Pasture Cover Research Articles

Small forest patches and landscape-scale fragmentation exacerbate forest fire prevalence in Amazonia.

Over recent decades, forest fire prevalence has increased throughout the tropics, necessitating improved understanding of the landscape-scale drivers of fire occurrence. Here, we use MapBiomas land-cover and fire scar data to evaluate relationships between forest fragmentation, land-use, and forest fire prevalence in a typically consolidated Amazonian agricultural frontier: Portal da Amazonia, Mato Grosso, Brazil. Using zero-/zero-one-inflated Beta regressions, we investigate effects of forest patch (area, shape, surrounding forest cover) and landscape-scale variables (forest edge length, land-cover composition) on forest fire occurrence and density between 1985 and 2021. We show that fire density was greatest in small, complex forest patches. Small patches (≤100ha) were also the dominant contributors to annual, regional forest fire cover. At the landscape-scale (100km2), forest edge length and urban land cover were positively associated with forest fire occurrence and density. Furthermore, forest fires were most likely to occur in landscapes consisting of ∼45% pasture cover, while fire density increased roughly linearly with pasture cover. Cropland cover was negatively associated with forest fire occurrence and density. Our findings indicate clear links between forest fragmentation and increased forest fire prevalence. This is cause for global concern, given that fragmentation rates throughout Amazonia are increasing, and fires are eroding the Amazon's capacity to act as a carbon sink. Efforts to minimise further fragmentation within Amazonia would likely help reduce forest fire prevalence. Within already fragmented regions, the conversion of pasture into crops, alongside targeted efforts to suppress fires within small forest patches and urbanized areas, may also limit fire prevalence.

Abundance of fecal indicator bacteria and diversity of Escherichia coli associated with poultry farms and pasture land cover in streams of northwestern South Carolina

Livestock can contribute fecal indicator bacteria (FIB) to waterbodies. However, few studies have examined the relationship between watershed land use or land cover involving livestock production and the genetic diversity of Escherichia coli in freshwater ecosystems. Our major goal was to determine if FIB abundance and E. coli phylogenetic group distributions in headwater streams are related to livestock production in rural watersheds in South Carolina. In both 2017 and 2018, grab samples were collected from streams at summer baseflow. In 2017, we collected samples from watersheds with or without poultry rearing facilities (PRFs). In 2018, we collected samples from streams draining watersheds with mixed forest and pasture cover and from streams in mostly forested watersheds. In both summers, we measured concentrations of total coliforms, E. coli, and Enterococcus. We also categorized E. coli isolates into one of four phylogenetic groups (A, B1, B2, D). Streams with PRFs in their watersheds had significantly higher concentrations of Enterococcus but not total coliforms or E. coli than streams in watersheds without PRFs. Also, B2 isolates were less frequent and B1 isolates were more frequent in watersheds with PRFs than in those without. Streams draining mixed forest/pasture watersheds had significantly higher concentrations of total coliforms and E. coli but not Enterococcus, as well as higher frequencies of B1 isolates, than streams in mostly forested watersheds. Overall, the most frequent E. coli phylogenetic groups in watersheds with animal production appeared consistent with the phylogenetic groups that are especially abundant in poultry or mammalian livestock feces.

Assessing flood risk and vegetation dynamics: Implications for sustainable land management in Fars province

The design of effective flood risk mitigation strategies and their subsequent implementation is crucial for sustainable development in mountain areas. The assessment of the dynamic evolution of flood risk is the pillar of any subsequent planning process that is targeted at a reduction of the expected adverse consequences of the hazard impact. This study focuses on riverbed cities, aiming to analyze flood occurrences and their influencing factors. Through an extensive literature review, five key criteria commonly associated with flood events were identified: slope height, distance from rivers, topographic index, and runoff height. Utilizing the network analysis process within Super Decision software, these factors were weighted, and a final flood risk map was generated using the simple weighted sum method. 75% of the data was used for training, and 25% of it was used for testing. Additionally, vegetation changes were assessed using Landsat imagery from 2000 and 2022 and the normalized difference vegetation index (NDVI). The focus of this research is Qirokarzin city as a case study of riverbed cities, situated in Fars province, with Qir city serving as its central hub. Key rivers in Qirokarzin city include the Qara Aghaj River, traversing the plain from north to south; the primary Mubarak Abad River, originating from the east; and the Dutulghaz River, which enters the eastern part of the plain from the southwest of Qir, contributing to plain nourishment during flood events. The innovation of this paper is that along with the objective to produce a reliable delineation of hazard zones, a functional distinction between the loading and the response system (LS and RS, respectively) is made. Results indicate the topographic index as the most influential criterion, delineating Qirokarzin city into five flood risk zones: very low, low, moderate, high, and very high. Notably, a substantial portion of Qirokarzin city (1849.8 square kilometers, 8.54% of the area) falls within high- to very-high flood risk zones. Weighting analysis reveals that the topographic humidity index and runoff height are the most influential criteria, with weights of 0.27 and 0.229, respectively. Conversely, the height criterion carries the least weight at 0.122. Notably, 46.7% of the study area exhibits high flood intensity, potentially attributed to variations in elevation and runoff height. Flood potential findings show that the middle class covers 32.3%, indicating moderate flood risk due to changes in elevation and runoff height. The low-level risk is observed sporadically from the east to the west of the study area, comprising 12.4%. Analysis of vegetation changes revealed a significant decline in forest and pasture cover despite agricultural and horticultural development, exacerbating flood susceptibility.

Through a collapse to restoration: the non-stationary dynamics of the rodent community in a new cycle of desertification in Kalmykia

The grazing ecosystems of Kalmykia are extremely dynamic, this being associated with the high variability of grazing pressure in the region: a drastic reduction in the number of livestock in the 1990’s led to the restoration of pastures and the transition of their functioning from the “desert” to the “steppe” regime. Since the late 2000’s, new desertification processes have been gaining momentum, these being caused by increased grazing pressure and droughts. The vegetation cover of pastures quite quickly began to respond to the increase in livestock numbers by reducing the projective cover, while the species composition of plants sharply changed to “desert” only a few years later. Against the background of increasing desertification, the rodent community first collapsed and then recovered. Apparently, the collapse is a belated reaction to the steppefication of pastures that preceded desertification, this leading to a reduced number of desert species and an impoverished community, thereby slowing down its revival during a new cycle of desertification. Thus, both vegetation cover and rodent community demonstrated non-stationary dynamics with changing the regimes and a delayed response (inertia) in response to landscape desertification.

Spatio-Temporal Modeling of Land and Pasture Vulnerability in Dairy Basins in Northeastern Brazil

The objective of this study is to evaluate the spatio-temporal dynamics of land vulnerability and pasture areas in the dairy basins of the states of Pernambuco and Alagoas, which are part of the Ipanema River Watershed (IRW) in the Northeast Region of Brazil. Maps of the Land Use and Land Cover (LULC); the Index of Vulnerability to Degradation (IVD); the Land Vulnerability Index (LVI); time series of Effective Herd (EH), Milked Cows (MC), and Milk Production (MP); and Pasture Cover (PC) and Quality (PCQ) were created as parameters. An opposite pattern was observed between the land use classes of Livestock, Agriculture, and Forest. The IRW area has predominantly flat terrain with a very high risk of degradation. The analysis of MC was consistent with the information from the EH analysis as well as with MP. When assessing Pasture Quality, Severe Degradation areas increased from 2010 to 2014, decreased after 2015, and rose again in 2020. Moderate Degradation areas remained high, while Not Degraded pasture areas were consistently the lowest from 2012 to 2020. Over the 10 years analyzed (2010–2020), the area showed a strong degradation process, with the loss of approximately 16% of the native vegetation of the Caatinga Biome and an increase in pasture areas and land vulnerability.

Evaluating pasture cover density mapping: a comparative analysis of Sentinel-2 and Spot-5 multispectral sensor images

Vegetation density extraction is influenced by the characteristics of satellite images, vegetation type, classification algorithm, and region, but there is little information about multispectral imaging (MSI). Studying the compatibility of the information content of sensors to replace sensors in areas where there is no easy access to their data is necessary for remote sensing (RS) studies. This study aims to assess the suitability of MSI from Sentinel-2 and Spot-5 satellites for generating pasture density maps. The Middle Kashkan watershed in the Lorestan Province of Iran was the study area. Geometric correction of the images was performed using ground control points (GCP) and the area's digital elevation model, achieving an accuracy of 0.21 pixels or better. Supervised classification techniques including parallelogram, minimal distance, maximum likelihood, and artificial neural network (ANN) algorithms were applied to the primary MSI of each satellite, as well as the integrated image of Spot-5 and the resulting pasture density map. Three density categories were considered: 5–25%, 25–50%, and over 50%. To validate the accuracy of the classification, a ground truth map of the region was created by interpreting a referenced official digital orthophotomosaic image at a scale of 1:40,000. Comparative analysis of the classified images revealed that the Sentinel-2 image with PCA-2-8 band composition and ANN classification algorithm yielded superior results, with an overall accuracy of 65.72% and a kappa coefficient of 0.08, compared to the Spot-5 image with PCA-3-1 band composition and the ANN classification algorithm. Spot-5 satellite images demonstrated greater effectiveness in generating pasture cover maps across the three density categories. These findings suggest that satellite images with suitable spatial and spectral resolution can be effectively utilized for generating accurate pasture density maps and monitoring long-term pasture preservation, particularly in regions characterized by high aerial photography altitudes in pasture areas. This approach holds the potential for effective pasture management and conservation efforts on a global scale.

Streamflow response to land use/land cover change in the tropical Andes using multiple SWAT model variants

Study regionTropical watershed in the Colombian Andes, the Chico River (CR) watershed. Study focusHydrological models are widely used to project the impacts of LULC (Land Use/Land Cover) change on water budget. However, their ability to produce reliable predictions depends on how accurately they represent the role of vegetation in the watershed’s water balance. We analyze how different representations of Leaf Area Index (LAI) affect streamflow responses to LULC change using the Soil and Water Assessment Tool (SWAT) model. We also examine streamflow response to 100 % pasture cover (PAS), 100 % forest cover (FOR), and a control scenario using the original SWAT model, SWAT-T, and a proposed new variant (SWAT-Tb), which improves LAI bimodal representation for tropical regions. New hydrological insights for the regionSWAT-T and SWAT-Tb reproduce observed LAI and streamflow in the CR watershed. However, SWAT-T restricts LAI simulation to unimodal seasonality, while the original SWAT reproduces streamflow but not LAI seasonality. Results using SWAT-T (unimodal LAI) and SWAT-Tb (constant and bimodal LAI) show streamflow increases during the dry seasons for the FOR scenario and decreases for the PAS scenario. Conversely, the original SWAT, with its default LAI representation, tends to underestimate and overestimate streamflow changes in the FOR and PAS scenarios, respectively. Our results highlight that an unrealistic LAI representation can mislead LULC change impact assessments on streamflow in the tropical Andes.

Design of an Ultrasound Sensing System for Estimation of the Porosity of Agricultural Soils.

The design of a readily useable technology for routine paddock-scale soil porosity estimation is described. The method is non-contact (proximal) and typically from "on-the-go" sensors mounted on a small farm vehicle around 1 m above the soil surface. This ultrasonic sensing method is unique in providing estimates of porosity by a non-invasive, cost-effective, and relatively simple method. Challenges arise from the need to have a compact low-power rigid structure and to allow for pasture cover and surface roughness. The high-frequency regime for acoustic reflections from a porous material is a function of the porosity ϕ, the tortuosity α∞, and the angle of incidence θ. There is no dependence on frequency, so measurements must be conducted at two or more angles of incidence θ to obtain two or more equations in the unknown soil properties ϕ and α∞. Sensing and correcting for scattering of ultrasound from a rough soil surface requires measurements at three or more angles of incidence. A system requiring a single transmitter/receiver pair to be moved from one angle to another is not viable for rapid sampling. Therefore, the design includes at least three transmitter/reflector pairs placed at identical distances from the ground so that they would respond identically to power reflected from a perfectly reflecting surface. A single 25 kHz frequency is a compromise which allows for the frequency-dependent signal loss from a natural rough agricultural soil surface. Multiple-transmitter and multiple-microphone arrays are described which give a good signal-to-noise ratio while maintaining a compact system design. The resulting arrays have a diameter of 100 mm. Pulsed ultrasound is used so that the reflected sound can be separated from sound travelling directly through the air horizontally from transmitter to receiver. The average porosity estimated for soil samples in the laboratory and in the field is found to be within around 0.04 of the porosity measured independently. This level of variation is consistent with uncertainties in setting the angle of incidence, although assumptions made in modelling the interaction of ultrasound with the rough surface no doubt also contribute. Although the method is applicable to all soil types, the current design has only been tested on dry, vegetation-free soils for which the sampled area does not contain large animal footprints or rocks.

Состояние почвенного покрова и фитомелиорация пастбищ в районах Восточного Предкавказья

Introduction. The arid zone of the Eastern Ciscaucasia, and specifically the extremely arid and arid areas of the Stavropol Territory, with low-fertile pasture soil cover, are subject to degradation associated with both soil and climatic conditions and anthropogenic technological load on the soil. Materials and methods. The manifestation and areas occupied by soil degradation factors (the presence of salt marshes, salt marshes, erosion and deflation) in each of the districts are different, therefore, for a comprehensive assessment of the level of degradation in a particular area, calculations of the generalized indicator of degradation of the soil cover of pastures are carried out. Results and discussion. Based on a systematic analysis, with an assessment of the desirability and weight of each of the degradation factors, it was found that the soil cover of the pastures of the Kursk region is subject to a moderate level of degradation (Dp=0.95), Ipatovsky district with Dp=0.90 – increased, and Apanasenkovsky Turkmen, Arzgir, Levokumsky, Neftekumsky districts – a high level of degradation with Dp=0.822–0.828. Сonclusion. In an area with a moderate level of degradation of the pasture soil cover, a superficial improvement of the natural herbage is proposed with the addition of perennial grasses to it: Medicagovaria, Melilotusofficinalis, Melilotus album, Agropyron fragile, Kochiaarenaria. With an increased and high level of degradation of pasture soils, it is advisable to radically improve with the use of legume-cereal grass mixtures from Medicagofalcata, Medicagovaria, Onobrychisarenaria, Agropyron fragile, Elytrigiaintermedia, Bromopsisinermis, Kochiaarenaria. On saline soils, it is also effective to use both Medicago falcate and Medicagovaria and Agropyrondesertorum, Agropyroncristatum, Elytrigiaintermedia, Bromopsisinermis, Kochiaarenaria, Bassiaprostrata, Melilotusofficinalis, Melilotus album, Festucavalesiaca, Leymusracemosus. Suggestions for practical application and direction of future research. The developed map-scheme of degradation of the soil cover of pastures of the Stavropol Territory districts, indicating the numerical values of the complex indicator Dp, allows you to make certain technological decisions on carrying out a complex of phyto-meliorative measures on pastures specifically for each district of the Eastern Caucasus.

Grazing behavior of dairy cows under contrasting pasture allocation frequencies and areas

This study aimed to compare grazing behavior of dairy cows with highly contrasting pasture allocation frequencies. The study ran from September 9, 2022, to December 2, 2022 (12 wk), during a time when daily pasture growth was expected to exceed daily herd intake. Three pasture allocation frequencies were compared, each with 11 spring-calving cows grazing a 4-ha farmlet. The allocations were high frequency rotational grazing (HFRG; 32.5 m2/cow per allocation and 4 allocations/d), rotational grazing with weekly allocations (7RG; 909 m2/cow per allocation and each allocated area continuously grazed over 7 d), and continuous grazing (CG; 1,818 m2/cow per allocation). Animal behavior was monitored using IceQube accelerometers (Peacock Technology) and CowManager ear tags (Agis Automatisering BV). Milk yield and composition were measured and pasture cover was estimated. Daily eating time was highest for CG animals, whereas lying time, lying bouts, and ruminating time were lowest, with no differences between HFRG and 7RG. There were no differences in fat- and protein-corrected milk yield between farmlets; however, estimated accumulated pasture yield was greater with more frequent allocations. Although milk production did not differ between treatment groups, this appeared to be achieved through greater eating times when allocated pasture less frequently, at the expense of time spent lying.

APPLICATION OF SATELLITE TECHNOLOGIES FOR THE EFFECTIVE DEVELOPMENT OF PASTURE LIVESTOCK FARMING

The goal of the work was to determine the possibilities of using images obtained from satellite services to study the vegetation cover of natural pastures. The work was carried out on pasture plots of the Ipatovsky district in the conditions of the agricultural production complex «Plemzavod Vtoraya Pyatiletka ». Remote methods for assessing agricultural territory are a developing area not only in agronomy, but also in livestock farming, namely pasture farming. In the work, to process images obtained from satellite services, we used tools from the OpenStreetMap and Satellite services, as well as Copernicus Global Land Cover Layers: CGLS-LC100 Collection 3. Using image processing tools obtained from satellite systems, the boundaries of the studied pastures were determined, and the pastures were conditionally divided into four classes depending on the spectral characteristics of the vegetation cover. As a result of field trips, the NDVI vegetation index of the studied areas was determined by contact method using a GreenSeeker hand-held sensor. The calculated normalized vegetation index NDVI reflects the objectivity of the clustering performed. The data obtained will make it possible to more objectively draw up technological maps for animal grazing with the least time and material costs.

Modelling potential human exposure to the urease inhibitor NBPT through the environment-food pathway

The urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) has recently attracted a lot of attention attributing to its efficiency in reducing ammonia loss from urea fertiliser applied to temperate grassland soils. Ammonia gas lost to the environment causes soil acidification, eutrophication and contributes to global warming through increased greenhouse gas emissions and ozone layer depletion. The active chemical NBPT blocks the soil microbial enzyme (urease) and reduces ammonia emission. Furthermore, NBPT’s use in agriculture might benefit farmers by reducing reliance on expensive nitrate fertiliser and aiding in a shift to more urea-based fertiliser (using NBPT co-applied with urea is more cost-effective). The present study was carried out to characterise the potential transfer of NBPT from grass to liquid milk and compute the associated human health risks. Using probabilistic risk assessment techniques, an exposure assessment model was developed to calculate the Estimated Daily Intake (EDI) of NBPT from milk, following co-application of NBPT with a urea N-fertiliser. Results show that the predicted mean concentration of NBPT in milk is 2.5 × 10−8 mg NBPT/kg milk, while the mean daily intake (EDI) of NBPT is 5 × 10−11 mg NBPT /kg BW/day). Back-calculations revealed that, under the studied conditions, for the EDI to exceed ADI of 3 × 10−2 mg NBPT/kg BW/ day, the NBPT application rate would need to exceed the NBPT fertiliser limit (0.09–0.2% by mass of urea nitrogen) set in the Commission Regulation (EC) No 1107/2008, and the bio-transfer factor would need to be over 100% (implausible). Sensitivity analysis revealed soil pH (SPH), phytoaccumulation factor (PF), NBPT permissible levels in fertiliser (NBPT%), pasture cover (P), and grazing rotation length (t) as critical factors influencing the EDI of NBPT. The present study concludes that NBPT presents negligible risk to human health under the conditions and assumptions studied.

Unlocking environmental contamination of animal tuberculosis hotspots with viable mycobacteria at the intersection of flow cytometry, PCR, and ecological modelling

Mycobacterium bovis, a member of the Mycobacterium tuberculosis complex (MTBC), circulates in multi-host mammal communities. While interactions between different host species are mainly indirect, current knowledge postulates interspecific transmission is favored by animal contact with natural substrates contaminated with droplets and fluids from infected animals. However, methodological constraints have severely hampered monitoring of MTBC outside its hosts and the subsequent validation of this hypothesis.In this work, we aimed to evaluate the extent to which environmental contamination with M. bovis occurs in an endemic animal TB setting, taking advantage of a new real-time monitoring tool we recently developed to quantify the proportion of viable and dormant MTBC cell fractions in environmental matrices. Sixty-five natural substrates were collected nearby the International Tagus Natural Park region, in the epidemiological TB risk area in Portugal. These included sediments, sludge, water, and food deployed at unfenced feeding stations. The tripartite workflow included detection, quantification, and sorting of different M. bovis cell populations: total, viable, and dormant. Real-time PCR targeting IS6110 to detect MTBC DNA was performed in parallel. The majority of samples (54 %) contained metabolically active or dormant MTBC cells. Sludge samples had a higher burden of total MTBC cells and a high concentration of viable cells (2.3 × 104 cells/g). Ecological modelling informed by climate, land use, livestock and human disturbance data suggested eucalyptus forest and pasture cover as potential major factors affecting the occurrence of viable MTBC cells in natural matrices.Our study demonstrates, for the first time, the widespread environmental contamination of animal TB hotspots with viable MTBC bacteria and with dormant MTBC cells that are able to recover metabolic activity. Further, we show that viable MTBC cell load in natural substrates is superior to the estimated minimum infective dose, providing real-time insights into the potential magnitude of environmental contamination for indirect TB transmission.

Plant potential and ecological and economic suitability of reindeer pastures on the right bank of the Norilsk River

Purpose : identification of plant potential, ecological and economic suitability of deer pastures of the forest-tundra zone located in the zone of anthropogenic influence Material and methods . Ground geobotanical survey of the vegetation cover of deer pastures was carried out by route method in accordance with the method of geobotanical studies. The ecological and economic value of each type of pasture was determined based on the data of the ecological and economic classification of deer pastures in the north. Results . 25 species of reindeer pastures are described on the right bank of the Norilsk River in the northwestern part of the Putorana Plateau. On the basis of signs of uniformity in the structure of vegetation (proximity of species composition, similarity of vertical and horizontal structures), they are combined into 4 types: tundra, swamps, shrubs and light forests. Tundra (30.9%) and shrub (27.6%) types of pastures dominate. The most important feature is the active participation in the structure of phytocenoses of shrubs (Betula nana s. str, Salix glauca s. str, S. lanata s. str.) and shrubs (Ledum palustre. Vaccinium uliginosum s. str, V. vitis-idaea s. str.). Green fodder is most nutritious in the first half of summer. The nutritional value of fruticose lichens does not change during the year. Reindeer pastures with lichen cover and high (from 5 to 12 o-days/ha) reindeer capacity during the snowy period occupy insignificant (24.3%) areas. Basically, these are willow and dwarf dwarf shrub-lichen tundras and larch sparse forests of dwarf-shrub moss-lichen. The participation of lichens in the ground cover of plant communities does not exceed 25–35%. The following lichen species have been recorded: Cladonia arbuscula, C. stellaris, C. rangiferina, C. cornuta, C. deformis, C. mitis, Cetraria cucullata, and C. islandica. The most widespread species of the genus Cetraria: Cetraria islandica and C. cucullata, with a clear advantage of the latter. The main forage species of the genus Cladonia (Cladonia arbuscula, C. stellaris, C. rangiferina) are not widely distributed. Pastures with a high (from 9 o-days/ha to 14 o-days/ha) reindeer capacity in the summer, early autumn and late spring periods prevail in the study area. Basically, these are communities of shrub and marsh types. Shrubs (Salix glauca s. str, S. lanata s. str., S. hastata, Betula nana s. str.), shrubs (Salix reticulata, Vaccinium vitis-idaea s. str.) and forbs (species of the genera Petasites, Pedicularis, Astragalus, Hedysarum, Equisetum, Bistorta).

Spatiotemporal isolation of oilseed rape fields reduces insect pest pressure and crop damage

Abstract Pest management is essential to maintain agricultural production, but recent shifts in policies and the development of insecticide resistance have restricted the availability of insecticides for pest suppression. Identifying the landscape‐level resource requirements of pests to complete their life cycles might unveil new sustainable solutions to regulate their populations and prevent crop damage. We assessed the effects of landscape composition and configuration at different spatial scales on flea beetle densities and crop damage in 56 spring oilseed rape fields sampled over 5 years in Sweden. We considered the cover of non‐crop habitats as an aspect of landscape composition and the distances to the host crop and an alternative host crop in the previous year, edge density and crop diversity as aspects of landscape configuration. The distance from spring oilseed rape in the previous year reduced flea beetle densities and crop damage across most species and spatial scales. Edge density reduced the densities of two flea beetle species, predominantly at the 500 m radius landscape scale. The cover of forests and permanent pastures as well as crop diversity in the previous year increased the densities of different species at several, mostly larger (1000–2000 m) spatial scales. Increasing permanent pasture cover at the 500 m scale also increased crop damage. Synthesis and applications: We find that there is no one fits all approach in designing landscapes for flea beetle regulation as habitat use and scales of effect are species‐specific for these pests. However, increasing the spatiotemporal isolation of host crop fields is a promising and potentially more general means of disrupting pest populations and reducing crop damage. Considering the ecological traits of the pest species is a possible next step to optimise landscape‐based pest management.

Simulation of degradation of pasture ecosystems of arid zone

New approaches to the study of succession dynamics are based on the original concept of system dynamics, which was used in the development of simulation models reflecting the dynamics of pasture ecosystems. The temporal dynamics of the soil and vegetation cover of the natural pastures of the Black Lands of Kalmykia reflects the degradation processes that are studied by simulation modeling. The processes of pasture degradation in the subarid belt of Southern Russia were described by ordinary differential equations. This concept is the basic one in the development of simulation models. The dynamics of changes in effective coatings for phytocenoses of pastures of Black Lands in the process of degradation was traced from the original pastures to complete desertification. Analytical solutions for various conditions of succession dynamics in the degradation of natural pasture lands are a convenient test for assessing the adequacy of simulation modeling. The initial time periods of space observations of effective coatings of phytocenoses were used to parametrize simulation models. The models are implemented in the AnyLogic simulation system. The model development process is based on visual programming using the graphical user interface. Information flows in the Anylogic environment are redistributed over time through a system of storage devices interconnected by an oriented graph of the model. A computational experiment demonstrating simulation results with different parameters was used for an indicative (qualitative) assessment of ecosystem sustainability. The results of analytical modeling using ordinary differential equations and simulation modeling showed a high identity. The study of the dynamics of pasture ecosystems using a variation experiment demonstrates the possibility of visual (cognitive) selection of the parameters of the model that determines the conditions of stationarity of pasture ecosystems. Studying the dynamics of successions of pasture phytocnoses by this method opens up new opportunities for solving problems of optimal use of biological resources and sustainability of pasture ecosystems.

Priming effect depending on land use and soil types in a typical semi-arid landscape in Kenya

Addition of labile carbon (C) inputs to soil can accelerate or slow down the decomposition of soil organic matter (SOM), a phenomenon known as priming effect (PE). However, the magnitude and direction of PE is often difficult to predict, consequently making its relationship with labile C inputs and nutrient availability elusive. To assess this relationship, we added 13C labelled glucose (corresponding to 50% of initial soil microbial biomass C) to two soil types (Vertisol and Acrisol) with different concentrations of available N and from four land use systems (agricultural, pasture, grassland and shrubland). Parallel laboratory incubations i.e. short-term (6 days) and long-term (6 months), were set up to determine the effect of land use and soil type (N availability) on PE. Addition of labelled glucose in solution led to the retardation of SOM mineralization (negative PE) in both soil types and across all land use systems. This is attributed to preferential substrate utilization characterized by the higher mineralization of added glucose. Land use systems and soil types with higher N-availability displayed weaker negative PE, which is in line with the stoichiometric decomposition theory. In conclusion, our study demonstrate that N-availability plays a major role in determining mineralization of labile C inputs, magnitude and direction of PE in the studied dryland soils and land use systems. The fact that 15–27% of the added 13C remained in the soil at the end of the 6 months incubation and PE was negative, indicates that continuous labile C inputs could contribute to C immobilization and stabilization in these semiarid soils. Moreover, 13C glucose remaining in soils after 6 months in semi-natural pastures was comparable to those under natural grassland and shrubland systems especially in Acrisols. This demonstrates that incorporation and maintaining a perennial cover of native pastures has the potential to increase C sequestration in African semi-arid agricultural soils and landscapes.

Spatial Dynamics of the Shore Coverage within the Zone of Influence of the Chambo River, Central Ecuador

The predominant aim of the current study was to evaluate the spatial dynamics of the riparian coverage of the area of influence of the Chambo River in the area of the river’s source (middle-high basin), between 2500 and 3000 m.a.s.l. For its execution, Landsat 7 images from the year 2000, RapidEye from the year 2009, and Spot 6 from the year 2019 were used in the time range of 2000–2009 and 2009–2019. These were subjected to supervised classification by applying the maximum likelihood algorithm, identifying five classes of soil cover, being pasture, crops, soil-remnants of paramo, forest, and anthropic. The classification results were validated by calculating the precision measures and the kappa index. With the use of cross-tabulation matrices, the gains, losses, and persistence in the two periods studied were identified. There, it was determined that, in the first study period, the soil cover-paramo remnants presented the highest percentage of loss (26.70%), the crop cover the highest percentage of gain (28.91%), and in the second period, the crop class presented the highest percentages of losses (18.94%) and gains (17.29%). The cartographic projection of the area for the year 2030 predicts that the areas anthropic category will increase by 1.27%, that of forest will decrease by 1.19%, that of soil-remnants of paramo will gain 0.79%, and crop and pasture cover will decrease by 0.45% and 0.43%, respectively. The results obtained allow for the transitions between coverages to be attributed to population growth, afforestation, reforestation, deforestation and agricultural activities, volcanic eruptions, land colonization, and expansion of agricultural activity. Complementary studies are recommended that involve livelihoods and water quality, which facilitate the identification of vulnerable areas to propose adaptation, prevention, and/or restoration measures.

Long-term monitoring and modelling of pasture regeneration and water quality from a Bothriochloa pertusa site in the Great Barrier Reef catchments

There has been considerable investment in grazing land management in Australia’s Great Barrier Reef catchments targeted at improving off-site runoff and water quality. This study used a systems modelling framework to analyse an 18-year monitoring data set from an Indian couch (Bothriochloa pertusa) dominated hillslope flume site in the Burdekin catchment, Australia. The analyses show important functional differences in B. pertusa pastures, relative to the native tussock pastures they replaced, with implications for how they are monitored and managed: (1) rates of landscape recovery were far slower than rates of degradation. In the practical time frames of most land managers, transition to a B. pertusa state is effectively irreversible, so historical management practices will have to adapt; and (2) transformations in pasture composition and structure can lead to misinterpretation of monitored trends in ground cover (a common proxy for land condition). At 50% pasture cover, B. pertusa pastures have only 33% of the biomass of local tussock pastures. Where B. pertusa invasions are occurring, inferences from positive associations between changes in cover and landscape function can break down: increases in ground cover can instead be accompanied by decreases in biomass, productivity, and runoff retention. The paper contributes an initial calibration of the GRASP pasture grazing systems model for a transformed B. pertusa site, capturing the observed relationships between grazing management, pasture biomass, ground cover and water quality. This serves as a starting point from which these landscapes, of growing extent and concern in Great Barrier Reef catchments, can be better represented in monitoring and modelling assessments, and for revised management options to be explored. The calibrated model was able to accurately represent long-term average runoff and sediment yield (both within 2% of observed) but was only able to adequately represent the year-to-year variation in runoff (not sediment).

ОЦЕНКА ДИНАМИКИ РАСТИТЕЛЬНОГО ПОКРОВА ОЛЕНЬИХ ПАСТБИЩ ПОЛУОСТРОВА ЯМАЛ ПРИ ПОМОЩИ МЕТОДА ПОЛУАВТОМАТИЧЕСКОЙ КЛАССИФИКАЦИИ СПУТНИКОВЫХ СНИМКОВ

The research on current changes in the vegetation cover of reindeer pastures in the subzones of northern and southern tundra of the Yamal peninsula was carried out. The area of the sites disturbed by reindeer grazing from 2013 to 2022 was identified based on field and remote sensing data. Processing of Landsat-8 -9 images using the semi-automatic classification method made it possible to highlight the most common ecotopes with their inherent plant communities, including reindeer-damaged areas with disturbed plant communities and deflationary outcrops. It was revealed that due to the high concentration of reindeers in the southern regions of the Yamal peninsula, the area of the territory disturbed by intensive reindeer grazing is 7.7 times larger than in the subzone of northern subarctic tundra. The weather anomalies determine the character of seasonal reindeer migration and have an impact on the degree of the vegetation transformation caused by grazing. In 2014, the load on ecosystems in the southern tundra increased, and the best conditions for reindeer migration to the summer pastures in the northern tundra were in 2016. The herd expansion in the peninsula's south causes an expressed positive trend in the dynamics of areas degraded by reindeer grazing (2.1% per year) and practically its absence for the northern tundra. For the same reason, intensive grazing in the southern tundra significantly contributes to the increase in the area of sandy outcrops (r = 0.94). The growth trend of the NDVI values noted by many researchers in the tundra of Western Siberia, has not been noted by us in the subzone of the southern subarctic tundra. Here, reindeer grazing and a large area of disturbed tundra lead to a decrease in photosynthetically active phytomass.