Vegetation Landscape Research Articles

SSA research on electromagnetic scattering in arid zone

Abstract This paper investigates the electromagnetic scattering characteristics in arid zone and proposes methods for monitoring and improving ecological agriculture, vegetation landscape and desertification in arid zone, based on the modified small slope approximation (SSA) electromagnetic scattering model. The dielectric properties of dryland soils are studied in the paper, and the variation curves of soil dielectric constant with humidity and electromagnetic frequency are plotted. In order to reproduce the geomorphological features of the dryland areas, a two-dimensional geometric model of the ground environment is established using Monte Carlo methods combined with Gaussian spectral functions. An algorithm model based on the modified SSA is developed, and the algorithm was validated and analyzed to verify its reliability. In the simulations, the southeastern region of Ejina Banner, Inner Mongolia was taken as a typical arid region, and the simulation parameters are obtained from the actual measurement data of the region. The study finds that the electromagnetic scattering characteristics of the arid zone are influenced by soil water content, ground roughness and incident wave electromagnetic frequency, and there is regularity. The results of this paper can be effectively combined with remote sensing technology to contribute to many researches on soil moisture inversion and ecological condition of vegetation, which are important in many aspects such as irrigation control, ecological research, vorticity covariance, and climatology of slope stability.

Combining optical and microwave remote sensing for assessing gullies in human-disturbed vegetated landscapes

The accurate assessment of the gully is key to stopping soil loss, especially in agricultural landscapes. This study aims to combine freely distributed remote sensing data for the evaluation of gullies located in a tropical watershed with a history of cattle production. Eighty-four vectorized gullies were defined in the Pirizal River basin, part of the highly eroded Upper Taquari (Brazil). We examined 56 variables from Sentinel-1/2 and ALOS-PALSAR-1 datasets, including SAR products and optical products like textures, water, vegetation, and terrain indices. Following a correlation analysis, 19 variables were selected for mapping in a Random Forest classifier by considering samples of active (soil) and stabilized (vegetation) pixels. The method reached an overall accuracy of 89%, in which soil abundance was responsible for 44% of the overall importance in the classification. Optical indices and texture products outperformed SAR products, whose importance represented only 14%. In the studied river basin, about 63% of the gullies were found stabilized, 30% in the process of stabilization, and only 7% active. The method proved effective, low cost, and promptly replicable to general river basins with gullies, mainly those in the tropics where vegetation has a significant role in soil loss control.

Bats and birds control tortricid pest moths in South African macadamia orchards

The global macadamia industry is growing rapidly, and the world's biggest macadamia nut producer, South Africa, is continuously expanding its production. Insect pest mitigation and research are mainly focused on the damage caused by heteropteran pest species, whereas the damage associated with lepidopteran tortricid moths in South African macadamia orchards is understudied. Here we explore the potential biocontrol of tortricid moths by natural predators through full exclosure of bats and birds, daytime only exclosure (birds), night exclosure (bats and possibly nocturnal birds), and control treatments. The exclusion experiment showed that bats and birds are effective natural predators, which can reduce tortricid moth damage by more than 35%. Impacts of biocontrol are higher at natural orchard edges next to natural or semi-natural vegetation, compared to human-modified edges (12.4% damage decrease in 2017, 10.6% in 2018). At the full exclosure, there was no difference in damage between natural orchard edges and human-modified edges, in both years of our study (56.5% vs. 56.6% in 2017, 19% vs. 18.5% in 2018). We recommend increased preservation efforts of more heterogeneity with semi-natural vegetation in agricultural landscapes to ensure the conservation of biocontrol services, as their loss can be expected to result in significant negative impact on macadamia production. This biological pest control can be used as part of integrated pest management to reduce the reliance on chemical pesticides, so decreasing sustainability challenges.

Spatio-temporal Variation in PM2.5 Concentration and Its Relationship with Vegetation Landscape Patterns in Typical Economic Zones in China from 2000 to 2020

This study explored the temporal and spatial variation in PM2.5 concentration and its relationship with the vegetation landscape pattern in three typical economic zones in China, which is of great significance for regional PM2.5pollution control and atmospheric environmental protection. In this study, the pixel binary model, Getis-Ord Gi* analysis, Theil-Sen Median analysis, Mann-Kendall significance test, Pearson correlation analysis, and multiple correlation analysis were used to explore the spatial cluster and spatio-temporal variation in PM2.5 and its correlation with the vegetation landscape index in the three economic zones of China on the basis of PM2.5 concentration data and MODIS NDVI data set. The results showed that PM2.5 in the Bohai Economic Rim was mainly dominated by the expansion of hot spots and the reduction in cold spots from 2000 to 2020. The proportion of cold spots and hot spots in the Yangtze River Delta showed insignificant changes. Both cold and hot spots in the Pearl River Delta had expanded. PM2.5 showed a downward trend in the three major economic zones from 2000 to 2020, and the magnitudes of increasing rates were higher in the Pearl River Delta, followed by those in the Yangtze River Delta and Bohai Economic Rim. From 2000 to 2020, PM2.5 exhibited a downward trend in the context of all vegetation coverage grades, and PM2.5 had most significantly improved within extremely low vegetation coverage in the three economic zones. On the landscape scale, PM2.5 values were mostly correlated with aggregation index in the Bohai Economic Rim, with the largest patch index in the Yangtze River Delta and Shannon's diversity in the Pearl River Delta, respectively. Under the context of different vegetation coverage levels, PM2.5showed the highest correlation with aggregation index in the Bohai Economic Rim, landscape shape index in the Yangtze River Delta, and percent of landscape in the Pearl River Delta, respectively. PM2.5 showed significant differences with vegetation landscape indices in the three economic zones. The combined effect of multiple vegetation landscape pattern indices on PM2.5 was stronger than that of the single vegetation landscape pattern index. The above results indicated that the spatial cluster of PM2.5 in the three major economic zones had changed, and PM2.5 showed a decreasing trend in the three economic zones during the study period. The relationship between PM2.5 and vegetation landscape indices exhibited obvious spatial heterogeneity in the three economic zones.

Distinguishing Buildings from Vegetation in an Urban-Chaparral Mosaic Landscape with LiDAR-Informed Discriminant Analysis

Identification of buildings from remotely sensed imagery in urban and suburban areas is a challenging task. Light detection and Ranging (LiDAR) provides an opportunity to accurately identify buildings by identification of planar surfaces. Dense vegetation can limit the number of light particles that reach the ground, potentially creating false planar surfaces within a vegetation stand. We present an application of discriminant analysis (a commonly used statistical tool in decision theory) to classify polygons (derived from LiDAR) as either buildings or a non-building planar surfaces. We conducted our analysis in southern Texas where thornscrub vegetation often prevents a LiDAR beam from fully penetrating the vegetation canopy in and around residential areas. Using discriminant analysis, we grouped potential building polygons into building and non-building classes using the point densities of ground, unclassified, and building points. Our technique was 95% accurate at distinguishing buildings from non-buildings. Therefore, we recommend its use in any locale where distinguishing buildings from surrounding vegetation may be affected by the proximity of dense vegetation to buildings.

Paleoenvironmental Reconstruction for the Last 3500 Years in the Southern Pyrenees from a Peat Bog Core in Clots de Rialba

Vegetation landscape dynamics are derived from the relationships established between anthropic activities and climate conditions over time. Paleoenvironmental research in the Pyrenees range (north-eastern Iberian Peninsula) has revealed what these dynamics were like in some regions during the Holocene. However, some fields of biogeography still present questions that need to be addressed, such as the patterns of Fagus sylvatica and Abies alba and the importance of the fire regime during the Meghalayan (late Holocene). We present a multiproxy study performed in a sedimentary record from the Clots de Rialba peat bog, located at 2093 m a. s. l. (Lleida, southern slope of the Pyrenees mountain range), that covers the last c. 3500 years. Analyses were performed on the organic matter content, pollen, non-pollen palynomorphs, and sedimentary charcoals larger than 150 μm. The palynological spectra revealed a maximum extension of Abies alba at about 3500 cal yr BP in the Bronze Age, while Fagus sylvatica showed its maximum extent between 3300 and 2800 cal yr BP. A dominance of Pinus was detected throughout the studied period. Other taxa such as cereals, herbaceous plants, aquatic plants, and coprophilous fungi have also been discussed to identify anthropic pressure and climate pulses. In addition, the study of sedimentary charcoals reveals the main forest fire episodes and their recurrences, some of them linked to anthropogenic activities and/or climate variations. These anthropogenic activities would include the use of opening and maintaining forest fires in deforestation in order to obtain pastures and spaces dedicated to cereal agriculture and the appearance of some taxa linked to or introduced by human communities.

Contributions of Green Infrastructure-Oriented Planning and Designing in Residential Gardens to the City’s Ecosystem: Case of Trabzon City, Turkey

The ratio of green areas belonging to residential areas and their location in the city is too important to ignore. However, when we look at urban planning, it is seen that green areas belonging to common public areas are generally evaluated within the scope of ecosystem services, while residential gardens that are within the scope of private property are ignored. In this context, the main purpose of the study is to examine the contribution of the residential gardens, in which the landscape value is kept to the forefront, to the ecosystem services. Within the scope of this main purpose, this study analyzes how the green areas of the residential gardens in Trabzon can be designed through a focus on green infrastructure (GI) within the axis of landscape value and how these designs will serve the ecosystem services in this perspective. Following the study, it has been determined that both spatial needs and ecosystem benefits can be met with the same GI elements, while, on the other hand, it has been conferred that the landscape value, as a significant factor in the design of residential gardens, is supported by several GI elements of an edible garden, pollinator garden, rain garden, biological pond, and green roof. It has been determined that GI elements, where vegetation and water landscape elements are used together, have a higher potential for ecosystem services. In addition, it has been concluded that the green areas of the residential gardens should not be planned and designed solely within their own areas. Based on these analyses, it has been determined that the benefits are considerably increased when the green areas of the residential gardens are planned and designed through a holistic GI-oriented design approach based on the total building parcel. Thus, it is very important to consider GI systems with a holistic approach in residential gardens throughout the city. This holistic approach will allow the benefits of GI to be spread throughout the city and will ensure that the benefits are homogenized within the city.

Millimetre‐scale pollen analysis of non‐varved lacustrine sediments from Onepoto maar palaeolake, Auckland, reveals distal vegetation responses and landscape recovery following the ~25.5‐ka Ōruanui supereruption, New Zealand

ABSTRACTThe ~25.5‐ka Ōruanui supereruption (Taupō volcano, New Zealand) erupted >1100 km3 of pyroclastic material during the Last Glacial Maximum. The impacts of this event on climate and the New Zealand environment remain unresolved, particularly on ecological timescales. Using sediment cores from Onepoto maar palaeolake, Auckland (~240 km upwind from source), we have analysed pollen assemblages at contiguous 1‐mm intervals, around an intact 3‐cm layer of the Kawakawa‐Ōruanui Tephra to resolve and assess post‐eruption vegetation impacts and landscape recovery. Sediments immediately above the tephra record a decline in the relative abundance of the dominant canopy species of Fuscospora, and concurrent increase in the abundances of grasses, herbs, ferns and shrubs. These changes reflect a brief (<10 years) part‐defoliation of canopy trees, permitting more light to penetrate and to encourage sub‐canopy vegetation growth. A short‐lived volcanogenic cooling inferred from Antarctic ice core records may have contributed to the changes but cannot be separated from the immediate and direct ecological impacts of ashfall on vegetation following the eruption. Our results, here applied to the world's most recent supereruption, more generally demonstrate the value of millimetre‐scale stratigraphic pollen analysis from non‐varved lacustrine sediments as a tool for assessing past eruptive impacts on sub‐decadal timescales.

High-frequency time series comparison of Sentinel-1 and Sentinel-2 satellites for mapping open and vegetated water across the United States (2017–2021)

Frequent observations of surface water at fine spatial scales will provide critical data to support the management of aquatic habitat, flood risk and water quality. Sentinel-1 and Sentinel-2 satellites can provide such observations, but algorithms are still needed that perform well across diverse climate and vegetation conditions. We developed surface inundation algorithms for Sentinel-1 and Sentinel-2, respectively, at 12 sites across the conterminous United States (CONUS), covering a total of >536,000 km2 and representing diverse hydrologic and vegetation landscapes. Each scene in the 5-year (2017–2021) time series was classified into open water, vegetated water, and non-water at 20 m resolution using variables from Sentinel-1 and Sentinel-2, as well as variables derived from topographic and weather datasets. The Sentinel-1 algorithm was developed distinct from the Sentinel-2 model to explore if and where the two time series could potentially be integrated into a single high-frequency time series. Within each model, open water and vegetated water (vegetated palustrine, lacustrine, and riverine wetlands) classes were mapped. The models were validated using imagery from WorldView and PlanetScope. Classification accuracy for open water was high across the 5-year period, with an omission and commission error of only 3.1% and 0.9% for the Sentinel-1 algorithm and 3.1% and 0.5% for the Sentinel-2 algorithm, respectively. Vegetated water accuracy was lower, as expected given that the class represents mixed pixels. The Sentinel-2 algorithm showed higher accuracy (10.7% omission and 7.9% commission error) relative to the Sentinel-1 algorithm (28.4% omission and 16.0% commission error). Patterns over time in the proportion of area mapped as open or vegetated water by the Sentinel-1 and Sentinel-2 algorithms were charted and correlated for a subset of all 12 sites. Our results showed that the Sentinel-1 and Sentinel-2 algorithm open water time series can be integrated at all 12 sites to improve the temporal resolution, but sensor-specific differences, such as sensitivity to vegetation structure versus pixel color, complicate the data integration for mixed-pixel, vegetated water. The methods developed here provide inundation at 5-day (Sentinel-2 algorithm) and 12-day (Sentinel-1 algorithm) time steps to improve our understanding of the short- and long-term response of surface water to climate and land use drivers in different ecoregions.

Fire Has a Positive Effect on the Abundance of Sun Spiders (Arachnida: Solifugae) in the Cerrado-Pantanal Ecotone

Fire is an important disturbance factor in shrublands, grasslands, and savannas. It alters the habitat of a multitude of species and, under natural dynamics, is a major determinant of landscape vegetation patterns. Here, we evaluate the effects of different wildfire regimes on the abundance of sun spiders in the Cerrado-Pantanal ecotone. To study how different fire regimes affect the number of individual sun spiders, we considered the frequency of fire occurrences in the last 20 years and classified locations as high frequency or low frequency. We also classified the time of the last fire in 2020 as occurring in the first or second half of the year. In addition, we compared the number of individual sun spiders before and after fire. We found no effects of fire frequency and period when the fire occurred in 2020, but the number of individual sun spiders was higher after wildfires. Although ground-dwelling are considered fire sensitive, some can employ strategies to tolerate fire so that they are able to not only survive, but also reproduce in fire-prone landscapes. Thus, we suggest that sun spiders are resilient, can explore sites under different fire regimes, and can be considered pyrophilous species.

The Potential of UAV Data as Refinement of Outdated Inputs for Visibility Analyses

Visibility analyses in geographical information systems (GIS) are used to quantify the visible and non-visible parts of the landscape. This study aims to evaluate the changes in viewshed outputs after the unmanned aerial vehicle (UAV) data refinement for the near surroundings of the observer. This research accounts for the influence of data age, mainly due to vegetation growth, and the impact of the input data quality on the final study output. The raw data that were used for UAV refinement were publicly available data (one dataset at the global level, two datasets at the national level of the Czech Republic) and airborne laser scanning (ALS) data. Three localities were selected in order to compare the viewshed evaluation that was processed over ten raster elevation models. The comparison was performed using the kappa coefficient, which considers not only the matching visible pixels, but also false visibility and invisibility. Over the span of five years (2013–2018), the visible area at two sites has decreased by more than 7%. Although with some variations (kappa coefficient varied from 0.02 to 0.92), all the study sites showed a decreasing trend of the visible area with the data aging, which was caused by the vegetation growth or landscape changes. The results showed the effect of data aging in forested areas on the resulting visibility within a couple of years. At all the sites, major changes in visibility were observed after three years (2021 vs. 2018) due to vegetation growth, forest management, and natural phenomena, such as windfalls. This study concludes that UAV data will increase the accuracy of visibility analysis, even when using freely available low-resolution data, and may also help us to update obsolete input data. The results of this research can be used to refine visibility analysis when current digital surface model (DSM) data is not available.

Environmental heterogeneity increases the conservation value of small natural features in karst landscapes

Local biodiversity hotspots are often located within regions where extreme and variable environmental – e.g., climatic and soil – conditions occur. These areas are conservation priorities. Although environmental heterogeneity is recognised as an important determinant of biodiversity, studies focusing on the effects of multiple environmental heterogeneity components in the same ecosystem are scarce. Here we investigate how topography and related microclimatic variables and soil properties may influence the biodiversity and conservation value of karst landscapes. Karst landscapes of the world contain millions of dolines (i.e. bowl- or funnel-shaped depressions) that may function as ‘small natural features’ with a disproportionately large role in maintaining biodiversity relative to their size. We assessed the diversity of microclimates, soils and vegetation and their relationships in six microhabitats (south-facing slopes, east-facing slopes, west-facing slopes, north-facing slopes and bottoms of dolines, and the adjacent plateau) for nine large dolines in a grassland ecosystem. Although there were remarkable differences among the conservation value of these microhabitats (e.g., representation of different species groups, presence of ‘climate relicts’), each microhabitat had an important role in maintaining species that are rare or absent in other microhabitats in the landscape. We found that the studied dolines exhibited highly variable environmental conditions and promoted a high diversity of vegetation types with unique species composition, contributing to the topographic, climatic, soil, vegetation and land cover heterogeneity of karst landscapes. Therefore, our findings highlight that dolines may function as local biodiversity hotspots and have a crucial conservation importance. As dolines are widespread topographic features in many karst landscapes throughout the world, our results could be directly applied to other regions as well. An integrated approach is urgently needed to provide guidelines for landscape management, promoting the retention of the microhabitat diversity of small natural features for species vulnerable to climate change and/or various disturbances.

Expansion of the Grassland Biome in the eastern Karoo corresponds with changes in rainfall and livestock numbers

The persistent spread of shrublands is a global phenomenon observed across semiarid grassland-shrubland boundaries. Observations in South Africa, however, have detected a contrasting trend of increasing grass cover across the transition between the Nama-Karoo and Grassland Biomes over the last few decades. A west-to-east gradient of increasing mean annual rainfall, and underlying geology, controls the natural transition of Karoo dwarf shrublands to semiarid grasslands. The availability of historical vegetation surveys and landscape photographs, weather, and livestock census records, made it possible to assess the nature, extent, and drivers of vegetation change across this biome transition. Rainfall has been generally higher over the last four decades compared to the years prior to the original surveys. This, together with a reduction in livestock numbers, is the main driver of the westward expansion by ∼100 km of perennial grasses, and a general increase in dwarf shrub and total vegetation cover. Rangeland condition, as indexed by estimates of grazing capacity, has improved significantly. Despite a structural shift towards grassland-dominance, the original species complement has persisted. The rainfall-driven increase in grass fuel loads in the region, however, places these rangelands at risk of becoming altered by increasing fire frequency.

A multi-staged drift sand geo-archive from the Netherlands: New evidence for the impact of prehistoric land use on the geomorphic stability, soils, and vegetation of aeolian sand landscapes

The drift sand area near Hilversum, the Netherlands, holds a geo-archive with multiple drift sand phases and intercalated palaeosols. We studied this area to test earlier theories on the development of podzols in such aeolian sands, the occurrence of sand drifting, and the contemporary vegetation development, and to gain insight into the early human impacts on these fragile ecosystems. Based on OSL and radiocarbon datings, palaeoecological studies, and soil chemical analyses, the age and origin of the drift sand phases and palaeosols were established. Sand drifting started around 6000 BCE (Late Mesolithic), the drift sand covering a distinct podzol in the Younger Cover Sand II. A second Late Mesolithic drift sand phase dated from ca. 4900–4500 BCE. Three later drift sand phases were distinguished of which the last is the classic Late Medieval (and younger) phase, while the first two date from the Neolithic. All intercalated palaeosols exhibited more or less prominent podzolisation. The palaeocological data showed that, prior to the Neolithic, in the forest open patches had developed with non-arboreal vegetation, dominated by Poaceae and Ericaceae. This changed during the Neolithic, most probably linked to the introduction of crop farming, the vegetation gradually acquiring the characteristics of the classic heathland with patches of trees/shrubs. The early sand drifting, podzolisation and opening of the forest are attributed to Mesolithic land use, with intentional burning as major factor. We conclude that the local destruction of the deciduous forests by fire and associated creation of open patches with bare sand were essential for the early sand drifting and podzolisation to occur. The results shed new light on the origin of drift sands, heathlands, and podzols in the Netherlands, and on the environmental impacts of Mesolithic people, and testify to the fundamental instability of these dry inland dune ecosystems.

Modelling Mediterranean oak palaeolandscapes using the MaxEnt model algorithm: The case of the NE Iberia under the Middle Holocene climatic scenario

The Mediterranean Basin is a global biodiversity hotspot, and oak tree species play an important role in it. Since the beginning of the Holocene (∼11.4 kyr BP), the distribution of forests has not occurred uniformly, resulting in diverse types of vegetation landscapes. In this study, we used a maximum entropy algorithm (MaxEnt) to obtain the ecological niche model (ENM) of two sub-Mediterranean oak species, Quercus pubescens Willd. (pubescent oak) and Quercus ilex subsp. ilex (holm oak), both in the present day in the Iberian Peninsula and within a Middle Holocene (8.2–4.2 kyr BP) climatic scenario in the NE Iberian Peninsula. Moreover, we used the locations of Neolithic archaeological sites containing anthracological data to analyze the relationship between human occupations and oak habitats. Our results suggest that the two oaks have responded differently to the climatic conditions that have occurred, and show changes in both potential distributions. The palaeolandscape vegetation map shows a denser vegetation cover in the lowlands and a more open landscape in the highlands, with a higher dominance of Quercus pubescens in the septentrional areas, while Quercus ilex was more restricted to certain coastal areas. Temperature and precipitation factors, mainly seasonal climatic conditions, have had a greater impact on the distribution of vegetation than other factors. We found a good overlap between the ENM of the two oaks and the locations of the Neolithic sites analysed, and determined that the distribution of Neolithic archaeological sites is not random. The Neolithic populations in the study area depended heavily on the resources of the deciduous and evergreen sub- Mediterranean forest, although they also exploited the resources of the mountain pine forest. Neolithic sites distribution suggests that Neolithic human groups were aware of the potential of forests and probably gathered woody resources in their surroundings.

Spatial Modeling of Vegetation Cover for Soil Erosion Control Based on Arc GIS and the RUSLE Models

Deforestation in the Serayu watershed, Central Java province, Indonesia for agriculture and other uses leaves only 0.73% of vegetation. It has triggered a number of problems such as soil loss (erosion), landslides, floods and sedimentation downstream. Environmental damage control needs to be applied through appropriate conservation programs. This study aims to understand the distribution of soil erosion and the effectiveness of soil erosion control by using vegetation cover. Soil erosion modeling and its correlation to vegetation cover was performed by using an Arc GIS based model of the Revised Universal Soil Loss Equation (RUSLE) through five scenarios of vegetation landscape cover such as 10%, 15%, 20%, 25%, and 30% of the total area of the study site. Five parameters namely rain erosivity (R), soil erodibility (K), slope-length (LS) and crop management (C) and conservation practices (P) factor were used to calculate soil erosion. The results indicated 82.25 tons/ha/year soil erosion reduction due to enhancement of vegetation cover from the actual condition 0.73% to the 30% vegetation cover condition. The increase of 5% vegetation landscape cover (forest) detracted the soil erosion rate by 10,20 tons /ha/year. Very high and high soil erosion hazard levels were found in the northern, east, and west watershed areasKeywords: Soil erosion, RUSLE model, GIS, Serayu watershed, Vegetation cover

‘What Am I Going to Do with My Philodendron?’ Looking at a Plant in Desk Set

Desk Set, a 1957 20th Century Fox studio comedy, made with the sponsorship of IBM, charts the relationship between a reference librarian, Bunny Watson, and Richard Sumner, the inventor of a computer which appears to threaten her job. The film displays a thriving philodendron within Bunny’s skyscraper office, illustrating her organic style of thinking, and implicitly inviting us to see the plant in opposition to the computer. The suggestion that the plant is in some sense excessive, claiming attention beyond the norms of the ornamental background houseplant, opens questions about how we look at plants on film. We find here a reframing of figure and ground, which relates the philodendron to moments where plants become conspicuous in early film and in horror. Desk Set reflects a vegetal landscape characterised by all the commonplace instrumentalising of plants in modernity, amongst which the philodendron emerges as an exception. The plant does not point outwards to a putative wilderness. Instead, our looking at it allows us to contemplate it as an individuated specimen, and to move from that act of looking to recognise its deep entanglement with the urban environment, and with human care.

Response of the plant–soil system to desertification in the Hulun Buir Sandy Land, China

AbstractIn this study, the vegetation and soils of different desertification landscapes (sandy grassland, and fixed, semi‐fixed, semi‐mobile, and mobile dunes) in the Hulun Buir Sandy Land were examined to quantify the impacts of desertification on plants, soils, and microbes, and the key limiting factors of restoration. Desertification caused soil quality to decline and led to an imbalance of nitrogen (N) and phosphorus (P) supplies (N:P ratios decreased significantly from 3.55–1.8, p < 0.05). Desertification did not change the stoichiometric relationships among plant carbon (C), N, and P at a community level, but promoted redistribution of nutrients from roots to aboveground tissues. The aboveground biomass N and P increased by 9.8% and 39.3%, respectively from grassland to mobile dunes, but these of the underground biomass decreased by 26.1% and 37.7%, respectively. N limitation (plant N:P < 10) occurred at the community level. Desertification led to the change of dominant species from perennial herbs to annual psammophytes, and plant diversity (from 1.15–0.79) and productivity (from 880.6 to 128.6 g m−2) first increased slightly (p > 0.05) and then decreased sharply (p < 0.05) with increasing desertification, but with no significant (p > 0.05) change of the microbial community. Redundancy analysis showed that the main environmental drivers were the soil N:P (with an explanation of 29.6%), followed by pH, electrical conductivity, and the soil's fine particles (with a total explanation of 24.3%). Based on these results, three reference frames were proposed for the restoration of the near‐original vegetation community.

Wildfire hazard mapping in the eastern Mediterranean landscape

Background Wildfires are a growing threat to many ecosystems, bringing devastation to human safety and health, infrastructure, the environment and wildlife. Aims A thorough understanding of the characteristics determining the susceptibility of an area to wildfires is crucial to prevention and management activities. The work focused on a case study of 13 countries in the eastern Mediterranean and southern Black Sea basins. Methods A data-driven approach was implemented where a decade of past wildfires was linked to geoclimatic and anthropic descriptors via a machine learning classification technique (Random Forest). Empirical classification of fuel allowed linking of fire intensity and hazard to environmental drivers. Key results Wildfire susceptibility, intensity and hazard were obtained for the study area. For the first time, the methodology is applied at a supranational scale characterised by a diverse climate and vegetation landscape, relying on open data. Conclusions This approach successfully allowed identification of the main wildfire drivers and led to identification of areas that are more susceptible to impactful wildfire events. Implications This work demonstrated the feasibility of the proposed framework and settled the basis for its scalability at a supranational level.

Holocene Climate Variability Over the Vegetation Landscape in Western-Central Mexico and Evaluation of Anthropogenic Activities

Holocene Climate Variability Over the Vegetation Landscape in Western-Central Mexico and Evaluation of Anthropogenic Activities