Mountain Environments Research Articles

New Ediacaran biota from the oldest Nama Group, Namibia (Tsaus Mountains), and re-definition of the Nama Assemblage

AbstractThe Nama Group, Namibia (≥550.5 to <538 million years ago, Ma), preserves one of the most diverse metazoan fossil records of the terminal Ediacaran Period. We report numerous features that may be biological in origin from the shallow marine, siliciclastic, lowermost Mara Member (older than ca. 550.5 Ma) from the Tsaus Mountains. These include forms that potentially represent body fossils,Beltanelliformisand an indeterminate juvenile uniterminal rangeomorph or arboreomorph frond, plug trace fossils,Bergaueria, as well as sedimentary surface textures, which are possibly microbially induced. These are the oldest documented macrofossils in the Nama Group. They represent taxa that persist from the Avalon or White Sea assemblages prior to the later appearance of new biota, including calcified metazoans, calcified and soft-bodied tubular taxa including all cloudinids, as well as more complex trace fossils.Using a new age model that allows more accurate stratigraphic placement of major Ediacaran macrofossil morphogroups and taxa, we propose a re-definition of the Nama Assemblage following the practice for Phanerozoic evolutionary faunas to include only new morphogroups of soft-bodied tubular, calcified taxa and complex trace fossils, defined by first appearance ofCloudina, which postdates deposition of the Kanies and lower Mara members and first appears ca. 550 Ma and persists until at least 539 Ma.Finally, the Tsaus Mountain environment is pristine, unspoilt by geologists and naturalists. Following World Heritage Convention, we suggest a pledge of non-destructive excavation that all future scientists should be able to make in publications of work that involve research in this area.

Characterization and sources of water-soluble organic species in PM2.5 in a remote mountain environment in Southeastern China

A comprehensive campaign was conducted in 2014–2015 to characterize and identify potential sources of water-soluble organic matter (WSOM) in a remote mountain area in Southeastern China. Weekly measurements of PM2.5 and its dominant chemical components, including organic carbon (OC), elemental carbon (EC), water-soluble inorganic ions (WSIIs), water-soluble organic carbon (WSOC), Humic-like Substances (HULIS), water-soluble organic species (sugar alcohols, anhydrosugars, primary sugars, and carboxylic acids), and trace elements were conducted. PM10, PM2.5, NO2, O3, and meteorological parameters were also routinely measured at the same site. WSOM was dominated by HULIS (49%), carboxylic acids (12%), and saccharides (3%, a sum of sugar alcohols, anhydrosugars, and primary sugars). Carboxylic acids exhibited a flat seasonal variation, while high mass concentrations of sugar alcohols and anhydrosugars were observed in summer and winter, respectively. The converting factor from WSOC to WSOM was estimated to be 2.1 for this mountain site. Six major source factors were identified for WSOM using positive matrix factorization (PMF) analysis, which include aqueous processes, biogenic secondary organic aerosols (SOAs), biomass burning, mixed urban aerosols, soil dust, and secondary nitrate. These factors contributed 34 ± 22%, 20 ± 24%, 18 ± 18%, 14 ± 8%, 10 ± 13%, and 5 ± 10%, respectively, to annual WSOM mass concentration. Results of this study suggest that aqueous chemical reactions of gaseous pollutants during the transport process, the transport of biomass burning, urban aerosols and dust storm, and local formation of biogenic SOAs contributed to WSOM in the remote area of Southeastern China.

A Novel Integrated Spatiotemporal-Variable Model of Landscape Changes in Traditional Villages in the Jinshaan Gorge, Yellow River Basin

Spatiotemporal studies of landscape pattern evolution in traditional villages are beneficial for addressing complex urbanization and global climate change. Using the traditional villages of Jiaxian and Linxian in the Jinshaan Gorge of the Yellow River Basin, this study employed a three-dimensional (3D) analysis involving three spatial scales (macro, meso, and micro), temporal scales (past, present, and future), and variables (humanity, society, and nature) based on the methods of spatiotemporal data analysis (SDA), geographic information system, remote sensing, and landscape pattern index (LPI) by Fragstats. On the macro scale, a significant turning point in ecological conservation awareness was indicated by LPI and SDA. Urban and rural construction land continuously increased because of urbanization. Plowland, grassland, and woodland were the main influencing factors in the evolution of rural settlements, with a 0.42% cumulative transformation rate. On the meso scale, the interactions and mutual promotion of mountain and aquatic environments, aquatic facilities, agricultural production, and cultural heritage have shaped the socioeconomic dimensions of evolution. On the micro scale, with urbanization, some traditional humanistic spaces have lost their original functions. A novel spatiotemporal-variable quantitative model explored the spatiotemporal evolution characteristics of human–land coupling, which can be used for the sustainable development of river basins worldwide.

Landslide risk evaluation and its causative factors in typical mountain environment of China: a case study of Yunfu City

The urban area of Yunfu City is a typical mountain environment with the thin surface soil layer, broken terrain, and the fragile geological environment, which is a landslide hazard prone region, seriously threatening the safety of residents' lives and property. It is crucial to accurately reveal the landslide risk and its causative factors to develop regional geological disaster prediction and mitigation strategies. However, the risk assessment and cause analysis of landslides in Yunfu City are rarely studied at present. Therefore, this study selects 11 causative factors (elevation, slope, slope aspect, bedding structure, distance from fault, lithology, precipitation, distance from water, normalized vegetation index (NDVI), distance from road, and land use), and integrates the modified frequency ratio model and geographic detector method to analyze the spatial distribution pattern of landslide risk and its causative factors. The results indicate that the maximum predicted area under the receiver operating characteristic curve (AUC) and the average predicted AUC of the modified frequency ratio model perform best at the precision of 5, with the values of 0.83921 and 0.81872, respectively, which can accurately reveal the landslide risk evaluation in the study area. According to the experimental results, the landslide risk in the study area generally shows a trend of high in the north and low in the south. Besides, the overall risk of landslide hazards is low, with the area of very low grade and low grade accounting for 75.20% of the total area. Among the selected 11 potential factors, precipitation, NDVI, slope aspect, distance from water and slope are the main causative factors to induce landslide hazards. Furthermore, this study also describes in detail the combination of factors that are conducive to landslide hazards, which can provide a decision basis for relevant departments to carry out regional landslide hazards prevention and mitigation strategies, and can also provide a reference for geological hazard risk evaluation study in other mountain environment.

Flood and drought susceptibility zonation in the mountain environment: a case study of Upper Siang district, Eastern Himalayas, India

Flood and drought susceptibility zonation in the mountain environment: a case study of Upper Siang district, Eastern Himalayas, India

Go or grow? Feedbacks between moving slopes and shifting plants in high mountain environments

High mountains are climate change hotspots. Quickly rising temperatures trigger vegetation shifts such as upslope migration, possibly threatening mountain biodiversity. At the same time, mountain slopes are becoming increasingly unstable due to degrading permafrost and changing rain and snowfall regimes, which favour slope movements such as rockfall and debris flows. Slope movements can limit plant colonization, while, at the same time, plant colonization can stabilize moving slopes. Thus, we here propose that response of high mountain environments to climate change depends on a ‘biogeomorphic balance’ between slope movement intensity and the trait-dependent ability of mountain plants to survive and stabilize slopes. We envision three possible scenarios of biogeomorphic balance: (1) Intensifying slope movements limit vegetation shifts and thus amplify instability. (2) Shifting ecosystem engineer species reduce slope movement and facilitate shifts for less movement-adapted species. (3) Trees and tall shrubs shifting on stable slopes limit slope instability but decrease biodiversity. Previous geomorphic, ecological and palaeoecological studies support all three scenarios. Given differences in ecologic and geomorphic response rates to climate change, as well as high environmental heterogeneity and elevational gradients in mountain environments, we posit that future biogeomorphic balances will be variable and heterogeneous in time and space. To further unravel future biogeomorphic balances, we propose three new research directions for joint research of mountain geomorphologists and ecologists, using advancing field measurement, remote sensing and modelling techniques. Recognizing high mountains as ‘biogeomorphic ecosystems’ will help to better safeguard mountain infrastructure, lives and livelihoods of millions of people around the world.

Optimal Energy Consumption Path Planning for Unmanned Aerial Vehicles Based on Improved Particle Swarm Optimization

In order to enhance the energy efficiency of unmanned aerial vehicles (UAVs) during flight operations in mountainous terrain, this research paper proposes an improved particle swarm optimization (PSO) algorithm-based optimal energy path planning method, which effectively reduces the non-essential energy consumption of UAV during the flight operations through a reasonable path planning method. First, this research designs a 3D path planning method based on the PSO optimization algorithm with the goal of achieving optimal energy consumption during UAV flight operations. Then, to overcome the limitations of the classical PSO algorithm, such as poor global search capability and susceptibility to local optimality, a parameter adaptive method based on deep deterministic policy gradient (DDPG) is introduced. This parameter adaptive method dynamically adjusts the main parameters of the PSO algorithm by monitoring the state of the particle swarm solution set. Finally, the improved PSO algorithm based on parameter adaptive improvement is applied to path planning in mountainous terrain environments, and an optimal energy-consuming path-planning algorithm for UAVs based on the improved PSO algorithm is proposed. Simulation results show that the path-planning algorithm proposed in this research effectively reduces non-essential energy consumption during UAV flight operations, especially in more complex terrain scenarios.

The impact of cold, hypoxia, and physical exertion on pistol accuracy and tactical performance

The purpose of this study was to examine the impact of independent cold and combined cold and hypoxic exposures on operational-specific task performance including pistol marksmanship, pistol magazine reload ability, and subjective and objective thermal indices before and after a whole-body physical exertional task. Twelve participants were exposed to Thermoneutral Normoxic (24 °C; FiO2 21%), Cold Normoxic (10 °C; FiO2 21%), and Cold Hypoxic (10 °C; FiO2 14%) conditions for 30min before performing pistol marksmanship at distances of 6.40 and 13.72m and a pistol magazine reload task before and after 3 sets of sandbag deadlifts at 50% body mass. Thermal perception and hand temperatures were collected before and after the physical exertion task. There were no significant differences in Pistol Accuracy performance at distances of 6.40 and 13.72m due to physical exertion, cold, or hypoxia. Following physical exertion, Pistol Accuracy was similar between Thermoneutral and Cold Normoxic conditions but lead to 17% and a 10% reduction in performance during the Cold Hypoxic condition, compared to Thermoneutral and Cold Normoxic conditions. There was no change in Pistol Accuracy for the Thermoneutral Normoxic condition. The pistol magazine reload task was not impacted by physical exertion, but there was a reduction in performance in Cold Normoxic 21% (4.04s) and Cold Hypoxic 16% (3.08s) conditions. Physical exertion did not impact hand temperature but did increase thermal perception scores for all conditions. These findings indicate that cold exposure reduced both tactical dexterity and pistol marksmanship, however, physical exertion may offset these deficits via an increase in thermal perception. Additionally, hypoxemia was the primary mediator of marksmanship performance in cold hypoxic environments following an acute bout of physical exertion. Thus, in cold mountainous environments, marksmen should be aware of their elevation and utilize brief episodes of physical activity to enhance their thermal state when marksmanship is a priority for operational success.

Isotope-derived young water fractions in streamflow across the tropical Andes mountains and Amazon floodplain

Abstract. The role of topography in determining water transit times and pathways through catchments is unclear, especially in mountainous environments – yet these environments play central roles in global water, sediment, and biogeochemical fluxes. Since the vast majority of intensively monitored catchments are at northern latitudes, the interplay between water transit, topography, and other landscape and climatic characteristics is particularly underexplored in tropical environments. To address this gap, here we present the results of a multiyear hydrologic sampling campaign (twice-monthly and storm sampling) to quantify water transit in seven small catchments (<1.3 km2 area) across the transition from the Andes mountains to the Amazon floodplain in southern Peru. We use the stable isotope composition of water (δ18O) to calculate the fraction of streamflow comprised of recent precipitation (“young water fraction”) for each of the seven small catchments. Flow-weighted young water fractions (Fyw) are 5 %–26 % in the high-elevation mountains, 22 %–52 % in the mid-elevation mountains, and 7 % in the foreland floodplain. Across these catchments, topography does not exert a clear control on water transit; instead, stream Fyw is apparently controlled by a combination of hydroclimate (precipitation regime) and bedrock permeability. Mid-elevation sites are posited to have the highest Fyw due to more frequent and intense rainfall; less permeable bedrock and poorly developed soils may also facilitate high Fyw at these sites. Lowland soils have low Fyw due to very low flow path gradients despite low permeability. The data presented here highlight the complexity of factors that determine water transit in tropical mountainous catchments, particularly highlighting the role of intense orographic precipitation at mountain fronts in driving rapid conveyance of water through catchments. These results have implications for the response of Earth's montane “water towers” to climate change and for water–rock reactions that control global biogeochemical cycles.

Climate change and health in rural mountain environments: summary of a workshop on knowledge gaps, barriers, and opportunities for action

Climate change and health in rural mountain environments: summary of a workshop on knowledge gaps, barriers, and opportunities for action

The effects of grazing and fencing on grassland productivity and diversity in alpine grassland ecosystem in the Tibetan highland

Anthropogenic activities, such as grazing and fencing, have been known to alter the productivity and biodiversity of grassland ecosystems, potentially affecting their functioning. However, the impact of these activities on aboveground biomass (AGB) and plant diversity in alpine grasslands at different altitudes, as well as how they may be affected by soil nutrients and environmental climate, is not well understood. To address this knowledge gap, a study was conducted in the Lhasa Valley of Tibet. In 2013, twelve metal fences were set up at mountainous transects, and field surveys were conducted at twelve paired sites in early August 2021. The results of the study showed that AGB was slightly higher in fenced sites compared to grazed sites at altitudes from 4000 to 5100 m, but decreased with altitude at a slower rate in grazed sites. Plant diversity indices exhibited a unimodal pattern with increasing altitude, with no significant differences between fenced and grazed sites. Soil nutrients and environmental climate were found to be positively correlated with plant diversity indices and AGB at both fenced and grazed sites. Multiple linear regression models revealed that AGB and the Shannon index were largely influenced by soil nutrients (AP and AN) rather than by growing season soil temperature at fenced sites, while AGB and the Shannon index were more impacted by growing season soil temperature than by soil nutrients at grazed sites. These findings provide important insights into the impacts of grazing and fencing on above-ground biomass and plant diversity in mountainous environments.

Geological Hazard Assessment of Secondary Collapses Due to Volcanic Earthquakes on Changbai Mountain in China

In recent years, the volcanic activity of Changbai Mountain has been accompanied by several earthquakes, and the frequent human engineering activities have led to a gradual increase in the number of collapses in the region, which severely impacts residents’ lives and property safety. In northeastern China, the Changbai Mountain area in the southeastern Jilin Province is a typical mountain environment. This paper selects 12 evaluation indicators to build a hazard assessment system, including slope, aspect, elevation, curvature, lithology, NDVI, land use type, distance from the fault, the river from the road, volcanic earthquake, and annual average precipitation. Using emotional weight (G1 method) and objective weight (WOE-CV method), the hazard due to collapses in the study area is evaluated too. Among them, the transcendence probability of volcanic earthquakes greater than VI degree represents the relationship between Changbai Mountain volcanic earthquakes and the assessment of geological collapse hazard. The results show that high- and very high-hazard areas are mainly distributed in densely populated areas and national and provincial trunk lines, with apparent spatial agglomeration characteristics. The low-hazard area, medium-hazard area, high-hazard area and very high-hazard area accounted for 19.33%, 44.19%, 33.85% and 2.63% of the total area of the study area, respectively. By comparing the previous geological hazard survey reports in the area with the collapse hazard zoning map in this paper, 87.72% of the known collapse hazard areas are distributed within high and very high hazard zones, indicating that the conclusions of the article are more accurate and in line with the actual situation. Results from collapse-related hazards can provide relevant guidance for preventing and controlling geological risks posed by volcanic earthquakes affecting Changbai Mountain.

Machine learning-based digital mapping of soil organic carbon and texture in the mid-Himalayan terrain.

Mountain soils have received significant attention due to their profound influence on ecological processes and environmental factors. However, mapping these soils in digital soil mapping technique encounters several challenges, including high local variability, non-linear relationships between environmental covariates and soil properties, limited accessibility in complex topographical settings, and the absence of universally applicable covariates for soil formation. To address these issues, this study integrates soil-forming factors of the scorpan model to map soil organic carbon (SOC) and soil texture in the mid-Himalayas. By considering over 100 environmental covariates, with a focus on terrain parameters relevant to mountainous environments, the study aims to enhance the accuracy of ML regression models through augmentation techniques that overcome data insufficiency. Using augmented soil observations and covariates, a non-parametric random forest regression model is trained and applied to predict soil variables across the study area, generating a continuous fine-resolution map. The model's performance, evaluated against an unknown dataset, was significant with an R-square of 0.80, 0.79, 0.72, and 0.84 for clay, sand, silt, and SOC, respectively. Furthermore, a sensitivity analysis of the environmental covariates and their impact on the model revealed that all the soil-forming factors make a significant contribution to the model's effectiveness. The insights gained from this research contribute to a better understanding of mountain soils and facilitate the development of effective conservation and sustainable management strategies for mountainous regions.

Prescribed fire application in a Brazilian mountain environment: Changes in soil organic matter quality in the short and medium term

Prescribed fire (PF) is a management practice used ecosystems where the occurrence of wildfires is high due to the accumulation of biomass on the surface. In general, studies dealing with fire-affected soils evidence the degradation of less thermo-labile structures, with the preservation of more thermo-stable phases. As studies in mountain environments in Brazil are scarce and considering that the practice of PF has been on the rise in recent years, the present study aimed to quantifying and characterizing the impact of PF on soil organic matter in the Itatiaia National Park, Rio de Janeiro-Brazil. In a 240 days period, we assessed the impact of PF on soil pH, base cations release, available P, C and N contents and stocks, soil organic matter (SOM) quality. Among other techniques, we applied ATR-FTIR and 13 C NMR spectroscopy. Soil chemical and physical attributes were also quantified. At 10 days, PF application caused the release of labile organic carbon (LOC) forms, inducing an increase in content of humic fractions in the form of C-FA and C-HA. The humification process, nevertheless, occurred at a lower speed than the incorporation of LOC. Humin contents, in fact, did not systematically increase with time. At 10 days following PF, a decrease in carbohydrates and peptides occurred, with greater HA aromaticity. After 240 days since PF, the structural characteristics of HA were restored to levels like the original (pre-PF) condition. At 120 days after PF, the pH value, base saturation, Mg, Na and P increased in soil. However, the amount of C and N accumulated in the soil did not increase with PF application. We observed that up to 120 days of PF, the mineralization process seems to occur in priority over humification. A period longer than 240 days seems anyway needed to restore soil C and N stocks.

Class A Prediction Symposium on Debris Flow Impact Forces on Single and Dual Barriers

Over recent years, significant advances have been made in the modelling of the impact dynamics between debris flows and single and dual rigid and flexible barriers. Numerical tools and analytical formulations have been proposed to predict the impact force, runup height, barrier deformation, and overflow and landing dynamics. However, there remains a dearth of well-recognised tools that can be used in routine engineering design practice because their reliability is unclear. On 8 and 9 May 2022, a virtual Class A Prediction Symposium on Debris Flow Impact Forces on Single and Dual Barriers was held to evaluate the reliability of existing design tools and identify areas for improvement to advance the current state of barrier design. The symposium was organised by The Hong Kong University of Science and Technology, Norwegian University of Science and Technology, Institute of Mountain Hazards and Environment of the Chinese Academy of Sciences, and the Geotechnical Engineering Office of the Civil Engineering and Development Department of the HKSAR Government. This paper summarises the existing research on flow-barrier interaction, and details of the symposium, including the prediction cases and results, roundtable discussion, and future research directions.

Comparison of two individual identification algorithms for snow leopards (Panthera uncia) after automated detection

Photo-identification of individual snow leopards (Panthera uncia) is the primary data source for density estimation via capture-recapture statistical methods. To identify individual snow leopards in camera trap imagery, it is necessary to match individuals from a large number of images from multiple cameras and historical catalogues, which is both time-consuming and costly. The camouflaged snow leopards also make it difficult for machine learning to classify photos, as they blend in so well with the surrounding mountain environment, rendering applicable software solutions unavailable for the species. To potentially make snow leopard individual identification available via an artificial intelligence (AI) software interface, we first trained and evaluated image classification techniques for a convolutional neural network, pose invariant embeddings (PIE) (a triplet loss network), and compared the accuracy of PIE to that of the HotSpotter algorithm (a SIFT-based algorithm). Data were acquired from a curated library of free-ranging snow leopards taken in Afghanistan between 2012 and 2019 and from captive animals in zoos in Finland, Sweden, Germany, and the United States. We discovered several flaws in the initial PIE model, such as a small amount of background matching, that was addressed, albeit likely not fixed, using background subtraction (BGS) and left-right mirroring (LR) techniques which demonstrated reasonable accuracy (Rank 1: 74% Rank-5: 92%) comparable to the Hotspotter results (Rank 1: 74% Rank 2: 84%)The PIE BGS LR model, in conjunction with Hotspotter, yielded the following results: Rank-1: 85%, Rank-5: 95%, Rank-20: 99%. In general, our findings indicate that PIE BGS LR, in conjunction with HotSpotter, can classify snow leopards more accurately than using either algorithm alone.

Cyclic landslide-flood chains along a major mountain river

Landslides are a crucial Earth surface process in mountain landscapes, rapidly transporting large amounts of sediment into lower-elevation areas, and periodically negatively impacting people and their livelihoods. Most studies focus on their immediate, local-scale impacts, but few recognize their remote impacts in mountain environments. In particular, major landslides along rivers can block river channels to form lakes through backwater inundation, posing a flood hazard to downstream areas. In 2018, two landslides occurred along the Baige section of the Jinsha River, eastern Tibetan Plateau, forming two landslide lakes and subsequently, causing two flood events. In this study, we explore the impacts of these events on hillslopes along the river banks, upstream and downstream of the Baige site. Using small baseline subset Interferometric synthetic-aperture radar (SBAS InSAR), we find many active landslides along the Jinsha River and detect a sudden acceleration in these instabilities following the 2018 events. We attribute upstream instabilities to an increase in river width and depth, related to the remains of the landslide dam, while downstream slope instability is likely caused by undercutting along the outburst route. Modelling indicates that failure of these newly detected landslides may block the river again and potentially extend the hazard chain. This work demonstrates that landslides along major rivers can initiate new instabilities, and that even a short-lived landslide-dammed lake can have long-term impacts on stability of hillslopes in river valleys.

Tatras Phoenix. Restoration Architecture in the alpine environment of the High Tatras

The architectural concepts of the High Tatras region reside mainly in the foothills, where they form the basis of mountain tourism. On the exposed terrain of the Tatra Mountains there are huts that were once the result of craftsmanship, but today there is an increased concentration of architectural interest. We are focusing on architectural design in the context of adapting the typology to the visitor’s needs or in response to the challenges of extreme environments. The focus involves the structural alteration, restoration or reconstruction of a building that represents an architectural discussion of the alpine environment. The huts under study trace the colonization of different vegetation zones and the different typological standards of the hut. The architectural planning process represents an example of restoration of a post-war modernism work, its reconstruction into a new form and the response to the problem of avalanches in the alpine environment. Through the prism of the social situation and technological innovations, we explore the transformation of the hut typology and its relationship to its setting. At the same time, we look for a connection to the original building destroyed by fire or avalanche or a reflection on regionalism or the general architectural discourse. The article presents a brief introduction to the architectural scene in the High Tatra region from the perspective of socio-political changes. The main question was: what principles does architecture apply in a high mountain environment? Differences and innovations are sought in the context of design in the foothills and urbanised areas, as well as in the context of the social situation and the authors of the project themselves.

A Multi-Strategy Improved Differential Evolution algorithm for UAV 3D trajectory planning in complex mountainous environments

In response to the complexity of power repair in mountainous areas and the limitations of traditional vehicles due to terrain constraints, this study focuses on the three-dimensional trajectory planning problem of UAVs (Unmanned Aerial Vehicles) in mountainous environments. Our goal is to provide effective solutions for the trajectory planning problem of UAVs in mountainous environments. Firstly, a UAV trajectory planning model is established, incorporating optimization objectives such as energy consumption, trajectory cost, obstacle avoidance cost, smoothing cost, and stability cost. The trajectory planning problem is transformed into an objective function optimization task with multiple performance constraints. To overcome the inefficiency and infeasibility of traditional algorithms in solving complex three-dimensional flight environments, we propose improvements to the Differential Evolution (DE) algorithm through three strategies: incorporating mutation crossover factor optimization strategy, an adaptive guidance mechanism, and an elite disturbance mechanism based on population classification. The Multi-Strategy Improved Differential Evolution (MSIDE) algorithm is introduced, and its time and space complexity are analyzed. Finally, the proposed method is compared with various algorithms through benchmark functions tests, Friedman test, Wilcoxon rank-sum test, simulation experiments in three-dimensional environments, and parameter sensitivity analysis experiments. The simulation results show that compared with the current state-of-the-art algorithms, the MSIDE algorithm improves the objective function value by 11.34% on average in regular terrain and 5.04% on average in complex terrain environments. The results demonstrate the convergence, multi-objective search capability, and global search ability of MSIDE, validating its effectiveness in solving the trajectory planning problem of UAVs in complex mountainous environments.

Waste Management Policy and Practices in Mountain Expeditions in Nepal: Stakeholder's Perspective on Implementation of Mountaineering Expedition Rules

Purpose: This study investigates the current implementation status of the Mountaineering Expedition Rules (MER) of 2002 in Nepal, focusing on waste management practices during mountain expeditions from the stakeholder's perspective.
 Methodology: The study used a descriptive research design with a mixed approach, collecting primary data through structured questionnaires and key informant interviews. Data analysis is conducted using descriptive statistics for quantitative data and content analysis for qualitative data.
 Main Findings: The findings highlight the need for improvement in waste management during mountain expeditions in Nepal. While climbers demonstrate a moderate to high level of awareness and implementation of waste management practices, challenges such as limited budgets, lack of self-awareness among expeditioners, and slow decay of waste in cold weather persist. The study emphasizes the importance of proper implementation of mountaineering expedition rules, particularly in waste management.
 Implications: This study contributes to the development of sustainable tourism practices in Nepal and the preservation of the mountain environment. The study recognizes the efforts made by the Nepalese government through policies and regulations to address waste management issues. The goal is to protect the fragile mountain ecosystem while facilitating the growth of sustainable mountain tourism.
 Novelty: It offers practical recommendations based on stakeholder perspectives, which can inform policy formulation in Nepal and other countries with similar mountain tourism contexts.