High Vegetation Cover Research Articles

Alternance of alternative stable states influence the functional diversity of microcrustaceans in a shallow subtropical lake

AbstractShallow lakes in subtropical climate regions may have a clear water state with a predominance of submerged or floating macrophytes and a turbid water state with a predominance of phytoplankton. The relationship between microcrustaceans and these changes in alternative states is still incipient in the literature. And to better understand these relationships, the functional approach is an excellent tool. Thus, the present work seeks to test the hypothesis that changes in alternative stable states over time reflect the variability of composition and functional diversity of microcrustaceans. For this, samples of microcrustaceans collected in a subtropical shallow lake, which underwent alternate state changes in the period to 2000–2014, were used. Our results demonstrate a variation in composition and functional diversity among alternative states, thus supporting our hypothesis. In periods of clear water with a predominance of floating macrophytes, we found a greater functional diversity and richness of genera. This result may be associated with several factors such as greater habitat heterogeneity and lower predation pressure. The lowest values of functional diversity found in periods of turbid waters with predominance of phytoplankton and periods of clear waters with submerged macrophytes are related to the dominance of functional traits, such as scraper feeding type, herbivorous/omnivorous trophic group, littoral habitat and asexual reproduction. These traits are functional features of most Ostracoda genera, a taxonomic group abundant in these two alternative states. The predominance of this group may be related to the environmental characteristics of these periods, such as the high vegetation cover and the availability of niches unoccupied by more sensitive species, since most Ostracoda have high environmental tolerance. We conclude that the functional traits approach combined with taxonomic groups respond to temporal variations of alternative stable states and are important tools to detect environmental changes.

Impacts of Spatial Components on Outdoor Thermal Comfort in Traditional Linpan Settlements.

Traditional settlements have received increasing attention because of China’s rural revitalization. Traditional settlements with excellent thermal comfort in rural areas can attract urban residents, so it is vital to explore the thermal comfort of traditional settlements. For this paper, we studied Linpan settlements, which are scattered traditional settlements that are mainly composed of buildings and trees. Firstly, we visually interpreted Linpan settlements by ArcGIS. A total of 1194 Linpan settlements were classified to obtain the spatial components. The statistical results of Linpan were used in the subsequent experimental design. Then ENVI-met was used to simulate 25 different spatial forms of Linpan obtained by statistical results and orthogonal experiment to explore the most comfortable Linpan layout. The results showed the following: (1) Linpan could improve thermal comfort in both winter and summer. Adjusting the spatial arrangement could maximally increase the mean physiological equivalent temperature (PET) of the whole Linpan area by 1.03 °C in winter and reduce it by 3.02 °C in the summer. (2) At different time points, the influence of different space factors on thermal comfort was also different. The overall significance of each factor on thermal comfort was addressed as follows: vegetation coverage (highly significant) > building number (highly significant) > building form (highly significant) > vegetation distribution (significant), but the building distribution was not significant. (3) The best spatial arrangement scheme was high vegetation coverage, a large number of buildings, tri-courtyard buildings, surrounding vegetation distribution, and surrounding building distribution. The innovation of this paper lies in introduced thermal comfort into the traditional Linpan settlement, extracted spatial features of buildings and vegetation by visual interpretation combined with GIS software, and the fact that we conducted the experimental design of microclimate and thermal comfort based on spatial features. The research results can guide the outdoor thermal environment renewal design of Linpan and other traditional settlements.

ESTIMATING TREE CANOPY HEIGHT IN DENSELY FOREST-COVERED MOUNTAINOUS AREAS USING GEDI SPACEBORNE FULL-WAVEFORM DATA

Abstract. Tree canopy height is an important parameter for estimating forest carbon stock, and mountainous areas with dense vegetation cover are the main distribution areas of trees, so it is important to accurately measure the forest canopy height in mountainous areas with high vegetation cover. This paper focuses on the problem of poor inversion accuracy of canopy height estimation in large scale densely forest-covered mountainous areas, uses the complex echoes of GEDI full-waveform spaceborne laser in mountainous forests as the data source, improves the accuracy of forest canopy height estimation from multiple perspectives by improving the detection capability of weak and overlapping waves and constructing a canopy height model considering slope correction and environmental features. The results show that the modified RGD algorithm proposed in this paper can effectively detect the weak and overlapping waves in the echoes and improve the DTM/DSM inversion accuracy significantly (FVC>90%, R2=0.8663/R2=0.8073). In addition, the forest canopy height model is constructed on the basis of the physical geometric model of mountain slope and spatial environment characteristics, and finally the canopy height inversion accuracy of this paper is higher (FVC>90%, R2=0.6729). The experiment proves that the model constructed in this paper is not only applicable to densely forest-covered mountainous areas, but also improves the accuracy of forest canopy height inversion in other environments. This study can provide technical and decision support for forest resource survey and global carbon balance.

Estimating spatio-temporal variability of aerosol pollution in Yunnan Province, China

Generally, areas with more anthropogenic emissions are more polluted. However, Yunnan Province, located in the southwest of China, has experienced serious aerosol pollution in recent years despite overall low anthropogenic emissions and high vegetation coverage. To explore the spatio-temporal variability of aerosol pollution in Yunnan, this study retrieved the near-surface PM2.5 and PM10 from 2017 to 2020 using random forest method based on Himawari-8 AOD data, and the influences of meteorological factors and terrain are also considered. The results show that aerosol pollution in Yunnan Province has significant spatio-temporal variety. Specifically, the annual average PM2.5 and PM10 of the whole province are 39.16 μg/m3 and 68.87 μg/m3 respectively, which are mainly contributed by the particulate matter in dry season (November to April), especially that in March and April. And PM distribution here differs greatly from north to south with 25° N as the boundary in dry season. From November to January, pollution level in the northern part is higher than that in the southern, while it is the opposite from February to April, which is mainly affected by the regional transport of pollutant, rather than the changes of local emissions or meteorological conditions.

Regional Evapotranspiration Estimation by the Improved MOD16-sm Model and Its Application in Central China

Evapotranspiration (ET) is a key component of the hydrological cycle, but traditional monitoring approaches are always based on measurements, which cannot satisfy the requirements of research on a regional scale. Hence, ET estimation by remote sensing is essential. MOD16 is a remote-sensing model based on the P-M equation and has good applicability. However, it describes soil moisture indirectly by RH, etc., which may cause uncertainties in ET estimating, so this study attempts to utilize the NDWI as a supplement to soil moisture information and makes improvements on the MOD16 model (with the resultant new model being named MOD16-sm). Specific work includes two aspects: one is model verification through making comparisons between ET estimates and measurements, and the other is a model application effect test analyzing the spatiotemporal characteristics of ET and exploring how ET responds to climate and land-use changes. Model verification indicated that the accuracy of the improved MOD16-sm model increased, with a higher R2 of 0.71, a lower RMSE 0.9 mm, and a lower MAE 0.91 mm, and that the improved MOD16-sm model was convincing. The application effect test of the MOD16-sm model showed that the average relative change rate of annual ET was 1.7%, showing an upward trend, and areas with growth trends of ET also had high vegetation coverage. As for the impacts of climate and land-use changes on ET, ET was positively correlated with precipitation, whereas it had no relevant correlation with air temperature in most areas, and the ET of all land-use types displayed significant increasing trends resulting from climate change. The application effect test demonstrated that ET estimates by the improved MOD16-sm model were reasonable.

High semi-natural vegetation cover and heterogeneity of field sizes promote bird beta-diversity at larger scales in Ethiopian Highlands

High semi-natural vegetation cover and heterogeneity of field sizes promote bird beta-diversity at larger scales in Ethiopian Highlands

Characterizing urban growth in Vientiane from 2000 to 2019 using time-series optical and SAR-based estimates of urban land

While annual urban growth rates are declining in many highly urbanized regions of the world, Southeast Asia (SEA) is experiencing an accelerated urbanization process in small and medium-sized cities (SMCs), to which little attention has been paid. High-precision urban land information is a prerequisite for analyzing urban expansion characteristics for SMCs. However, accurately extracting urban land information for SMCs in SEA has remained challenging, considering the lower urban land density, higher vegetation cover, and complex landscape mosaic. This study systematically analyzed the capacities of a set of statistical indicators of time-series optical and synthetic aperture radar (SAR) images in impervious surface extraction. Then, an automatic urban land mapping method was developed by integrating time-series optical and SAR statistical indicators to map urban land area at a finer spatial resolution. The method was applied to Vientiane, Laos, as a case to explore the characteristics of the rapid urbanization process over 2000–2019 and problems related to sustainable urban development. Our results show the statistical indicators of SWIR1, SWIR2, VV, and VH can distinguish urban land from bare soil and cropland, and statistical indicators of NDVI can separate urban land from seasonal vegetated land. The overall accuracies of our products on Vientiane exceeded 95%, and the kappa coefficient was close to 0.90. The study found that the city was experiencing accelerated urban growth, and the urban land area increased from 25.93 km2 in 2000 to 37.23 km2 in 2010 and 62.12 km2 in 2019. Spatially, the urbanization patterns of Vientiane showed a certain degree of sprawl, especially in the suburbs. Rapid urban sprawl poses a significant threat to the urban environment and sustainable development.

A Case Study of the Relationship Between Vegetation Coverage and Urban Heat Island in a Coastal City by Applying Digital Twins.

While urban vegetation affects the urban thermal environment directly, the effects of different plant layouts and vegetation cover on urban microclimate regulation are different. This study has applied digital technologies to advance urban environmental research and forestry analysis. With a focus on a coastal city located on the eastern coast of the North Temperate Zone as a study area, this study collected the Landsat archive satellite remote sensing image data covering the study area in 2000–2020 and analyzed the temporal and spatial distribution characteristics of vegetation coverage, land surface temperature, and urban heat island (UHI) ratio index. The study results included the following findings: (1) The area of high fractional vegetation cover (FVC) (0.8–1.0) in the study area is increasing. Those areas are located in the mountain forests in the near-coastal area. The lowest temperature was also detected in the mountain area. (2) The distance from the coastline causes a negative correlation between land surface temperature and FVC. The land surface temperature in the regions with a distance of more than 25 km from the coastline decreases obviously with increasing FVC in summer. However, the correlation between the land surface temperature and FVC showed a slight change in the winter period. (3) UHI ratio index decreases along with the area of high FVC (H-FVC) area. The influence of ocean climate on seasons is different, which results in the reduced effect of the H-FVC area and differences in the UHI ratio index. (4) The distance from the coastline should be considered as an important factor in the forestry development planning of the coastal cities.

Estimation of annual rate and spatial distribution of soil erosion in the Jamuna basin using RUSLE model: A geospatial approach

Soil erosion poses a serious threat to the western Jamuna sub-basin area in Bangladesh, comprising of 8 districts and 202 unions. The Revised Universal Soil Loss Equation (RUSLE) methodology integrated with Remote Sensing and Geographic Information System (GIS) was applied to compute the annual soil erosion rate for the western Jamuna sub-basin area. Primarily open-source data was utilized in this study to propose a low-cost and rapid soil erosion monitoring framework. Results indicate that a total of 598,232 tons of soil is being lost annually from the study area. Furthermore, the study estimates a potential average soil erosion rate of approximately 29.5 tons/ha/year in the 202 unions. The spatial distribution of soil erosion suggests that the unions of Bogra, Sirajganj and Jamalpur districts undergo higher soil loss compared to the unions of Pabna and Natore districts. The three unions with dominant mean soil erosion rates are the Bhandarbari and the Sariakandi Paurashava of Bogra district, and the Kaoakola union of the Sirajganj district. Heavy rainfall after a prolonged dry season, the presence of steep slopes and the susceptibility of the unions located in proximity to the Bangali river and the Jamuna river leading to higher rates of surface runoff and floods resulted in higher rates of soil erosion. On the contrary, the Atgharia Paurashava and Debottar unions of Pabna district and the Moshinda union of Natore district are the unions with minimal soil erosion rates, which likely be attributed to the presence of flat terrain, low annual rainfall, higher vegetation cover and the predominance of clayey soils. Overall, the study identifies an increasing trend of soil erosion rates from the south-western part of the study area towards the central, north-eastern and south-eastern parts which are close to the Jamuna river. Such quantification of annual soil loss is necessary for the formulation and implementation of effective soil conservation strategies.

NPP plays a constraining role on water-related ecosystem services in an alpine ecosystem of Qinghai, China

Understanding the constraint effects of ecosystem services, which can indicate thresholds and other key features, is helpful to formulate reasonable measures of ecosystem service protection. In Qinghai Plateau, exploring threshold effects and scale effects of net primary production (NPP) on multiply water-related ecosystem services and the associated influencing factors are crucial to maintain its status of “Asian Water Towers”. In this study, NPP and the multiply water-related ecosystem services, including surface runoff, soil water, and subsurface runoff were evaluated by Carnegie-Ames-Stanford Approach and Community Land Model from 2000 to 2018. The constraint effects between NPP and each water-related ecosystem service were analyzed by a segmented quantile regression approach at the scales of region and functional zones. The thresholds, slopes, and constant terms of the regression equations were used to characterize the key features of the constraint lines. Finally, we analyzed the environmental factors affecting the key features of constraint effects. The results showed that the constraint lines of all paired ecosystem services were hump-shaped curves, negative lines, inverted S curves, or logarithmic curves. The shapes of the constraint lines of NPP and soil water varied greatly with scale. The soil, terrain, and other ecological contexts may shape the constraint lines, and the climate factors and vegetation coverage determined the values of the key features. The NPP thresholds generally range from 400 gC m−2 to 800 gC m−2 on the hump-shaped constraint lines, which indicates that too high vegetation coverage should not be pursued in the alpine ecosystem of Qinghai, but the ranges of NPP values where water-related ecosystem services decrease with increasing NPP could be narrowed with the management of surface vegetation. The slopes and constant terms on the negative constraint lines were dominated by climate factors and not easily changed by surface vegetation factors. Appropriate adjustment of surface vegetation in response to climate change could weaken the constraint effect of NPP on the water-related ecosystem services and achieve synergy of multiple ecosystem services, thereby protecting water-related ecosystem services and promoting sustainability in the alpine ecosystem.

The potential of remotely-sensed data to identify suitable sites for the reintroduction of Arabian Oryx (Oryx leucoryx)

We assessed vegetation cover density and distribution in Eastern Jordanian rangeland reserves (2411 km2) using a series of Landsat images (34 year’s period) and ground cover survey (2020) to identify proper sites for reintroducing Arabian Oryx (Oryx leucoryx). The natural reserves were Burqu Nature Reserve site-1, and site-2 (Dmetheh), and Al Dahek Nature Reserve. Satellite sensor data from Landsat-8-OLI and Landsat- 5-TM were used to derive Normalized Difference Vegetation Index (NDVI) between 1986 and 2020 and across growing seasons (March and April). The Dmetheh site had the highest vegetation cover density over the growing season and across years (1986-2020). Scattered shrubs and grasses (NDVI: 0.1–0.2) consistently covered more than 40% (600-700 km2) of the Dmetheh reserve, while in the other reserves vegetation cover were inconsistent and covered less than 500 km2. Considering the Landsat- NDVI results, Dmetheh site was selected for further assessment. Ground survey of Dmetheh site showed that there were 54 palatable species (53% of total plants) and total ground vegetation cover (%) of the site in March was about 22.5%. The relationship between Landsat-NDVI values and ground vegetation cover was significant (R2=73.3, P<0.001). Overall, remotely-sensed data hold promise for the assessment process of identifying proper sites to reintroduce Arabian Oryx in arid environments.

Changes in taxonomic and functional diversity of dung beetles along a forest disturbance gradient in tropical karst ecosystems on islands of Vietnam

AbstractTropical karst ecosystems are an exceptionally unique and important landscape element of South East (SE) Asia. Unfortunately, these ecosystems have been increasingly disturbed due to forest conversions to anthropogenic land uses, illegal logging, and limestone quarrying. Karst regions have a high degree of endemic species, so their loss is likely to have negative consequences for species conservation as well as ecological processes. We investigated dung‐beetle communities from primary forests (PF), old secondary forests (&gt;15 years since abandonment, OSF), young secondary forests (&lt;10 years since abandonment, YSF), and Acacia plantations (&lt;10 years old, AP) of karst ecosystems on Cat Ba Island (northern Vietnam). Our main aim was to provide a thorough and quantitative assessment of the taxonomic and functional diversity of dung beetles in the examined forests, and subsequently to determine the value of specific types of disturbed forests for biodiversity conservation. In total, 1458 dung beetles of 34 taxa were recorded. Community composition varied significantly among the forest types and was broadly separated into two groups: old‐growth forests (i.e., PF and OSF) and young‐growth forests (i.e., YSF and AP). While YSF and AP hosted severely impoverished dung‐beetle communities, OSF with a high forest canopy cover and high ground vegetation cover harbored species‐rich dung‐beetle communities similar to those found in PF. However, functional diversity significantly differed between PF and OSF. The data also revealed that community responses were due to changing patterns of trait compositions rather than species richness.

Niche Variation in Endemic Lilium pomponium on a Wide Altitudinal Gradient in the Maritime Alps.

The relationship between altitudinal and ecological gradients has long been a dominant theme in plant ecology; moreover, how species respond to climate change has renewed this interest. Mediterranean mountains are often hotspots of endemism, and some endemic species have local distributions that span different climatic belts; hence, local variations in topography and fine-scaled niche conditions may play crucial roles in their persistence along such gradients. Studies of the fine-scaled niche are, however, very rare; most studies involve broad-scale variations in climatic parameters. The Turban lily, Lilium pomponium L. is endemic to the Maritime and Ligurian Alps, where it occurs across a wide altitudinal gradient. Previous work has shown no link between climatic marginality and geographic range limits on morphological traits and genetic variability; however, possible variations of local topographic and ecological parameters have not yet been examined. The objective of this paper is to characterise local ecological niche conditions of L. pomponium populations in the different bioclimatic zones it occupies along the altitudinal gradient. The species occurs in four main types of microecological niches. One of these niche types, with a high mineral cover, is the most abundant—type 2: it was detected in 39% of sampled quadrats and occurs across the whole bioclimatic gradient. Other niche types are more limited to subsections of the gradient: type 3 (in 19% of sampled quadrats) is restricted to high-altitude sites (>1070 m.a.s.l.) and is characterised by high vegetation and litter cover; type 4 (26%) corresponds to more forested habitats on substrates with low water retention capacities, in more inland zones close to the centre of L. pomponium distribution and across a range of altitudes; and type 1 (16% of quadrat) only occurs in the Mediterranean part of the gradient, close to distribution limits in pockets of soil among large blocks of rocks, mainly found at mid-altitudes. Despite heterogeneity in the spatial locations of niche types, there is no correspondence between ecological gradients and the distribution limits of this species. Knowledge of the fine-scaled ecological conditions that determine niche types is thus essential for conservation management of the habitats of this species and for the exploration of its possible response to ongoing climate change.

Taxonomy of seasonal and diurnal clear-sky climatology of surface urban heat island dynamics across global cities

Knowledge of the temporally continuous dynamics of seasonal and diurnal surface urban heat islands (SUHIs) as well as their underlying determinants is crucial to better understand their variations at multiple time scales. Owing to the orbital limitation of satellites, previous studies primarily focused on SUHI dynamics at limited time-nodes, either in a diurnal or seasonal cycle. However, a joint investigation of the continuous dynamics of seasonal and diurnal SUHIs (hereafter referred to as SUHIsea and SUHIdiu) remains lacking. The comprehensive taxonomy of the patterns of continuous SUHIsea and SUHIdiu dynamics across global cities is also not clear. Using satellite-derived land surface temperature (LST) data, we investigated the prevalent patterns of continuous SUHIsea and SUHIdiu dynamics across global cities by combining annual and diurnal temperature cycle models and the k-means clustering algorithm. Our results showed that: (1) Both SUHIsea and SUHIdiu dynamics exhibited six typical patterns including, single-peak type (SPT), single-valley type (SVT), peak-valley type (PVT), valley-peak type (VPT), two-peak type (TPT), and two-valley type (TVT). (2) The daytime SUHIsea dynamics pattern was closely related to the background climate, with SPT and PVT mainly occurring in cities located in the warm temperate and snow zones, SVT and VPT in the arid zone, and TPT and TVT in the equatorial zone. In contrast, the nighttime SUHIsea dynamics pattern depended more on rural land cover type, with SPT, PVT, and TPT mostly occurring in cities surrounded by barren lands with high albedo and SVT, VPT, and TVT in cities surrounded by dense vegetation with low albedo. We also find a significant negative relationship between daytime SUHIsea dynamics and urban-rural contrast in vegetation and between nighttime SUHIsea dynamics and urban-rural contrast in albedo across cities. (3) For SUHIdiu dynamics, SPT, PVT, and TVT were mainly located in cities with higher vegetation coverage in rural than in urban areas, while SVT, VPT, and TPT were in cities with higher vegetation coverage in urban areas. The SUHIdiu dynamics were found to be synthetically affected by the urban-rural contrast in vegetation and albedo. We consider these findings to be beneficial for deepening the understanding of SUHI dynamics at various time scales.

Spatiotemporal variation and driving forces of NDVI from 1982 to 2015 in the Qinba Mountains, China.

The spatiotemporal variation and driving force of the Normalized Difference Vegetation Index (NDVI) are helpful to ecological environment protection and natural resource management. Using the Sen and Mann-Kendall methods, Hurt index, and the Geodetector, this study investigated the temporal and spatial changes and driving forces of NDVI during 1982-2015. The results showed that (1) From 1982 to 2015, the high vegetation coverage was mainly distributed in the Qinling Mountains and the Daba Mountains, while the low vegetation coverage was in high altitude areas in the west, low altitude in the east, and the Hanjiang River valley. (2) NDVI in the Qinba Mountains increased continuously accounting for 81.1%, with 68% showing slow growth. In the future, only 37.8% of the vegetation will have significant change. The area of vegetation increase will be greater than the area of decrease. (3) NDVI increased firstly and then decreased with the increase of altitude, reaching the maximum value at 1100m. NDVI showed a trend of fluctuating growth. It reached the maximum value of 0.86 in 2015. (4) Through the Geodetector, the main factors affecting NDVI were natural factors mainly including rainfall, soil type, and digital elevation model (DEM), while human activities, including population density, had little influence on NDVI. Natural environment factors and human activities together had a greater impact on the spatial distribution of NDVI. This study could provide help for the sustainable development of the natural environment in the Qinba Mountains.

Vegetation increases abundances of ground and canopy arthropods in Mediterranean vineyards

The decline of arthropod populations observed in many parts of the world is a major component of the sixth mass extinction with intensive agriculture being one of its main drivers. Biodiversity-friendly farming practices are taking centre stage in the recovery process. In vineyards, vegetation cover is commonly used for production purposes, to reduce soil compaction by machinery use and soil erosion. Here we examined the effects of vegetation cover and soil management on the abundance of ground- (spiders, beetles, Hemiptera and harvestmen) and canopy-dwelling (wild bees, green lacewings, beetles and Hemiptera) arthropods in three categories of vineyards: (i) vineyards with no vegetation, (ii) partially vegetated (every second inter-row is vegetated) and (iii) all inter-rows are vegetated. We recorded a general positive effect of a decrease in soil perturbation intensity and corresponding higher vegetation cover on arthropod abundance. Plant species richness was the most important vegetation parameter, with a positive effect on spiders, harvestmen, hemipterans and beetles (ground and canopy) abundances. Using a path analysis, we also highlighted the central role of inter-row vegetation management in trophic and non-trophic relationships between vegetation and arthropods, and between arthropod groups. Our results demonstrate the benefits of a softer soil management preserving a diverse vegetation cover for the conservation of arthropods in Mediterranean vineyards.

Exploring the Spatial Pattern of Damage Caused by Typhoon Meranti on the Urban Green Space on Xiamen Island

Typhoons are the main cause of disturbances in the natural environment of coastal cities. Typhoons often damage the urban green space (UGS) of coastal cities, and the spatial pattern of such damages provides important information for disaster recovery. For acquiring such information, remote sensing technology offers a fast and effective means. This study investigated the spatial pattern of typhoon damage to UGS using Sentinel-2 data. To this end, the damage caused by Typhoon Meranti to the UGS of Xiamen Island (including Gulangyu Island) in 2016 was taken as a case study. The results showed that the overall area without vegetation coverage increased by 1159.7 ha. Areas with high vegetation coverage experienced less damage than areas with low vegetation coverage. A coldspot map of damage clusters was generated, and the map showed that severely damaged green areas were distributed in a striped pattern, indicating serious damage to road greening. In terms of direction, east-west roads experienced a higher degree of damage than north-south roads. The determined spatial pattern of the damage caused by Typhoon Meranti on the UGS of Xiamen Island provides a basis for the post-disaster restoration of the landscape of Xiamen Island.

Evaluation of the Air Pollution Tolerance Index of 12 Plant Species Growing in Environments with Different Air Pollution Levels

Background and objective Particulate matter (PM) is the most dangerous form of air pollution, and causes many diseases. Plants act as bio-filters to help reduce PM in the atmosphere. PM also influences the growth of plants, so selecting suitable plant species for specific environmental conditions is very important. The air pollution tolerance index (APTI) was used to determine the tolerance level of each plant species to air pollution. The purpose of this study was to determine the tolerance to air pollution of various plant species in order to identify plant species that can be grown in polluted environments; this was achieved by evaluating the APTI of plants. This study analyzed the biochemical parameters of 12 plant species at two sites with different air pollution levels (urban forest and roadside) to assess and compare the APTI of plant species. Methods The healthy leaves of 12 plant species (6 broad leaves and 6 needle leaves) that are commonly used in landscapes in Korea were chosen for this study. The same plant species were collected from two sites with different pollution levels and were analyzed immediately; one site was an urban forest (Chungcheongbuk-do Forest Environment Research Institute) with an area of 25 ha and featuring high vegetation coverage, while the other was at a high-traffic roadside next to a crossroads near the Cheongju Express Bus Terminal. We used the leaf samples to analyze four biochemical parameters of each plant: leaf extract pH (pH), relative leaf water content (RWC), total chlorophyll (TChl), and ascorbic acid. Finally, based on these values, APTI values were calculated. Results The APTI values were different between all 12 plant species at both sites with different levels of pollution. APTI had a significant correlation with the biochemical parameters of plants. Plants in the urban forest and at the roadside showed APTI values ranging from 6.89–9.37 and 7.57–9.94, respectively. The APTI of the roadside plant species tended to be higher than that of the plants from the urban forest. Among 12 plant species, Acer palmatum, Acer buergerianum, and Pinus densiflora had high APTI values. These plant species can serve as biofilters in environments with high air pollution. Conclusion The APTI of the 12 plant species in this study can aid in the selection of suitable plant species from environments with different levels of air pollution. The high APTI of some roadside plant species may show their tolerance under environmental pollution-related stress, or demonstrate their adaptability to the polluted environment. In the future, we need to examine more plant species under various environmental conditions to understand their tolerance levels to air pollution and to correlate plants with air pollution. Further, more studies on other air pollutants that can influence plant growth, such as SO2 and NOx, should be conducted.

Does Microhabitat Segregation Explain Coexistence of Globose Cactus Species?

The factors determining cactus species richness and distribution at broad scales are well understood; however, the mechanisms explaining these parameters at local scales are poorly known, particularly in mesic regions. The aim of this study was to analyze if globose cactus species are segregated in terms of the microhabitats they occupy in Córdoba Mountains, central Argentina. In an area of about 40 ha, 19 rocky outcrops including all cactus species (a total of seven species) and covering the main vegetation and topographical conditions were selected. In each of the outcrops, 10 1x1 m randomly selected plots were established. The following variables were measured in each plot: cactus species presence; cover of graminoids, forbs, bare soil, and rock (%); rock size (small, medium and large); slope inclination (°) and aspect; soil depth (cm); and vegetation height (cm). A principal component analysis was performed with environmental variables. Then, segregation of the different cactus species along the three first axes of the PCA, which accounted for most of the environmental heterogeneity, was analyzed. Echinopsis aurea and Gymnocalycium mostii occurred at sites dominated by rock with low vegetation cover. Gymnocalycium bruchii, G. capillense and Parodia submammulosa were present at sites with low rock cover, deep soils and high vegetation cover. Out of the seven cactus species, Parodia submammulossa, Gymnocalycium bruchii and G. capillense did not differ significantly in microhabitat characteristics. Thus, these three species occupied sites with similar microenvironmental conditions, whereas the remaining species occupied sites with particular environmental characteristics. Four of the seven species inhabit unique environments (they do not overlap with the other species in the multivariate space). Moreover, these three species not only are present in similar environments, but also co-occur (they were found together in the same plots). Our results indicate that at the local scale, segregation in space is an important mechanism explaining plant coexistence and local species richness.

Dynamic monitoring and analysis of the earthquake Worst-hit area based on remote sensing

The earthquake and its secondary geological disasters have some long-term effects on vegetation recovery, and the spatiotemporal differentiation of vegetation coverage in earthquake-stricken areas are often not valued by researchers. Beichuan County in Sichuan Province is the worst-hit area during Wenchuan earthquake, tracking the vegetation coverage in this disaster area can provide feedback for post-earthquake ecological restoration. Based on remote sensing (RS) and Geographic information system (GIS), this paper relies on dimidiate pixel model (DPM) and vegetation coverage transfer matrix to explore the vegetation coverage of the earthquake worst-hit area. The results show that the overall level of vegetation coverage in Beichuan county is high, and earthquakes are dominant in the areas with high vegetation coverage. Besides, earthquake can do most severe damages to the areas with high vegetation coverage, followed by medium damage impacting to the areas with medium vegetation coverage, but the damage of other areas are relatively small. From 2007 to 2020, the average vegetation coverage in Beichuan County decreased from 0.835 in 2007 to 0.755 in 2008, then gradually recovered to 0.826 in 2020, experiencing a sharp decline and then a steady increase. The recovery of vegetation coverage is improved over time, but the spatiotemporal differences of the recovery process are obvious. Elevation has the largest driving force on vegetation coverage (q = 0.569, p less than 0.001), followed by temperature and rainfall; the interaction between factors has a significant increasement in the spatial differentiation of vegetation coverage, indicating that vegetation coverage is a combination result of multiple factors. The research findings can help construct the scientific management of the eco-environment in the disaster area, it can also help builda medium to long-term ecological restoration plan according to the variation in vegetation coverage.