Bats are indispensable members of the natural world, supporting its delicate balance. Bats have vital roles in controlling insect populations and enhancing soil fertility. They also help in the harvesting and dispersal of seeds, pollination in plants, and nutrient recycling and distribution. However, through evolution over millions of years, they have also adapted their immune system so that they may carry numerous types of pathogens, the majority of which are viruses, without these pathogens having any serious ill effects on bats themselves. Their anatomical adaptation to flight and the reduced immune response to DNA damage during flight have also contributed to bats becoming reservoirs of deadly pathogenic diseases. This review discusses the different adaptations of bats with a special focus on the immune system that have helped them evolve as a reservoir for various viruses. The study also enumerates how the increase in global warming, the consequent changes in climatic conditions, habitat destruction, and bushmeat consumption increase the chances of an outbreak of novel zoonotic disease when humans come in contact with bats.
Permafrost degradation on the Tibetan Plateau (TP) has triggered widespread retrogressive thaw slumps (RTSs), affecting hydrology, carbon sequestration and infrastructure stability. To date, there is still a lack of long-term monitoring of RTSs across the TP, the thaw dynamics and comprehensive driving factors remain unclear. Here, using time-series Landsat imagery and change detection algorithm, we identified RTSs on permafrost regions of the TP from 1986 to 2020. Existing RTSs inventories and high-resolution historical imagery were employed to verify the identified results, the temporal validation of RTSs disturbance pixels demonstrated a high accuracy. In the study area, a total of 3537 RTSs were identified, covering a total area of 5997 ha, representing a 26-fold increase since 1986, and 69.2 % of RTSs formed since 2010. Most RTSs are located on gentle slope (4-12 degrees) at elevations between 4500 m and 5300 m, with a tendency to form in alpine grassland and alpine meadow. Annual variations in RTSs area exhibited a significant positive correlation with minimum air temperature, mean land surface temperature, and annual thawing index, while it showing a significant negative correlation with the decrease in downward shortwave radiation. Spatially, RTSs were more common in areas with higher soil water content and shallower active layer. Landsat imagery captured the vast majority of RTSs on the TP and revealed interannual disturbance details, but the 30 m resolution remains inadequate for delineating the refined boundaries of some micro-scale (< 0.18 ha) RTSs. Detected RTSs disturbances on the TP will aid in hazard management and carbon feedback assessments, and our findings provide novel insights into the impacts of climate change and permafrost environments on RTSs formation.
Cycas panzhihuaensis inhabits regions where summer temperatures can exceed 40 degrees C, and these extreme conditions may intensify with ongoing global warming. However, how this species adapts to such thermal extremes is not well understood. To investigate the responses of C. panzhihuaensis to heat stress, some physiological characteristics along with lipid and fatty acid profiles were analyzed. The results show that heat stress induced soil water loss but did not cause leaf water loss and visible symptoms of leaf damage. However, photoinhibition was induced and heat dissipation was inhibited under the stress. In the recovered plants, both heat dissipation and maximum photochemical efficiency exhibited significant increases compared to the stressed plants but did not return to the control level. Most lipid categories including phospholipids and saccharolipids accumulated significantly following both the stress and subsequent recovery. However, the content of total neutral glycerolipids maintained unchanged after various treatments. The ratio of phosphatidylcholine/phosphatidylethanolamine decreased significantly and the ratios of both digalactosyldiacylglycerol/monogalactosyldiacylglycerol and triacylglycerol/diacylglycerol increased significantly in the stressed plants. Compared to the control plants, the relative content of polyunsaturated fatty acids significantly increased, while that of both saturated and monounsaturated fatty acids significantly declined in both stressed and recovered plants. Under stress conditions, the unsaturation levels of total neutral glycerolipids and their constituent components significantly increased, whereas those of phosphatidylglycerol and total saccharolipids exhibited a marked decrease. In conclusion, C. panzhihuaensis can tolerate extremely high temperatures to some extent which might be associated with the adjustments in lipid composition and unsaturation levels.
Southeast Tibet is characterized by extensive alpine glaciers and deep valleys, making it highly prone to cryospheric disasters such as avalanches, ice/ice-rock avalanches, glacial lake outburst floods, debris flows, and barrier lakes, which pose severe threats to infrastructure and human safety. Understanding how cryospheric disasters respond to climate warming remains a critical challenge. Using 3.3 km resolution meteorological downscaling data, this study analyzes the spatiotemporal evolution of multiple climate indicators from 1979 to 2022 and assesses their impacts on cryospheric disaster occurrence. The results reveal a significant warming trend across Southeast Tibet, with faster warming in glacier-covered regions. Precipitation generally decreases, though the semi-arid northwest experiences localized increases. Snowfall declines, with the steepest decrease observed around the lower reaches of the Yarlung Zangbo River. In the moisture corridor of the lower reaches of the Yarlung Zangbo River, warming intensifies freeze-thaw cycles, combined with high baseline extreme daily precipitation, which increases the likelihood of glacial disaster chains. In northwestern Southeast Tibet, accelerated glacier melting due to warming, coupled with increasing extreme precipitation, heightens glacial disaster probabilities. While long-term snowfall decline may reduce avalanches, high baseline extreme snowfall suggests short-term threats remain. Finally, this study establishes meteorological indicators for predicting changes in cryospheric disaster risks under climate change.
Alpine treelines ecotones are critical ecological transition zones and are highly sensitive to global warming. However, the impact of climate on the distribution of treeline trees is not yet fully understood as this distribution may also be affected by other factors. Here, we used high-resolution satellite images with climatic and topographic variables to study changes in treeline tree distribution in the alpine treeline ecotone of the Changbai Mountain for the years 2002, 2010, 2017, and 2021. This study employed the Geodetector method to analyze how interactions between climatic and topographic factors influence the expansion of Betula ermanii on different aspect slopes. Over the past 20 years, B. ermanii, the only tree species in the Changbai Mountain tundra zone, had its highest expansion rate from 2017 to 2021 across all the years studied, approaching 2.38% per year. In 2021, B. ermanii reached its uppermost elevations of 2224 m on the western aspects and 2223 m on the northern aspects, which are the predominant aspects it occupies. We also observed a notable increase in the distribution of B. ermanii on steeper slopes (> 15 degrees) between 2002 and 2021. Moreover, we found that interactions between climate and topographic factors played a more significant role in B. ermanii's expansion than any single dominant factor. Our results suggest that the interaction between topographic wetness index and the coldest month precipitation (Pre(1)), contributing 91% of the observed variability, primarily drove the expansion on the southern aspect by maintaining soil moisture, providing snowpack thermal insulation which enhanced soil temperatures, decomposition, and nutrient release in harsh conditions. On the northern aspect, the interaction between elevation and mean temperature of the warmest month explained 80% of the expansion. Meanwhile, the interaction between Pre(1) and mean temperature of the growing season explained 73% of the expansion on the western aspect. This study revealed that dominant factors driving treeline upward movement vary across different mountain aspects. Climate and topography play significant roles in determining tree distribution in the alpine treeline ecotone. This knowledge helps better understand and forecast treeline dynamics in response to global climate change.
The global cryosphere is retreating under ongoing climate change. The Third Pole (TP) of the Earth, which serves as a critical water source for two billion people, is also experiencing this decline. However, the interplay between rising temperatures and increasing precipitation in the TP results in complex cryospheric responses, introducing uncertainties in the future budget of TP cryospheric water (including glacier and snow water equivalents and frozen soil moisture). Using a calibrated model that integrated multiple cryospheric-hydrological components and processes, we projected the TP cryospheric water budgets under both low and high climatic forcing scenarios for the period 2021-2100 and assessed the relative impact of temperature and precipitation. Results showed (1) that despite both scenarios involving simultaneous warming and wetting, under low climatic forcing, the total cryospheric budget exhibited positive dynamics (0.017 mm yr-1 with an average of 1.77 mm), primarily driven by increased precipitation. Glacier mass loss gradually declined with the rate of retreat slowing, accompanied by negligible declines in the budget of snow water equivalent and frozen soil moisture. (2) By contrast, high climatic forcing led to negative dynamics in the total cryospheric budget (-0.056 mm yr-1 with an average of -1.08 mm) dominated by warming, with accelerated decreases in the budget of all cryospheric components. These variations were most pronounced in higher-altitude regions, indicating elevation-dependent cryospheric budget dynamics. Overall, our findings present alternative futures for the TP cryosphere, and highlight novel evidence that optimistic cryospheric outcomes may be possible under specific climate scenarios.
The acclimation capacity of Betula pendula and Betula pubescens was studied over 4 years in common gardens in central Italy (43 degrees N) and southern (61 degrees N) and northern Finland (67 degrees N), representing drastically different photoperiod and climate in temperate, boreal and subarctic vegetation zones. Two study sites that differed in soil fertility were established at each location, giving a total of six common gardens. The birch material was micropropagated from naturally regenerated stands of B. pendula and B. pubescens from Susa Valley and Rochemolle Valley in northern Italy, Punkaharju in southern Finland and Kittil & auml; in northern Finland. The plants were measured for height growth, stem diameter, leaf chlorophyll content, leaf herbivory and pathogen damage. The effects of soil fertility on the common garden results were also analyzed. The results showed high acclimation capacity of B. pendula and B. pubescens after a long-range transfer from southern to northern Europe, despite the major shift in climate and photoperiod. First-year growth on average was best in boreal southern Finland for all origins. Betula pendula grew more than B. pubescens in Italy and southern Finland, while B. pubescens grew more in northern Finland and better tolerated the northward transfer. The height growth of origins showed a clear latitude gradient from slowly growing northern to fast growing southern origins in the nursery and laboratory, but not in the field. Soil fertility explained a significant part of variation among locations not only for growth variables, but also for leaf chlorophyll content and leaf herbivory and pathogen damage. Leaf herbivore and pathogen damage was greatest in southern Finland. Our results demonstrate good survival of birch from northern Italy in Finnish conditions and support the possibility of long-range south-to-north transfer of Betula species to provide resistant planting material in boreal forests for the rapidly changing climate.
Background and aimsFrequent extreme weather poses significant threats to agricultural production and biological communities. Understanding the microbiological mechanisms that determine plant health under warming fluctuations (including short-term warming (WM, 45 degrees C for lasting 10 days) and recovery from warming (RE, the end of warming and returning to 25 degrees C for lasting 10 days)) is crucial for achieving sustainable agricultural development.MethodsHere, we explored the effects of warming fluctuations on the plant health index (PHI) and on the bacterial and fungal communities in both bulk soil and rhizosphere.ResultsWarming fluctuations did not change the rhizosphere bacterial or fungal alpha diversity but did affect the community structure and composition in both the bulk soil and rhizosphere. Moreover, warming fluctuations altered the stability and complexity of the bacterial and fungal networks, and the changes exhibited obvious differences between the bulk soil and rhizosphere. Bacterial and bulk soil fungal taxa enhanced their cooperation to adapt to WM, while rhizosphere fungal taxa became more competitive. In addition, warming fluctuations reduced the wheat health index and caused irreversible damage. Biotic factors, particularly core taxa such as Nocardioidaceae, Trueperaceae, Microbacteriaceae, and 67-14 of bacteria, as well as Diversisporaceae, Glomeraceae, Entolomataceae, and Orbiliales of fungi, have emerged as the main driving forces affecting wheat health. These core taxa can directly influence wheat health or indirectly regulate network complexity and competition among taxa.ConclusionsOur study underscores the significance of core taxa in modulating soil microbiome dynamics and safeguarding plant health, offering valuable insights and strategies for enhancing crop productivity and fostering sustainable agricultural development amidst increasingly frequent extreme weather events.
Permafrost underpins engineering in cold regions but is highly sensitive to climate change. The mechanisms linking climate warming, precipitation changes, and permafrost degradation to infrastructure stability remain poorly understood on the Qinghai-Xizang Plateau (QXP). Here, we present a multi-factor framework to quantify climate impacts on permafrost engineering stability. Our findings reveal a 26.7% decline in permafrost engineering stability from 2015 to 2100, with areas of extremely poor stability expanding by 0.3 x 104 km2 per decade (SSP2-4.5) and 0.6 x 104 km2 per decade (SSP5-8.5). Meanwhile, regions with relatively better stability shrink by 2.0 x 104 km2 and 2.9 x 104 km2 per decade, respectively. These changes driven primarily by a warming and wetting climate pattern. Moreover, engineering stability is maintained in northwestern and interior regions, whereas warmer, ice-saturated areas in the central plateau and southern Qilian Mountains degrade rapidly. Notably, cold permafrost is warming faster than warm permafrost, increasing its vulnerability. These insights provide a critical basis for guiding the future design, construction, and maintenance of permafrost infrastructure, enabling the development of adaptive engineering strategies that account for projected climate change impacts.
This study investigates the negative impact of climate change on water resources, specifically water for agricultural irrigation. It describes how to optimize swelling, gel properties and long-term water retention capacities of Na-CMC/PAAm hydrogels for managing drought stress of Sugar beet plants through techniques such as changing the composition, synthetic conditions and chemical modification. Gamma radiation-induced free radical copolymerization was used to synthesize superabsorbent hydrogels using sodium carboxymethyl cellulose (Na-CMC) and acrylamide (AAm). The study also explored how varying Na-CMC/AAm ratio and radiation dose influence their swelling behaviour, gel fraction, and water retention. FTIR showed that CMC and PAAm components are part of the hydrogel structure. The equilibrium swelling reached a maximum value of similar to 500 g/g at a Na-CMC/AAm ratio of 60/40. High content of AAm reduced swelling because it caused increased hydrophobicity while high radiation doses up to 50 kGy increased crosslinking resulting in improved but limited swelling from 65 to 85 (g/g). After the second cycle, KOH modification reached maximum swelling capacity by introducing anionic carboxylate groups up to 415 (g/g). SEM images revealed uniform pores in an unmodified scaffold while larger cavities were formed upon modification facilitating Water absorption. Surprisingly, the improved hydrogels retained more water: about 75% even after 16 days as opposed to a 50% drop within five days in the case of unmodified ones. This hydrogel significantly enhanced shoot length by 18%, root length by 32%, fresh weight shoot by 15%, and dry weight shoot by 15% under severe drought conditions. As a result, yield increased by 22%, proteins went up by 19%, and carbohydrates rose by 13%. Leaf chlorophyll content increased with a corresponding decline in stress enzymes indicating decreased oxidative damage. This eco-friendly Na-CMC/PAAm-based hydrogel seems to have potential use for addressing water scarcity and agricultural challenges.