Semi-arid Ecosystems Research Articles

Functional Activity of the Antioxidant System of Artemisia Genus Plants in the Republic of Buryatia (Russia) and Its Significance in Plant Adaptation.

Plants are sessile organisms and any changes in environmental factors activate various responses and defense mechanisms. Artemisia plants widely inhabit harsh conditions of arid and semiarid ecosystems. Using two species-a subshrub, Artemisia frigida, and an annual-biennial herb, Artemisia scoparia-the functioning of the antioxidant system of plants in semiarid territories have been examined. The activity of enzymatic antioxidants and the content of non-enzymatic antioxidants in both species as well as the antiradical activity of their extracts have been shown. Although the plants were collected in areas differing in moisture supply, the activity of enzymatic antioxidants and the content of non-enzymatic antioxidants corresponds to their physiological level, within the range of the norm of reaction, in wormwood. Consequently, conditions of differing moisture deficiency do not cause a specific biochemical response at the level of the antioxidant system in the studied species, which confirms their adaptability to these conditions. Meanwhile, A. frigida plants show greater morphological and biochemical plasticity than A. scoparia under changing growth conditions. Both species contain tissue monoterpenoids and sesquiterpenoids, the emission of which provides additional protection against high temperatures and drought. Their composition and contents of phenolic components illustrates the differences in adaptation between perennial and annual plants.

Exploring plant diversity and aesthetic service of mountain and plain landscapes in semiarid ecosystems

Aesthetic services convey express people’s opinion about natural word and are crucial to the planning of biodiversity-related environmental protection. This study presents a comprehensive approach for quantifying the aesthetic services provided by landscapes using integrated plant traits in Iran’s semiarid Iranian ecosystems. Using the opinion of expert, the significance of each plant trait for aesthetic services was examined. According to the structure equation model, the most important traits for a species’ ability to provide aesthetic services were flower, leaf, fruit, crown, and stem respectively (p < 0.01). The weighted traits and the frequency of observed species in field data were integrated to quantify aesthetic services provided by plant communities A strong synergy relationship existed between aesthetic services and forbs diversity in semiarid ecosystems (p < 0.001). The findings showed that the plain had less potential to supply aesthetic services than the mountain landscape which is a hotspot plant diversity with twice as much potential (p < 0.05). The approach described in this study, which is based on the quantification of aesthetic services and combined with biodiversity, helps to alter the way that nature is used and to advance conservation efforts, taking into account the crucial requirement for human participation in conservation plans.

Monitoring of indicators and bacterial succession in organic-amended technosols for the restoration of semiarid ecosystems

Restoration of mining sites is essential to ensure ecosystem services and biodiversity. One restoration strategy employed in arid and semi-arid zones is the use of organic amendments to establishment technosols. However, it is necessary to monitor the restoration progress in order to select appropriate amendments. This study monitored the effects of compost gardening, greenhouse horticulture and stabilized sewage sludge, and their blends. We focused on soil physical and chemical indicators and bacterial community structure and diversity during the 30 months after application. Organic amendments increased total organic carbon and nitrogen within six months, staying elevated compared to natural soils over 30 months. Electrical conductivity rose then stabilized, the pH slightly decreased but stayed alkaline, and water holding capacity improved in treated technosols. Bacterial diversity increased in amended technosols compared to control. Alpha diversity varied with treatment and time, peaking at 18 months. Technosols with plant compost showed reduced bacterial richness at 30 months, while those with sewage sludge and its mixtures maintained it. The bacterial community analysis showed significant differences among treatments and times, highlighting dominant phyla like Proteobacteria and Bacteroidetes. PCoA analysis showed clear separation of bacterial communities from treated, natural, and control soils, with notable differences between plant and sludge treatments. Soil variables such as TOC, TN, EC and water holding capacity explained more than 82 % of the variation in bacterial communities. Eighty-three indicator taxa were identified that explained the differences between the microbial communities of treated and untreated soils, highlighting the importance of taxa such as Pelagibacterium spp., Roseivirga spp. and Cellvibrio spp. in preserving soil health. In short, organic amendments improve soil properties and promote the diversity and stability of beneficial microbial communities in semi-arid mined soils, underlining their crucial role in the restoration and long-term maintenance of degraded soils.

PSXIII-16 Kinematics and viability of spermatozoa from Criollo and Angus bulls in a low-input system

Abstract The Chihuahuan Criollo cattle is a genetic resource with special adaptive characteristics to rough, arid and semi-arid ecosystems. There is a great interest in incorporating such adaptations into beef production systems as one of the strategies for sustainable production to face the climate change challenge. Reproductive success is determinant to achieve sustainability in animal production systems. Most research efforts to improve reproductive efficiency have focused on the study of females. However, it has been shown that much of the economic losses caused by embryonic deaths are due to the bull. The aim of this study was to evaluate the quality of thawed semen from Angus and Criollo bulls kept in a low-input system. Thirteen healthy bulls (n = 7 Angus and 6 = Chihuahuan Criollo), with an average age of 4.3 ± 0.48 yr, grazing in the same rangeland and subjected to natural pasture conditions, were studied. Semen obtained by electroejaculation, were frozen and subsequently thawed for analyses. Characteristics of motility, vitality (V), morphology (M) and plasma membrane integrity (PMI) were evaluated in fresh and thawed semen, whereas movement kinetics (MK) and acrosome reaction (AR) were evaluated in thawed semen. Statistical analysis was performed using the PROC GLM of SAS Studio 2022 including the fixed effects of breed, semen condition and their interaction for variables of progressive motility (PM), V, M, PMI and the effect of breed for variables of MK and AR. As expected, PM and V were less (P &amp;lt; 0.05) in thawed (57.93 ± 4.1 and 53.69 ± 2.7) compared with fresh (72.64 ± 3.9 and 74.98 ± 2.6) semen, whereas no differences (P &amp;gt; 0.05) were found in M. However, the interaction between semen condition and breed for PMI tended to the significance (P = 0.08) with a PMI of 68.95 ± 4.6 and 58.98 ± 4.3 for Criollo and Angus, respectively, in fresh semen, whereas in thawed semen this difference was inverted (52.08 ± 4.6 and 58.40 ± 4.6). It is important to note that the semen retained quality traits with values above the minimum accepted for use in artificial insemination, despite the scarcity of resources of the system in which the animals were kept. There were no differences by breed in the main MK variables; however, AR reported as live unreacted sperm was less (P &amp;lt; 0.05) in Criollo (40.49 ± 4.49) compared with Angus bulls (58.48 ± 4.49). In conclusion, it is important to incorporate the assessment of membrane integrity and acrosome reaction in thawed semen evaluation to obtain a more accurate prediction of the potential fertility of samples, even if motility parameters appear to be optimal.

Detection of Trypanosoma cruzi DNA in lizards: Using non-lethal sampling techniques in a sylvatic species with zoonotic reservoir potential in Chile

Several reptile species have been described as hosts of Trypanosoma cruzi, the causative agent of Chagas disease, and therefore, they have become vertebrates of epidemiological interest. In recent decades, there has been a growing interest in animal welfare, especially in populations with small numbers where lethal sampling could have catastrophic consequences, and non-lethal methodologies have been developed for detecting zoonotic parasites. In this study, we compared three non-lethal sampling methodologies for detecting T. cruzi DNA in 21 captured specimens of the native lizard Liolaemus monticola, collected from the semiarid Mediterranean ecosystem of Chile. Specimens were subjected to xenodiagnosis (XD), tail clipping, and living syringe sampling procedures to evaluate whether lizards could serve as sentinel species for T. cruzi in endemic regions. To detect the protozoan, real-time PCR (qPCR) was performed on the DNA extracted from the samples (intestinal contents, tail tissues, and blood from living syringes). Trypanosoma cruzi DNA was detected in 12 of 21 lizards, considering all three methodologies. By XD, 12 specimens showed infection (57.1 %), and both living syringe and tail sampling methodologies detected only one infected lizard (4.8 %). Therefore, T. cruzi can be detected in lizards by qPCR using the three methodologies but XD is by far the most effective non-lethal detection methodology. The use of tail and living syringe methodologies showed a large underestimation; however, they might be options for monitoring the presence of T. cruzi in lizard populations when large sample sizes are available.

Agricultural Biotechnological Potential of Bacillus velezensis C3-3 and Cytobacillus sp. T106 from Resource Islands of a Semi-arid Zone of La Guajira-Colombia

Resource islands are vegetative formations in arid and semi-arid ecosystems that harbor microorganisms facing extreme conditions. However, there is a limitation in the knowledge of the agricultural biotechnological potential of microorganisms present in these islands. This study aimed to determine the capacity of Bacillus velezensis C3-3 and Cytobacillus sp. T106 isolates from resource islands to promote plant growth and control the phytopathogen Rhizoctonia solani. The bacteria were sequenced, and both grew at 50 °C, resisted 5% NaCl, withstood UV exposure, and grew in extreme pH conditions. Sixty-six genes in C3-3 and 71 in T106 were identified associated with plant growth promotion, and C3-3 was shown to promote leaf growth in lettuce plants. This promotional effect was associated with the production of indole-3-acetic acid (IAA), phosphorus solubilization, and the presence of genes related to the assimilation of rhizosphere exudates. Both strains inhibited R. solani through the production of volatile compounds and antagonism. Forty-five and 40 of these genes in C3-3 and T106, respectively, were associated with the production of proteases, lipases, siderophores, antimicrobial compounds, degradation enzymes, and secretion systems. Notably, Cytobacillus sp. has not been previously reported as a biocontrol agent. This work contributes to the evidence of the biotechnological potential of semi-arid region bacteria, offering prospects for improving agricultural production in areas with limiting conditions.

Machine Learning-Based Remote Sensing Inversion of Non-Photosynthetic/Photosynthetic Vegetation Coverage in Desertified Areas and Its Response to Drought Analysis

Determining the responses of non-photosynthetic vegetation (NPV) and photosynthetic vegetation (PV) communities to climate change is crucial in illustrating the sensitivity and sustainability of these ecosystems. In this study, we evaluated the accuracy of inverting NPV and PV using Landsat imagery with random forest (RF), backpropagation neural network (BPNN), and fully connected neural network (FCNN) models. Additionally, we inverted MODIS NPV and PV time-series data using spectral unmixing. Based on this, we analyzed the responses of NPV and PV to precipitation and drought across different ecological regions. The main conclusions are as follows: (1) In NPV remote sensing inversion, the softmax activation function demonstrates greater advantages over the ReLU activation function. Specifically, the use of the softmax function results in an approximate increase of 0.35 in the R2 value. (2) Compared with a five-layer FCNN with 128 neurons and a three-layer BPNN with 12 neurons, a random forest model with over 50 trees and 5 leaf nodes provides better inversion results for NPV and PV (R2_RF-NPV = 0.843, R2_RF-PV = 0.861). (3) Long-term drought or heavy rainfall events can affect the utilization of precipitation by NPV and PV. There is a high correlation between extreme precipitation events following prolonged drought and an increase in PV coverage. (4) Under long-term drought conditions, the vegetation in the study area responded to precipitation during the last winter and growing season. This study provides an illustration of the response of semi-arid ecosystems to drought and wetting events, thereby offering a data basis for the effect evaluation of afforestation projects.

A Review on Soil Moisture Dynamics Monitoring in Semi-Arid Ecosystems: Methods, Techniques, and Tools Applied at Different Scales

A Review on Soil Moisture Dynamics Monitoring in Semi-Arid Ecosystems: Methods, Techniques, and Tools Applied at Different Scales

Novel Chemical Routes for Carbon Dioxide and Methane Production from Lignin Photodegradation: The Role of Environmental Free Radicals.

Sunlight irradiation significantly mediates plant litter's carbon dynamics and volatile carbon release in semi-arid and arid ecosystems. In this process, carbon loss is controlled by lignin, but the mechanisms of production of CO2 and CH4 during lignin photolysis are ambiguous. In this study, the photomineralization of plant litter and the lignocellulosic component collectively indicate that lignin is a major source of CO2 and CH4 emissions. Characterization and free radical analysis reveal that the production of CO2 is due to the oxidation and ring-opening reaction of the coniferyl alcohol unit, with the subsequent decarboxylation of carboxylic acid as an oxidation product. This reaction involves o-quinone formation by the reactions between O2, superoxide radical (O2·-), and persistent free radicals (PFRs)-bearing lignin. Of this, O2·- contributes to 43.2% of the photogenerated CO2, as a new pathway, derived from the electron transfer from PFRs to O2. Interestingly, photoinduced demethylation of the dimethoxybenzene-type compounds as the photolysis products of lignin results in a never-before-reported CH4 formation chemical route independent of that of O2. This mechanistic insight into the role of lignin in volatile carbon production from the irradiative plant litter will contribute to a deeper understanding of carbon balance in water-limited ecosystems.

Assessing open-pit mining impacts on semi-arid grassland: A framework for boundary and intensity quantification

Coal mining in northern China's grasslands faces significant environmental challenges due to the fragile semi-arid ecosystem and the abundance of mineral resources. However, current research lacks clarity in both theoretical understanding and effective quantification of its impacts. Insufficient distinction between direct and indirect environmental effects, the oversight of interactions from neighboring activities, and inaccurate measurements of impact intensity all hinder a comprehensive understanding. These limitations also prevent the precise delineation of ecological protection compensation areas. In this study, we developed a comprehensive framework utilizing Landsat time-series images (1989–2017) and field sampling data (228 sample locations in 2017) to assess the boundaries and intensities of mining impacts. First, the k-means clustering algorithm was applied to identify the Normalized Difference Vegetation Index (NDVI) time-series trajectories and map the spatial information of direct impacts. Then, a buffer zone was established and an amplitude model was proposed for determined the cross-impacts and their intensities based on the volatility of NDVI trajectories. Accordingly, a Trend-thresholds model was proposed to automatically extract the indirect impacts boundary of mining-dominated on vegetation under varying intensities. The Soil Quality Index (SQI) ∼ distance curves were fitted and a derivative model was employed for determine the boundary of indirect impacted on soil. We applied this assess framework in Baorixile coalfield (i.e., Baorixile coal mine (BM), DongMing coal mine (DM), Shunxing coal mine (SX)) a typical semi-arid grassland mining area, and quantified three types of impacts: direct, indirect, and cross-impacts. Findings reveal negative coal mining impacts primarily confined to permitted mining areas and decreasing over time. Direct impacts boundary limited in the mining sites and its impact intensity shows a dual nature, with a negative weakening and a positive strengthening trend. Widespread negative indirect impacts exist outward the mining area displays spatial heterogeneity, and its intensity attenuation with distances. In there, the very severe effect (D1) is predominantly focusing on the grassland where near by the mining work face (BM maximum range 1.2 km, DM maximum range 0.55 km, SX maximum range 0.4 km). Moreover, our study indicated that vegetation and soil exhibited consistent responses to coal mining impacts within 1 km, demonstrating the feasibility of using remote sensing data to qualify the impact boundary on the grassland environment. Besides, we further identify significant cross-impacts surrounding the mining areas, characterized by strong negative effects, particularly in the southeastern region of BM. This research offers valuable insights for effective ecological compensation governance and scientific environmental management in similar global contexts.

Effects of long-term nighttime warming on extractable soil element composition in a Mediterranean shrubland

Understanding the soil biogeochemical responses to increasing global warming in the near future is essential for improving our capacity to mitigate the impacts of climate change on highly vulnerable Mediterranean ecosystems. Previous studies have primarily focused on the effects of warming on various biogeochemical processes. However, there is limited knowledge about how the changes in water availability associated to high temperatures can alter the bioavailability and dynamics of soil elements, thereby impacting ecosystem productivity, species composition, and pollution through soil biogeochemical and hydrological processes. In this study, we investigated the effects of long-term nighttime warming on the extractable concentrations of organic carbon (EOC), total nitrogen (ETN), total phosphorus (ETP), and 17 mineral elements (arsenic (As), calcium (Ca), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), mercury (Hg), potassium (K), magnesium (Mg), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), sulfur (S), strontium (Sr), vanadium (V), and zinc (Zn)) through environmental experiments in a semi-arid Mediterranean shrubland. We explored the potential biotic and abiotic mechanisms underlying the seasonal and long-term changes in extractable-mobilizable elemental composition and concentrations. Our findings revealed that prolonged warming led to higher mean annual soil temperature (with an average increase of 0.67 °C from 1999 to 2014), accumulation of soil organic matter (EOC) and extractable concentrations of soil elements (particularly increased ETP and extractable Ca, Mg, Cu, Sr, Mn, and As). These changes were attributed to uniformly higher activities of extracellular soil enzymes and/or lower plant photosynthetic and nutrient uptake capacity linked to more water deficit under warmer conditions. Seasonality unevenly altered element extractable concentrations, with soil microclimate (temperature and water content) and biological (soil microbial and plant) activity being the main drivers of this variability, thus influencing soil element composition. These results suggest significant fluctuations in the extractable concentrations of specific mineral elements in these soils, implying potential future variations in soil element composition as well as the loss of total element concentrations/contents in semi-arid Mediterranean ecosystems due to increasing warming. Therefore, these findings enhance our ability to predict ecosystem management strategies and mitigate the observed negative impacts on plant-soil systems and water quality in the context of climate change.

Litter covering decreases moss activity, mediating the relationships between moss biocrusts and shrub patches in semiarid dryland ecosystems

Litter covering decreases moss activity, mediating the relationships between moss biocrusts and shrub patches in semiarid dryland ecosystems

The Activity Patterns and Grouping Characteristics of the Remaining Goitered Gazelle (Gazella subgutturosa) in an Isolated Habitat of Western China.

Wildlife activity patterns, which reveal the daily allocation of time and energy, are crucial for understanding survival pressures, adaptive strategies, and behavioral characteristics in different environments. Among ungulates, grouping behavior is a prevalent adaptive trait that reflects the population structure, mating systems, and life history strategies formed over long-term evolutionary processes. This study aimed to elucidate the daily activity patterns and grouping characteristics of the rare goitered gazelle (Gazella subgutturosa) in the Helan Mountains of western China from 2022 to 2023 using camera trap monitoring. With a total of 3869 camera days of effective trapping, we recorded 442 independent detections of goitered gazelles. The results revealed the following: (1) Goitered gazelle is primarily active during the day, showing an activity pattern similar to crepuscular animals, with two activity peaks occurring after dawn and before dusk. (2) Daily activity patterns showed both seasonal and sex differences. In the warm season, morning activity peaks occurred earlier, and afternoon peaks occurred later compared to the cold season. The overlap in daily activity patterns between females and males in the warm season was lower than that in the cold season, and this trend persisted throughout the year. (3) The number of times different types of groups were observed varied significantly, with single males and single females accounting for a larger proportion of all observed groups. There was no significant difference in group size across seasons, with groups typically consisting of 1-2 individuals. Our study provides detailed insights into the temporal ecology and population structure of goitered gazelles in arid and semi-arid ecosystems. This information will guide the identification of future conservation priorities and the development of management plans for the reserve.

Modelling vegetation dynamics for future climates in Australian catchments: Comparison of a conceptual eco-hydrological modelling approach with a deep learning alternative

Dynamically simulating leaf area index assists in modelling the feedbacks between eco-hydrologic and climatic processes. The particular challenge for Australia is the prevalence of arid and semi-arid ecosystems where water availability plays a crucial role in vegetation productivity. To understand whether existing LAI models can capture plant dynamics under changing climates, we tested two competing models across Australia's different climate zones: a conceptual eco-hydrologic model that applies water use efficiency term to relate LAI to water uptake, and a deep learning approach. An initial virtual catchment experiment with deep learning showed that it only uses information from potential evapotranspiration. For future climates, the conceptual model captured a negative trend and increasing variance in LAI, which is plausible given projected rainfall changes, while deep learning did not. Our study demonstrated an example of ‘right answer for the wrong reasons’, and the importance of incorporating knowledge of water-carbon coupling for appropriate scenarios.

The Origin and Type of Inoculum Determine the Effect of Arbuscular Mycorrhizal Fungi on Tomato under Different Irrigation Regimes

Arbuscular mycorrhizal fungi (AMF) play a crucial role in the resilience of plants subjected to water deficit. The objective of this study was to evaluate the impact of AMF from a semi-arid and humid ecosystem, applied as inocula (two monospecific and two consortia), and three irrigation doses (100%, 85%, and 70%) on tomato plant growth. A factorial experiment in a completely randomized design was used. Colonization with monospecific inocula (EH and ES) showed contrasting differences at 85% and 100% irrigation rates. With gradually increasing irrigation rates, colonization decreased with the CH consortium, while the CS consortium showed similar colonization levels at all three irrigation rates. AMF from humid environments (monospecific or in a consortium) did not affect equatorial diameter when the irrigation rate was reduced by 15%, while polar diameter was similar at all three irrigation rates. Inocula from the semi-arid ecosystem promoted the greatest equatorial and polar diameters at the 100% irrigation dose. The monospecific inoculum of C. etunicatum (ES) showed great potential to promote plant growth and development at the 100% irrigation dose and could be a biotechnological tool to improve tomato yield under conditions similar to those of this study.

Concurrent nitrogen and phosphorus enrichment increases ecosystem carbon use efficiency in an alpine grassland

Ecosystem carbon use efficiency (CUEe) is a crucial indicator for assessing the capacity of ecosystems to sequester atmospheric carbon (C). However, it remains unclear how nitrogen (N) and phosphorus (P) influence CUEe and how climatic factors regulate CUEe. Here, a four-year manipulative experiment was conducted in a semi-arid alpine grassland ecosystem to explore the response of CUEe to N and P additions with fluctuating interannual precipitation. Our study revealed that the N and P combination synergistically improved CUEe; the single additions of N or P did not affect CUEe. The variation in CUEe was correlated to a larger in net ecosystem CO2 exchange (NEE) relative to gross ecosystem productivity (GEP). Similarly, the combination of N and P significantly increased aboveground biomass, whereas addition alone did not. Under the combined addition of N and P, a significant decrease in species diversity led to decreases in CUEe. Moreover, precipitation indirectly increased CUEe by increasing NEE. Our findings underscore the co-limitation of N and P resources for CUEe in the alpine grassland ecosystem and identify community structure and climate factors as key drivers of CUEe variations following nutrient enrichment.

Non-Linear Relationships between Fine Root Functional Traits and Biomass in Different Semi-Arid Ecosystems on the Loess Plateau of China

As a key soil carbon process, changes in plant root growth may have a dramatic impact on the global ecosystem’s carbon cycle. Fine root functional traits and fine root biomass can be used as important indexes of plant root growth. Compared with the much better understood relationships between aboveground plant functional traits and aboveground biomass, knowledge on the relationships between fine root functional traits and belowground biomass still remains limited. In this study, plant fine roots in 30 abandoned lands, 9 woodlands, 29 alfalfa grasslands, 30 Caragana shrublands and 29 croplands were sampled at 0–20 and 20–40 cm soil depths in Zhonglianchuan, Yuzhong County, Gansu Province, China (36°02′ N, 104°24′ E), to clarify the characteristics of the relationships between fine root functional traits (e.g., diameter, specific root area (SRA) and specific root length (SRL)) and fine root biomass at 0–20 and 20–40 cm soil depths. The results showed that the relationships between the fine root functional traits and fine root biomass in these ecosystems were robust, allowing for the use of an allometric growth model at both 0–20 and 20–40 cm soil depths (p &lt; 0.05). Specifically, the relationship between root diameter and fine root biomass was consistent with highly significant positive power, while highly significant negative power relationships of SRA and SRL with fine root biomass were observed (p &lt; 0.01, except the root diameter–biomass models in the woodlands in the 0–20 cm soil layer (p = 0.017) and 20–40 cm soil layer (p = 0.025)). The results can provide some parameters for these terrestrial ecosystem process models. From this perspective, our study is beneficial in the construction of suitable strategies to increase plant biomass, which will help with the restoration of the semi-arid region of the Loess Plateau of China.

Aridity shapes distinct biogeographic and assembly patterns of forest soil bacterial and fungal communities at the regional scale

Climate change is exacerbating drought in arid and semi-arid forest ecosystems worldwide. Soil microorganisms play a key role in supporting forest ecosystem services, yet their response to changes in aridity remains poorly understood. We present results from a study of 84 forests at four south-to-north Loess Plateau sites to assess how increases in aridity level (1- precipitation/evapotranspiration) shapes soil bacterial and fungal diversity and community stability by influencing community assembly. We showed that soil bacterial diversity underwent a significant downward trend at aridity levels >0.39, while fungal diversity decreased significantly at aridity levels >0.62. In addition, the relative abundance of Actinobacteria and Ascomycota increased with higher aridity level, while the relative abundance of Acidobacteria and Basidiomycota showed the opposite trend. Bacterial communities also exhibited higher similarity-distance decay rates across geographic and environmental gradients than did fungal communities. Phylogenetic bin-based community assembly analysis revealed homogeneous selection and dispersal limitation as the two dominant processes in bacterial and fungal assembly. Dispersal limitation of bacterial communities monotonically increased with aridity levels, whereas homogeneous selection of fungal communities monotonically decreased. Importantly, aridity also increased the sensitivity of microbial communities to environmental disturbance and potentially decreased community stability, as evidenced by greater community similarity-environmental distance decay rates, narrower habitat niche breadth, and lower microbial network stability. Our study provides new insights into soil microbial drought response, with implications on the sustainability of ecosystems under environmental stress.

Characterizing Vegetation Phenology Shifts on the Loess Plateau over Past Two Decades

Phenology is a critical mirror reflecting vegetation growth and has a major impact on terrestrial ecosystems. The Loess Plateau (LP) is a paramount ecological zone in China that has experienced considerable vegetation changes. However, understanding the dynamics of vegetation phenology is limited by ambiguous vegetation interpretation and anthropogenic-induced forces. This study combined the multi-climatic and anthropogenic datasets to characterize the interactions between phenology shifts and environmental variables. The principal findings were as follows: (1) Phenological shifts exhibit spatial heterogeneity and an interannually increasing trend in greenness (R2 &gt; 0.6, p &lt; 0.05). Notably, SOS (the start of the growing season) advances while EOS (the end of the growing season) delays in both the southeastern and northwestern regions. (2) SOS and EOS, primarily in the range of 100–150 and 285–320 days, respectively. Phenological changes vary depending on vegetation types. The forest has an early SOS, within 80–112 days, and a delayed EOS, within 288–320 days. The SOS of shrub is mainly within 80–144 days. (3) EOS shows a strong response to the preseason of each climate variable. Precipitation (R = 0.76), soil moisture (R = −0.64), and temperature (R = 0.89) are the governing determinants in shaping vegetation phenology. In addition, agriculture and urbanization play a significant role in shaping the spatial variations of SOS. These findings provide a basis for a systematic understanding of the processes that affect vegetation growth, which is crucial for maintaining the health and sustainability of arid and semiarid ecosystems.

Natural History of the Genus Elasmoderus Saussure, 1888 (Orthoptera: Tristiridae), an Endemic and Eremic Element of the Transitional Coastal Desert of Chile.

The genus Elasmoderus belongs to the family Tristiridae, an orthopteran group that is distributed across the transitional region of South America and represented in the Andean areas of Peru, Argentina, and Chile. The species of Elasmoderus have morphological adaptations that make them especially suited for surviving in extreme arid environments and are an endemic and eremic group of the north-central region of Chile. On the basis of field samplings, direct observations, and a comprehensive literature review, we collected information about the genus Elasmoderus. The objectives of this research were: (i) to provide updated information on the geographical distribution range of the species of the genus Elasmoderus, and (ii) to collect and synthesize the most relevant information on the natural history and ecology of this orthopteran group as a basis for future long-term studies of its populations. Although this genus is underrepresented compared to other orthopteran families, it has developed interesting adaptations to extreme arid environments that remain unstudied to this date. E. lutescens is known to be one of the species with a wider latitudinal distribution, mostly on the coast and longitudinal valley of Atacama. E. minutus has a more restricted distribution, whereas E. wagenknechti is concentrated in coastal and interior environments of the Coquimbo region, an area where it reaches high population densities, thus affecting crops and natural vegetation and polluting water sources. Our findings underscore the importance of conducting comprehensive research on native insect groups that are poorly known but crucial for arid and semiarid ecosystems. These data will serve as a starting point for conducting long-term studies on this orthopteran group to gain a better understanding of the importance and role of these species in the semiarid ecosystems of northern Chile.