Search Results (19)

The taxonomic composition and structure of invertebrate assemblages in five lakes from the Kulunda steppe, located in an arid region of southwestern Siberia (Russia), were studied. The lakes varied greatly in their total salinity (5 to 304 g L⁻¹) and carbonate alkalinity (0.03 to 4.03 mol-eq L⁻¹). The invertebrate fauna was characterized by low diversity. Only five taxa of macrozoobenthos and two taxa of planktonic invertebrates were identified. As water salinity increased, the taxonomic diversity of the studied lakes decreased, and at salinities > 276 g L⁻¹, monodominant assemblages were formed. The high numbers and biomass of aquatic organism provide a rich food supply for native and migratory waterfowl. The low taxonomic diversity of the invertebrate assemblages of the lakes makes them vulnerable to any negative external impact. The climate in the Kulunda steppe demonstrates a long-term aridization trend. If this continues in the future, then over time, this may lead to the gradual salinization of lakes and a further decrease in the taxonomic diversity of hydrobiological assemblages. This emphasizes the ecological importance of the studied territory and the necessity for its inclusion in the list of sites protected by the Ramsar Convention. Full article

Methane (CH₄) is a potent greenhouse gas with a significant impact on short- and medium-term climate forcing, and its atmospheric concentration has been increasing rapidly in recent decades. This study aims to analyze spatio-temporal patterns of atmospheric methane concentrations between 2019 and 2025, focusing on comparisons between regions characterized by high and low emission intensities. Level-3 XCH₄ data from the TROPOspheric Monitoring Instrument (TROPOMI) onboard the Sentinel-5 Precursor satellite were used, which were aggregated into seasonal and annual composites. High-emission regions, such as the Mekong Delta, Nile Delta, Eastern Uttar Pradesh and Bihar, Central Thailand, Lake Victoria Basin, and Eastern Arkansas, were contrasted with low-emission areas including Patagonia, the Mongolian Steppe, Northern Scandinavia, the Australian Outback, the Sahara Desert, and the Canadian Shield. The results show that high-emission regions exhibit substantially higher seasonal amplitude in XCH₄ concentrations, with an average seasonal variation of approximately 30.00 ppb, compared to 17.39 ppb in low-emission regions. Methane concentrations generally peaked at the end of the year (Q4) and reached their lowest levels during the first half of the year (Q1 or Q2), particularly in agriculturally dominated regions. Principal component and cluster analyses further confirmed a strong spatial differentiation between high- and low-emission regions based on both temporal trends and seasonal behavior. These findings demonstrate the potential of satellite remote sensing to monitor regional methane dynamics and highlight the need for targeted mitigation strategies in major agricultural and wetland zones. Full article

Salicornia europaea L. is a well-known model plant for studying the mechanism of salt tolerance. A substantial decline in the S. europaea population has been observed in the semi-arid steppe of the Mongolian Plateau. The relationship between environmental factors and its population dynamics in the grassland ecosystem remains inadequately investigated. Rhizosphere microbial communities, representing the most direct and influential biological factors affecting plant populations, have received limited research attention in the context of halophytes. Four density treatments of S. europaea (bare land—SEB, low density—SEL, medium density—SEM, and high density—SEH) in a single-factor randomized-block design with five replications were established to evaluate the relationship between rhizosphere soil bacterial communities and environmental factors. The results showed that as the density of S. europaea increased, the soil pH decreased, while available phosphorus increased. Rhizosphere soil bacterial communities associated with S. europaea populations in the saline-alkali wetland were dominated by Proteobacteria, Bacteroidota, Actinobacteria, Gemmatimonadota, and Halobacterota. Notably, the genera Antarcticibacterium, Wenzhouxiangella, BD2-11_terrestrial_groupBD2-11, Halomonas, and Natronorubrum were found to be particularly abundant. The Simpson index of the rhizosphere soil bacterial community in the S. europaea treatments was significantly higher than that in bare land. Soil pH and nitrate nitrogen were the primary environmental drivers of the rhizosphere bacterial community. Overall, the rhizosphere soil’s bacterial diversity in saline wetlands under a high-salt environment was not affected by the decrease in the S. europaea population. S. europaea plays an important role in shaping soil bacterial community structure through its influence on the surrounding soil environment. The cultivation of S. europaea is a phytoremediation strategy to improve soil salinization. Full article

In an attempt to boost the potential ecological viability of wetlands, this study aimed to discover the relationship between soil salinity and vegetation composition in a quasi-pristine saline pond, “El Hito Lagoon”. This wetland is situated in the largest continuous natural semi-arid steppe land of western Europe (specifically in Castilla La Mancha, Central Spain). Several soil profiles and a series of surface samples (0–10 cm) extracted from a systematic network throughout the saline pond were described, sampled, and analyzed. The most significant results included the detection of elevated levels of soil salinity, with distinctive sub-areas of extreme elevated surface salinity where the pH reading peaked at 9.89 and the electrical conductivity was higher than 40 (dS/m). The very high content of total available P displayed quite an irregular scatter within the soil profile. Specifically, the range oscillated between 8.57 mg/kg and 388.1 mg/kg, several samples having values greater than 100 mg/kg. An aspect that the abundant presence of Salsola soda, a plant frequently found growing in nutrient-rich wetlands, was able to confirm. Full article

Hereby, we report the new experimental data of plant biomass and biological productivity (net primary production, NPP) of wetland/peatland plant communities of oligotrophic bogs located on the same latitude, but at a distance of 1300 km west-east in the forest–steppe region of Western Siberia. The data were collected by implementing direct in situ measurements based on a unique methodology developed by authors. The study revealed that the values of net primary production (NPP) are basically constrained by the live fraction of plant biomass (or phytomass). It also revealed that the dead fraction of plant biomass (mortmass), along with the live fraction of biomass (phytomass) and net primary production (NPP), all major components of the carbon cycle, differ significantly at the two study sites. The values of dead biomass (mortmass), live biomass (phytomass) and net primary production (NPP) were found at significantly higher values in bog ecosystems studied in western regions than in those of the eastern regions. Full article

The land surface temperature (LST) is an important indicator reflecting the ecological environment condition. As a sensitive area to climate change, mastering the spatial and temporal changes of summer LST in the Bosten Lake basin (BLB) helps gain insight into the evolution of the thermal environment in the Bosten Lake basin and for long-term monitoring of the basic ecological changes in the basin. Based on MOD11A1 data from 2005 to 2020, this paper investigates the diurnal LST spatiotemporal series variation and its influencing factors in the Bosten Lake basin by using surface temperature class classification, trending analysis, the Hurst index, and geographic probes. The results show that (1) the wetland grasslands in and around the Bayinbruck steppe in the northwestern part of the study area exhibit a heat island effect during the day, while the opposite is true at night. In terms of temporal changes, LST changes in the BLB fluctuate widely, having a general rising and then decreasing trend. (2) The decreasing trend of LST from 2005 to 2020 is significant during the daytime and vice versa at night, and the change at night is greater than during the day. The areas with significantly higher diurnal LST in the future have all expanded compared to the area occupied by them now, with an overall trend of a steady increase. (3) The dominant factor of LST variation has the strongest explanatory power when altitude and NDVI are combined during the daytime and the strongest explanatory power when NPP and temperature are combined at night. Full article

River delta soils are the final spatial units of the matter flow within the whole river catchment. Due to their spatial position in the catchment and due to their fine grain size composition, river delta soils are important matter sinks in general, especially for heavy metals. The article presents the results of spectrometric analysis of heavy metals in the soils of the Ili River Delta and State Natural Reserve “Ili-Balkhash” in 2021. This area is included in the list of wetlands of international importance under the Convention on Wetlands. Heavy metals in the samples were determined using the flame atomic absorption spectrometric method using the AA-7000 atomic absorption spectrophotometer. The spatial distribution of the metals was visualized in the ArcGIS 10.5 environment. Copper concentrations were measured in the soils of the dry steppe, semi-desert and desert zones with average values up to 28.5 mg kg⁻¹ and a maximum level of 75.1 mg kg⁻¹. The concentrations of lead are 8.0–15.9 mg kg⁻¹. The cadmium content exceeds the standards from 2.1 to 6.5 mg kg⁻¹ on the whole territory at MPC 2.0 mg kg⁻¹, reaching up to 3.3 MPC (Maximum Permissible Concentration). The cobalt concentration ranges from 6.7 to 20.6 mg kg⁻¹, and nickel ranges from 11.3 to 22.2 mg kg⁻¹. Soil contamination due to cobalt and nickel is observed in the northern and eastern parts of the study area. The received data about pollution of the soil cover by heavy metals makes it possible to assess the degree of anthropogenic load of the unique natural environment in the Ili River Delta and natural reserve. Full article

The United Nations defines desertification as the loss of productivity in arid and semiarid environments. The extended steppes of Patagonia harbor small meadows whose compounded area is comparatively small, but their aboveground net primary production (ANPP) is up to ten times higher than their surroundings. These meadows then represent a key ecosystem for cattle grazing systems, but there are no descriptions of the trends in their ANPP and, consequently, their carrying capacity, and, as a result, their degradation syndromes. Our objectives were as follows: (1) analyze the trends of mean and spatial heterogeneity of annual ANPP in meadows and neighboring steppes and relate them with precipitation and temperature, (2) evaluate the impact on the livestock carrying capacity of meadows in the region, and (3) evaluate the degradation trends of these meadows, based on a novel description proposed to characterize the trend syndromes of these type of ecosystems. We identified meadow areas across a subcontinental scale in Patagonia, covering a mean annual precipitation range from 129 to 936 mm. We estimated ANPP on a monthly basis from 2000 to 2019 via regional calibrated remote sensing information. In the last two decades, ANPP decreased in 74% of the studied meadow areas, while remaining relatively stable in the nearby steppes. This decrease was relatively higher in the arid end of the analyzed precipitation gradient. Hence, the global carrying capacity for all the studied meadow areas decreased by 8%. Finally, we identified four trend syndromes based on the combination of the ANPP trend and its spatial heterogeneity, calculated as the spatial standard deviation. The predominant trend syndrome, in 55% of the area, was associated with a negative trend of both ANPP and spatial heterogeneity. These results could help prioritize areas where specific management decisions, given the different trend syndromes, could help revert ANPP negative trends. Full article

Analysis of the database of Beringian subfossil insect assemblages showed a relatively low role of aquatic, riparian, and wetland species of insects with hard exoskeleton in the Pleistocene communities and an increase in their proportions and taxonomic diversity in the Holocene. Aquatic insects were represented in all types of geological deposits and in some paleosols, but their proportions varied in different depositional environments. Poor representation of aquatic insects and a lack of freshwater invertebrates in the Late Pleistocene ice-rich deposits of Beringia called Siberian Yedoma or Yukon Muck attest to the predominantly aeolian origin of this phenomenon. Full article

Human appropriation of net primary productivity (HANPP) integrates ecological and socioeconomic perspectives on land use by quantifying the amount of net primary production (NPP) appropriated by society through biomass harvest from the ecosystem. The main objective of this study was to determine the spatial patterns of HANPP related to lamb and wool production from sheep farms across the province of Santa Cruz. The HANPP was obtained by dividing the sum of the biomass used in livestock products (lamb and wool) by the NPP. In addition, we examined the spatial relationship between HANPP and potential plant biodiversity and net carbon balance at the farm level under livestock land use across our study region. At the regional level, livestock production accounted for an average of 11.35% of appropriated NPP, and HANPP ranged from 0.75 to 50%. The map of HANPP across Santa Cruz showed low values in the vegetation transition (ecotone) between Nothofagus antarctica forests and grasslands in the west, in the south, and in wetlands where the most productive rangelands dominate. High values were observed in the northwest and central areas of the province. There were differences in HANPP across vegetation types with mean values that varied from 3.93% in grasslands on the Humid Magellanic Steppe to 12.33% in the Central Plateau. Simple linear regression analysis for HANPP evaluated in Southern Patagonia showed a negative linear relationship (p < 0.05) with vascular plant biodiversity and net carbon balance at the farm level. The method used to map HANPP related to livestock provisioning ecosystem services (ES) in the present study (lamb and wool), may be integrated into decision support systems. In this context, low HANPP values (<9%) promote sustainability-oriented economies within the region. Furthermore, keeping plant biodiversity and net carbon balance at the farm level could bring Patagonian export commodities recognition in international markets. Full article

This study presents detailed suspended sediment budget for the four Siberian river deltas, representing contrasting conditions between Northern and Southern environments. Two of the studied rivers empty their water and sediments into the marine located in the permafrost zone in the Arctic region (Lena and Kolyma), and the other two (Selenga and Upper Angara) flow into Lake Baikal located in the steppe and forest-steppe zone of Southern Siberia. For the first time, these poorly monitored areas are analyzed in terms of the long-term and seasonal changes of spatial patterns of suspended sediment concentrations (SSC) over distributaries systems. Remote sensing reflectance is derived from continuous time series of Landsat images and calibrated with the onsite field measurements of SSC. Seasonal variability of suspended sediment changes over deltas was captured for the period from 1989 to 2020. We identify significant variability in the sedimentation processes between different deltas, which is explained by particularities of deltas networks and geomorphology and the existence of specific drivers—continuous permafrost impact in the North and abundant aquatic vegetation and wetland-dominated areas in the South. The study emphasizes that differences exist between Northern and Southern deltas regarding suspended sediments transport conditions. Mostly retention of suspended sediment is observed for Southern deltas due to sediment storage at submerged banks and marshlands located in the backwater zone of the delta during high discharges. In the Northern (arctic) deltas due to permafrost impacts (melting of the permafrost), the absence of sub-aquatic banks and river to ocean interactions of suspended sediment transport is mostly increased downwards, predominantly under higher discharges and along main distributary channels. These results shine light on the geochemical functions of the deltas and patterns of sequestering various metals bound to river sediments. Full article

Wind speed (u) is a significant constraint in the evapotranspiration modeling over the highly heterogeneous regional surface due to its high temporal-spatial variation. In this study, a satellite-based Wind Speed Avoiding Priestley–Taylor (WAPT) algorithm was proposed to estimate the regional actual evapotranspiration by employing a u-independent theoretical trapezoidal space to determine the pixel Priestley–Taylor (PT) parameter Φ. The WAPT model was comprehensively evaluated with hydro-meteorological observations in the arid Heihe River Basin in northwestern China. The results show that the WAPT model can provide reliable latent heat flux estimations with the root-mean-square error (RMSE) of 46.0 W/m² across 2013–2018 for 5 long-term observation stations and the RMSE of 49.6 W/m² in the growing season in 2012 for 21 stations with intensive observations. The estimation by WAPT has a higher precision in the vegetation growing season than in the non-growing season. The estimation by WAPT has a closer agreement with the ground observations for vegetation-covered surfaces (e.g., corn and wetland) than that for dry sites (e.g., Gobi, desert, and desert steppe). Full article

Diffuse water pollution from agriculture (DWPA) is one of the major factors causing water pollution in Lakes Palić and Ludaš, the two largest shallow lakes of the Pannonian Basin in Serbia. These two lakes are protected under national and international law. On the basis of the number of strictly protected bird species, Ludaš Lake has been classified as a wetland of international importance since 1977 (Ramsar site 3YU002); in 2021, both lakes were nominated as potential Natura 2000 areas. Despite the degree of protection and ecological significance of the area, agricultural land prevails. By a process of land expropriation during 2019, the buffer zone began to expand around the lakes, which should lead to a reduction in pollution. One of the goals of buffer-zone development is to enhance and restore the ecological connectivity of the remaining forest-steppe habitats. During the expropriation process, soil was sampled to record areas with the highest pollution. This paper assesses the environmental risk caused by phosphorus, nitrogen, and the accumulation of heavy metals (Zn, Cu, Pb, Cr, Ni, Mn, Cd, and Hg). For each heavy metal, the corresponding pollution indices (Igeo, PI, EF, Eri, RI, Nemerow) and soil contamination level were calculated. Pollution indices indicate the ecological risk under the influence of heavy metals in the following order: Cd > Cu > Ni > Zn > Pb > Cr > Hg. Results showed that concentrations of Cd exceeded the maximal permissible concentration in all examined soil samples, and high ecological risk areas were determined. High concentrations of nitrogen, phosphorus, and potassium were detected, which could be as a result of intensive agricultural activity. Current conservation measures in this area have not provided adequate protection of the natural environment. Accordingly, existing measures must be controlled or new, more restrictive measures must be prescribed. Full article

Mongolia has globally significant biodiversity and pastoral traditions, and scarce water resources on which wildlife and people depend. Rapid growth of the mining sector is a threat to water resources and specifically river riparian zones. Mongolia has passed progressive laws for water and habitat conservation, including establishment of Integrated Water Resource Management (IWRM) and river basin governance organizations, and laws protecting the river riparian zone, but implementation has been hindered by limited technical capacity and data-scarcity, specifically because consistent, accurate maps of the riparian zone did not exist. To address this gap, WWF-Mongolia and partners developed a national delineation of riparian areas based on a spatial model, then validated this with local river basin authorities and provincial governments to designate legal protection zones. As a result, 8.2 million hectares of water protection zones including riparian areas have been legally protected from mining and industrial development in the globally significant landscapes and riverscapes of the Amur, Yenisey, and Ob Rivers headwaters, the Altai Sayan ecoregion, and the Gobi-Steppe ecosystem. These findings demonstrate a pathway for implementing broad-scale, durable legal protection of riverine wetlands through a data-driven, participatory process. Full article

Downward surface shortwave radiation (DSSR) plays an important role in the energy balance of the earth’s surface. Accurate estimate of DSSR is of great significance for the rational and effective use of solar energy. Some parameterization schemes were proposed to estimate DSSR using meteorological measurements given ground-based radiation observation sites are scare and uneven. With the development of remote sensing technique, remotely sensed data can be applied to obtain continuous DSSR in space. Commonly, the spatial resolution of most radiation products is relatively low and cannot meet the needs of certain fields. Moreover, some retrieval algorithms based on the radiation transfer models are complicated for non-professionals. In this study, a back-propagation (BP) neural network method with Levenberg–Marquardt (LM) algorithm (hereafter referred to as LM-BP) was applied to predict DSSR by building the relationship between measured DSSR and high-resolution remote sensing data from the Advanced Space-borne Thermal Emission Reflectance Radiometer (ASTER). The DSSR observations from the four-component radiation sensor installed at the land covered by vegetable, village, maize, orchard, Gobi, sandy desert, desert steppe, and wetland were used to validate the model estimates. The results showed that the estimates of DSSR from LM-BP agreed well with the site measurements, with the root mean square error (RMSE) and the mean bias error (MBE) values of 27.34 W/m² and −1.59 W/m², respectively. This indicates that by combining the LM-BP network model and ASTER images can obtain precise DSSR in heterogenous surface. The DSSR results of this study can provide accurate high-spatial resolution input data for hydrological, evapotranspiration, and crop models. Full article