Bare Soil Cover Research Articles

Soil benzene emissions and inhalation health risks affected by various land covers

Accurate quantification of soil volatile organic compounds (VOCs) flux is crucial for assessing inhalation environmental health risks and developing region-specific remediation strategies. However, land cover significantly influences VOCs emissions from soil. This study investigated benzene, a representative VOCs, using a laboratory flux chamber and numerical simulations to evaluate its release patterns under different surface covers, including bare soil (no cover), clay brick, cement, and grass. In the experiment, gaseous benzene was collected using an adsorption tube filled with Tenax-TA adsorbent. The collected samples were subsequently analyzed using thermal desorption coupled with gas chromatography-mass spectrometry. By integrating these findings with environmental health risk assessment methodologies, we developed a tailored approach for assessing inhalation health risks at benzene-contaminated sites with varying land covers. Additionally, we conducted application studies of this method across various scenarios. The results indicate that soil benzene emissions could be reduced by using low-permeability coverings such as clay brick and cement, as well as by planting vegetation. The average fluxes of benzene through covering materials were of the order of 1.22 × 10−2, 4.37 × 10−3, 2.47 × 10−3, and 9.88 × 10−4 mg m−2·s−1 for bare soil, clay brick, grass, and cement, respectively. The application of clay brick and cement coverings on the soil surface results in more pollutants remaining in the soil in liquid and adsorbed states, making them less likely to volatilize. The inhalation carcinogenic risk (CR) values for soil benzene at an abandoned oil refinery site in Northwestern China under bare soil, brick, and cement cover are 1.3 × 10−6, 1.22 × 10−6, and 9.73 × 10−7, respectively. Low-permeability covers such as clay brick and cement reduces the inhalation CR of gaseous benzene from the surface soil, and delays the growth trend of cumulative inhalation CR.

Addressing the impact of land use land cover changes on land surface temperature using machine learning algorithms

Over the past two and a half decades, rapid urbanization has led to significant land use and land cover (LULC) changes in Kabul province, Afghanistan. To assess the impact of LULC changes on land surface temperature (LST), Kabul province was divided into four LULC classes applying the Support Vector Machine (SVM) algorithm using the Landsat satellite images from 1998 to 2022. The LST was assessed using Landsat data from the thermal band. The Cellular Automata-Logistic Regression (CA-LR) model was applied to predict the future patterns of LULC and LST for 2034 and 2046. Results showed significant changes in LULC classes, as the built-up areas increased about 9.37%, while the bare soil and vegetation cover decreased 7.20% and 2.35%, respectively, from 1998 to 2022. The analysis of annual LST revealed that built-up areas showed the highest mean LST, followed by bare soil and vegetation. The future simulation results indicate an expected increase in built-up areas to 17.08% and 23.10% by 2034 and 2046, respectively, compared to 11.23% in 2022. Similarly, the simulation results for LST indicated that the area experiencing the highest LST class (≥ 32 °C) is expected to increase to 27.01% and 43.05% by 2034 and 2046, respectively, compared to 11.21% in 2022. The results indicate that LST increases considerably as built-up areas increase and vegetation cover decreases, revealing a direct link between urbanization and rising temperatures.

Soil multifunctionality increases after grazing abandonment in semiarid rangelands

Grazing by domestic animals is an economic activity that can alter the ecosystem structure and functioning of drylands. Some rangelands are experiencing a temporary or complete abandonment of grazing, but the effects of these practices on the ecology of drylands are poorly studied. Plant patches are recognized as fertility islands in drylands. Unvegetated inter-patches, far from being lifeless, harbor diverse soil microbial communities, habitually in the form of biocrusts. Here, we determined changes in plant, biocrust, and bare soil cover after grazing cessation over a 63-year period in Patagonian semiarid drylands. We also quantified, at microsite (2.25 m2) and plot (2500 m2) scales, temporal changes in soil multifunctionality by using four specific soil multifunctionality indexes associated with soil carbon, fertility, biogeochemical cycling, and stability. Our results indicate that biocrusts, although with low cover values, colonize new soil areas following grazing cessation, whereas bare soil cover increases at the expense of plants. We found that soil multifunctionality consistently increased with time since grazing cessation at the microsite scale, with biocrusts showing the highest multifunctionality values. We also observed that soil multifunctionality increased over time after grazing cessation at the plot scale, with bare soil and plants being more important than biocrusts due to their greater cover. Overall, our field study shows that the abandonment of grazing leads to a natural recovery of soil functioning in semiarid rangelands, with biocrusts and microbial communities of bare soils playing central roles, but at different spatial scales.

Clover (Trifolium spp.) Inclusion in Kentucky Bluegrass (Poa pratensis) Lawns

Historically, white clover (Trifolium repens) seed was included in turfgrass seed mixtures to provide biodiversity and nitrogen (N) to lawns. White clover dicultures have been studied recently for inclusion in both warm- and cool-season turfgrasses, with the goals of reducing fertilizer applications and providing pollinator forage in lawns; however, other clovers have not been as widely researched in turfgrass. The objectives of this study were to evaluate 1) if white, strawberry (T. fragiferum), crimson (T. incarnatum), and rose (T. hirtum) clovers can persist in dicultures with Kentucky bluegrass (Poa pratensis); 2) if clover inclusion in dicultures impacts broadleaf weed cover; and 3) if low levels of N fertilization impact clover persistence or quality of clover–bluegrass dicultures. Kentucky bluegrass was grown as a monoculture or as a diculture with each of the four clover species. Each mono- or diculture was then treated with a low rate of N fertilizer (48.8 kg⋅ha–1 N) or no N fertilizer to determine quality and percentage of grass, clover, or weed and bare-soil cover. Dicultures contained similar or less weed and bare-soil cover, and maintained similar or greater quality compared with bluegrass monocultures, indicating clover and Kentucky bluegrass dicultures are suitable alternatives to Kentucky bluegrass monoculture lawns, and can potentially lead to reduced fertilizer and pesticide requirements. Fertilizer generally had no effect on cover, likely because of the low rates of N applied.

Application of Remote Sensing for Identifying Soil Erosion Processes on a Regional Scale: An Innovative Approach to Enhance the Erosion Potential Model

Soil erosion represents a complex ecological issue that is present on a global level, with negative consequences for environmental quality, the conservation and availability of natural resources, population safety, and material security, both in rural and urban areas. To mitigate the harmful effects of soil erosion, a soil erosion map can be created. Broadly applied in the Balkan Peninsula region (Serbia, Bosnia and Herzegovina, Croatia, Slovenia, Montenegro, North Macedonia, Romania, Bulgaria, and Greece), the Erosion Potential Method (EPM) is an empirical erosion model that is widely applied in the process of creating soil erosion maps. In this study, an innovation in the process of the identification and mapping of erosion processes was made, creating a coefficient of the types and extent of erosion and slumps (φ), representing one of the most sensitive parameters in the EPM. The process of creating the coefficient (φ) consisted of applying remote sensing methods and satellite images from a Landsat mission. The research area for which the satellite images were obtained and thematic maps of erosion processes (coefficient φ) were created is the area of the Federation of Bosnia and Herzegovina and the Brčko District (situated in Bosnia and Herzegovina). The Google Earth Engine (GEE) platform was employed to process and retrieve Landsat 7 Enhanced Thematic Mapper plus (ETM+) and Landsat 8 Operational Land Imager and Thermal Infrared Sensor (OLI/TIRS) satellite imagery over a period of ten years (from 1 January 2010 to 31 December 2020). The mapping and identification of erosion processes were performed based on the Bare Soil Index (BSI) and by applying the equation for fractional bare soil cover. The spatial–temporal distribution of fractional bare soil cover enabled the definition of coefficient (φ) values in the field. An accuracy assessment was conducted based on 190 reference samples from the field using a confusion matrix, overall accuracy (OA), user accuracy (UA), producer accuracy (PA), and the Kappa statistic. Using the confusion matrix, an OA of 85.79% was obtained, while UA ranged from 33% to 100%, and PA ranged from 50% to 100%. Applying the Kappa statistic, an accuracy of 0.82 was obtained, indicating a high level of accuracy. The availability of a time series of multispectral satellite images for each month is a crucial element in monitoring the occurrence of erosion processes of various types (surface, mixed, and deep) in the field. Additionally, it contributes significantly to decision-making, strategies, and plans in the domain of erosion control work, the development of plans for identifying erosion-prone areas, plans for defense against torrential floods, and the creation of soil erosion maps at local, regional, and national levels.

Effect of shade on simultaneous estimation of non-photosynthetic and photosynthetic vegetation cover using the NDVI-NSSI normalized difference triangular space

ABSTRACT The non-photosynthetic vegetation – soil separation index (NSSI) and normalized difference vegetation index (NDVI) can be used to simultaneously estimate the fractional cover of non-photosynthetic vegetation (fNPV), photosynthetic vegetation (fPV), and bare soil (fBS) in vegetation ecosystems. However, these estimates suffer from problems due to shading by dense vegetation or topography. Based on field-measured data and on hyperspectral data acquired by unmanned aerial vehicles, we analyse how shading affects the morphology of NDVI-NSSI and enhanced vegetation index – NSSI (EVI-NSSI). We also investigate the simultaneous estimation of fNPV, fPV, and fBS. The results show that the NDVI-NSSI normalized difference feature space mitigates the impact of shade. Shade causes the NDVI-NSSI and EVI-NSSI to shift rightward parallel to the BS axis and leftward parallel to the PV axis, respectively. Although such shifts may hinder the determination of NPV, PV, and BS endmembers, they do not affect the spectral separation of NPV. Overall, with the NDVI-NSSI and EVI-NSSI methods, the estimation error for fNPV under shaded conditions is approximately 5% greater than that under illuminated conditions. Shaded green vegetation more strongly affects the estimation error of fPV and fBS in EVI-NSSI than in NDVI-NSSI, whereas fBS and fPV depend more strongly on shade than fNPV.

Influence of ground cover and tunnels on production of Red Russian kale in urban gardes

Kale, Brassica oleracea L. var. acephala, is an important urban crop for human health and may potentially be grown year-round even in a temperate climate. We investigated black plastic and straw mulch compared to bare soil cover in low tunnels at 10 urban garden sites and in low tunnels within a high tunnel in the USA to ascertain the influence on yield and nutrients of Red Russian kale, soil temperature, air temperature, weed pressure, and aphid abundance. Kale had low yield in garden sites, likely because the outside environment was too cold for low tunnels to gain and retain heat. Cultivating kale in a high tunnel resulted in good yields, especially when paired with a low tunnel and plastic or straw mulch, which resulted in the highest air and soil temperatures. The amount of minerals in plants within the high tunnel largely did not vary across combinations of low tunnels and ground covers, except for copper and sulfur, which were lowest in plots with no low tunnel or ground cover. Also, dietary fiber was higher when no low tunnel or ground cover was used compared to plots with a low tunnel and no ground cover. Weeds were suppressed by straw and black plastic mulch, but none of the ground covers influenced aphid abundance. Overall, our work demonstrates that Red Russian kale can be grown in a temperate climate during winter with some combinations of tunnels and ground covers.

Biophysical characteristics, distribution and conservation challenges of critically endangered Bhutan poppy (Papaver bhutanicum) in Jigme Dorji National Park, Bhutan

AbstractThe occurrence of certain rare plant species in specific ecological habitats is intricately linked to a myriad of environmental conditions, encompassing both biotic and abiotic factors. The prioritisation of monitoring efforts becomes more impactful when conservationists possess a comprehensive understanding of the ecology and distribution of rare species within their designated habitats and across the entire range of the species. In September 2023, a study was conducted in Jigme Dorji National Park to assess the ecology, distribution and threats to the critically endangered Bhutan poppy. This survey, employing random sampling, covered approximately 87 ha across Tshophu, Tshophu base and Jichudrakey base in Soe Gewog and analysed 202 2 × 2 m plots. The survey revealed 57 plant species from 24 families, with Asteraceae (17.5%) and Papaveraceae (12.3%) dominating. Notably, 46% of families comprised a single species, and significant species richness differences were observed between Tshophu, Tshophu base and Jichudrakey base. Correlations between species richness and environmental variables, including slope, rock cover (%), bare soil cover (%) and herb cover (%), were identified as significant. The Bhutan poppy was positively and significantly associated with the southwest aspect, occupying 59% of surveyed plots. Species distribution modelling predicted a distribution area of approximately 37.29 square kilometres within the national park. However, future climate scenarios indicated a significant shift in the distribution of the Bhutan poppy. By 2041–2060, there is an anticipated decrease of 33% in its distribution area, with a shift towards the northeast. In the period from 2061 to 2080, the distribution is expected to increase by 8% from its current range, maintaining the northeast shift. The study identified three primary threats: grazing, trampling and harvesting, with livestock activities prevalent in 92% of plots and signs of harvesting in 45%. These findings provide crucial insights into the ecological dynamics, distribution patterns and potential conservation challenges facing the Bhutan poppy in Jigme Dorji National Park's alpine habitats, emphasising the need for informed conservation strategies amidst changing environmental conditions.

Mapping Fractional Vegetation Cover Using Unoccupied Aerial Vehicle Imagery to Guide Conservation of a Rare Riparian Shrub Ecosystem in Southern California

The use of unoccupied aerial vehicles (UAVs) for vegetation monitoring is widespread in agriculture and forestry but far less so in ecological restoration where it has tremendous unrealized potential. We tested the ability of multispectral data and a derived vegetation index to classify shrub, herbaceous vegetation, and bare soil cover in a rare alluvial floodplain vegetation community in semiarid Southern California, where shrub cover is manipulated in restoration efforts aimed to provide open habitats required by several threatened and endangered species. Three classifiers and three levels of spatial aggregation were compared for their ability to provide accurate shrub cover estimates at a scale commensurate with the needs of conservation managers. We used object-based image analysis (OBIA) and compared maximum likelihood (ML), support vector machine (SVM), and random forest (RF) classifiers applied to high-spatial resolution (0.14 m) data from a four-band Parrot Sequoia+ multispectral sensor. The SVM and RF classifiers yielded similarly high classification accuracy evaluated using the training data (overall accuracy of 96.4% and 97.6%, respectively), much higher than ML (88%). Aggregating shrub cover data to 25 and 50 m resolutions yielded more accurate and well-calibrated cover estimates (mean absolute error 12% and 11%, respectively, for RF) than 10 m aggregation (MAE 19% for RF). Shrub cover estimated using RF and SVM was able to meet the restoration monitoring needs to distinguish the three phases of shrub habitat characterized by their cover (10–30%, 30–75%, >75%) that differ in habitat quality and restoration prescriptions.

A regional, remote sensing-based approach to mapping land degradation in the Little Karoo, South Africa

There is growing global consensus that assessments of land degradation be conducted at regional or smaller scales. Working at this scale allows for locally relevant environmental and land use conditions to be incorporated into the assessment methodology. In this paper, a recently developed regional approach to assessing land degradation in the Hardeveld bioregion of the Succulent Karoo is applied to the Little Karoo region of this biome. The methodology uses fuzzy classification statistical techniques to combine field data with multiple Sentinel-2A and Landsat vegetation indices, as well as regionally modelled soil variables. The resultant habitat condition archetype map values show strong correlation with field observations of perennial plant and bare soil cover in 96 ground-truthed plots. The archetype map indicates that heavily degraded hotspots of high bare ground cover occur throughout the project region, although there is an overall lower average habitat condition in the western half of the Little Karoo. The mean habitat condition archetype value for the entire project area is 0.54 (standard deviation = 0.13), on a continuous scale where 0 and 1 represent the most degraded and pristine extremes, respectively. Random forest regression analysis of various environmental covariates of degradation indicates a strong relationship between habitat condition and topographic as well as rainfall variables, although the limited accuracy of modelled livestock data may obscure the negative impacts of overgrazing. The 30 m resolution habitat condition archetype map builds upon previous degradation research in the Little Karoo and has the potential to inform future conservation, restoration, and rangeland management decisions. The methodology was successfully transferred to a new region and provides an opportunity to improve reporting on the extent of land degradation across South Africa.

Association between bryophytes and seedlings in Nothofagussub‐Antarctic forests

AbstractBryophytes, which include mosses, liverworts and hornworts, indeed play a significant role in the natural dynamics of native forests. They contribute to fundamental ecological processes such as tree regeneration. In this context, the objective was to analyse the association of bryophytes with Nothofagus seedlings, as well as whether the substrates where bryophytes grew influenced bryophyte‐tree seedling association, in sub‐Antarctic forests at two contrasting landscapes (coastal and mountain) of Tierra del Fuego (Argentina), to better understand their impacts on the natural regeneration processes. We hypothesized that bryophytes act as a substrate for seed germination and initial regeneration growth in pure and mixed forests of N. pumilio and N. betuloides, resulting in widespread tree seedlings–bryophyte associations in all landscapes. In each forest and landscape location, 60 transects were established (10 m in length) to evaluate bryophyte cover (by point intercept method) and substrate type (bare soil, decaying wood and litter cover) where they were growing. An adaptation of the relative interaction index (RII) based on tree seedling cover associated with bryophyte species (%) and tree seedling cover in the absence of bryophytes (%) was calculated and analysed to assess competition or facilitation between bryophytes and tree seedlings. Nothofagus pumilio seedlings were less abundant in bryophytes compared to other substrates, suggesting an inhibitory effect on the germination and/or survival of N. pumilio. In contrast, the seedlings of N. betuloides, in both pure and mixed forests, exhibited higher abundance on bryophyte substrates, particularly in mosses at mountain landscape (RII = 0.83 ± 0.08 in litter and 0.62 ± 0.11 in decaying wood). These findings suggest that bryophytes play a facilitating role for N. betuloides seedlings during germination and initial phases of growth, mainly in the mountain. Therefore, their conservation promotes N. betuloides forest continuity, both in pure and mixed structures.

Prediction of the spatiotemporal evolution of vegetation cover in the Huainan mining area and quantitative analysis of driving factors.

The prediction of the spatiotemporal dynamic evolution of vegetation cover in the Huainan mining area and the quantitative evaluation of its driving factors are of great significance for protecting and restoring the environment in this area. This study uses the Landsat 5 TM and Landsat 8 OLI time-series data to estimate the vegetation cover and uses the transition matrix to analyze the spatiotemporal transfer of vegetation cover from 1989 to 2004, 2004 to 2021, and 2021 to 2030. In addition, a structural equation model (SEM) was established in this study to assess the driving factors of vegetation cover. The quantitative analysis and the cellular automata (CA)-Markov model were performed to predict the future vegetation cover in the Huainan mining area. The results are as follows: (1) In different periods, the vegetation cover types were mainly high cover types transferred to other vegetation cover types; (2) human activities are the key factors affecting the vegetation growth, while topographical factor is the most influential factor promoting the vegetation growth; (3) highly consistent CA-Markov and multi-criteria evaluation (MCE) predicted results of vegetation cover in 2030 compared to that in 2021. The proportion of bare soil and low cover types had increased significantly, mainly concentrated in the internal area of the mines. The prediction of the spatiotemporal evolution of vegetation cover in the Huainan mining area and the quantitative change in driving factors are of significant importance for the restoration of the environment in mining areas.

Pitting fails to sustain increases in ecosystem structure in arid rangelands

Mechanized approaches to the rehabilitation of degraded rangeland have been extremely popular since the early 1930s but their effectiveness depends on climatic and environmental conditions (e.g. soil texture, pre‐treatment plant cover). We evaluated the effects of pitting, a popular rehabilitation technique based on the creation of elongated soil depressions (pits), on ecosystem structure from 14 trials conducted at 10 sites across an extensive area (~100,000 km2) of rangelands in eastern Australia. Averaged across all sites and rehabilitation times, pitting had a significant positive effect on the cover of perennial forbs and annuals, and suppressed bare ground compared with untreated sites. However, these treatment effects varied with different site conditions such as soil texture, and pre‐treatment rainfall and plant cover among individual sites. Pre‐treatment plant cover, and rainfall in the 3 months prior to measurements increased the effects of pitting on litter cover, and time since treatment increased the relative effect of pitting on annual plant cover. Negative effect of pitting on the cover of bare soil declined with increasing rainfall. Soil moisture was generally greater beneath pits than either control soils or soils between the pits (inter‐pits). Despite some positive effects on annual plant and litter cover, pitting effects were generally short lived, suggesting that a single pitting treatment may fail to achieve long‐term rehabilitation. Given that these field trials were conducted half a century ago under conditions of higher average rainfall, the prognosis for the success of pitting under current conditions of lower rainfall and higher temperature is generally poor.

Effectiveness of Sawdust and Rice Straw Mulch Strips to Control Runoff and Sediment Yield in Skid Trails

Abstract Mulches can be effective for reducing sediment loss and erosion from forest harvesting activities. This study evaluates the use of rice straw and sawdust as mulch covers for skid trails on clay loam soil. The treatments with three replications each included combinations of two levels of slope gradient (≤ 20% and > 20%), three types of mulch cover (bare soil, sawdust, and rice straw cover), three levels of mulching application schemes (1/3, 2/3, and 3/3 of the plot length), and two levels of surface cover rates (50% and 70%). Increasing levels of mulch cover had significantly lower runoff and sediment yields throughout the trails. The average runoff rates and sediment yield from the machine operating trails treated with sawdust cover (SC) (30.2 l and 2.7 g m-2) were lower than on trails covered with rice straw mulch (RSC) (36.8 l and 3.5 g m-2), which were, in turn, lower than on untreated bare soil (BS) trail sectors (48.80 l and 5.34 g m-2). Overall, mulching was more effective when applied over the entire plot length than over the 1/3 and 2/3 plots length strips, both in terms of runoff and sediment yield.

Native palms and trees mediate drought impacts on dry neotropical pastures

Abstract Dry forests are the most threatened biome across the global tropics. Despite their massive conversion into agricultural landscapes, local farmers often retain disperse trees and palms within grazing pastures. Understanding how on‐farm tree cover in the dry neotropics impacts the environmental and productive functions of pastures is key for biodiversity conservation and the development of climate‐resilient production systems. We studied tree composition of 23 dry cattle pastures in Yucatan, Mexico. We assessed the effects of palms, N2−fixing trees and non‐N2‐fixing trees on microsite environmental conditions, bare soil cover and the performance of grasses and woody plants in their understory during the dry and wet seasons of 2018 and 2019. We found that 45% of the total pool of tree species of the native dry forest is conserved in the pastures of Yucatan. Palms were the most abundant overstory functional group with a relative abundance of 45%, followed by N2‐fixing trees and non‐N2‐fixing trees with 33% and 22%. Palms and trees ameliorated the impact of seasonal drought on grasses but slowed down their recovery during the wet season. Palms had overall higher positive effects on grass greenness and height than N2‐fixing trees and non‐N2‐fixing trees and these effects were higher during the driest season. Palms decreased bare soil less than trees. Shrubs and tree seedlings tended to increase in the understory of all functional groups as the canopies of palms and trees became denser. Synthesis and applications. Climate warming and the alteration of precipitation regimes are expected to compromise pasture and cattle productivity worldwide. Our results show that fostering the maintenance of a diversity of native palms and trees has positive effects on the functioning of cattle pastures, especially during dry periods. A larger appreciation and understanding of the facilitative effects of remnant palms and trees on pastures during seasonal droughts may help developing more climate‐resilient livestock systems that maintain productivity during dry conditions while contributing also to tree biodiversity conservation.

The effect of grassland type and proximity to the city center on urban soil and vegetation coverage

Urban soils with associated vegetation are important components of urban ecosystems, providing multiple regulating and supporting ecosystem services. This study aimed to analyze the differences in the soil chemistry and vegetation of urban grasslands considering urbanization gradient and urban grassland type (UGT). We hypothesized that the chemical properties of soil, such as metal content, as well as vegetation traits, differ according to grassland type (lawns, grasslands in parks, grasslands on river embankments, and roadsides) and the location of grassland patches (city center versus peripheries). Our samples included 94 UGT patches which each patch represented by four square sampling plots sized 1 m2. The results showed high differentiation of measured traits unrelated to UGT and location. The exception was K content, with a relatively high concentration in lawns, and some metals (Cd, Cu, Pb, Zn), with higher concentrations in the city center than in the peripheries. We found two grassland patches located in the city center where the concentrations of Pb, Zn, and Cu exceeded the level authorized by Polish standards. In the case of vegetation traits, the variability was not structured considering the UGT and location of the patches, except for bare soil cover, which was higher in lawns in the city center compared to embankments in the peripheries. We observed correlations between vegetation traits and soil chemical properties. The vascular plant species richness decreased when N, P, and C content, along with an increase in grass cover and a decrease in herbs.

Understory Vegetation Response to Thinning Pinyon-Juniper Woodlands

Portions of the western United States, extending from west Texas to eastern Oregon, are thin to densely populated with juniper (Juniperus spp.) woodlands. Managing tree densities, such as through mechanical thinning, has numerous ecological implications for rangeland watersheds and wildlife habitat. The objective of this study was to determine vegetation response to juniper removal in a pinyon (Pinus edulis Engelm)− and juniper (Juniperus monosperma Engelm)− dominated landscape in north-central New Mexico. Herbaceous cover and standing crop were collected from six 1.00- to 1.35-ha catchments situated within the New Mexico State University (NMSU)−Santa Fe Ranch, Santa Fe County, New Mexico, before treatment and at 5 and 10 yr following juniper removal. About 70% of mature juniper trees were cut in 2009 in three of the catchments (treated) while the remaining catchments were left as controls (untreated). Herbaceous cover and standing crop were measured in 2009 (pretreatment), 2014, and 2019 (post treatment) to test our hypothesis that juniper reductions would significantly increase herbaceous standing crop. After 10 yr, gravel, grass, and forb cover were comparable in the treated and the untreated, whereas bare soil cover was significantly decreased in the treated (30% ± 2.5) compared with the untreated (42% ± 2.5). Litter cover in the treated was higher (18% ± 2.6) than the untreated (5% ± 2.6). Herbaceous standing crop significantly increased in the treated compared with the untreated. Standing crop of grass in the treated was two to three times greater than the untreated. Forb standing crop was not influenced by treatment but increased over time in both treatments. Study findings provide land managers with critical information regarding one-seed juniper clearing effects on herbaceous vegetation response in the warm-climate rangeland ecosystems of the southwestern United States.

Using NDVI-NSSI feature space for simultaneous estimation of fractional cover of non-photosynthetic vegetation and photosynthetic vegetation

The NDVI-NSSI feature space, which is constructed by the NPV soil separation index (NSSI) calculated from the two near-infrared bands and the normalized difference vegetation index (NDVI), is often represented as a triangle. It can be combined with the pixel decomposition method to achieve simultaneous estimation of the fractional cover of non-photosynthetic vegetation, photosynthetic vegetation, and bare soil (fNPV, fPV, and fBS, respectively). However, NDVI saturation in dense vegetation and the deleterious effects of shading due to topography are inevitable. To overcome this difficulty, we compare and analyze the NDVI-NSSI and enhanced vegetation index-NSSI (EVI-NSSI) triangular spaces and their differences when applying on the Sentinel-2A/B images. The results show that EVI-NSSI index combination still forms a triangle-like feature, with the triangle transformed from obtuse to acute, and it can be better used for pixel three-decomposition when PV cover is high. NDVI-NSSI underestimates (overestimates) fPV when PV cover is low (high). The NDVI-NSSI and EVI-NSSI produce significantly different estimates of fPV and fBS but similar estimates of fNPV and can be combined for estimation of a wider range of NPV cover in different seasons, including sparse or dense green vegetation scenarios.

A 29-year time series of annual 300 m resolution plant-functional-type maps for climate models

Abstract. The existing medium-resolution land cover time series produced under the European Space Agency's Climate Change Initiative provides 29 years (1992–2020) of annual land cover maps at 300 m resolution, allowing for a detailed study of land change dynamics over the contemporary era. Because models need two-dimensional parameters rather than two-dimensional land cover information, the land cover classes must be converted into model-appropriate plant functional types (PFTs) to apply this time series to Earth system and land surface models. The first-generation cross-walking table that was presented with the land cover product prescribed pixel-level PFT fractional compositions that varied by land cover class but that lacked spatial variability. Here we describe a new ready-to-use data product for climate modelling: spatially explicit annual maps of PFT fractional composition at 300 m resolution for 1992–2020, created by fusing the 300 m medium-resolution land cover product with several existing high-resolution datasets using a globally consistent method. In the resulting data product, which has 14 layers for each of the 29 years, pixel values at 300 m resolution indicate the percentage cover (0 %–100 %) for each of 14 PFTs, with pixel-level PFT composition exhibiting significant intra-class spatial variability at the global scale. We additionally present an updated version of the user tool that allows users to modify the baseline product (e.g. re-mapping, re-projection, PFT conversion, and spatial sub-setting) to meet individual needs. Finally, these new PFT maps have been used in two land surface models – Organising Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) and the Joint UK Land Environment Simulator (JULES) – to demonstrate their benefit over the conventional maps based on a generic cross-walking table. Regional changes in the fractions of trees, short vegetation, and bare-soil cover induce changes in surface properties, such as the albedo, leading to significant changes in surface turbulent fluxes, temperature, and vegetation carbon stocks. The dataset is accessible at https://doi.org/10.5285/26a0f46c95ee4c29b5c650b129aab788 (Harper et al., 2023).

Spatial Overlap and Habitat Selection of Corvid Species in European Cities

Understanding habitat and spatial overlap in sympatric species of urban areas would aid in predicting species and community modifications in response to global change. Habitat overlap has been widely investigated for specialist species but neglected for generalists living in urban settings. Many corvid species are generalists and are adapted to urban areas. This work aimed to determine the urban habitat requirements and spatial overlap of five corvid species in sixteen European cities during the breeding season. All five studied corvid species had high overlap in their habitat selection while still having particular tendencies. We found three species, the Carrion/Hooded Crow, Rook, and Eurasian Magpie, selected open habitats. The Western Jackdaw avoided areas with bare soil cover, and the Eurasian Jay chose more forested areas. The species with similar habitat selection also had congruent spatial distributions. Our results indicate that although the corvids had some tendencies regarding habitat selection, as generalists, they still tolerated a wide range of urban habitats, which resulted in high overlap in their habitat niches and spatial distributions.