Heterogeneous Vegetation Research Articles

Machine Learning in the Analysis of Carbon Dioxide Flow on a Site with Heterogeneous Vegetation

The article presents the results of studies of carbon dioxide flow in the territory of section No. 5 of the Eurasian Carbon Polygon (Russia, Republic of Bashkortostan). The gas analyzer Sniffer4D V2.0 (manufactured in Shenzhen, China) with an installed CO2 sensor, quadrocopter DJI MATRICE 300 RTK (manufactured in Shenzhen, China) were used as control devices. The studies were carried out on a clear autumn day in conditions of green vegetation and on a frosty November day with snow cover. Statistical characteristics of experimental data arrays are calculated. Studies of the influence of temperature, humidity of atmospheric air on the current value of CO2 have been carried out. Graphs of the distribution of carbon dioxide concentration in the atmospheric air of section No. 5 on autumn and winter days were obtained. It has been established that when building a model of CO2 in the air, the parameters of the process of deposition by green vegetation should be considered. It was found that in winter, an increase in air humidity contributes to a decrease in gas concentration. At an ambient temperature of 21 °C, an increase in humidity leads to an increase in the concentration of carbon dioxide.

Response of vegetation dynamics in environmentally sensitive and fragile areas to natural and anthropogenic factors: A case study in Inner Mongolia Autonomous Region, China

Vegetation dynamics is crucial for understanding vegetation ecosystem processes in arid and semi-arid regions. The Inner Mongolia Autonomous Region (IMAR) is a typical arid and semi-arid region in China, where vegetation has been significantly altered in response to multiple disturbances over recent decades. However, vegetation dynamics under changing environment and the integrated driving effects on natural and anthropogenic factors are unclear for environmentally sensitive and fragile areas. Therefore, Normalized Difference Vegetation Index (NDVI) as an indicator of vegetation status to systematically analyze the temporal and spatial characteristics of the vegetation dynamics in the IMAR from 2000 to 2020, and we quantify the independent and integrated effects of natural and anthropogenic factors on vegetation changes through Geo-detector. Additionally, we quantitatively separate the driving factors of vegetation from the perspective of dry-wet zones, and explored the different regional vegetation dynamics and its relationship with natural and human activities. The results showed that: (1) Vegetation had generally shown an upward trend with an interannual variability of 0.0186 a−1 from 2000 to 2020. (2) The spatial pattern of vegetation had obvious differences. Most of the improvement was mainly concentrated in the east of IMAR covered 69.14%, and degradation in the western desert region. (3) Natural factors were more influential than anthropogenic factors, precipitation had the greatest explanatory power for the spatial heterogeneity of vegetation with a q value of 80.28%, and the integrated effects on vegetation changes were strongest for precipitation and other drivers. (4) The main drivers affecting NDVI changes are more variable in different wet-dry zones, and precipitation gradients determined explanatory power and the relative importance of natural and anthropogenic factors for vegetation changes. These results contributed more insight into the driving mechanisms underlying vegetation dynamics, while being critical for predicting and evaluating vegetation recovery and vegetation ecosystem stability in the context of global climate change, especially in environmentally sensitive and fragile areas.

Landscape agroecology: woody vegetation heterogeneity and its association with natural and human factors at a multifunctional peasant socio-ecosystem from a semi-arid mountain range area (Dry Chaco, Argentina)

ABSTRACT In this study we investigate the landscape of a multifunctional peasant socio-ecosystem using a dialectic and complex theoretical-methodological framework rooted in agroecology. We describe vegetation floristics and structure, as well as biophysical and anthropic variables. We use maps, multivariate analysis and validation workshops to integrate and analyze information. The vegetation showcases distinct typologies, marked by gradual, non-linear variations, without precise boundaries tied to biophysical and anthropic drivers. Furthermore, based on vegetation structure and floristic heterogeneity, this agroecosystem constitutes a well-managed multifunctional native forest landscape, exemplifying a case of biocultural conservation.

ENVIRONMENTAL QUALITY IN EUCALYPTUS SPP. PLANTATIONS DETERMINED FROM FUNCTIONAL PROCESSES OF ITS LITTER

The objective of the study was to understand the influence of Eucalyptus spp. cultivation on the quality of the environment in which it is inserted. For this, three sampling areas of eucalyptus plantations and a control area composed of heterogeneous vegetation. Measurements of leaf litter mass loss, water retention capacity (WRC) tests, and measurements of the content of macronutrients and organic fractions (lignin, cellulose and polyphenols) were carried out in the litter. The litter samples from the control area showed a decomposition coefficient (k) (0.78; 0.82; 0.87) significantly higher than the samples from Eucalyptus spp. (0.51; 0.52; 0.55). For WRC, samples from the control area showed values between 161% and 339%, with an average value of 260%. These were significantly higher than those in the eucalyptus areas, which varied between 72% and 156%, with an average value equal to 112%. As for the content of macronutrients, for the concentration of N, Mg and S in the litter, the samples collected in the control area showed average values significantly higher than the samples from the eucalyptus areas. Regarding the contents of lignin and polyphenols, the samples collected in the eucalyptus areas showed significantly higher values than those presented by the control area. The results obtained showed a strong statistical correlation between the contents of N, Mg, lignin and polyphenols in the sampled leaf material, decomposition rates and water retention capacity. The decomposition of Eucalyptus spp. presented slow decomposition, strongly linked to its chemical composition, which hinders the action of decomposing agents.

Evaluation of a forest radiative transfer model using an extensive boreal forest inventory database

The forest reflectance and transmittance model (FRT) is applicable over a wide swath of boreal forest landscapes mainly because its stand-specific inputs can be generated from standard forest inventory variables. We quantified the accuracy of this model over an extensive region for the first time. This was done by carrying out a simulation study over a large number (12,369) of georeferenced forest plots from operational forest management inventories conducted in Southern Finland. We compared the FRT simulated bidirectional reflectance factors (BRF) with those measured by Landsat 8 satellite Operational Land Imager (OLI). We also quantified the relative importance of several explanatory factors that affected the magnitude of the discrepancy between the measured and simulated BRFs using a linear mixed effects modelling framework. A general trend of FRT overestimating BRFs is seen across all tree species and spectral bands examined: up to ∼0.05 for the red band, and ∼0.10 for the near infrared band. The important explanatory factors associated with the overestimations included the dominant tree species, understory type of the forest plot, timber volume (acts as a proxy for stand maturity), vegetation heterogeneity and time of the year. Our analysis suggests that approximately 20% of the error is caused by the non-representative spectra of canopy foliage and understory. Our results demonstrate the importance of collecting representative spectra from a diverse set of forest stands, and over the full range of seasons.

Effects of Biomass and Soil Water Content Distribution on Cosmic Ray Neutron Probe Measurement

Cosmic ray neutron probes (CRNPs) provide continuous monitoring of average near-surface soil water content (SWC) on hectometer scales. However, the performance of CRNPs on surfaces of highly heterogeneous vegetation and SWC remains uncertain. This study evaluated three vegetation calibration methods with the correction of vegetation distribution developed for a CRNP on the Loess Plateau of China. Three plots with different vegetation distributions were selected and equipped with CRNPs and SWC sensors, and their biomass as well as distribution were measured by an unmanned aerial vehicle (UAV) equipped with a RedEdge multispectral camera. We found that the parameter N0, which is neutron flux in dry soil, was best represented by the biomass at average growth conditions of the monitoring period, yielding the lowest RMSE (0.068). The Veg–N0 vegetation calibration method reduced the RMSE the most between the CRNP SWC and the Kriging-weighted SWC, and the correction of the spatial distribution of the vegetation further reduced the RMSE. The cooperation between the CRNP and the UAV could obtain the regional averaged SWC accurately. This study makes up for the lack of vegetation calibration for the CRNP on the Loess Plateau, which should help develop sustainable vegetation management and ecohydrological management strategies on the Loess Plateau, so as to protect water security in the region.

Diversity – volume relationships: adding structural arrangement and volume to species – area relationships across forest macrosystems

The species – area relationship (SAR) is a common pattern in which diversity increases with the area sampled, but ecosystems are three‐dimensional (3D) and diversity – volume relationships (DVRs) may exist in ecosystems that vary substantially in their vegetation volume. We tested whether forest vegetation volume, as a 3D extension of area in SARs, was a significant predictor of taxonomic (species) and structural (arrangement) diversity in five groups of organisms across the National Ecological Observatory Network (NEON). Vegetation volume and four structural arrangement metrics within the area of NEON plots were measured using NEON's discrete return lidar. Species richness was measured as the number of species within the respective NEON plot sampling area for understory plants, trees, breeding land birds, small mammals, and ground beetles. We found that volume negatively predicted understory plants and positively predicted tree and beetle species richness across the USA forest macrosystem, but not bird and small mammal species richness. Furthermore, volume was a significant predictor of several metrics that describe the internal and external heterogeneity of vegetation in forests (structural arrangement) within the ecosystem across the USA forest macrosystem. There were several significant within site‐level relationships, but not at all sites, between volume and species richness or structural arrangement in organism groups. Our study indicates that previous work that has focused on a 2D conceptualization of habitat can be expanded to 3D habitat space, but that the strength and the positive or negative direction of DVRs may vary taxonomically or geographically.

3D-гидродинамическое моделирование потоков СО2 и CH4 в приземном слое атмосферы (На примере лесного участка «Рошни-Чу»)

Introduction: The aim of this study is to evaluate the spatial variability of carbon dioxide (CO2) and methane (CH4) fluxes at the reference site "Roshni-Chu" of the carbon measurement megasites of the Chechen Republic using modeling experiments with in-situ measurements and remote sensing data. Methods and materials: Measurements of carbon dioxide (CO2) and methane (CH4) fluxes at the soil surface at the "Roshni Chu" forest site in the mountainous forest region of the Chechen Republic were conducted using a dynamic closed chamber connected to a portable gas analyzer G4301 (Picarro, USA). Leaf photosynthesis and respiration parameters of the main edificators and sub-edificators of premontane broadleaf forests were measured using the portable photosynthetic system LI-6800 (LI-COR, USA). Landsat 8 data were used to produce digital maps of surface topography and Nor-malized Difference Vegetation Index (NDVI). A 3D process-based atmospheric transfer model was chosen to describe the spatial variability of carbon dioxide and methane fluxes within the atmospheric boundary layer. The model is based on a one-and-a-half closure scheme for the Navier-Stokes and continuity equations, solved using Reynolds averaging and the Bussiness conjecture. Results: It was shown that a three-dimensional (3D) mathematical transfer models based on the solution of the equations of thermo-hydrodynamics are among the most effective methods for estimating vertical and horizontal fluxes of greenhouse gases in the atmosphere, taking into account the heterogeneous vegetation structure and surface topography. Based on the modeling results, maps of spatial distribution of turbulent exchange coefficient and horizontal wind speed at 5 m height, and maps of spatial distribution of CO2 and CH4 methane fluxes at 5, 25 and 50 m height were created. It was revealed that the "Roshni-Chu" forest area serves as a CO2 sink from the atmosphere under warm sunny weather in summer. The greatest uptake is detected near the local elevations. The fluxes of CH4 are almost negative, the lowest values of CH4 uptake are connected with uneven topography and are observed in small depressions between the hills. Conclusions: Based on the study of the wind field and the greenhouse gas fluxes at the carbon experimental site "Roshni-Chu" in the Chechen Republic, a significant spatial heterogeneity of the vertical CO2 and CH4 fluxes was revealed. The model approach, together with field measurements and remote sensing data, can be very effective for assessing the spatial heterogeneity of greenhouse gas fluxes at sites with non-uniform topography and vegetation. The method of modeling the spatial distribution of CO2 and CH4 fluxes within the atmospheric boundary layer can be used in different forest regions of the North Caucasus to describe the regional greenhouse gas balance.

Effects of long‐term fixed fire regimes on African savanna vegetation biomass, vertical structure and tree stem density

Abstract Fire plays an integral role in shaping the vegetation structure of savanna ecosystems. However, the effects of fire regime characteristics, such as frequency and season of burn, on savanna vegetation structure, biomass and tree abundance across landscape types are largely unknown. We used high‐resolution airborne light detection and ranging (LiDAR) to investigate the long‐term effects of fire manipulation on savanna vegetation in Kruger National Park, South Africa. We analysed the effects of fire exclusion and experimental burns every 1, 2, 3, 4 and 6 years and during different seasons on aboveground biomass (AGB), tree stem densities and vegetation vertical height profiles across a rainfall gradient and on contrasting geologies. Across savanna types, and especially in drier savannas, fire season was more influential for constraining AGB than fire frequency. Plots experiencing fires during the late‐ and mid‐dry season had 44.50% and 43.60%, respectively, lower AGB relative to unburnt plots than wet‐season fires. However, in mesic savannas, fire frequency interacted with fire season to influence AGB: plots subjected to high frequency, dry‐season fires had 55.35% lower AGB than unburnt plots, whereas plots burnt in the wet season at lower frequencies had lower AGB (24.40% lower than unburnt plots) than plots subjected to high frequency, wet‐season fires (13.74% lower AGB than unburnt plots). Fire regimes had variable effects on tree densities, and effects varied with the savanna type. Woody vertical vegetation profiles showed the largest differences in response to dry‐season fires, with the greatest divergence in vegetation height classes <5 m. Synthesis and applications. Understanding the influence of fire regimes on vegetation structure has important implications for the management of savanna heterogeneity and for predicting trajectories of change in savanna vegetation as fire regimes vary with climate change. We show that the magnitude of the effect of fire on woody vegetation structure varies with savanna context. Our results suggest that heterogeneous vegetation structure can be achieved by applying fires in the dry season in mesic savannas, whereas in dry savannas, variation in fire regimes is less consequential for constraining biomass accumulation and altering vegetation structure.

Vegetation structure from LiDAR explains the local richness of birds across Denmark.

Classic ecological research into the determinants of biodiversity patterns emphasised the important role of three-dimensional (3D) vegetation heterogeneity. Yet, measuring vegetation structure across large areas has historically been difficult. A growing focus on large-scale research questions has caused local vegetation heterogeneity to be overlooked compared with more readily accessible habitat metrics from, for example, land cover maps. Using newly available 3D vegetation data, we investigated the relative importance of habitat and vegetation heterogeneity for explaining patterns of bird species richness and composition across Denmark (42,394 km2 ). We used standardised, repeated point counts of birds conducted by volunteers across Denmark alongside metrics of habitat availability from land-cover maps and vegetation structure from rasterised LiDAR data (10 m resolution). We used random forest models to relate species richness to environmental features and considered trait-specific responses by grouping species by nesting behaviour, habitat preference and primary lifestyle. Finally, we evaluated the role of habitat and vegetation heterogeneity metrics in explaining local bird assemblage composition. Overall, vegetation structure was equally as important as habitat availability for explaining bird richness patterns. However, we did not find a consistent positive relationship between species richness and habitat or vegetation heterogeneity; instead, functional groups displayed individual responses to habitat features. Meanwhile, habitat availability had the strongest correlation with the patterns of bird assemblage composition. Our results show how LiDAR and land cover data complement one another to provide insights into different facets of biodiversity patterns and demonstrate the potential of combining remote sensing and structured citizen science programmes for biodiversity research. With the growing coverage of LiDAR surveys, we are witnessing a revolution of highly detailed 3D data that will allow us to integrate vegetation heterogeneity into studies at large spatial extents and advance our understanding of species' physical niches.

Historical fire regimes and contemporary fire effects within sagebrush habitats of Gunnison Sage‐grouse

AbstractThe historical role of fire in sagebrush (Artemisia tridentata) landscapes remains poorly understood, yet is important to inform management and conservation of obligate species such as the threatened Gunnison Sage‐grouse (GUSG; Centrocercus minimus). We reconstructed fire histories from tree‐ring fire scars at sagebrush–forest ecotones (10 sites, 111 trees) to better understand the role of fire in sagebrush landscapes of the Upper Gunnison Basin (UGB), Colorado, and how fire may have changed following Euro‐American settlement. We assessed likely influences of historical fire by surveying plant composition and structure at 100 sagebrush sites with and without recent (2001–2020) fires. Tree‐ring fire scars revealed a history of repeated low‐severity fire at sagebrush–forest ecotones until 1892, followed by over a century without fire. Between 1684 and 1892, the mean fire interval (MFI) among sites averaged 49.6 years (ranging from 18.2 to 119 years). Fire over this period occurred synchronously at two or more sites on average every 23.6 years, potentially indicative of spread between sites. Most (70%) of the historical fires burned in the early growing season, consistent with times of strong wind. Recent burns exhibited reductions in sagebrush cover (5% vs. 25% in unburned sites) and concomitant increases in herbaceous cover (55% vs. 40%). These differences declined over time but persisted for at least two decades. Burned sites were dominated by native perennial grasses, forbs, and resprouting shrub species. Historically, such openings may have served as seasonal GUSG habitat. Our results indicate that parts of the UGB sagebrush landscapes were characterized historically by frequent fire and dynamic vegetation mosaics that included open, grassy patches. These findings support the use of prescribed fire to restore and maintain this ecological process and vegetation heterogeneity. However, the contemporary context for fire has changed and now includes substantially reduced, Endangered Species Act (ESA)‐listed GUSG populations, increased risk of non‐native plant invasion, and climate warming. These circumstances highlight new risks, information needs, and opportunities for key knowledge co‐production via management–research partnerships.

1100-years history of transformation of the East European forest-steppe into arable land: Case study from Kursk region (Russia)

Large parts of the East European forest-steppe are covered by agricultural and pastoral landscapes with decreasing proportions of semi-natural meadow steppes and fragments of semi-natural woodland. Although numerous palynological records indicate that a total deforestation occurred in the last 500 years, the details of the transformation from natural vegetation into an agrarian landscape are still lacking as well as an evaluation of the political role in this process. This study focuses on the vegetation and fire history at the northern edge of the forest-steppe in the Kursk region (Russia) and aim to reconstruct the transformation process in its historical context. New pollen, non-pollen palynomorphs and charcoal records with decennial to centennial resolution obtained from the Seim River region enable a comprehensive reconstruction of the local and regional landscape history over the last 1,100 years. The palynological records provide unique insights into the heterogeneous vegetation cover of microregions and evidence spatial asynchronous deforestation and crop field creation. Our findings highlight a crucial role of political systems on the formation of agro-pastoral landscapes with small remaining forest patches of today. The heterogeneity of the natural vegetation distribution before major deforestation as well as the duration of human impact should be considered in ecosystem restoration projects. All raw data are submitted to PANGAEA database (https://www.pangaea.de/: Peny PDI-34573, Razdolye PDI-34620). All pictures of NPP are submitted to NPP-ID (http://non-pollen-palynomorphs.uni-goettingen.de/).

Seasonality regulates the structure and biogeochemical impact of ectomycorrhizal fungal communities across environmentally divergent neotropical dry forests

Abstract Ectomycorrhizal (ECM) symbioses support forest functioning globally, yet both the structure and function of ECM fungal communities in seasonally dry neotropical forests (SDTFs), known for extreme heterogeneity in vegetation and edaphic properties, remain under characterized. Here, we evaluated the relative influences of seasonal versus spatial variation in ECM fungal community structure in soils from four environmentally divergent SDTFs. We also assessed the importance of biotic and abiotic drivers of SDTF ECM fungal community structure at regional scales, as well as ECM impacts on soil carbon (C) and nitrogen (N) cycling. ECM fungal frequency, relative abundance and richness all increased in the wet season, but spatial rather than seasonal effects explained more variation in community composition. Across the four SDTFs investigated, differences in tree communities drove ECM fungal community turnover more than geographic distances, site abiotic conditions or soil chemistry. Although soil moisture and ECM tree basal area were stronger predictors of soil biogeochemistry, incorporating ECM fungal community composition and relative abundance added explanatory power to models of soil C and N cycling in the wet season. Synthesis: Our results highlight the importance of seasonality and plant community composition in shaping different aspects of SDTF ECM fungal community structure and diversity as well as the potential for both the plant and fungal components of ECM symbioses to impact soil functioning across heterogenous SDTFs. Furthermore, our findings suggest that alterations in SDTF plant community composition due to climate or land‐use change will have important consequences for ECM fungal diversity and associated effects on soil biogeochemical cycling.

Convection Initiation Associated with a Boundary Layer Convergence Line over a Real-World Sharp Vegetation-Contrast Area

Abstract Convection initiation (CI) has remained a major challenge in weather forecasting worldwide. The Hetao area in North China, the location of Asia’s largest irrigation area, contains highly heterogeneous vegetation where near-surface convergence lines (boundaries) parallel to the oasis–desert border often emerge over the desert and initiate convection. This study investigated the evolution of such a boundary and its influence on the CI process where a series of cells were successively initiated along the boundary on 4 June 2013. Our results indicated that uneven surface heating across the oasis–desert border produced mesoscale thermal circulation. The westerly oasis breeze in the thermal circulation converged with the southerly background wind and formed a boundary over the desert along the high-temperature contrast line. A middle-hemisphere westerly trough further enhanced uplift and facilitated CI. Our simulation revealed that the first 30-dBZ parcels in each cell originated from either the desert side at a low level or the oasis side at a middle level, rather than from the oasis at a low level, as indicated by previous idealized studies. Southerly low-level parcels veered above the boundary and experienced a longer lifting time over the desert, while western parcels originating from the oasis experienced a shorter lifting time and smaller vertical displacement, resulting in middle-level parcels instead of low-level parcels that reached their level of free convection. Even though CI occurred over a surface boundary without a near-surface stable layer, the inflow may have originated from middle levels rather than in contact with the surface. Significance Statement The purpose of this study is to understand the evolution of a real-world near-surface convergence line and the associated deep convection initiation (CI) along the border of Asia’s largest irrigation area and the desert in northern China. Notably, previous works have mainly focused on shallow convection over uneven vegetation distributions based on idealized simulations, which may be quite different from real-world interactions between thermal circulation and background flow. Our results highlight different parcel sources in different convections initiated by the same convergence line, which is different from the idealized situation where parcels mainly originate from the low-level oasis side.

Detecting long-term effects of mining-induced ground deformation on plant succession in semi-arid areas using a cellular automata model

Mining-induced ground deformation affects various plant communities in different ways. However, little is known about the effects of ground deformation on plant succession; no known quantitative approach currently exists to detecting the long-term effects. To address this issue, a plant community succession model based on cellular automata was developed. Plant succession over 30 years within a subsidence area in the Yungang mining area in China was simulated and compared under mining and non-mining scenarios, including under two sets of initial conditions (vegetated and bare). The normalized mean square error was applied to test the accuracy of the plant community succession model and to reveal the effects of ground deformation at the patch scale, which was 0.06–0.59 for simulated and observed plant patterns. Landscape indicators including contagion, patch cohesion, interspersion and juxtaposition, Shannon’s diversity, Shannon’s evenness, and aggregation indices were calculated and compared to reveal the effects of mine subsidence at the landscape scale. The results showed that the interspersion and juxtaposition, Shannon’s diversity, Shannon’s evenness, and aggregation indices were significantly influenced by ground deformation (P < 0.05) under vegetated conditions, indicating that ground deformation resulted in a loose, isolated, and mixed pattern of vegetation. In terms of the shrub and tree communities, the normalized mean square errors fluctuated at a high level under bare conditions, especially at the patch scale of 10 × 10 m, where it remained at greater than 0.5. Overall, mining-induced ground deformation had long-term effects on plant succession by limiting tree communities and promoting shrub communities, as well as by leading to a heterogenous vegetation pattern. Ground deformation altered the topography of the previously mined area, influencing hydrological processes such as rainfall, infiltration, and evaporation, which were closely related to plant succession. Although these long-term effects were not directly a result of ground deformation, changes in the topography of a subsidence area would interfere with the spontaneous succession of plant communities. Therefore, the long-term effects of mining-induced ground deformation should be considered during the ecological restoration of a mining area, which can promote the application of nature-based solutions and the natural regeneration of plant communities.

Forest conversion into pasture selects dung beetle traits at different biological scales depending on species pool composition.

The conversion of forests into open areas has large effects on the diversity and structure of native communities. The intensity of these effects may vary between regions, depending on the existence of native species adapted to open habitats in the regional pool or the time since habitat change.We assess the differences in species richness and functional diversity of dung beetle communities (Coleoptera: Scarabaeinae) between native forests and novel pasturelands of the Atlantic Forest and the Cerrado, two biomes with contrasting histories of human occupation in Brazil. We conducted standardized surveys in seven forest fragments and adjacent pastures in each region and measured 14 traits in individuals collected in each type of habitat at each particular site. We calculated functional richness, functional evenness, functional divergence, and community-weighted mean of traits for each area, and analyzed individual variation through nested variance decomposition and Trait Statistics.Communities were richer and more numerous at the Cerrado. We did not find any consistent relationship between functional diversity and forest conversion beyond the changes in species diversity. Although landscape changes were more recent at the Cerrado, the colonization of the new habitat by native species already adapted to open habitats lessens the functional loss in this biome. This indicates that habitat change's effects on trait diversity depend on the regional species pool rather than on time since land conversion.Forest conversion effects were primarily due to internal filtering. The effects of external filtering only appear at the intraspecific variance level, with contrasting differences between the Cerrado, where traits related to relocation behavior and size are selected, and the Atlantic Forest, where selection operates for traits related to relocation behavior and flight. These results evidence the importance of considering individual variance to address the responses of dung beetle communities to forest conversion.

Modeling Tool for Estimating Carbon Dioxide Fluxes over a Non-Uniform Boreal Peatland

We present a modeling tool capable of computing carbon dioxide (CO2) fluxes over a non-uniform boreal peatland. The three-dimensional (3D) hydrodynamic model is based on the “one-and-a-half” closure scheme of the system of the Reynolds-Averaged Navier–Stokes and continuity equations. Despite simplifications used in the turbulence description, the model allowed obtaining the spatial steady-state distribution of the averaged wind velocities and coefficients of turbulent exchange within the atmospheric surface layer, taking into account the surface heterogeneity. The spatial pattern of CO2 fluxes within and above a plant canopy is derived using the “diffusion–reaction–advection” equation. The model was applied to estimate the spatial heterogeneity of CO2 fluxes over a non-uniform boreal ombrotrophic peatland, Staroselsky Moch, in the Tver region of European Russia. The modeling results showed a significant effect of vegetation heterogeneity on the spatial pattern of vertical and horizontal wind components and on vertical and horizontal CO2 flux distributions. Maximal airflow disturbances were detected in the near-surface layer at the windward and leeward forest edges. The forest edges were also characterized by maximum rates of horizontal CO2 fluxes. Modeled turbulent CO2 fluxes were compared with the mid-day eddy covariance flux measurements in the southern part of the peatland. A very good agreement of modeled and measured fluxes (R2 = 0.86, p &lt; 0.05) was found. Comparisons of the vertical profiles of CO2 fluxes over the entire peatland area and at the flux tower location showed significant differences between these fluxes, depending on the prevailing wind direction and the height above the ground.

Combining bird tracking data with high-resolution thermal mapping to identify microclimate refugia

Elevated temperatures can have a range of fitness impacts, including high metabolic cost of thermoregulation, hence access to microclimate refugia may buffer individuals against exposure to high temperatures. However, studies examining the use of microclimate refugia, remain scarce. We combined high resolution microclimate modelling with GPS tracking data as a novel approach to identify the use and availability of cooler microclimate refugia (sites > 0.5 °C cooler than the surrounding landscape) at the scales experienced by individual animals. 77 little bustards (Tetrax tetrax) were tracked between 2009 and 2019. The 92,685 GPS locations obtained and their surrounding 500 m areas were characterised with hourly temperature and habitat information at 30 m × 30 m and used to determine microclimate refugia availability and use. We found that the semi-natural grassland landscapes used by little bustards have limited availability of cooler microclimate areas—fewer than 30% of the locations. The use of cooler microclimate sites by little bustards increased at higher ambient temperatures, suggesting that individuals actively utilise microclimate refugia in extreme heat conditions. Microclimate refugia availability and use were greater in areas with heterogeneous vegetation cover, and in coastal areas. This study identified the landscape characteristics that provide microclimate opportunities and shelter from extreme heat conditions. Little bustards made greater use of microclimate refugia with increasing temperatures, particularly during the breeding season, when individuals are highly site faithful. This information can help identify areas where populations might be particularly exposed to climate extremes due to a lack of microclimate refugia, and which habitat management measures may buffer populations from expected increased exposure to temperature extremes.

Assessment of NDVI Dynamics of Maize (Zea mays L.) and Its Relation to Grain Yield in a Polyfactorial Experiment Based on Remote Sensing

Remote sensing is an efficient tool to detect vegetation heterogeneity and dynamics of crop development in real-time. In this study, the performance of three maize hybrids (Fornad FAO-420, Merida FAO-380, and Corasano FAO-490-510) was monitored as a function of nitrogen dose (0, 80 and 160 kg N ha−1), soil tillage technologies (winter ploughing, strip-tillage, and ripping), and irrigation (rainfed and 3 × 25 mm) in a warm temperature dry region of East-Central Europe. Dynamics of the Normalized Difference Vegetation Index (NDVI) were followed in the vegetation period of 2021, a year of drought, by using sensors mounted on an unmanned aerial vehicle. N-fertilization resulted in significantly higher NDVI throughout the entire vegetation period (p &lt; 0.001) in each experimental combination. A significant positive effect of irrigation was observed on the NDVI during the drought period (77–141 days after sowing). For both the tillage technologies and hybrids, NDVI was found to be significantly different between treatments, but showing different dynamics. Grain yield was in strong positive correlation with the NDVI between the late vegetative and the early generative stages (r = 0.80–0.84). The findings suggest that the NDVI dynamics is an adequate indicator for evaluating the impact of different treatments on plant development and yield prediction.

New 14C data of megafaunal remains from Lithuania – implications for the palaeoenvironmental interpretation of the Middle Weichselian

Palaeobiological data, supplemented by new 14C dates in conjunction with palaeobotanical and lithological information, have allowed reconstruction of Middle Weichselian (MIS 3) environmental fluctuations in the southern Eastern Baltic region. Palaeoenvironmental reconstructions implying non-glacial conditions during the Middle Weichselian (MIS 3) are supported by the spatial and temporal context of recently discovered remains of Mammuthus primigenius Blumenbach and Rangifer tarandus Linnaeus, 1758. Recording both cold and warm climatic reversals of MIS 3, representatives of the megafauna thrived in an environment characterized by a heterogeneity of vegetation and climate. 14C dating shows that the majority of the megafaunal remains analysed represent the 38–45 cal kyr BP time-interval, which correlates with the Nemunas 2c cold interval (cryomer), and the 31–34 cal kyr BP or Mickñnai 3 thermomer. From pollen data, the palaeovegetation pattern varied from tree-less tundra to birch-predominating forest with an admixture of temporal tree species providing additional information about the diet and habitat preferences of these herbivores in the context of the MIS 3 climatic events.