Disturbed Lands Research Articles

Sub-regional to local topographic features shape resources, land use and disturbances determining forest distribution in old-growth grasslands of subtropical South America

What determines the presence (or lack) of trees in grasslands is a long-standing question in ecology. Views of trees in grasslands have shifted from generally considering grasslands as degraded forests that need to be restored, to a more recent perspective on many regions as ancient grassy biomes that have long been neglected and are, according to their climate conditions, maintained as stable biomes by internal feedbacks involving fire and/or herbivory. In addition, there are currently concerns about trends of woody expansion or “encroachment” in grasslands, i.e. potential transitions between grassy and wooded ecosystems driven by local and global changes.In this study, we use high-resolution local databases and generalized additive models (GAMLSS) to analyze the factors that determine forest cover in the Campos grasslands of Uruguay in southeastern South America. We consider climate, local conditions, land use and disturbances to understand what explains the distribution of forests. Forests were associated with areas of steeper slopes, watercourses and higher surface runoff, in deeper soils with higher water availability, along a longitudinal climatic gradient, with less livestock and land-use intensity and higher human presence. We discuss how, in ancient grasslands such as this one, sub-regional geology and local topography can be permanent features that generate spatial heterogeneity in forest cover probability by mediating resource availability and influencing land use and disturbance regimes.

Monitoring of Anthropogenic Impact on the Baikal Natural Territory: munisipal Level

The purpose of the presented study is to develop a methodology for assessing the anthropogenic impact on the environment in the municipalities of the Baikal Natural Territory (BNT) and applying the obtained methodology to the studied territory. The article analyzes the existing methodological approaches to the assessment of anthropogenic impact on the environment. To carry out a comprehensive integrated assessment, the authors proposed an algorithm for calculating the anthropogenic impact index based on 22 indicators integrated into 7 subindexes (impact on the atmosphere, water and forest resources, agricultural impact, solid waste, disturbed lands and objects of accumulated harm, as well as background impact).The weight of the indicators was determined by interviewing experts representing the scientific community (leading experts in the field of integrated assessments of certain types of impacts or specialists in the field of environmental problems of the BNT), the expert community (leading analytical agencies developing environmental ratings), as well as the environmental management system of the regions included in the BNT. The inertial nature of the anthropogenic impact characteristic of municipalities within the boundaries of the BNT, as well as the general tendency to reduce the impact, has been revealed. At the same time, the absence of positive changes in the environmental state was noted, especially characteristic of the largest impact centers with their inherent unfavorable environment, which suggests the need to take measures to reduce the impact. The advantage of the methodology proposed by the authors can be considered the possibility of extending monitoring in the future, which opens up the possibility of using this algorithm to assess the environmental situation and form environmental policy priorities. The analysis of the results confirmed the quality of the integrated assessment methodology and showed that the districts, cities and towns of the BNT are highly polarized in terms of the level of anthropogenic impact concentrated in certain areas, primarily in the zone of atmospheric influence. The main strengthening of the AI is characteristic of municipalities located along transport corridors, the axis of which is the Trans-Siberian Railway, The Baikal–Amur Mainline and the «Power of Siberia» gas pipeline.

A novel method for identification of disturbance from surface coal mining using all available Landsat data in the GEE platform

Coal mining has contributed to a solid and stable global economy. Surface mining and underground mining are the principal methods for extraction of coal worldwide and given the developments in mining technology and equipment, these methods are increasingly generating more and more coal. Surface mining is also a subject that cannot be overlooked in the context of sustainable development because amongst human activities it causes comparatively strong land disturbance. Much of the damage and assessment of land and ecosystems from surface mining occurs at the site, and at the regional scale; hence access to the mining data is limited. Moreover, it is difficult for remote sensing to extract information on larger-scale areas with high precision. As a consequence, a frequency index of open coal mining can be created by merging the vast high-resolution images acquired by Landsat sensors with the spectral properties of open coal scraped from the overburden layer. Such indices and morphological principles can be used to develop strategies for quickly identifying the open coal boundaries in a vast area without mine-related information. In addition, LandTrendr may be used to reconstruct the spatial and temporal processes of surface disturbance and remediation caused by regional surface coal mining to identify surface mining disturbance and reclamation. Seven typical mining locations worldwide were selected to test and confirm the proposed method's practicality and robustness, including delivering accurate findings based on randomly testing sample points and comparing the mature data outputs. The results showed that: (1) the overall accuracy of the open coal areas identified by the OCFI (Open Coal Frequency Index) was over 85 % (range 0.85–0.96). In all study areas, the accuracy of recognizing disturbance and reclamation events was greater than 76 %. (2) The surface mining disturbed 3046.42 km2 of land and 1487.39 km2 was reclaimed in the seven mining areas investigated between 1986 and 2018, resulting in a reclamation rate of 48.82 %. The proposed method is more accurate and faster in identifying open coal locations than the current commonly used land cover datasets based on comparisons with other data products. The approach can extract surface coal mining in the absence of mining data and offer precise boundary data for mining research, which can be extremely useful for extending mining operations.

Opportunity mapping for nature-based solutions: Mitigating storm surge and land erosion in the Caribbean

The islands of the Caribbean are particularly susceptible to the effects of climate change due to their low-lying coastal areas and location within the Atlantic basin's hurricane belt. The UK Overseas Territory of Anguilla is one such island. The predicted increase in the severity of hurricanes and sea-level rise is highly likely to increase the flood risk of already vulnerable island communities. In this study, flood risk and erosion models are used to prioritise opportunity areas for nature-based restoration and to identify those that would have the greatest impact on coastal and in-land flood risk reduction. Two study sites in Anguilla were selected to highlight this ecologically-based modelling approach; Cove Bay and Pond, a degraded sand dune system and brackish pond, and the East End Pond, an Important Bird and Biodiversity Area that floods following heavy rainfall events. At the coastal site, the restoration of mangroves, sand dunes and coral reefs have the potential to provide flood risk reduction up to 500 m inland and protect homes, infrastructure and tourism developments. For the in-land East End Pond, areas of high erosion risk were predominately identified as bare or disturbed land within 1 km of the pond's basin. Habitat restoration of these areas was identified as having the greatest impact on reducing flood risk. The creation of flood risk, opportunity and impact models are invaluable tools that can be used to inform, advocate and justify the implementation of nature-based solutions to a range of stakeholders from policy-makers to local communties.

Mitigation of Mining Effects on the Environment

Editor’s note: The aim of the Geology and Mining series is to introduce early career professionals and students to various aspects of mineral exploration, development, and mining in order to share the experiences and insight of each author on the myriad of topics involved with the mineral industry and the ways in which geoscientists contribute to each. Abstract All human activities produce waste and affect our environment, including the solids and water involved during mining and metallurgical operations. The nature and characteristics of these impacts vary considerably depending on many factors, including the geology of the operation, type of mining and processing implemented, sensitivity of the local environment to the operation, and proximity to human settlements or sensitive environmental settings. Environmental challenges associated with mineral extraction and processing include impacts to land, air, water, soil, flora, fauna, and socioeconomic fabric. Mines can generate large land disturbances and can also result in sterilization of land through deposition of barren, nonreactive rock piles (termed waste) during production and after operation. Other mine waste piles can be chemically reactive and interact with precipitation and runoff, leading to metal and sulfate release into surface and ground water. Impacts on soils may result directly from weathering of mine waste or through interaction with affected waters. Interaction with the atmosphere may occur, with release of aerosol or airborne metals or minerals affecting air quality. In addition, the release of gases containing CO2, SOx, and NOx and halide gases can lead to acid rain or general lowering of air quality. These challenges can be predicted, quantified, and understood during the mine design and operations processes by application of geologic knowledge, geochemical and hydrogeological data, and mining experience. Such understanding can then identify appropriate solutions, including changes to operations through sequenced mining to reduce exposure of material with high metal or sulfide content; partial or full backfill of mine excavations; use of cemented waste backfill; modifications to water discharge designs; and treatment of water prior to discharge. A critical aspect of addressing environmental challenges and reducing environmental impact involves engagement with communities, government, and society. The confidence of society is essential to the delivery of long-term sustainable plans.

Geographic information systems as an innovative method for increasing the productivity of agricultural land

The goal is to identify and specify the stages of formation and development of geographic information systems (GIS) in agriculture, used to improve the efficiency of agricultural land. Methods – system analysis, monographic, statistical, economic, classification, grouping, logical generalization. Results – the author shows the problems of disseminating technologies that are geographically linked in the agricultural sector abroad and in Kazakhstan. The stages of cartography, remote sensing of the earth, organizational work to collect information on the biodiversity of the territory of foreign countries, starting from laboratories, then computer programming until the end of the cycle are outlined. Natural and climatic factors that influence the composition and change in the size of the land fund of the republic, in particular agricultural lands, are considered. Negative land management processes, the presence of a large amount of disturbed land resulting from industrial production, and the existence of anthropogenic pollution that worsen soil fertility are highlighted. Conclusions – the need for wide dissemination of GIS for the rational use of land resources arose during the monitoring and assessment of soil characteristics, the need to determine the forecast level of yield, water management, spatial planning and production decision-making. The argument for the use of GIS technologies is the modern land policy of the state, aimed at creating a rational balance between the sustainable development of the agroindustrial complex and the preservation of natural potential in order to improve living conditions in rural areas. Geographic information systems contribute to increasing the profitability of agricultural enterprises and optimizing its costs. Digital cartographic products are increasingly found in the practice of intensively developing farms.

Beyond protected areas: The importance of mixed-use landscapes for the conservation of Sumatran elephants (Elephas maximus sumatranus).

Elephants were once widely distributed across the Indonesian island of Sumatra but now exist in small, isolated populations. Using the best data available on elephant occurrence, we aimed to (a) predict potential habitat suitability for elephants (Elephas maximus sumatranus) across the island of Sumatra and (b) model landscape connectivity among the extant elephant populations. We used direct sightings and indirect observations of elephant signs, as well as six remotely sensed proxies of surface ruggedness, vegetation productivity and structure, and human land use and disturbance, to model habitat suitability in a Google Earth Engine (GEE) environment. We validated the habitat suitability prediction using 10-fold spatial block cross validation and by calculating the area under the precision-recall curve (AUC-PR), sensitivity, and specificity for each model iteration. We also used a geolocation dataset collected from global positioning system (GPS) collars fitted on elephants as an independent validation dataset. Models showed good predictive performance with a mean AUC-PR of 0.73, sensitivity of 0.76, and specificity of 0.68. Greater than 83% of the independent GPS collar geolocations were located in predicted suitable habitat. We found human modification, surface ruggedness, and normalized difference vegetation index to be the most important variables for predicting suitable elephant habitat. Thirty-two percent, or 135,646 km2, of Sumatra's land area was predicted to be suitable habitat, with 43 patches of suitable habitat located across Sumatra. Areas with high connectivity were concentrated in the Riau and North Sumatra provinces. Though our analysis highlights the need to improve the quality of data collected on Sumatran elephants, more suitable habitat remains on Sumatra than is used by known populations. Targeted habitat conservation, especially of the suitable habitat in and around the Lamno, Balai Raja, Tesso Tenggara, Tesso Utara, Bukit Tigapuluh, Seblat, Padang Sugihan, and Bukit Barisan Selatan ranges, may improve the long-term viability of this critically endangered species.

Influence of Natural, Climatic, and Industrial Factors on Air and Water Quality in The Kemerovo Region (Kuzbass, Russia)

Geographical and climatic features of the Kemerovo region (Kuzbass, Russia) determined the modern geological and geomorphological structure of the territory, as well as a characteristic pattern in the distribution of mineral deposits. The purpose of this work was to study the geomorphological and hydrological features of the Kemerovo region. Atmospheric circulation, relief, and vegetation are the climate's main factors. The combination of these factors forms the climatic characteristics of the region. Soils in open areas (meadows, hayfields) occupy a small area and have high economic and ecological value. Most of the forest is not affected by economic activities. The exception is disturbances in the territories affected by logging and mining enterprises, which especially affect the air and water quality in the region. All the obtained results of the assessment of the geomorphological and hydrological condition of the Kemerovo region should be used when planning further experiments on the stages of technical and biological reclamation of disturbed lands of mining enterprises to restore vegetation cover and the primary state of soils.

Ecological-economic aspects of mining thin coal seams in the Western Donbas


 
 
 The paper draws attention to the ecological-economic aspects of mining thin coal seams in the strategic coal-mining region of the Western Donbas and studies their causes and consequences in detail. It has been analyzed and determined that as a result of coal mining with complete caving of rocks, the processes of the earth’s surface subsidence above the mine fields occur. Due to the proximity of groundwater to the surface, waterlogging of territories and a change in the landscape occur. Using analytical calculations, it has been determined that the total surface subsidence value above the mine field of one of the Western Donbas mines is 1.2 m, which, according to the monitoring of environmental authorities, correlates well with the range of subsidence values in the region of 0.7-1.4 m. The places and parameters of rock dumps accumulating on the earth’s surface in coal mines are identified and analyzed, and the sources of waste rock formations in the technological system of coal mines are also studied. It has been revealed that the largest ingress of all waste rocks to the surface is caused by the stope operations conducted with undercutting of bottom rocks – 39% and underground mining operations to prepare new coal reserves for extraction – 33%. To date, it has been found that the volumes of waste rocks generated in mines are 1.5 times higher than the volumes of their utilization, and the prospect of disturbed land reclamation is limited in time, which, with today’s mining technology, will lead to an increase in their accumulation again. Based on a comprehen- sive study of the mined coal seam structure with a complex texture, using the example of one of the mines, it has been revealed that in the formation of operational ash content, the friable roof caving amounts to 13.0%, the seam rock interlayers – 19.2%, the coal seam natural ash content – 12.8%, and the seam bottom rock undercutting – 55.0%. A close linear relationship has been determined between the value of bottom rock undercutting with a shearer based on collected mine data and the indicator of mined coal operational ash content, which confirms the greatest importance of this factor. It has been proved that the most important factor influencing the formation of the mined coal operational ash content is the undercutting of the seam bottom rocks by a shearer, and with a 2-fold decrease in the ash content of coal, its energy potential increases by 1.25 times. Possible scenarios for the coal mining development in the Western Donbas are considered and a rational direction for solving the leading ecological-economic problems of underground mining of thin coal seams is proposed.
 
 

Woody species diversity and the carbon stock potentials of different land use types in agroecosystem of Jimma Ganati District, Western Ethiopia

We investigated the impact of land use types and topographical variables on the diversity of wood species and their carbon stocks in the studied agroecosystems. A generic allometric equation developed for woody plants in agricultural landscapes was used to estimate the carbon stock. We used a mixed-effects linear model using the lmer function in the lme4 package to test the effects of land use types and topographic variables on wood species diversity (Shannon diversity) and stem carbon stock potential. Our study result showed that there is significantly higher woody diversity (P < 0.05) in forests, home gardens and riverine than in grazing lands and croplands. Conversely, woody DBH (cm) and height (m) are relatively higher for croplands followed by grazing land, but lower for home garden and forest land use. There is a statistically significant difference between land use types in their carbon stock (χ² (4) = 18.164, p=0.0011), with forest having the highest total carbon stock, followed by home gardens, but grazing land having the relatively lower total carbon stock of woody species. The study finds that species diversity has a positive and significant (P<0.05) effect on both aboveground and belowground carbon stocks. However, its effect is modulated by land use types, where it is stronger in forest patches, but weaker in more disturbed land use types (e.g., grazing lands and cropland). The study also finds that topographical variables (elevation, slope, and aspects) have no significant (P>0.05) effect on aboveground and belowground carbon stock. The tree species' structural attributes such as height, DBH size, and basal area (BA) have a positive and statistically significant (P < 0.05) effect on carbon stock. The study also found that only a few high DBH class (old growth) tree individuals that are deliberately spared in cropland and grazing land matrix have a high carbon stock contribution. For example, seven species, Podocarpus falcatus, Ficus vasta, Prunus africana, Schefflera abyssinica, Ficus sur, Ekebergia capensis, and Apodytes dimidiate, contribute an estimated 70% of the estimated total carbon stock in the landscapes. These results indicate the need to protect such scattered old-trees in agricultural landscapes both for biodiversity conservation and carbon sequestration thereby integrating climate change adaptation and mitigation strategies into subsistence farming systems.

Specifics and practical examples of low-hazard industrial waste utilization for filling technogenic cavities

The presented research focuses on the pressing issues of restoration of land areas disturbed by mining operations. The paper studies legislative peculiarities of industrial waste utilization for the purpose of reclamation of disturbed lands in Ukraine. Real practical examples of using low-hazard industrial waste for reclamation of land areas disturbed by quarrying and failure zones are analyzed. It is noted that, provided that all legal and sanitary requirements are met, low-hazard class IV waste can be used at the mining-technical stage of quarry reclamation. Aspects of the prospects for restoring the earth’s surface level are clarified based on the development of directions for the backfill mass formation in technogenic cavities, which will provide stability and geomechanical reliability of the earth’s surface.

Ecological Assessment of Drilling Sludge and Development of a Method for their Bioremediation in Western Siberia

The article considers the issue of bioremediation of drilling sludge. The aim of the research is studying of the microbiological processes occurring in soils based on drilling sludge, with their subsequent application for the biological stage of reclamation of disturbed lands. Microbiological characteristics of drilling sludge and four samples of soils based on it with the addition of diatomite, dolomite flour, peat, gypsum, glauconite, humic preparation Rostock in different proportions were studied. Crops were shown on agarized medium: meat-peptone agar (MPA), starch-ammonia agar (SAA), Munz medium, Chapek medium, depending on the determined group of microorganisms. The total number of microflora, the number of saprophytes, microorganisms growing on starch-ammonia agar (SAA), hydrocarbon-oxidizing bacteria (PSB), micromycetes and actinomycetes were estimated. The mineralization coefficient is calculated. The total number of microflora in the samples ranged from 51 to 271 million CFU/g. The share of saprophytes was 16.724.8% of the total amount of microflora. The proportion of microorganisms growing on SAA was 15.6-36.6%. The minimum number of PSB was 2.0 million CFU/g of soil; the maximum was 22.0 million CFU/g. The mineralization coefficient varies from 0.81 to 1.63, which indicates different rates of mineralization processes. The number of micromycetes determined on the Chapek medium ranged from 0.01 to 3.33 million CFU/g, on SAA from 0.03 to 10.4 million CFU/g. At the same time, the number of micromycetes is much lower than the number of bacteria, which is normal for soils. The number of actinomycetes varied from 0.2 to 7.3 million CFU/g. The largest number of actinomycetes was noted when peat and humic preparation Rostock were introduced. The share of actinomycetes in the total number of microflora on the SAA ranged from 0.6 to 14%. There is a development of the total number of microflora, an increase in the diversity of microbocenosis, which indicates a decrease in the concentrations of water-soluble salts, petroleum products and the presence of an additional food source in the form of peat. Based on the data obtained, a conclusion was made about the possibility of using soils based on drilling sludge with the addition of peat and humic preparation Rostock for the reclamation of disturbed lands.

SEED GERMINATION AND GROWTH DYNAMICS OF SEEDLINGS OF SCOTS PINE (PINUS SYLVESTRIS L.) WITH A CLOSED ROOT SYSTEM ON DIFFERENT SUBSTRATES

The relevance of the study is due to the great needs of growing high-quality planting material in a short time for forestry reclamation on disturbed lands both during oil and gas exploration and during oil and gas production. The paper presents the results of studies of germination energy, germination and growth dynamics of Pinus sylvestris L. seedlings grown in RKL-81 cassettes in a greenhouse in 2022 and 2023. At the same time, the renewal of forests is possible after the technical and biological stages of recultivation when creating forest crops from indigenous forestforming species. In 2022 and 2023, experiments were conducted on different types of peat-based substrate, differing in density, nutrient content and additional components from a complex of humic acids and salts, mineral fertilizers, trace elements, strains of friendly soil microflora and mycorrhiza. Pre-sowing seed treatment and agrophysical properties of substrates affected the energy of seed germination and germination, as well as an increase in the total number of germinated seeds during the first month. Good germination results were obtained in 2022 with pre-sowing seed treatment with Borogum-M, Rich-Micro, Bionex-Kemi preparations in low-density peat, filled with the starting composition of fertilizers. However, the biometric indicators of seedlings were slightly higher on the substrate with the addition of humic acids and salts, mineral fertilizers, trace elements, strains of soil microflora and mycorrhiza. In 2023, agroperlite was added to one of the peat substrates to reduce density and increase porosity. The germination energy, germination rate and dynamics of the emergence of seedlings on this substrate turned out to be the highest (from 93 to 100%). It is proposed to grow pine seedlings during one growing season on low-density peat with the addition of agroperlite and a complex of mineral and organic components, including soil microflora and mycorrhiza. This will speed up the process of obtaining the planting material of scots pine for forestry reclamation on disturbed lands both during oil and gas exploration and during oil and gas production.

Bioenergy crop Miscanthus x giganteus acts as an ecosystem engineer to increase bacterial diversity and soil organic matter on marginal land

Cultivation of the bioenergy and bioproduct crop Miscanthus x giganteus (Miscanthus) on marginal lands (including those that are anthropogenically damaged) is attractive due to the robust growth of Miscanthus, leading to high yields even under stressful environmental conditions. Miscanthus growth and production may also build soil carbon, which is favorable for land restoration and climate change mitigation. Gaps in our understanding of the mechanisms facilitating soil carbon accumulation under Miscanthus persist, particularly regarding the role of the soil microbiome in facilitating these processes, and how land use histories (e.g. past disturbances) and management strategies (e.g., fertilizer additions) affect these mechanisms. To address these knowledge gaps, we measured plant performance, soil properties, and microbial parameters over the first three years of Miscanthus establishment across a gradient of land disturbance intensity and different fertilization strategies (none, organic, conventional). We determined that plant performance (e.g., aboveground biomass yield) increased over time during establishment under all disturbance intensities but remained lower overall at the most intensely disturbed site. Across all sites, bacterial diversity and microbial carbon use efficiency increased over time and were positively correlated with soil organic matter. We also observed increases in the relative abundance of key plant growth promoting microbes (e.g., mycorrhizal fungi and bacterial N-fixers). There was no effect of nutrient addition on plant yield, soil carbon concentrations, or microbial carbon use efficiency. All told, our results suggest that Miscanthus consistently increases microbial diversity and carbon use efficiency, facilitating soil organic matter accumulation across sites despite varying land use histories and soil properties. In this way Miscanthus acts as an ecosystem engineer, improving soil biological and chemical properties such that highly disturbed soils come to resemble less disturbed systems over time.

The Return of Lands Disturbed by Mining Production to a New Economic Turnover – As the Final Stage of Mining Production (On the Example of Open-Pit Mining)

Intensive development of mining production inevitably leads to depletion of natural resources, disruption of natural processes and pollution of the natural environment, which entails negative consequences for the socio-economic development of the region after the end of mining. During the extraction of minerals, the integrity of the subsoil is violated, the lithosphere is polluted, wastewater is discharged into the hydrosphere, and dust and harmful gases are released into the air. Mining production can be attributed to natural-technical (technological) systems. The main technological process is associated with the extraction of minerals from the bowels, i.e. the impact on the bowels of the Earth with the help of various technical means and technologies. The subsoil, atmosphere, hydrosphere, soil are elements of the natural system. The complex of technologies and technical means is a technical (technological) system, the choice of which is determined by the properties of the field. Mining production has its own life cycle, which begins with the justification of the feasibility of mining, and ends with the liquidation of mining production and the transfer of disturbed lands to a new economic turnover. In order to return the disturbed lands to a new economic turnover, it is necessary to recultivate (restore) the lands disturbed by mining production. The study examines the conditions for the return of lands disturbed by mining production to a new economic turnover – as the final stage of mining (on the example of open-pit mining), taking into account the life cycle of mining production.

Relationship of nematodes in natural and disturbed land with physicochemical properties in Magoebaskloof, Limpopo Province, South Africa

AbstractMagoebaskloof is an evergreen mountainous landscape covered with Afromontane forests. During a survey on soil nematode diversity, the soil samples were collected from the rhizosphere of a forest tree (no cultivation over 50 years), grassland, prepared kiwi land, oak tree, kiwifruits trees (37-year-old), and 8-year-old kiwifruit in the Limpopo Province, South Africa. Overall, results showed that a total of 30 nematode genera were found to be associated with the surveyed plant species. The frequency of occurrence showed Ditylenchus (100%), Acrobeloides (100%), and Nanidorus (100%), followed by Meloidogyne (83%) were the most distributed nematodes. The study of the relationship between nematodes with physicochemical properties in the soil using Pearson correlation revealed that clay percentage of the soil has a positive correlation with Pseudacrobeles (r = 0.684), Acrobeloides (r = 0.658) and Meloidogyne (r = 0.668) species. In contrast, clay percentage had a strong negative correlation (r = -0.900) with Filenchus. Soil pH showed no strong correlation with the nematodes. The principal component analysis placed kiwifruits and forest soil in two groups, indicating the biodiversity dynamics among the two locations. In conclusion, forest trees and grasslands showed a high diversity of free-living than disturbed land of kiwifruits. Additionally, plant-parasitic nematodes numbered more in the rhizosphere of kiwifruit trees. Our results suggest that the soil nematodes, especially free-living bacterivores, may mediate the effects of ecosystem disturbance on soil health.

Land disturbance tempo-spatial dynamics in mountainous urban agglomeration and its driving forces: A case study of west Sichuan urban agglomeration, China

Land disturbance (LD), commonly reflecting anthropogenic-induced land surface changes, has received unprecedented attention due to its contribution to achieving Sustainable Development Goal 15: life on land. Considerable LD in China, such as urban sprawl, farmland expansion and forest loss, have resulted in a spectrum of environmental problems in recent decades. To present function-based solutions to mitigate LD, the “productive-living-ecological” system (PLES) theory released by China’s government is more conducive to investigating LD and supporting plan-makers concerning regional territorial spatial planning. Currently, there is a relative lack of attention to LD studies in China’s mountainous areas. Hence, we selected the western Sichuan urban agglomeration (WSUA), a typical mountainous-hills urban agglomeration, as the study area, and presented a work that investigates the tempo-spatial dynamics of LD from 2000 − 2020, based on the PLES theroy and an interdisciplinary LD assessment framework of “process-structures” in WSUA. Finally, the contribution of the driving factors system, including geophysical, economic, and social, was investigated using a spatially geo-detector and bivariate Moran's I methodologies. In this work, we found the remarkable living land sprawl, and the productive-ecological and ecological land showed a dramatic decline trend, with a total 21,845.2 ha decline from 2000 to 2020 in WSUA. Although an encouraging increase in ecological land has been observed after 2010 with a total of 220,650 ha, urban sprawl has offset ecological restoration efforts. The LD hotspot patterns in SWUA were categorized into four types, which have led to general fragmentation of PLES land, and mainly clustering under 14° slope due to the scarcity of suitable land resources. In addition, we found that the geophysical driving force also significantly influences LD in mountains urban compared with the socioeconomic pillars. Finally, we provided SWUA’s plan-makers with recommendations and spatial solutions programs for harmonizing the PLES land disturbance and achieving sustainable development.

Peculiarities of species composition of phytocenoses with dominance and participation species of the genus Salsola L. in desert and semi-desert regions of Kazakhstan

The purpose of the research was to identify the features of the floristic composition of rammunities with representatives of the genus Salsola L. (North-Western (Aksai), Southem, South-Eastem regions of Kazakhstan). Traditional methods of field geobotanical researches were used in the process of studying. As a result of expedition works, 24 studied plant communities (with predominance and participation of various Salsola) were described. Communities differed from each other by species composition, which is caused by a variety of combination of habitat factors. The analysis of the floristic composition of the described rommunities resulted in the identification of two groups: 1) rommunities dominated by species of the genus Salsola; 2) rommunities in which the presence of species of the genus Salsola was insignificant. During the research, it was revealed that annual species S. nitraria Pall. and S. tragus L. are well adapted to the habitat conditions of desert and semi-desert regions and it was roncluded that they can be used for reclamation of disturbed lands.

Impact of Agricultural Land Use on Nematode Diversity and Soil Quality in Dalmada, South Africa

During a survey on soil nematode diversity, the soil samples were collected from Field-1 (3-months-not-used land), Field-2 (5-years-not-disturbed land), Field-3 (the rhizosphere of tomatoes), and Field-4 (natural land, not disturbed for 50 years), in Dalmada, Limpopo Province, South Africa. A total of 25 nematode genera were found to be associated with the surveyed plant species. The result showed Acrobeloides, Aphelenchus, Aporcella, Ditylenchus, Mesorhabditis, Pratylenchus, and Rotylenchus with a 100% frequency of occurrence. Meloidogyne was detected only in association with Field-3, with a low frequency of occurrence (25%). The study of the relationship between nematodes with physicochemical properties in the soil using Pearson correlation revealed that phosphate of the soil had a positive correlation (r = 0.977) with Bitylenchus and Pseudacrobeles species. In contrast, pH strongly correlated with Nanidorus (r = 0.928), Trypilina (r = 0.925), Xiphinema (r = 0.925), and Zeldia (r = 0.860). The principal component analysis placed Field-4 and Field-3 in two groups, indicating the biodiversity dynamics among the two locations. Soil texture showed that clay was correlated with Rotylenchulus. In contrast, soil texture had no effect on Meloidogyne. The Shannon index was the lowest (1.7) for Field-1 in Dalmada compared to the other Fields, indicating lower nematode diversity. The structure index showed that Field-2 was disturbed with a low C:N ratio. In contrast, Field-3 and Field-4 had suppressive soil but matured and fertile. The network analysis showed that Panagrolaimus was only found in Field-4 and was the most engaging genus describing soil quality in the soil system in Dalmada. In conclusion, Field-2 showed a high diversity of free-living nematodes than the disturbed land of tomatoes. Additionally, plant-parasitic nematodes numbered more in the rhizosphere of tomatoes. The results suggest that the soil nematodes, especially free-living bacterivores, may mediate the effects of ecosystem disturbance on soil health.

Frac Sand Facilities and Their Potential Effects on the Groundwater Resources of the Monahans-Mescalero Sand Ecosystem, Permian Basin, Texas

Up until the end of the oil and gas boom in 2014, much of the sand used in the Permian Basin for hydraulic fracturing was sourced from upper Midwest of the United States. Because of substantial cost savings, producers in the Permian Basin began using local sand resources, creating an associated boom in local frac-sand mining in the Monahans-Mescalaro Sand Ecosystem. By December 2018, 17 frac-sand operations had registered with the Texas Commission on Environmental Quality with 16 being operational with a cumulative annual capacity of 56.8 million tons and a self-reported 2,927 acres of disturbed land. We identified 230 production wells for the 16 facilities with depths ranging from 80 to 1,199 feet and most completed in the Pecos Valley Alluvium and/or Dockum aquifers. Estimated frac sand facility water use (10,000 to 40,000 acre-feet per year, based on 60 to 250 gallons of water consumed per ton of produced sand) rivals or exceeds that of water used in the four counties (Crane, Ector, Ward, and Winkler) with active frac sand facilities (23,500 acre-feet per year). Modeling suggests that long-term pumping of the unconfined Pecos Valley Aquifer may be a challenge requiring additional wells over time or the use of alternative water supplies. For the confined Dockum Aquifer, simulations suggest that pumping might completely deplete artesian pressure at the well field after 10 years.