factors (elevation and slope), climate factors (temperature), and proximity factors (distance to settlements, roads, and rivers). The Weights of these factors was calculated using IDRISI32 Multi-Criteria Evaluation (MCE) with the pair-wise comparison method. These weighted factor maps were then integrated through weighted overlay analysis to model wildlife habitat suitability. The analysis revealed five classes of habitat suitability; of the total land area studied, 1326.7 km2 (60%) was deemed suitable for the Mountain Nyala while 881.3 km2 (40%) was unsuitable. Specifically, 327.4 km2 (15%) was classified as highly suitable, 240.7 km2 (11%) as moderately suitable, 758.6 km2 (34%) as marginally suitable, 352.4 km2 (16%) as currently not suitable, and 528.9 km2 (24%) as permanently not suitable. The majority of suitable habitats are concentrated in the northern part of the park, along the western border, and in the Harrena forest area. This study provides vital insights into habitat suitability that are crucial for the conservation of the Mountain Nyala and the overall management of the park.

Spatiotemporal characteristics and socio-ecological drivers of ecosystem service interactions in the Dongting Lake Ecological Economic Zone

Uncovering the spatiotemporal characteristics of ecosystem services and their complex interactions is a prerequisite for managing multiple simultaneously. However, the prior research has predominantly overlooked cultural service objects and neglected the indirect socio-ecological impact pathways on ecosystem services. To delve into the dynamics and developmental trends of ecosystem alterations prior to and following the inception of an Eco-Economic Zone, this study quantitatively assessed four pivotal ecosystem services within the Dongting Lake Ecological Economic Zone spanning from 2000 to 2020. These services encompassed:crop production(CP), carbon sequestration(CS), habitat quality(HQ), and forest recreation (RS). The trade-offs and synergies between them were explored, and the driving mechanism of ecosystem services was explained based on the partial least squares-structural equation model (PLS-SEM). The results revealed that: (1) during the study timeframe, the crop production witnessed a pronounced upward trajectory, whereas the carbon sequestration, habitat quality and forest recreation remained relatively stable. Notably, the low habitat quality area (HQ ≤ 0.3) has been expanding, with a growth rate of 29.4 %; (2) the most trade-offs were observed between crop production and other ecosystem services, among which the trade-off effect between crop production and habitat quality was the strongest, with the highest average proportion of trade-off area, reaching 57.8 %. Among the six ecosystem service pairs, two are in a state of deterioration: the crop production and forest recreation, the carbon sequestration and habitat quality; (3)topographic factors were identified as the primary drivers of crop production, carbon sequestration, and habitat quality, whereas forest recreation was chiefly influenced by landscape configuration factors. Land use intensity and landscape configuration played crucial intermediary roles, with socio-economic elements adversely impacting all four ecosystem services directly, yet significantly contributed to the crop production and carbon sequestration through Suppression Effects. The research endorses the combined utilization of lake area land to improve human welfare, based on the principle of protecting the primary services of various functional sub-regions.