Bare Soil Cover Research Articles

Effects of prescribed fire timing on vigor of the invasive forb sericea lespedeza (Lespedeza cuneata), total forage biomass accumulation, plant-community composition, and native fauna on tallgrass prairie in the Kansas Flint Hills.

The predominant grazing-management practice of the Kansas Flint Hills involves annual prescribed burning in March or April with postfire grazing by yearling beef cattle at a high stocking density from April to August. There has been a dramatic increase in sericea lespedeza (Lespedeza cuneata [Dumont] G. Don) coincident with this temporally focused use of prescribed fire in the Flint Hills region. The species is an aggressive invader and a statewide noxious weed in Kansas. Control has generally been attempted using repeated herbicide applications. This approach has not limited proliferation of sericea lespedeza and resulted in collateral damage to nontarget flora and fauna. Alternative timing of prescribed fire has not been evaluated for its control. Our objectives for this 4-yr experiment were to (1) document the effects of prescribed burning during early April, early August, or early September on vigor of sericea lespedeza, standing forage biomass, and basal cover of native graminoids, forbs, and shrubs and (2) measure responses to fire regimes by grassland bird and butterfly communities. Whole-plant dry mass, basal cover, and seed production of sericea lespedeza were markedly less (P < 0.01) in areas treated with prescribed fire in August or September compared with April. Forage biomass did not differ (P ≥ 0.43) among treatments when measured during July; moreover, frequencies of bare soil, litter, and total basal plant cover were not different (P ≥ 0.29) among treatments. Combined basal covers of C4 grasses, C3 grasses, annual grasses, forbs, and shrubs also did not differ (P ≥ 0.11) between treatments. Densities of grasshopper sparrow (Ammodramus savannarum), dickcissel (Spiza americana), and eastern meadowlark (Sturnella magna) were not negatively affected (P > 0.10) by midsummer or late-summer fires relative to early-spring fires. There were no differences (P > 0.10) in densities of grassland-specialist butterfly species across fire regimes. Under the conditions of our experiment, prescribed burning during summer produced no detrimental effects on forage production, desirable nontarget plant species, grassland birds, or butterfly communities but had strong suppressive effects on sericea lespedeza. Additional research is warranted to investigate how to best incorporate late-summer prescribed fire into common grazing-management practices in the Kansas Flint Hills.

A Modified Bare Soil Index to Identify Bare Land Features during Agricultural Fallow-Period in Southeast Asia Using Landsat 8

Bare soil is a critical element in the urban landscape and plays an essential role in urban environments. Yet, the separation of bare soil and other land cover types using remote sensing techniques remains a significant challenge. There are several remote sensing-based spectral indices for barren detection, but their effectiveness varies depending on land cover patterns and climate conditions. Within this research, we introduced a modified bare soil index (MBI) using shortwave infrared (SWIR) and near-infrared (NIR) wavelengths derived from Landsat 8 (OLI—Operational Land Imager). The proposed bare soil index was tested in two different bare soil patterns in Thailand and Vietnam, where there are large areas of bare soil during the agricultural fallow period, obstructing the separation between bare soil and urban areas. Bare soil extracted from the MBI achieved higher overall accuracy of about 98% and a kappa coefficient over 0.96, compared to bare soil index (BSI), normalized different bare soil index (NDBaI), and dry bare soil index (DBSI). The results also revealed that MBI considerably contributes to the accuracy of land cover classification. We suggest using the MBI for bare soil detection in tropical climatic regions.

Cattle Grazing Exclusion Increases Basal, Crown and Mulch Cover in the Sierra de Órganos National Park, Sombrerete, Zacatecas, Mexico

Objective: To estimate the effects of cattle grazing exclusion on soil and vegetation conditions in grasslands of Sierra de Órganos National Park (SONP), Sombrerete, Zacatecas, Mexico. Design/Methodology/Approach: Four transects with cattle grazing exclusion were strategically established in SONP grasslands. In each transect the basal, crown and organic mulch cover, soil cover, bare soil, and the form of the autumn plant were measured from 2008, 2010, 2012 and 2014. Results: Cattle grazing exclusion caused an increase in basal, crown and organic mulch cover, soil cover, as well as over- rested plants and deteriorated plants; bare soil cover and the percentage of normal plants decreased. Study Limitations/Implications: Increase of organic mulch cover implies the accumulation of combustible material that represents a potential risk of fire occurring in the SONP. Findings/Conclusions: Increase of organic mulch, over-rested plants and deteriorated plants shows that SONP grasslandsare transiting to a less stable ecological state.

Temperate forests respond in a non-linear way to a population gradient of wild deer

Abstract Wild deer exert strong top–down control on forest composition by browsing on palatable trees, and these effects are exacerbated as red, fallow, and roe deer populations increase in northern temperate forests. However, the relationship between deer abundance and plant recruitment remains poorly documented. Here, we combined camera trap and vegetation plot data to quantify the shape of the relationship between habitat utilization by deer (red, fallow and roe deer) with different components of the forest understory in ten sites distributed across a temperate mixed forest in the Veluwe, the Netherlands. The list of forest attributes included the density, richness and diversity of saplings, the proportion of conifers to broadleaves, the number of browsed broadleaves and conifers, the forest basal area, the understory cover of shrubs, moss and bare soil and the depth of the litter layer. When applying General Linear Mixed Models to those camera trap data, six of the eleven forest variables were related to the utilization level (UL) by deer. With increasing UL by fallow deer, there was a decrease in sapling species richness (β = −0.26). With increasing UL by red deer, there was a decrease in litter depth (β = −0.14) and an increase in browsed broadleaf stems (β = 0.40). With increasing UL by roe deer, there was a decrease in species richness of sapling plants (β = −0.26), Shannon diversity (β = −0.11) and shrub cover (β = −0.36), whereas there was an increase in stem density (β = 0.06). When combining all deer species into one guild, a negative relation was found between UL by deer and sapling richness (β = −0.21), diversity (β = −0.09) and litter depth (β = −0.14) and a positive relation with sampling density (β = 0.04). The relationship between UL by deer and different forest attributes followed a linear log10 shape. When back transforming, the response was curvilinear with large changes at a low UL and small changes when the UL was high. Yet, the exact shape of the curve varied according to (a) biotic factors specific to each study location. The conservation of temperate forests can benefit from limiting the size of deer populations and the time deer spend browsing in forest patches with high biodiversity value.

Fire frequency affects fire behavior in open savannas of the Cerrado

Fire is an environmental factor that helps in shaping plant communities by influencing their structure and function. Frequency is an important component of the fire regime. In tropical savannas, fire frequency is high, mostly owing to the high production and accumulation of fuel, which mainly comprising grasses, the dominant growth form in the Cerrado (Brazilian savanna) open physiognomies. We evaluated how the quantity, quality, and horizontal and vertical distribution of fuel influence fire behavior. We performed fire experiments with different fire frequencies (annual and biennial, from 2013 to 2017) in open savannas of the Cerrado (Central Brazil). Before each experimental fire, the quantity and distribution of the fuel as well as the moisture content and estimated the percentages of bare soil, dead biomass, and grass cover in the community were evaluated. During the experiments, we measured wind speed, air temperature, and fire behavior parameters, such as flame height, fire propagation rate, flame temperature, and residence time of the fire. Finally, we calculated fire intensity. Annually burned plots showed a lower fuel load and higher percentages of bare soil than biennially burned plots. Regarding the fire parameters, the intensity, flame height, maximum temperatures, and residence time were lower in the annually burned plots than in biennially burned plots. After four years of fire treatment, the annual fire frequency changed the vegetation structure, and the fire parameters responded to these changes. Thus, we conclude that the fuel load distribution influences fire behavior alongside the quantity of fuel in open savannas. The percentage of soil covered by each of the community structural components influences fire temperatures and residence time, which in turn affects fire severity. These findings allow for a more precise evaluation of the fire effects on plant communities facing fire behavior and help in developing better management plans.

Quantifying plant-soil-nutrient dynamics in rangelands: Fusion of UAV hyperspectral-LiDAR, UAV multispectral-photogrammetry, and ground-based LiDAR-digital photography in a shrub-encroached desert grassland

Rangelands cover 70% of the world's land surface, and provide critical ecosystem services of primary production, soil carbon storage, and nutrient cycling. These ecosystem services are governed by very fine-scale spatial patterning of soil carbon, nutrients, and plant species at the centimeter-to-meter scales, a phenomenon known as “islands of fertility”. Such fine-scale dynamics are challenging to detect with most satellite and manned airborne platforms. Remote sensing from unmanned aerial vehicles (UAVs) provides an alternative option for detecting fine-scale soil nutrient and plant species changes in rangelands tn0020 smaller extents. We demonstrate that a model incorporating the fusion of UAV multispectral and structure-from-motion photogrammetry classifies plant functional types and bare soil cover with an overall accuracy of 95% in rangelands degraded by shrub encroachment and disturbed by fire. We further demonstrate that employing UAV hyperspectral and LiDAR fusion greatly improves upon these results by classifying 9 different plant species and soil fertility microsite types (SFMT) with an overall accuracy of 87%. Among them, creosote bush and black grama, the most important native species in the rangeland, have the highest producer's accuracies at 98% and 94%, respectively. The integration of UAV LiDAR-derived plant height differences was critical in these improvements. Finally, we use synthesis of the UAV datasets with ground-based LiDAR surveys and lab characterization of soils to estimate that the burned rangeland potentially lost 1474 kg/ha of C and 113 kg/ha of N owing to soil erosion processes during the first year after a prescribed fire. However, during the second-year post-fire, grass and plant-interspace SFMT functioned as net sinks for sediment and nutrients and gained approximately 175 kg/ha C and 14 kg/ha N, combined. These results provide important site-specific insight that is relevant to the 423 Mha of grasslands and shrublands that are burned globally each year. While fire, and specifically post-fire erosion, can degrade some rangelands, post-fire plant-soil-nutrient dynamics might provide a competitive advantage to grasses in rangelands degraded by shrub encroachment. These novel UAV and ground-based LiDAR remote sensing approaches thus provide important details towards more accurate accounting of the carbon and nutrients in the soil surface of rangelands.

Modelling and Delineation of Hydrocarbon Micro - Seepage Prone Zones on Soil and Sediment in Ugwueme, South Eastern Nigeria with Soil Adjustment Vegetation Index (SAVI)

Remote Sensing is an excellent tool in monitoring, mapping and interpreting areas, associated with hydrocarbon micro-seepage. An important technique in remote sensing known as the Soil Adjusted Vegetation Index (SAVI), adopted in many studies is often used to minimize the effect of brightness reflectance in the Normalized Difference Vegetation Index (NDVI), related with soil in areas of spare vegetation cover, and mostly in areas of arid and semi–arid regions. The study aim at analyzing the effect of hydrocarbon micro – seepage on soil and sediments in Ugwueme, Southern Eastern Nigeria, with SAVI image classification method. To achieve this aim, three cloud free Landsat images, of Landsat 7 TM 1996 and ETM+ 2006 and Landsat 8 OLI 2016 were utilized to produce different SAVI image classification maps for the study. The SAVI image classification analysis for the study showed three classes viz Low class cover, Moderate class cover and high class cover. The category of high SAVI density classification was observed to increase progressive from 31.95% in 1996 to 34.92% in 2006 and then to 36.77% in 2016. Moderately SAVI density classification reduced from 40.53% in 1996 to 38.77% in 2006 and then to 36.96% in 2016 while Low SAVI density classification decrease progressive from 27.51% in 1996 to 26.31% in 2006 and then increased to 28.26% in 2016. The SAVI model is categorized into three classes viz increase, decrease and unchanged. The un – changed category increased from 12.32km2 (15.06%) in 1996 to 17.17 km2 (20.96%) in 2006 and then decelerate to 13.50 km2 (16.51%) in 2016. The decrease category changed from 39.89km2 (48.78%) in 1996 to 40.45 km2 (49.45%) in 2006 and to 51.52 km2 (63.0%) in 2016 while the increase category changed from 29.57km2 (36.16%) in 1996 to 24.18 km2 (29.58%) in 2006 and to 16.75 km2 (20.49%) in 2016. Image differencing, cross tabulation and overlay operations were some of the techniques performed in the study, to ascertain the effect of hydrocarbon micro - seepage. The Markov chain analysis was adopted to model and predict the effect of the hydrocarbon micro - seepage for the study for 2030. The study expound that the SAVI is an effective technique in remote sensing to identify, map and model the effect of hydrocarbon micro - seepage on soil and sediment particularly in areas characterized with low vegetation cover and bare soil cover.

Both Mature Patches and Expanding Areas of Juniperus thurifera Forests Are Vulnerable to Climate Change But for Different Reasons

Research Highlights: Water use efficiency (WUE) varied along a gradient of Juniperus thurifera (L.) forest expansion, being higher in recently colonised areas. Background and Objectives: WUE is a classic physiological process of plants that reflects the compromise between carbon assimilation and water loss and has a profound influence on their performance in water-limited environments. Forest expansion in Mediterranean regions associated with land abandonment can influence the WUE of plants due to the existence of two opposing gradients: one of favourable–unfavourable environmental conditions and another one of increased–decreased intraspecific competition, the former increasing and the latter decreasing towards the expanding front. The main objective of this study was to elucidate how the WUE of Juniperus thurifera varied along the stages of forest expansion and to provide insight on how this variation is influenced by intraspecific competition and abiotic factors. Materials and Methods: Seventeen plots at different distances from the mature forest core were selected at three sites located in the centre of the Iberian Peninsula. For 30 individuals within each plot, we measured biometric characteristics, age, tree vigour, and C/N ratio in leaves, and the leaf carbon isotope signature (δ13C (‰)) as a proxy for WUE. Around each individual, we scored the percentage cover of bare soil, stoniness, conspecifics, and other woody species. Results: WUE of J. thurifera individuals varied along the forest expansion gradient, being greater for the individuals at the expanding front than for those at the mature forest. WUE was influenced by the cover of conspecifics, tree age, and C/N ratio in leaves. This pattern reveals that less favourable environmental conditions (i.e., rocky soils and higher radiation due to lower vegetation cover) and younger trees at the expanding front are associated with increased WUE. The increased cover of conspecifics decreases irradiance at the mature forest, involving milder stress conditions than at the expanding front. Conclusions: Lower WUE in mature forests due to more favourable conditions and higher WUE due to abiotic stress at expanding fronts revealed high constraints on water economy of this tree species in these two contrasting situations. Climate change scenarios bringing increased aridity are a serious threat to Juniperus thurifera forests, affecting both mature and juvenile populations although in different ways, which deserve further research to fully unveil.

Grazing by wild red deer maintains characteristic vegetation of semi‐natural open habitats: Evidence from a three‐year exclusion experiment

AbstractQuestionsConservation management of semi‐natural open habitats today has to compensate for the decline of traditional practices of agricultural land use. Can wild and free‐ranging ungulates, such as red deer, contribute to the preservation of characteristic open habitat plant communities?LocationGrafenwöhr military training area, Germany.MethodsWe set up a grazing exclusion experiment in grasslands (lowland hay meadows) and heathlands (European dry heaths) and monitored structural vegetation characteristics (sward height, bare soil, biomass contribution of Calluna vulgaris, litter height, woody species individuals) in open and fenced plots within a three‐year study period. We compared plant species richness, diversity and community composition before and after the experimental period.ResultsIn grasslands, plant species diversity was significantly reduced in fenced compared to open plots and in both habitat types, plant community composition responded to the exclusion of red deer. When fences prevented red deer grazing, increasing height of sward and litter in both habitat types as well as reduced cover of bare soil and increasing number of woody plant individuals in heathlands indicated beginning succession. In annually mown grasslands, where the regrowth provides attractive forage for red deer, the differences between open and fenced plots were most pronounced.ConclusionsOverall, our results indicate that the conservation value of the studied open habitat types started to decrease after red deer exclusion. Grazing by wild red deer can hence provide benefits to vegetation structure and diversity and could therefore enrich the set of tools available for the conservation management of semi‐natural open vegetation types.

Effect of Invasive Alien Species on the Co-Occurrence Patterns of Bryophytes and Vascular Plant Species—The Case of a Mediterranean Disturbed Sandy Coast

Cross-taxon analyses can explain patterns of interaction between taxa and their application in conservation studies can drive management actions. In a coastal sand dune system characterized by a high human pressure, we explored the co-occurrence patterns between vascular plants and bryophytes, with a focus on how the occurrence of invasive alien species (IAS) can affect those taxa and their relationships. Species congruences were evaluated at the community level considering taxonomic and functional diversities. Predictive co-correspondence analysis (Co-CA) was applied to quantify the strength of vascular plant communities in predicting bryophytes species composition. The relationship between the composition of vascular plants and bryophytes was significant, even if weak. Altitude and percentage of bare soil cover are the environmental variables exerting greater influence on the two taxa. The presence of IAS affects communities in an opposite way: for vascular plants, species richness increases with the presence of invasive alien species; for bryophytes, IAS’s presence has a low but significant negative influence, both on species richness and in terms of functional diversity. Results give elements for future studies on the effect of IAS on the bryophytes colonizing coastal sand dunes.

Long- Term Estimation of Actual Crop Evapotranspiration Based on Satellite Data Analysis

Abstract Arid regions conditions are overwhelmed with various water scarcities problems, however, one of the reasons of this problems may be due to climate change effect. Moreover, under these conditions, water is a crucial key for any agricultural development processes. Therefore, the aim of this study was to estimate the actual evapotranspiration of different crop pattern under climate change conditions based on satellite data analysis for long time effect (1985 – 2019). The study area is considered active agricultural area , the percentage of bare soil and vegetation cover were (86.9%) and (12.7) in 1985 while in 2019 the percentage of bare soil sharply decrease so it was reached to (34.1%) but the percentage of d vegetation cover was (64.2%). Satellite images have been gathered and analyzed from Landsat TM, Landsat ETM+ and Landsat OLI, through the studied period. However, Normalized Difference Vegetation Index (NDVI) had been obtained for estimating the actual evapotranspiration under the studied area conditions. Planning and management of water use by irrigation agriculture are especially important in an arid and semiarid areas like the study area so the understanding of the Actual Evapotranspiration (AET) prerequisite for better management and conservation of agriculture water, By determine the area of every crop pattern, actual evapotranspiration (AET) was estimated by m3/ha/day and m3/total cultivated area/day. Data analysis indicate that the minimum and maximum NDVI values had been ranged from 0.7 and 0.9 for mango trees from 1985 and 2019, 0.5 and 0.8 for olive trees, 0.4 and 0.8 for forests and 0.7 for annual crops within the studied period from 1985 to 2019. The minimum and maximum actual evapotranspiration under different crop pattern from 1985 to 2019 ranged from 2.6 and 4.9 mm/day, 1.7 and 4 mm/day, 1 to 4.4 mm/day and 2.7 mm/day for the same crop pattern respectively. This study can assist in water management practices for better irrigation management.

Do Fire Regime Attributes Affect Soil Biochemical Properties in the Same Way under Different Environmental Conditions?

Global change is altering fire frequency and severity in many regions across the world. In this work, we studied the impact of different frequency and severity regimes on the soil biochemical properties in burned areas with different environmental conditions. We selected three sites dominated by pine ecosystems along a Mediterranean-Transition-Oceanic climatic gradient, where we determined the fire frequency, and severity of the last wildfire. Four years after the last wildfire, we established 184 4 m2 plots. In each plot, we collected a composed soil sample from a 3 cm depth, and measured several ecological variables potentially affected by the fire frequency and severity (cover of bare soil, cover of fine and coarse plant debris, cover of vegetation, and vegetation height). From each soil sample, we analyzed the enzymatic activities corresponding to the biogeochemical cycles of carbon, nitrogen, and phosphorus (β-glucosidase, urease, and acid-phosphatase, respectively), and the microbial biomass carbon. The results indicated that fire frequency only played a significant role in soil biochemical properties at the Mediterranean and Transition sites. Specifically, we found that increases in frequency contributed to increased urease and phosphatase activities (at the Transition site), as well as microbial biomass carbon (at the Mediterranean and Transition sites). In relation to burn severity, we found opposite patterns when comparing the Mediterranean and Oceanic sites. Specifically, increased severity significantly decreased β-glucosidase, urease, and microbial biomass carbon at the Mediterranean site, whereas at the Oceanic one, severity significantly increased them. Burn severity also decreased microbial biomass carbon at the Transition site. Our results also indicated that, overall, fire frequency determined the studied ecological variables at the Mediterranean and Transition sites, but clear indirect effects on biochemical properties due to changes in ecological variables were not found. This study adds to the knowledge on the impact of shifts in fire regimes on soils in the current context of change.

Not all fuel‐reduction treatments degrade biocrusts: Herbicides cause mostly neutral to positive effects on cover of biocrusts

AbstractIn response to increasing fire, fuel‐reduction treatments are being used to minimize large fire risk. Although biocrusts are associated with reduced cover of fire‐promoting, invasive grasses, the impact of fuel‐reduction treatments on biocrusts is poorly understood. We use data from a long‐term experiment, the Sagebrush Steppe Treatment Evaluation Project, testing the following fuel‐reduction treatments: mowing, prescribed fire, and the use of two herbicides: one commonly used to reduce shrub cover, tebuthiuron, and one commonly used to combat cheatgrass, imazapic. Looking at sites with high cover of biocrusts prior to treatments, we demonstrate positive effects of the herbicide, tebuthiuron on lichens with an increase in cover of 10% and trending towards slightly negative effects on moss cover. Across plots, imazapic trended towards a decrease in lichen and moss cover without being statistically significant. Mowing and prescribed fire reduced cover of mosses, with the latter leading to greater declines across sites (declines of 18% vs. 32%). Reductions in moss cover mirrored gains in cover of bare soil, which is associated with increased risk of invasion by grasses responsible for increasing fire risk. We demonstrate that the use of herbicides simultaneously reduces fuels and maintains greater cover of lichens and mosses compared with other fuel‐reduction treatments, possibly reducing risk of invasion by annual grasses that are responsible for increasing fire risk.

The MODIS Global Vegetation Fractional Cover Product 2001–2018: Characteristics of Vegetation Fractional Cover in Grasslands and Savanna Woodlands

Vegetation Fractional Cover (VFC) is an important global indicator of land cover change, land use practice and landscape, and ecosystem function. In this study, we present the Global Vegetation Fractional Cover Product (GVFCP) and explore the levels and trends in VFC across World Grassland Type (WGT) Ecoregions considering variation associated with Global Livestock Production Systems (GLPS). Long-term average levels and trends in fractional cover of photosynthetic vegetation (FPV), non-photosynthetic vegetation (FNPV), and bare soil (FBS) are mapped, and variation among GLPS types within WGT Divisions and Ecoregions is explored. Analysis also focused on the savanna-woodland WGT Formations. Many WGT Divisions showed wide variation in long-term average VFC and trends in VFC across GLPS types. Results showed large areas of many ecoregions experiencing significant positive and negative trends in VFC. East Africa, Patagonia, and the Mitchell Grasslands of Australia exhibited large areas of negative trends in FNPV and positive trends FBS. These trends may reflect interactions between extended drought, heavy livestock utilization, expanded agriculture, and other land use changes. Compared to previous studies, explicit measurement of FNPV revealed interesting additional information about vegetation cover and trends in many ecoregions. The Australian and Global products are available via the GEOGLAM RAPP (Group on Earth Observations Global Agricultural Monitoring Rangeland and Pasture Productivity) website, and the scientific community is encouraged to utilize the data and contribute to improved validation.

Andean rolling mosses gather on stone pavements: Geoecology of Grimmia longirostris Hook. in a high periglacial páramo

Rolling mosses of Grimmia longirostris Hook. were studied in Páramo Piedras Blancas, a high Andean area in Venezuela, using a geoecological research framework focused on interactions between geomorphic, ecological, and soil processes. Spatial patterns of mosses were analyzed downslope from granitic outcrops on three slopes at 4445–4480 m elevation. Fragments from epilithic mosses on the apex outcrops were the source of other mosses. Distance of moss transport below rocks was measured at all sites; mosses on the gentlest (≤4°), 34 m-long, slope were censused along a belt transect on 17 contiguous quadrats; density of moss growth forms, stone size, percent of bare-soil cover, and surface soil properties were determined. Surface clast morphology and profile characteristics of a periglacial stone pavement at the slope base were also examined. Mosses on this site included four growth forms: epilithic mosses on outcrops; mobile, rolling moss balls; epilithic mosses on loose clasts; and unattached elongated mosses. Moss balls (density: ≤0.87 mosses/m2) lay on upper-transect plots over bare soils (≤92% cover) disturbed by needle ice. Soils here contained ~43–51% fine grains (≤0.063 mm) and 2.9–5.9% organic matter; this made them exceptionally prone to ice segregation and needle-ice formation. Lower-transect plots showed 78–100% stone cover—cobbles and blocks—but little exposed soil; mosses attached to loose clasts were exceedingly abundant (≤31/m2) on this section. Unattached elongated mosses, often resting along boundaries between adjacent stones, were also common (≤5.5/m2). The basal stone pavement showed a shallow (≤7 cm) rock veneer over a 24 cm-thick profile with exceptionally fine soil—up to 83.2% fine grains, ≤8.6% organic matter.A conceptual developmental model emphasizing the close linkages among the spatial distribution of mosses, patterns of surface clasts, and characteristics of soils and stone pavements is proposed: (i) Stones and mosses are transported downhill by needle ice and other frost agents; moss fragments gradually assume a globular shape, forming rolling moss balls. (ii) When these reach the stones and pavements on the basal slope, they cannot be transported any further, and remain immobile. (iii) Some mosses come to rest along boundaries between stones and develop into unattached elongated mosses or, (iv) they may become gradually attached to cobbles on the stone pavement; clasts with epilithic mosses can continue moving toward the basin floor. (v) Some mosses become fragmented and provide a source of elongated mosses, or remain partially attached to clasts. Stone pavements develop by a combination of rock accumulation following needle-ice transport, rock upheaving and sorting by ground frost, slope runoff, and downward soil illuviation.

Breeding habitat and nest-site selection by an obligatory "nest-cleptoparasite", the Amur Falcon Falco amurensis.

The selection of a nest site is crucial for successful reproduction of birds. Animals which re‐use or occupy nest sites constructed by other species often have limited choice. Little is known about the criteria of nest‐stealing species to choose suitable nesting sites and habitats. Here, we analyze breeding‐site selection of an obligatory “nest‐cleptoparasite”, the Amur Falcon Falco amurensis. We collected data on nest sites at Muraviovka Park in the Russian Far East, where the species breeds exclusively in nests of the Eurasian Magpie Pica pica. We sampled 117 Eurasian Magpie nests, 38 of which were occupied by Amur Falcons. Nest‐specific variables were assessed, and a recently developed habitat classification map was used to derive landscape metrics. We found that Amur Falcons chose a wide range of nesting sites, but significantly preferred nests with a domed roof. Breeding pairs of Eurasian Hobby Falco subbuteo and Eurasian Magpie were often found to breed near the nest in about the same distance as neighboring Amur Falcon pairs. Additionally, the occurrence of the species was positively associated with bare soil cover, forest cover, and shrub patches within their home range and negatively with the distance to wetlands. Areas of wetlands and fallow land might be used for foraging since Amur Falcons mostly depend on an insect diet. Additionally, we found that rarely burned habitats were preferred. Overall, the effect of landscape variables on the choice of actual nest sites appeared to be rather small. We used different classification methods to predict the probability of occurrence, of which the Random forest method showed the highest accuracy. The areas determined as suitable habitat showed a high concordance with the actual nest locations. We conclude that Amur Falcons prefer to occupy newly built (domed) nests to ensure high nest quality, as well as nests surrounded by available feeding habitats.

Biocrusts are associated with increased plant biomass and nutrition at seedling stage independently of root-associated fungal colonization

Plant-soil interactions are important drivers of plant productivity and community structure. Biocrusts – soil surface-dwelling biotic communities comprised of cyanobacteria, fungi, bryophytes, and/or lichens - are widespread in drylands globally. Biocrusts are described as “mantles of fertility” and have been shown to have facilitative, but species-specific effects on plant productivity. Yet, patterns and mechanisms underlying biocrust facilitation of plant productivity remain unclear. Using mesocosms with bare soil versus biocrust cover we investigated the effects of biocrusts on plant biomass allocation, leaf chemistry and colonization by root-associated fungi. Plant responses to biocrust presence were species-specific. Overall, biocrusts were associated with increased plant biomass and/or leaf N concentrations in Elymus elymoides, Bouteloua gracilis and Zea mays. However, plants grown in biocrusts had lower root-associated fungal colonization compared to bare soils. Biocrusts were associated with increased plant biomass and leaf N. Yet, plant growth responses to biocrusts were not correlated with differences in root-associated fungal colonization between soil mesocosm types. Understanding species-specificity in biocrust facilitation of plant growth may have important implications for understanding plant community structure in dryland ecosystems.

Using broadband crop residue angle index to estimate the fractional cover of vegetation, crop residue, and bare soil in cropland systems

Accurate estimation of fractional vegetation cover (FVC), crop residue cover (CRC), and bare soil (BS) in agricultural and vegetation-soil ecosystems is critically important. The traditional triangular space method uses a CRC spectral index (SI) and vegetation SI to create a two-dimensional scatter map in which the three vertices represent pure vegetation (FVC = 1), crop residue (CRC = 1), and bare soil (BS = 1). With this method, the CRC, FVC, and BS of each pixel are calculated based on their spatial locations in the triangular space. In practice, soil moisture and crop residue moisture (SM-CRM) affects the values of CRC spectral indices (SIs) for pure crop residue and soil, thereby reducing the accuracy of broadband remote sensing estimates of CRC, FVC, and BS. In the current work, we propose a new method for estimating fractional cover that uses a broadband spectral angle index (BAI) to estimate CRC. The proposed BAI is the included angle between (i) the line from the reflectance at band a to the reflectance at band b and (ii) the line from the reflectance at band b to the reflectance at band c, where bands a and b represent the VIS or NIR bands, respectively, and band c represents the SWIR1 or SWIR2 of the broadband remote sensing band. The proposed BAI method can mitigate the effects of soil and crop residue moisture content on spectral reflectance. This study evaluates proposed BAIs to estimate CRC and BAI-NDVI triangular space method to estimate CRC, FVC, and BS in cropland where water content varies greatly. Several different BAIs were validated using both laboratory-based measurements and field-based experiments using Sentinel-2 multispectral instrument imaging. We used two laboratory-based treatments (mixed spectral reflectance of dry, saturated soil and crop residue and the mixed spectral reflectance of winter wheat leaf and dry, saturated soil and crop residue) to analyze the response of BAIs to CRC, SM-CRM, FVC, and vegetation water content. Next, we evaluated the performance of different BAIs in determining CRC based on the mixed spectral reflectance of crop residue and soil, as well as the performance of the BAI-NDVI triangular space method and linear spectral unmixing analysis to estimate CRC, FVC, and BS from mixed spectral reflectance measurements. Our results indicate that the proposed methods reduce the influence of moisture on broadband CRC SIs, provide accurate estimates of cropland CRC and fractional estimates of CRC, FVC, and BS, and may be applied in croplands where soil and crop residue moisture content varies greatly.

Vegetation management intensity and landscape diversity alter plant species richness, functional traits and community composition across European vineyards

Land-use intensification at the field and landscape scale is a strong driver for declining biodiversity and ecosystem service provision. Vineyards are characterised by non-productive inter-rows, which could potentially host diverse plant communities. Mulching, tillage or herbicides are used to mitigate the competition between vines and the inter-row vegetation. As plant species with the same set of functional traits will respond similarly to environmental filters like management measures, knowledge about plant trait–environment-relations can be used to predict community and ecosystem processes which are essential for preserving ecosystem services like soil erosion mitigation. We hypothesized that higher vegetation management intensity reduces plant (functional) diversity, changes functional traits and community composition.Across Europe, four viticultural regions in Austria, France, Spain and Romania, which comprised 78 vineyards differing in vegetation management intensity (bare soil, temporary and permanent vegetation cover), were selected for sampling vascular plant diversity. Around each vineyard, the surrounding landscape composition and landscape diversity was investigated within a 750m radius. Rao's quadratic entropy as a measure of functional diversity was calculated based on a selection of plant functional traits. The effects of management and landscape variables on species richness, functional traits, functional diversity and vegetation cover were analysed by generalized linear mixed models and random forests (RF). Furthermore, plant community composition was analysed with non-metric multidimensional scaling (NMDS).Higher management intensities resulted in lower species richness, functional diversity and vegetation cover. The country with the related divergent edaphoclimatic conditions was a significant factor affecting most diversity and functional trait parameters, whereas landscape diversity increased plant species richness only slightly. Vegetation management intensity had the highest explanatory power for species richness, functional diversity and most functional traits according to RF analysis. Consequently, plant functional traits like a higher coverage of ruderals and annuals could be clearly related to bare soil management. Furthermore, the type of cover crops influenced the relationship between annual and perennial plant species, Grime plant strategy types and species diversity. Accordingly, NMDS showed a separation between permanent vegetation cover and bare soil vineyards. The overall positive effect of extensive management and the use of diverse cover crops or spontaneous vegetation in vineyard inter-rows should be better implemented in agricultural policies to support both, biodiversity and ecosystem provision.

Post‐fire soil erosion mitigation at the scale of swales using forest logging residues at a reduced application rate

AbstractMulching with forest residues has proved to be highly effective in reducing post‐fire soil losses at the plot scale. However, its effectiveness has not been quantified at the application rates that are typically used in operational post‐fire land management (2–3 Mg ha‐1 using straw), as well as at scales larger than 100 m2. The present study compared post‐fire erosion rates for six convergent hillslopes or swales of 500 to 800 m2, three of which were left untreated while the other three were mulched immediately after the fire with shredded eucalypt bark at a rate of 2.4 Mg ha‐1. Erosion rates were monitored at irregular intervals during the first three post‐fire years, whilst ground cover was assessed yearly. Selected topsoil properties (0–2 cm) such as organic matter content and aggregate stability were determined at a single occasion – two years after the wildfire, for three micro‐environments separately: bare soil, and under mulch/litter and vegetation. Soil losses on the untreated swales decreased with post‐fire year from 2.2 to 0.4 and 0.11 Mg ha‐1 yr‐1 (respectively for the first, second and third post‐fire years), while the mulched swales produced 84%, 77% and 38% less soil losses than the untreated swales.Soil losses also depended on slope aspect, with the north‐facing swales producing less erosion than the west‐facing ones. This could be linked to their significant differences in bare soil, vegetation and stone cover, or a combination thereof. The type of micro‐environment also played a significant role in topsoil properties (stone content, bulk density, resistance to penetration/shear stress, porosity and organic matter content). The present results add to the increasing evidence that forest residues should be duly considered for operational post‐fire land management. Forest residues were highly effective in reducing erosion from swales at application rates as low as the typical 2 Mg ha‐1 of post‐fire straw mulch. © 2019 John Wiley &amp; Sons, Ltd. © 2019 John Wiley &amp; Sons, Ltd.