Exploring the unique biophysical characteristics and ecosystem services of mountains: A review

Mountains are unique terrestrial ecosystems characterized by distinct physiography,biological diversity,and socio-economic features.These ecosystems provide numerous essential goods and services to communities within and beyond the mountains.Despite their significance,comprehensive studies that thoroughly characterize the ecosystem services of mountains are lacking.Such research is crucial to advance scientific understanding of mountain characteristics and ecosystem services.This study investigates mountain regions’unique characteristics and ecosystem services using global datasets such as the U.S.Geological Survey(USGS),the Global Mountain Biodiversity Assessment(GMBA),NASA EARTHDATA,and other relevant databases and literature review.The focus was to explore unique physiographic and socio-economic characteristics and ecosystem services provided by mountains.The results indicate that mountain ecosystems are pivotal in offering provisional,regulatory,and supporting ecosystem services on Earth.Despite their limited geographical area,these ecosystems supply substantial amounts of freshwater to communities living within and downstream of mountainous regions.Additionally,mountain ecosystems serve as global biodiversity hotspots,harboring a significant proportion of the world's species.However,mountain ecosystems face numerous natural and anthropogenic challenges,including climate change,habitat destruction,and resource overexploitation.Current efforts towards sustainable mountain development are inadequate.Enhanced scientific research and targeted policy measures are essential to address these challenges,protect mountain biodiversity,and ensure the continuous provision of vital ecosystem services.

Assessing the spatiotemporal distributions of evapotranspiration in the Three Gorges Reservoir Region of China using remote sensing data

Evapotranspiration(ET) is a critical component of the global hydrological cycle, and it has a large impact on water resource management as it affects the availability of freshwater resources. It is important to understand the hydrological cycle for the water resources planning and management. This study used Moderate Resolution Imaging Spectroradiometer(MODIS) satellite derived ET, and potential evapotranspiration(PET) and Tropical Rainfall Measuring Mission(TRMM) satellite derived precipitation datasets to assess the spatial and temporal distributions of ET, PET, and precipitation during the study period at Three Gorges Reservoir(TGR) region. Based on the topographic variations and land-use/land-cover distributions, the study region which includes five counties of Hubei Province and nineteen counties of Chongqing Municipality was divided into four study zones. The ET and precipitation data were evaluated using in situ observations. The ET, PET, and precipitation data were compared to analyze the spatial and long-term(2001-2016) temporal distributions of average annual ET, PET, and precipitation, and to understand the relationships between them in the study region. The results showed that each selected zone had highest ET at the counties with the Yangtze River passing through whereas lowest at the counties which were located away from the river. Results also showed increasing trends in ET and PET from south-west to north-east in the study region. Analysis showed TGR had a significant impact on spatial and temporal distributions of ET and PET in the study region. Therefore, this study helps to understand the impact of TGR on spatial and temporal distributions of ET and PET during and after the construction.

Modeling regional landslide susceptibility using dynamic soil moisture profiles

A landslide susceptibility mapping study was performed using dynamic hillslope hydrology. The modified infinite slope stability model that directly includes vadose zone soil moisture(SM) was applied at Cleveland Corral, California, US and Krishnabhir, Dhading, Nepal. The variable infiltration capacity(VIC-3L) model simulated vadose zone soil moisture and the wetness index hydrologic model simulated groundwater(GW). The GW model predictions had a 75% NASH-Sutcliffe efficiency when compared to California's in-situ GW measurements. The model performed best during the wet season. Using predicted GW and VIC-3L vadose zone SM, the developed landslide susceptibility maps showed very good agreement with mapped landslides at each study region. Previous quasi-dynamic model predictions of Nepal's hazardous areas during extreme rainfall events were enhanced to improve the spatial characterization and provide the timing of hazardous conditions.

Responses of bioenergy sorghum cell wall metabolism to agronomic practices

Maximum lignocellulose yield of biomass sorghum [Sorghum bicolor L. (Moench.)] is hampered by complex biological phenomena related to rotation, nitrogen (N) fertilization, soil tillage, and excessive biomass removal. The biochemical basis of the effects of agronomic practices on sorghum production was studied by the enzymology of the active peroxidase (EC 1.11.1.7) isoenzymes that synthesize lignin. All studied practices altered the peroxidase pI values. Control sorghum without rotation and without N fertilization had the most inhibited peroxidase with very low maximum velocity (Vmax) value (3.10 mmol·min﹣1), and very low lignin (857 kg·ha﹣1) yield, which could decrease soil organic carbon possibly leading to adverse changes in soil chemistry. Corn-sorghum rotations with and without N fertilization increased the Vmax values of peroxidase and lignin and cellulose yields. Rotated sorghum subjected to 50% residue return (the percentage of crop residue was returned to the plot immediately after grinding at harvest) and 280 kg·ha﹣1 N fertilization possessed very active peroxidase (Vmax value 66.4 mmole·min﹣1) and the highest lignin (1387 kg·ha﹣1) yield. The 25% residue return rate without N fertilization induced high lignin (1125 kg·ha﹣1) and cellulose (11,961 kg·ha﹣1) but the 25% residue return rate with 280 kg·ha﹣1 N fertilization induced lower lignin (1046 kg·ha﹣1) yield. Continuously cropped sorghum treated with 336 kg·N·ha﹣1 produced active peroxidase that shared competitive inhibition relationship with the peroxidase of the 84 kg·N·ha﹣1 treatment. Ridge tillage combined with 280 kg·ha﹣1 N fertilization under continuous sorghum resulted in inhibited peroxidase possessing low Vmax value (13.0 μmole·min﹣1). Changing to conventional tillage combined with 280 kg·ha﹣1 N fertilization relieved the inhibition and increased the Vmax value to 23.7 mmol·min﹣1. These biological anomalies of sorghum cell wall related to agronomic practices originated from doubly inhibited sorghum peroxidases. This understanding may guide the choice of sustainable agronomic practices for maximizing lignocellulose yields for the bioenergy industry while protecting the environment.

Grafting of Chitosan and Chitosantrimethoxylsilylpropyl Methacrylate on Single Walled Carbon Nanotubes-Synthesis and Characterization

Acid functionalized single walled carbon nanotubes （CNTs） were grafted to chitosan by first reacting the oxidized CNTs with thionyl chloride to form acyl-chlorinated CNTs. This product was subsequently dispersed in chitosan and covalently grafted to form CNT-chitosan. CNT-chitosan was further grafted onto 3-trimethoxysilylpropyl methacrylate by free radical polymerization conditions, to yield CNT-g-chitosan-g-3-trimethoxysilylpropyl methacrylate （TMSPM）, hereafter referred to as CNT-chitosan-3-TMSPM. These composites were characterized by Fourier Transform Infrared Resonance Spectroscopy （FTIR）, carbon-13 nuclear magnetic resonance （13C NMR）, Yhermogravimetric Analysis （TGA）, scanning electron microscopy （SEM） and transmission electron microscopy （TEM）. The composite showed improved thermal stability and could be of great potential use in bone tissue engineering.