Snowfall Shift and Precipitation Variability over Sikkim Himalaya Attributed to Elevation-Dependent Warming

Sikkim Himalaya hosts critical water resources such as glacial,rain,and snow-fed springs and lakes.Climate change is adversely affecting these resources in various ways,and elevation-dependent warming is prominent among them.This study is a discussion of the elevation-dependent warming(EDW),snowfall shift,and precipitation variability over Sikkim Himalaya using a high-resolution ERA5-land dataset.Furthermore,the findings show that the Sikkim Himalaya region is experiencing a warming trend from south to north.The majority of the Sikkim Himalayan region shows a declining trend in snowfall.A positive advancement in snowfall trend(at a rate of 1 mm per decade)has been noticed above 4500 meters.The S/P ratio indicates a shift in snowfall patterns,moving from lower elevations to much higher regions.This suggests that snowfall has also transitioned from Lachung and Lachen(3600 m)to higher elevated areas.Moreover,the seasonal shifting of snowfall in the recent decade is seen from January-March(JFM)to February-April(FMA).Subsequently,the preceding 21 years are being marked by a significant spatiotemporal change in temperature,precipitation,and snowfall.The potent negative correlation coefficient between temperature and snowfall(–0.9),temperature and S/P ratio(–0.5)suggested the changing nature of snowfall from solid to liquid,which further resulted in increased lower elevation precipitation.The entire Sikkim region is transitioning from a cold-dry to a warm-wet weather pattern.In the climate change scenario,a drop in the S/P ratio with altitude will continue to explain the rise in temperature over mountainous regions.

Effects of seasonal variations on soil microbial community composition of two typical zonal vegetation types in the Wuyi Mountains

Seasonal shifts play an important role in soil microbial community composition. This study examined the hypothesis that soil microbial community structure would vary with seasonal shifts in the Wuyi Mountains in Southeast China, and that two representative tree species （Castanopisi carlesii and Cunninghamia lanceolata） may have different soil microbial community composition. Phospholipids fatty acid analysis （PLFA） of seasonal shifts and was used to assess the effect vegetation types on soil microbial community structure. A total of 22 different PLFAs were identified from all the soil samples. The bacterial PLFAs accounted for 62.37% of the total PLFAs, followed by fungi （28.94%）, and the minimum was actinomycetes （6.41%）. Overall, the level of PLFAs in C. carlesii soil was greater than those in C. lanceolata soil, and significant differences were observed in some seasons. The amounts of total, bacteria, actinomycic and fungal PLFAs significantly changed with the seasons and followed a sequence order （summer 〉 autumn 〉 spring 〉 winter）. The bacteria/fungi PLFAs and G （＋）/G （-） PLFAs of two vegetation types also changed with the seasons and the ratios in summer and autumn were higher than those in spring and winter. The correlation analysis of microbial PLFAs and soil physicochemical properties showed that the total, bacteria, fungal, actinomycic, G （＋） and G （-） PLFAs were significantly positive correlation with TOC, TN, TP, TK and moisture content. We concluded that the seasonal shifts and vegetation types affect soil microbial community composition by changing the soil physicochemical properties.

Effects of seasonal variation on soil microbial community structure and enzyme activity in a Masson pine forest in Southwest China

Soil microbial communities and enzyme activities play key roles in soil ecosystems.Both are sensitive to changes in environmental factors,including seasonal temperature,precipitation variations and soil properties.To understand the interactive mechanisms of seasonal changes that affect soil microbial communities and enzyme activities in a subtropical masson pine(Pinus massoniana)forest,we investigated the soil microbial community structure and enzyme activities to identify the effect of seasonal changes on the soil microbial community for two years in Jinyun Mountain National Nature Reserve,Chongqing,China.The soil microbial community structure was investigated using phospholipid fatty acids(PLFAs).The results indicated that a total of 36 different PLFAs were identified,and 16:0 was found in the highest proportions in the four seasons,moreover,the total PLFAs abundance were highest in spring and lowest in winter.Bacteria and actinomycetes were the dominant types in the study area.Seasonal changes also had a significant(P<0.05)influence on the soil enzyme activity.The maximum and minimum values of the invertase and catalase activities were observed in autumn and winter,respectively.However,the maximum and minimum values of the urease and phosphatase acid enzymatic activities were found in spring and winter,respectively.Canonical correspondence analysis(CCA)analysis revealed that the seasonal shifts in soil community composition and enzyme activities were relatively more sensitive to soil moisture and temperature,but the microbial community structure and enzyme activity were not correlated with soil pH in the study region.This study highlights how the seasonal variations affect the microbial community and function(enzyme activity)to better understand and predict microbial responses to future climate regimes in subtropical area.

DNA metabarcoding reveals seasonal changes in diet composition across four arthropod-eating lizard species(Phrynosomatidae:Sceloporus)

Diet composition and its ecological drivers are rarely investigated in coexisting closely related species.We used a molecular approach to characterize the seasonal variation in diet composition in four spiny lizard species inhabiting a mountainous ecosystem.DNA metabarcoding revealed that the lizards Sceloporus aeneus,S.bicanthalis,S.grammicus,and S.spinosus mostly consumed arthropods of the orders Hemiptera,Araneae,Hymenoptera,and Coleoptera.The terrestrial lizards S.aeneus and S.bicanthalis mostly predated ants and spiders,whereas the arboreal–saxicolous S.grammicus and saxicolous S.spinosus largely consumed grasshoppers and leafhoppers.The taxonomic and phylogenetic diversity of the prey was higher during the dry season than the rainy season,likely because reduced prey availability in the dry season forced lizards to diversify their diets to meet their nutritional demands.Dietary and phylogenetic composition varied seasonally depending on the species,but only dietary composition varied with altitude.Seasonal dietary turnover was greater in S.spinosus than in S.bicanthalis,suggesting site-specific seasonal variability in prey availability;no other differences among species were observed.S.bicanthalis,which lives at the highest altitude in our study site,displayed interseasonal variation in diet breadth.Dietary differences were correlated with the species’feeding strategies and elevational distribution,which likely contributed to the coexistence of these lizard species in the studied geographic area and beyond.