Dry Climate Research Articles

Examining the effect of water and glass surface temperature on the rate of generation and heat transfer in triangular double-slope single-basin solar still in Kerman province

Freshwater is a fundamental ingredient and its shortage is a serious issue. High evaporation rates of some regions can be exploited for freshwater production using solar stills. Meanwhile, Kerman province in the south of Iran has a hot and dry climate and suffers from water shortages and drought. On the other hand, Iran has a lot of access to salt and open water and has a high evaporation capacity in many areas and has the facilities and technical knowledge in the field of using solar water desalinators. Therefore, in this research, the effect of temperatures of salty water and glass surfaces on the rate of freshwater production in Kerman province is investigated. A numerical approach is used in this study and experimental research is used as validation reference. Moreover, the grid independency study is performed with proper accuracy and an adequate number of meshes. In addition to, the rate of water production and average Nusselt number (Nuave) in different cases, temperature, mass fraction, streamlines and velocities are examined for evaluation of results. The results show that by increasing the glass surface and salty water temperatures and raising the difference between the salty water and glass temperatures, which is accompanied by an increase in the density gradient, the rate of freshwater production increases. Also, the highest rate has occurred at the water temperature of Tw = 65 °C and glass temperature of Tg = 61 °C.

Modeling urban expansion in Zahedan’s dry climate: insights from the SLEUTH model

IntroductionRapid uncontrolled growth of build-up areas has increasingly challenged the sustainable use of urban area simulating the growth patterns of fastest-growing cities is more necessary in dry climates, due to low ecological suitability for urban development and meeting the needs of citizens. Therefore, this research conducted aiming at predicting the expansion of urban land use in Zahedan City, Iran, which has a dry climate with an evenness landscape.MethodsUrban Expansion in Zahedan Modeled using SLEUTH (slope, land use, exclusion, urban extent, transportation and hillshade) in two historical and environmental scenarios until 2050. The input data were extracted from processing on DEM and remote sensing data and the SLEUTH model was calibrated in four stages from 1990 to 2020.Results and discussionThe results showed that the increase in Ahead extent in 2050 is more than twice as much as in 2020, and this increase was associated with a less dispersion of urban patches in the environmental scenario compared to the historical scenario. Also, the results clarified that the developable spaces are saturated in terms of slope in the east and there is the lack of urban green spaces. These results reveal the need for the attention of city managers in predicting the urban green space in the expected growth areas and compensating for the lack of vegetation cover in the former urban areas. Geographic extension of predicted urban land can be used in future environmental planning and urban developing strategies, as well as it is suggested to adopt this approach as a plan for urban planning in dry climates.

Tracking the past: Isotopic paleoecology (δ13C, δ18O) of the Late Pleistocene megafauna from northeast of South America

Fossils from natural tanks can contribute to the paleoenvironmental interpretation of the Brazilian Intertropical Region (BIR), an important study area for the Quaternary in South America. In this paper we present results of δ13C and δ18O for Eremotherium laurillardi (δ13C = −4.6 ‰, δ18O = 33.0 ‰), Toxodon platensis (δ13C = −3.8 ‰, δ18O = 35.5 ‰), and Notiomastodon platensis (δ13C = −2.9 ‰, δ18O = 31.6 ‰) from Zabelê tank, compared to other localities, suggesting that these taxa had a mixed-feeder diet with a higher consumption of C4 plants (pi > 60%), living in a transition zone between woodland savannah and open savannah. The Zabelê tank, northeastern Brazil, presents Optically Stimulated Luminescence ages ranging from 41.2 to 30.4 ky (Lujanian Stage/Age; Late Pleistocene). The origin of the fossiliferous layer through debris flow suggests short periods of intense rainfall under drier climatic conditions. Compared to other locations in the BIR, Zabelê documented a drier climate (δ18O = 31.6–33.4 ‰), which preceded the last glacial maximum. These new isotopic data to OSL ages associated with previous data from the BIR contribute to the understanding of the paleoecology and paleoenvironment dynamics of South America.

VERNACULAR ARCHITECTURE OF JODHPUR: A RESILIENT APPROACH TO SUSTAINABLE ENVIRONMENT

Sustainable architecture is the application of principles that contribute in the evolution of building designs and processes that reduce the negative environmental effects of construction. When contemplating Jodhpur's vernacular architecture, it becomes clear that traditional construction methods correspond to basic green design principles such as using energy-efficient locally available materials and resources. Many traditional aspects of Jodhpur architecture can be easily incorporated into contemporary environments to provide a sustainable atmosphere and natural accompaniment. This study presents the scope of eco-friendly development of the city by using traditional construction techniques and materials, built forms, and fabric with a thorough analysis of the hot and dry climate of the area. It also encompasses the use of this local architecture to help create an energy- efficient thermal comfort zone in similar climatic conditions in any part of the world. This work is an attempt to reclaim the ideals about good architecture towards this setting, in not only terms of identifying the hot and arid climate but also in terms of producing a design philosophy relevant to the manner of living in a conventional city.

Remote Quantification of Soil Organic Carbon: Role of Topography in the Intra-Field Distribution

Soil organic carbon (SOC) measurements are an indicator of soil health and an important parameter for the study of land-atmosphere carbon fluxes. Field sampling provides precise measurements at the sample location but entails high costs and cannot provide detailed maps unless the sampling density is very high. Remote sensing offers the possibility to quantify SOC over large areas in a cost-effective way. As a result, numerous studies have sought to quantify SOC using Earth observation data with a focus on inter-field or regional distributions. This study took a different angle and aimed to map the spatial distribution of SOC at the intra-field scale, since this distribution provides important insights into the biophysiochemical processes involved in the retention of SOC. Instead of solely using spectral measurements to quantify SOC, topographic and spectral features act as predictor variables. The necessary data on study fields in South-East England was acquired through a detailed SOC sampling campaign, including a LiDAR survey flight. Multi-spectral Sentinel-2 data of the study fields were acquired for the exact day of the sampling campaign, and for an interval of 18 months before and after this date. Random Forest (RF) and Support Vector Regression (SVR) models were trained and tested on the spectral and topographical data of the fields to predict the observed SOC values. Five different sets of model predictors were assessed, by using independently and in combination, single and multidate spectral data, and topographical features for the SOC sampling points. Both, RF and SVR models performed best when trained on multi-temporal Sentinel-2 data together with topographic features, achieving validation root-mean-square errors (RMSEs) of 0.29% and 0.23% SOC, respectively. These RMSEs are competitive when compared with those found in the literature for similar models. The topographic wetness index (TWI) exhibited the highest permutation importance for virtually all models. Given that farming practices within each field are the same, this result suggests an important role of soil moisture in SOC retention. Contrary to findings in dryer climates or in studies encompassing larger areas, TWI was negatively related to SOC levels in the study fields, suggesting a different role of soil wetness in the SOC storage in climates characterized by excess rainfall and poorly drained soils.

Water status dynamics and drought tolerance of juvenile European beech, Douglas fir and Norway spruce trees as dependent on neighborhood and nitrogen supply.

To increase the resilience of forests to drought and other hazards, foresters are increasingly planting mixed stands. This requires knowledge about the drought response of tree species in pure and mixed-culture neighborhoods. In addition, drought frequently interacts with continued atmospheric nitrogen (N) deposition. To disentangle these factors for European beech, Norway spruce and Douglas fir, we conducted a replicated 3-factorial sapling growth experiment with three moisture levels, (high, medium, and low), two N levels (high and ambient), and pure and mixed-culture neighborhoods. We measured biomass, stomatal conductance (GS), shoot water potential (at predawn: ΨPD, midday, and turgor loss point: ΨTLP), branch xylem embolism resistance (Ψ50) and minimum epidermal conductance (Gmin). The three species differed most with respect to Gmin (10-fold higher in beech than in the conifers), hydroscape area (larger in beech), and the time elapsed to reach stomatal closure (TΨGS90) and ΨTLP (TTLP; shorter in beech), while Ψ50 and ΨTLP were remarkably similar. Neighborhood (pure vs mixed-culture) influenced biomass production, water status and hydraulic traits, notably GS (higher in Douglas fir, but lower in spruce and beech, in mixtures than pure culture), hydraulic safety margin (smaller for beech in mixtures), and TΨGS90 and TTLP (shorter for spruce in mixture). High N generally increased GS, but no consistent N effects on leaf water status and hydraulic traits were detected, suggesting that neighbor identity had a larger effect on plant water relations than N availability. We conclude that both tree neighborhood and N availability modulate the drought response of beech, spruce, and Douglas fir. Species mixing can alleviate the drought stress of some species, but often by disadvantaging other species. Thus, our study suggests that stabilizing and building resilience of production forests against a drier and warmer climate may depend primarily on the right species choice; species mixing can support the agenda.

Thermal analysis of a building in hot and dry climate: a detailed study

Thermal analysis of a building in hot and dry climate: a detailed study

Using wood rings to determine age and climate constraints of grapevine (Vitis vinifera) radial growth

Summary Grapevine (Vitis vinifera) is the most widely cultivated and economically relevant crop in the world, but its productivity is menaced by aridification in some wine-growing regions such as the Mediterranean Basin. The impacts of climate on vines depend on regional conditions, cultivar, and vine age, among other factors. Hence, a better understanding of vine radial-growth responses to climate in different regions is sorely needed. First, we related climate data and drought severity with a long-term series of vine leaf unfolding from NE Spain to test if climate warming is advancing the onset of the growing season. Second, we used growth rings to estimate age and quantify climate-growth relationships of vines using dendrochronology. Three sites from different designations of origin and vine varieties were studied: Logroño in northern Spain (La Rioja, Tempranillo), San Martín del Río in northeast Spain (Calatayud, Garnacha) and Anzi in southern Italy (Aglianico, Aleatico). Vine leaf unfolding occurred earlier as winter-spring conditions were warmer and drier. Vine ages ranged between 16 (Logroño, Anzi) and 56 years (S. Martín del Río), and growth rates declined in the two youngest grapevines. Ring widths varied between 1.19 (S. Martín del Río) and 1.80 mm (Logroño), with Anzi showing intermediate values (1.37 mm). February precipitation enhanced vine growth in San Martín del Río () and Anzi (), whereas the correlation with soil moisture peaked in March in San Martín del Río (). Vine growth rates positively responded to September minimum temperatures in San Martín del Río () and Logroño (). Garnacha cultivar in San Martín del Río showed the highest responsiveness to water availability. Therefore, similar old grapevines from continental, seasonally dry areas could be the most negatively affected by future warmer and drier climate conditions.

Investigating the regional ecological environment stability and its feedback effect on interference using a novel vegetation resilience assessment model

Vegetation resilience is critical for understanding the dynamic feedback effect of regional ecological environment stability against interferences. Thus, based on quantify the interferences of climate dryness and vegetation water deficit affecting vegetation growth function, incorporate mechanical Hooke's law to develop a vegetation resilience assessment model by quantitatively expressing vegetation growth function maintenance ability, to reveal the ecological environment stability and its feedback effect on interferences in the study area. The essential discoveries of the study are as follows: (1) with the increase of precipitation and the improvement of afforestation on soil erosion, the interferences intensity of climate dryness and vegetation water deficit in the ecological environment decreased by 5.88 % and 4.92 % respectively, the regional vegetation growth function loss was improved, especially in the southern region; (2) the decrease of vegetation growth function loss promoted the vegetation resilience level fluctuated from class II to class IV, with the average annual vegetation resilience increased by 7.02 %, reflecting that the regional ecological environment stability increased from difficult to rapid recovery after disturbance, and the benefit was especially noticeable in the eastern and southern forested areas; (3) the contribution rates of climate dryness and vegetation water deficit to the variation of vegetation resilience caused by vegetation restoration were −1.38 % and 4.73 %, respectively, and the prominent positive feedback effect of increasing vegetation resilience with decreasing vegetation water deficit degree in forest restoration area, indicating that the vegetation water deficit greatly impacts ecological environment stability in the study area, and forest restoration constantly improves regional ecological environment stability more than grassland restoration. This research has crucial guiding implications for supporting the sustainable development of regional ecological environments.

Prehistoric subsistence strategy dynamics and their differences under a similar hyper-arid environment in the contiguous Turpan and Hami Basins of Xinjiang

Agropastoralism has prevailed in Inner Asia since the Bronze Age. It is an optimal subsistence strategy of inhabitants for adaptation to arid marginal environment. However, previous studies paid little attention to different development trajectories of this mixed economy within similar habitat. The Turpan and Hami Basins, located in eastern Tianshan Mountains of Xinjiang, are two typical desert oases with extremely dry climate, providing us with an appropriate region to investigate the issue. In present study, radiocarbon dates ( n = 154) of eight typical sites in these two basins were reviewed and used to reconstruct the prehistoric chronology sequence prior to Han Dynasty (2200 cal BP). Then the data of botanical and faunal remains and stable isotope analyses ( n = 159) of human diets from these sites were also reviewed for reliably revealing the subsistence economy pattern. Combining the time scale with multiple biological proxies, results show that, from the Bronze Age to early Iron Age, inhabitant subsistence in the Turpan Basin was dominated by livestock herding and supplemented by low-investment cereal crop cultivation, while the agriculture in Turpan Basin has developed significantly by the later period of Subeixi Culture. In contrast, agriculture-based economy was continuously developed in the Hami oases. Although the climate is very dry in both basins, temperature in warm seasons is much higher in the Turpan Basin. Besides thermal condition, size, range and convenient availability of highland pasture located at the southern flank of the Tianshan Mountains, are main driving factors leading to differentiated development trajectories of agropastoralism. Apart from that, cultural factors like economy, culture and technology communication along with population migration also impact local subsistence economy pattern.

Effects of climate variability and/or land use dynamics on the hydrological balance of the Cavally river catchment at Toulepleu, West Africa

Abstract The study focuses on assessing the individual and combined impacts of climate variability and land use change on hydrological responses. The results indicate that the basin, urban area, cropland, degraded forest, and open forest shows an increasing trend, while gallery forest show a decreasing trend over the period 1992–2015. Climatic variability is marked by two climatic periods (a wet one from 1980 to 1996 and a dry one from 1997 to 2016) with a 35% decrease in rainfall. Regardless of the state of the landcover used, the simulated mean annual runoff decreases by 67.92% between the wet and dry climate periods. Changes in land use between 1992 and 2015 reduce mean annual runoff by 4.71%. Analysis of the joint effect of climatic and LU variation shows a 68.96% reduction in runoff. In this catchment, the joint impact has a clearly greater effect on runoff than the climatic impact, which is greater than that of human activities. There is a need for policymakers to prioritise sustainable land use practices and integrated water resource management strategies in the area to mitigate the combined effects of climate variability and anthropogenic activities, ensuring the long-term resilience of the ecosystem and water availability for local communities.

Comparison of Juvenile Development of Maize and Sorghum in Six Temperate Soil Types under Extreme Water Regimes

Climate change requires the introduction of alternative crops in certain temperate areas due to the warmer and drier growing seasons. Maize, one of the most important crops, is projected to become less tolerant of a drier climate. Therefore, it is necessary to find an alternative species that is less susceptible to environmental stressors. This study compared the germination, growth vigour, and stress tolerance of maize and sorghum grow in six types of soil under three water regimes. The results indicate that sorghum germination is faster and more uniform. The most significant differences in germination rates were found in chernozem (88.9% and 72.2% for sorghum and maize, respectively) and saline solonetz (74.4% and 63.3% for sorghum and maize, respectively). Maize exhibited higher growth vigour only in three cases, i.e., under solonetz–flooding, shifting sand–drought, and brown forest floor–flooding conditions. An ANOVA showed a significant difference between sorghum and maize stress conditions due to soil conditions and water availability (p < 0.0001). Sorghum can be a suitable alternative to maize, but only in areas with hot, dry periods and in areas where the soil is not too prone to waterlogging, regardless of its quality.

Last-Century Forest Dynamics in a Highland Pyrenean National Park and Implications for Conservation.

Ecological records from before and after the creation of natural parks are valuable for informing conservation and management but are often unavailable. High-resolution paleoecological studies may bridge the gap and provide the required information. This paper presents a 20th-century subdecadal reconstruction of vegetation and landscape dynamics in a national park of the Pyrenean highlands. The park lands had traditionally been used for cultivation, extensive grazing, forest exploitation, and hydroelectricity generation following the damming of numerous glacial lakes. A significant finding is that forests have dominated the landscape, with negligible changes in composition, and only experienced fluctuations in forest cover, influenced by both climatic and anthropogenic factors. The creation of the park (1955) and the initial restrictions on forest exploitation did not significantly affect vegetation cover or composition. Major forest expansion did not occur until several decades later, 1980, when the park was enlarged and forest exploitation was further restricted. This expansion peaked in the 1990s, coinciding with a warming trend and a decrease in fire incidence, before declining due to warmer and drier climates. This decline was coeval with the ongoing global forest dieback and may be exacerbated by the predicted global warming in this century, which could also increase fire incidence due to dead-wood accumulation. Currently, the main threats are global warming/drying, fire, and tourism intensification. Similar high-resolution paleoecological records in protected areas are globally scarce and would be capable in providing the long-term ecological scope required to properly understand forest dynamics and optimize conservation measures.

How much evaporation occurs in Brazilian reservoirs? A multi-model perspective

Estimating evaporative losses from reservoirs is essential for water resource management. While remote sensing provides great opportunities for better constrain this process, there are still large uncertainties related to the behavior of evaporative losses across large domains. Here, we present a multi-model approach combined with remote sensing data to estimate evaporation losses at a national scale for dozens of reservoirs in Brazil. Open water evaporation (Ew) rates were obtained using two surface energy balance (SEB) models (the Google Earth Engine implementation of the Surface Energy Balance Algorithm for Land (geeSEBAL) and the Simplified Surface Energy Balance (SSEBop)). Due to the lack of in situ evaporation data, the estimations were cross-validated with results from the validated product Moderate-Resolution Imaging Spectroradiometer (MODIS) Water Reservoir Monthly Level 3 Global (MOD28C3) and the widely used open water evaporation equation described by Penman. Ew estimates were obtained for 74 large reservoirs, representing almost 70% of the area occupied by artificial water bodies in Brazil. Monthly estimates of Ew showed satisfactory agreement among the models, especially for geeSEBAL, SSEBop, and MOD28C3. Reservoirs with higher Ew were located in the semi-arid Caatinga Biome. The total annual evaporation and net evaporation (difference between lake Ew and surrounding evapotranspiration) for the assessed reservoirs were 46.6 ± 1.0 km³ and 16.4 ± 0.5 km³, respectively, for the period 2003–2021, based on an average of geeSEBAL and SSEBop. We also found that net evaporation is very high in dry climate zones and lower in tropical and humid subtropical climate zones. Our results show the advantage of integrating remote sensing datasets and evaporation models with cloud computing to obtain evaporation estimates in a tropical region and over a large domain. These multi-model evaporation estimates can improve our understanding of water resources in ungauged regions at a large spatial scale.

Soil organic matter dynamics and stability: Climate vs. time

Climate and time are among the most important factors driving soil organic carbon (SOC) stability and accrual in mineral soils; however, their relative importance on SOC dynamics is still unclear. Therefore, understanding how these factors covary over a range of soil developmental stages is crucial to improve our knowledge of climate change impact on SOC accumulation and persistence. Two chronosequences located along a climate gradient were investigated to determine the main interactions among time (age) and climate (precipitation and temperature) on SOC stability and stock with depth. Considering a common depth (0–15 or 0–30 cm), in the drier chronosequence, the older soil showed the highest SOC stock, while the younger exhibited the lowest carbon accumulation. Considering the whole profile, the SOC stock increased with age. In the wetter chronosequence, the younger soil showed the highest SOC stock considering a common depth, whereas, when the entire profile is taken into account, the older one accumulated 2–3 times more SOC than the others. In both chronosequences, significant stocks of SOC (∼42 %) were accumulated below 30 cm. Soil organic matter stability, assessed by thermal analysis and heterotrophic respiration, increases with depth and age only in the drier chronosequence. Soils from the wetter chronosequence were instead characterized by a greater quantity of labile and/or not-stabilized SOC; here, the amorphous Fe/Al-rich secondary mineral weathering products showed an essential predictor function of SOC storage, although they do not seem to be involved in SOC stabilization mechanisms. Otherwise, the interaction of SOC with fine particles, short-range order minerals, and organo-metal complexes represent the significant stabilization mechanisms in soils from drier climate. The results highlighted how the age factor plays an unassuming role in geochemical processes influencing SOC dynamics; however, climate determines different trajectories of soil development and SOC dynamics for a given soil age. Thus, soil age shows a key role in SOC stabilization especially in drier climatic conditions, while wetter conditions determine an accumulation of a higher yet more labile amount of SOC.

Paleodepositional environments, lithostratigraphic bounding surfaces and basin-fill model of Mundeck Formation in Yabassi, NE Douala sub-basin

Lithofacies, sedimentologic and x-ray analytical techniques were employed to reconstitute paleodepositional environments, bounding surfaces and basin-fill model of Mundeck Formation during Lower Cretaceous in Yabassi, NE Douala sub-basin. The basin-fill comprises fissile gravel, sand and mud (GSF) facies from which eighteen sub-facies were identified and grouped under five facies associations (FA1-FA5). These correspond to alluvial settings (FA1), braided channels (FA2), cross-bedded tidal channels (FA3), ephemeral fluvio-lacustrine lake with short-lived marine incursion (FA4), fluvial channels with deeply incised erosional surfaces (FA5). Four hierarchical lithostratigraphic bed bounding surfaces were defined; incipient or intraformational hardgrounds, erosional surfaces abutted by ripped-up mud clasts, an obvious transgressive surface marked by the occurrence of ammonitic in lamellibranch and gastropod-rich silty-mudstones and shales. Humid and warm climates during Lower Cretaceous could be inferred from secondary mineral suites: clays (kaolinite, chlorite, illite and smectite); oxides (hematite and hydralsite); and oxy-hydroxides (goethite). Hematite-rich incipient hardgrounds surfaces depict warm and dry climates, while paleosols suggest channel abandonment, subaerial exposure and pedogenetic processes. Sediment transport regimes have evolved from low velocity cohesive flow regime in braided channels and overbank to high velocity and cohesion-less flow regime in multi-storey cross-bedded sand bars. Granulometric results reveal angular to sub-rounded, coarse-grained to gravelly clast sizes with unimodal, bimodal- and trimodal distributions, whereby all analyzed samples are positively skewed towards fine-grained sands. Morphoscopic analysis reveals 65–90% of very angular to angular and shinning quartz (VAAS), compared to 10–35% sub-angular and sub-rounded (SASR) and 0% rounded (R) shapes which indicate short transport distance from source areas. Sorting index (So) and deviation quartile (dQ) values of analyzed sands vary from 1.52 to 2.89, and 0.38–0.88 respectively and are indicative of moderate to very poor sorting.

Rising Temperatures, Falling Leaves: Predicting the Fate of Cyprus's Endemic Oak under Climate and Land Use Change.

Endemic island species face heightened extinction risk from climate-driven shifts, yet standard models often underestimate threat levels for those like Quercus alnifolia, an iconic Cypriot oak with pre-adaptations to aridity. Through species distribution modelling, we investigated the potential shifts in its distribution under future climate and land-use change scenarios. Our approach uniquely combines dispersal constraints, detailed soil characteristics, hydrological factors, and anticipated soil erosion data, offering a comprehensive assessment of environmental suitability. We quantified the species' sensitivity, exposure, and vulnerability to projected changes, conducting a preliminary IUCN extinction risk assessment according to Criteria A and B. Our projections uniformly predict range reductions, with a median decrease of 67.8% by the 2070s under the most extreme scenarios. Additionally, our research indicates Quercus alnifolia's resilience to diverse erosion conditions and preference for relatively dry climates within a specific annual temperature range. The preliminary IUCN risk assessment designates Quercus alnifolia as Critically Endangered in the future, highlighting the need for focused conservation efforts. Climate and land-use changes are critical threats to the species' survival, emphasising the importance of comprehensive modelling techniques and the urgent requirement for dedicated conservation measures to safeguard this iconic species.

Mixed siliciclastic-carbonate-tuffaceous sedimentation in a rift lacustrine basin: A case study of the Lower Cretaceous Jiufotang Formation in the Luxi sag, Songliao basin

The Lower Cretaceous Jiufotang Formation lacustrine successions in the rift Luxi sag, Songliao Basin are characterized by mixed siliciclastic-carbonate-tuffaceous and organic-rich deposits. Ten facies were recognized and were formed in fan delta, delta, littoral-sublittoral lacustrine and deep lacustrine environments. A depositional sequence characterized by significant changes in facies and lake regime has been defined, and is divided into lowstand systems tract (LST), transgressive systems tract (TST), and highstand systems tract (HST) that are separated by sequence boundaries, initial flooding surfaces, and maximum flooding surfaces, respectively. During the LST, the delta and fan delta deposits covered the marginal area and extended into littoral-sublittoral lacustrine and deep lacustrine environments, respectively. During the TST, the areas of delta and fan delta decreased and lake areas increased, and the carbonate-dominated shoals and mixed siliciclastic-carbonate shorelines occupied the edge of the Majiapu highland belt. During the HST, the lake areas further expanded, and the fan delta deposits extended into deep lacustrine environments and formed deposits of underflows and turbidites. A depositional model in the rift lacustrine Luxi sag is proposed, incorporating the effects of tectonics and sediment supply, climate and carbonate production, hydrodynamic conditions, and lake-level fluctuations. During the LST, the active tectonic movement, high input of siliciclastic sediments, and subaerial volcanic eruptions resulted in the wide distribution of mixed siliciclastic-tuffaceous sedimentation. During the TST, the brackish lake water controlled by periodic dry and hot climate facilitated the carbonate deposition in shallow water, and tractional currents onto the lake shore carried sediments to form the mixed siliciclastic-carbonate-tuffaceous facies. During the HST, more humid climate and increased runoff allowed formation of widely distributed, mostly oil shale-rich deposits, and the gravity flows carried the sediments into the deeper part of basin to form the mixed siliciclastic-carbonate-tuffaceous facies. The depositional model of mixed deposits in this rift lacustrine basin has been proposed here in order to encourage comparison with other similar basins.

To the Ecology of Bumblebees (Hymenoptera, Apidae, Bombus) in Talysh

The Talysh zone (Lenkoran natural area), due to different types of landscapes and climate, has a rich fauna and flora, many of which are endemic. There are 28 species of bumblebees living here, belonging to 7 zoogeographical complexes, which makes up 55% of the bumblebee fauna of Azerbaijan. In the lowlands and in foothill landscapes up to an altitude of 1000 m, where a humid subtropical climate prevails, only 4 species of bumblebees were found. In the zone of dry steppes and settled meadows, at approximately an altitude of 1400 to 2400 m, where a dry continental climate prevails, bumblebees are represented by 18 species. Bumblebees, with their perfect social life, are active throughout the season. As a result of studying the phenology of bumblebees’ flight, it was revealed that in the study area they begin flying from the beginning of April (4 species). During the summer months the number of species reaches its maximum (an average of 25 species). From the beginning of autumn, the growing season of flowering plants ends, and the number of bees decreases, but the number of bumblebee species is comparatively greater.

Contrasting shrub and grass hydraulic responses to experimental drought.

Whole-plant hydraulics provide important information about responses to water limitation and can be used to understand how plant communities may change in a drier climate when measured on multiple species. Here, we measured above- and belowground hydraulic traits in Cornus drummondii, an encroaching shrub within North American tallgrass prairies, and Andropogon gerardii, a dominant C4 grass, to assess the potential hydraulic responses to future drought as this region undergoes woody expansion. Shelters that reduced precipitation by 50% and 0% were built over shrubs and grasses growing in sites that are burned at 1-year and 4-year frequencies. We then measured aboveground (Kshoot), belowground (Kroot), and whole-plant maximum hydraulic conductance (Kplant) in C. drummondii and Kroot in A. gerardii. We also measured vulnerability to embolism (P50) in C. drummondii stems. Overall, we show that: (1) A. gerardii had substantially greater Kroot than C. drummondii; (2) belowground hydraulic functioning was linked with aboveground processes; (3) above- and belowground C. drummondii hydraulics were not negatively impacted by the rainfall reductions imposed here. These results suggest that a multi-year drought will not ameliorate rates of woody expansion and highlight key differences in aboveground and belowground hydraulics for dominant species within the same ecosystem.