Different Types Of Vegetation Cover Research Articles

Beyond the surface: microbiological and biochemical attributes as indicators of soil quality in Atlantic Forest ecosystem

The objective of this study was to determine the biochemical and microbiological attributes in areas with different vegetation covers (mature forest, secondary forest, and sugar cane monoculture) and seasonal changes, and to compare the sensitivity of these attributes types (mycorrhizal, enzymatic, and carbon attributes) in response to changes in vegetation cover and season. Soil samplings were conducted over two years (one per semester, during the dry and wet periods of 2007 and 2008) in three types of areas: (I) mature forest; (II) secondary forest; and (III) sugar cane crop. The enzymatic activity of fluorescein diacetate, dehydrogenase, saccharase, basal carbon respiration, the carbon content of microbial biomass, the microbial coefficient, total and easily extracted glomalin soil-related proteins, mycorrhizal colonization, the number of glomerospores, total organic carbon, fulvic and humic acid content, and the fulvic/humic acid ratio were analyzed. In general, mycorrhizal parameters were more sensitive in distinguishing areas with different types of vegetation cover. Additionally, carbon stocks in areas of mature and secondary forest were higher compared to areas cultivated with sugar cane. The study reveals that mycorrhizal properties, such as root colonization and GRSP fractions, are more sensitive indicators of soil health than soil C attributes, providing a cost-effective alternative for evaluating soil health in the Atlantic Forest. The confirmed hypothesis supports the effectiveness of microbiological activity and C dynamics in discerning significant changes between sugar cane cultivation and forested areas. The study underscores the vital role of conserving forested areas, serving as crucial carbon reservoirs, and emphasizes the potential for enhanced sustainability through conservation practices and rapid soil function recovery in secondary forests within the Atlantic Forest.

Response of the subalpine bunchgrasses to wildfires and its effects in the relative abundance of the volcano rabbit in the Ajusco-Chichinautzin Mountain Range.

The volcano rabbit (Romerolagus diazi) is a lagomorph endemic to the central mountains of the Trans-Mexican Volcanic Belt and is classified as threatened at extinction risk. It is a habitat specialist in bunchgrass communities. The annual wildfires that occur throughout its distribution range are a vulnerability factor for the species. However, the effects of wildfires on volcano rabbit populations are not fully understood. We evaluated the occupancy and change in the volcano rabbit relative abundance index in the burned bunchgrass communities of the Ajusco-Chichinautzin Mountain Range during an annual cycle of wildfire events. Additionally, we assessed the factors that favor and limit occupation and reoccupation by the volcano rabbit using the relative abundance index in burned plots as an indicator of these processes. The explanatory factors for the response of the volcano rabbit were its presence in the nearby unburned bunchgrasses, the height of three species of bunchgrass communities, the proportion of different types of vegetation cover within a 500 m radius around the burned plots, heterogeneity of the vegetation cover, and the extent of the wildfire. Statistical analyses indicated possible reoccupation in less than a year in burned bunchgrass communities adjacent to unburned bunchgrass communities with volcano rabbits. The relative abundance index of volcano rabbits was not favored when the maximum height of the Muhlenbergia macroura bunchgrass community was less than 0.77 m. When the vegetation around the burned plots was dominated by forest (cover >30% of the buffer) and the fire was extensive, the number of latrines decreased per month but increased when the bunchgrass and shrub cover was greater around the burned plots. While the statistical results are not conclusive, our findings indicate a direction for future projects, considering extensive monitoring to obtain a greater number of samples that contribute to consolidating the models presented.

Effects of different types of vegetation cover on soil microorganisms and humus characteristics of soda-saline land in the Songnen Plain.

In the soda-saline grasslands of the Songnen Plain, Jilin Province, China, the prohibition of grazing has led to significant changes in plant communities and soil properties. However, the intricate interplay between soil physical and chemical attributes, the soil microbial community, and their combined influence on soil humus composition remains poorly understood. Our study aimed to evaluate the impact of natural vegetation restoration on soil properties, microbial community diversity, and composition in the soda-saline soil region of the Songnen Plain. We conducted assessments of soil physical and chemical properties, analyzed community diversity, and composition at a soil depth range of 0-20 cm. The study covered soils with dominant soda-saline vegetation species, including Suaeda glauca Bunge, Puccinellia chinampoensis Ohwi, Chloris virgata Swarta, Phragmites australis (Clay.), Leymus chinensis (Trin.), and Tzvelev. We compared these vegetated soils to bare land devoid of any plants. We found that soil organic content (SOC) in vegetation restoration areas was higher than in bare land, with SOC content varying between 3.64 and 11.15 g/kg in different vegetated areas. Notably, soil pH emerged as a pivotal factor, explaining 11.4% and 12.2% of the variance in soil bacteria and fungi, respectively. There were correlations between SOC content and the relative abundance of specific microbial groups, with Acidobacteria and Mortierella showing a positive correlation, while Actinobacteria, Gemmatimonadetes, and Ascomycota exhibited significant negative correlations with SOC. The disparities in SOC composition and content among the soda-saline vegetation types were primarily attributed to variations in pH. Consequently, reducing soil pH is identified as a critical step in the process of vegetation restoration in soda-saline land. Prohibiting grazing has the potential to increase soda-saline SOC content and enhance microbial diversity, with Leymus chinensis and Phragmites australis showing particularly promising results in terms of higher SOC carbon content and microbial diversity.

Soil and water conservation effects of different types of vegetation cover on runoff and erosion driven by climate and underlying surface conditions

Quantitative analyses of runoff and erosion under specific climatic (precipitation characteristics) and underlying surface conditions (slope, antecedent soil moisture) with different types of vegetation cover (or plant measures hereafter) remains a challenging research topic in semi-arid regions. The research site located in the Anjiagou watershed of Gansu Province, China, and used for this study has long-term monitoring data (1987 to 2019) of precipitation conditions, antecedent soil moisture, and runoff and erosion rates from a set of modified standard erosion plots characterized by different vegetation covers or plant measures (arbor forest land, shrub forest land, artificial grassland, natural grassland, and agricultural land) at three slopes (10°, 15°, 20°). Collected data was subjected to path analysis and stepwise regression to determine the main driving factors of runoff and soil erosion, as well as proper input variables for modeling. The results showed that models could be constructed with different variables for different types of vegetation cover (P < 0.05, ra2 > 0.55). The analyses also showed that moderate rain (10 – 25 mm) accounted for >60% of the variation in runoff and plant effects on runoff and soil erosion varied with the measures. Among plant measures, shrub forest had the best performance in reducing runoff and erosion for short-term precipitation events (shorter than 24 hrs), but under the long-durations (72 hrs) precipitation, natural grassland performed the best to prevent the occurrence of runoff and soil erosion. Compared with agricultural land, the rest of the plant measures had an average erosion reduction rate of 73%, which was about twice the runoff reduction rate (37%). Slope was found to play some role in controlling runoff and erosion variation. Compared to slopes of 10° and 20°, runoff and erosion reduction rates at 15° plots were lower. The key variables determining runoff rates under different plant measures included precipitation and maximum 30-minute precipitation intensity, followed by types of vegetation cover. In contrast, erosion rates mostly depended upon runoff and maximum 30-min precipitation intensity. We also found that coupling precipitation characteristics with antecedent soil moisture in the modelling could help produce a more accurate assessment of runoff and soil and water conservation as part of ecological restoration efforts involving typical plant measures under different topographical conditions in semi-arid areas.

Photosynthetically Active Radiation and Foliage Clumping Improve Satellite-Based NIRv Estimates of Gross Primary Production

Monitoring gross primary production (GPP) is necessary for quantifying the terrestrial carbon balance. The near-infrared reflectance of vegetation (NIRv) has been proven to be a good predictor of GPP. Given that radiation powers photosynthesis, we hypothesized that (i) the addition of photosynthetic photon flux density (PPFD) information to NIRv would improve estimates of GPP and that (ii) a further improvement would be obtained by incorporating the estimates of radiation distribution in the canopy provided by the foliar clumping index (CI). Thus, we used GPP data from FLUXNET sites to test these possible improvements by comparing the performance of a model based solely on NIRv with two other models, one combining NIRv and PPFD and the other combining NIRv, PPFD and the CI of each vegetation cover type. We tested the performance of these models for different types of vegetation cover, at various latitudes and over the different seasons. Our results demonstrate that the addition of daily radiation information and the clumping index for each vegetation cover type to the NIRv improves its ability to estimate GPP. The improvement was related to foliage organization, given that the foliar distribution in the canopy (CI) affects radiation distribution and use and that radiation drives productivity. Evergreen needleleaf forests are the vegetation cover type with the greatest improvement in GPP estimation after the addition of CI information, likely as a result of their greater radiation constraints. Vegetation type was more determinant of the sensitivity to PPFD changes than latitude or seasonality. We advocate for the incorporation of PPFD and CI into NIRv algorithms and GPP models to improve GPP estimates.

Modificação dos atributos físicos do solo em função da operação de subsolagem sob diferentes manejos

ABSTRACT Subsoiler performance can be influenced by crop residue in the soil through different types of vegetation cover. In any of these cover systems, the use of subsoilers for decompaction changes soil physical properties. The present study aimed to evaluate soil physical properties in different management systems using several subsoiling speeds and soil depths. The experiment was conducted at IF Goiano, Morrinhos Campus, Goiás state, Brazil. A completely randomized design was used in a split-plot scheme with 12 treatments and five replicates, totaling 60 plots. The factors corresponded to two management areas (rainfed and pasture), two subsoiling speeds (2.5 and 4.5 km h-1) and three soil depths (0.00-0.015; 0.15-0.30 and 0.30-0.45 m). The main plot consisted of the two management areas and the subplot the combination of the other two factors. Penetration resistance, bulk density, water content, soil mobilization and soil volumetric expansion were evaluated. The results were then submitted to analysis of variance and Tukey’s test (p ≤ 0.05). Penetration resistance and bulk density differed before and after subsoiling. The subsoiling speeds altered penetration resistance and soil mobilization. Pasture areas showed greater root penetration resistance, provided lower water content and favored greater soil volumetric expansion.

INDICATOR ATTRIBUTES OF SOIL QUALITY IN AREAS UNDER DIFFERENT LAND USE SYSTEMS, IN THE WESTERN AMAZON

The anthropization of natural environments, when performed inadequately, promotes the disruption of the ecological balance and can influence the fauna, flora and biodiversity in general, including the edaphic environment and its components. The objective was to evaluate the soil attributes in areas with different types of vegetation cover and different forms of soil management. The study was carried out in native forest area (Subperennial Equatorial Forest) and cultivated area (annual species), in Porto Velho, Rondônia, Brazil. Samples were collected in two layers (0-10 and 10-20cm), on a Latossolo Vermelho-Amarelo, to evaluate microbial biomass by the fumigation-extraction (FE) method, as well as the chemical and physical soil attributes. It was possible to verify a significant increase in soil density and reduction of moisture and improvement of chemical attributes resulting from the use of the area. The organic matter content decreased sharply in the managed area (25%), compared to the forest, in the superficial layer (0-10cm). Microbial C-biomass under the native forest showed 54% higher mean value (883 mgC g-1) compared to the managed area (410 mgC g-1) in the superficial layer. The microbial N-biomass ranged from 21.3 to 19.5 mgN.g-1 in the native forest area, and from 9.3 to 11.5 mgN g-1 in the managed area, respectively in the 0-10 and 10-20cm layers. In the native forest area, the addition of organic matter to the soil by the vegetation litter was an important conditioning factor for the microbial community, demonstrating the use of this attribute as an indicator of soil quality.

Accelerating Effect of Vegetation on the Instability of Rainfall-Induced Shallow Landslides

Rainfall-induced shallow landslides are widespread throughout the world, and vegetation is frequently utilized to control them. However, in recent years, shallow landslides have continued to frequently occur during the rainy season on the vegetated slopes of the Loess Plateau in China. To better probe this phenomenon, we considered vegetation cover in the sensitivity analysis of landslide hazards and used the transient rainfall infiltration and grid-based regional slope stability (TRIGRS) model to quantitatively describe the impacts of different types of vegetation cover on slope stability. Based on the rainfall information for landslide events, the spatiotemporal distributions of the pore water pressure and the factor of safety of the vegetated slopes were inverted under the driving changes in the soil properties under different vegetation types, and the average prediction accuracy reached 79.88%. It was found that there was a strong positive correlation between the cumulative precipitation and the proportion of landslide-prone areas in woodland covered by tall trees, grassland covered by shrubs and grasses, and cultivated land. The highest landslide susceptibility, which has the greatest potential to hasten the occurrence of rainfall-induced landslides, is found in woodland with tall trees. Therefore, this paper proposes the promoting relationship between vegetation and landslide erosion, which provides a new scientific perspective on watershed management to prevent shallow landslide disasters and manage and develop watershed vegetation.

UAV-based classification of maritime Antarctic vegetation types using GEOBIA and random forest

Development of vegetation communities in areas of Antarctica without permanent ice cover emphasizes the need for effective remote sensing techniques for proper monitoring of local environmental changes. Detection and mapping of vegetation by image classification remains limited in the Antarctic environment due to the complexity of its surface cover, and the spatial heterogeneity and spectral homogeneity of cryptogamic vegetation. As ultra-high resolution aerial images allow a comprehensive analysis of vegetation, this study aims to identify different types of vegetation cover (i.e., algae, mosses, and lichens) in an ice-free area of Hope Bay, on the northern tip of the Antarctic Peninsula. Using the geographic object-based image analysis (GEOBIA) approach, remote sensing data sets are tested in the random forest classifier in order to distinguish vegetation classes within vegetated areas. Because species of algae, mosses, and lichens may have similar spectral characteristics, subclasses are established. The results show that when only the mean values of green, red, and NIR bands are considered, the subclasses have low separability. Variations in accuracy and visual changes are identified according to the set of features used in the classification. Accuracy improves when multilayer information is used. A combination of spectral and morphometric products and by-products provides the best result for the detection and delineation of different types of vegetation, with an overall accuracy of 0.966 and a Kappa coefficient of 0.946. The method allowed for the identification of units primarily composed of algae, mosses, and lichens as well as differences in communities. This study demonstrates that ultra-high spatial resolution data can provide the necessary properties for the classification of vegetation in Maritime Antarctica, even in images obtained by sensors with low spectral resolution.

An Impact of Short-Term Climate Oscillations in the Late Pleniglacial and Lateglacial Interstadial on Sedimentary Processes and the Pedogenic Record in Central Poland

Environmental studies based on analyses of fluvio-aeolian successions with paleosols in central Poland, forming the central part of the European Sand Belt, are presented. Paleogeographic reconstruction was based on high-resolution analyses of four sites using sedimentological and paleopedological methods as well as forty-four optically stimulated luminescence and fourteen radiocarbon dating measurements. Age-identified individual lithological and soil units were first correlated between sites, emphasizing the differences between them. The results were then correlated with Greenland ice-core stratigraphic units reflecting global environmental changes in the Late Pleniglacial and Lateglacial interstadial, thus ranging from GS-2.1a, through the GI-1 complex (seven subunits), to GS-1. Studies revealed considerable sensitivity of fluvio-aeolian succession to climate changes and oscillations. Climate ameliorations are recorded in fossil soil horizons developed beneath different types of vegetation cover. We detected that the climate cooling GI-1d (the Older Dryas) was not the main phase of dune formation as had been claimed earlier. It is postulated that dunes in the extraglacial zone were formed mainly in GI-1c2 (the Early Allerød). Preexisting dunes were transformed in GS-1 (the Younger Dryas) and in the Early Holocene, locally interrupted by soil formation.

Analysis of spatial and temporal changes of vegetation cover and its driving forces in the Huainan mining area.

The Huainan mining area is rich in coal resources and has sparse vegetation and many collapsed waterways. Large-scale and long-term underground coal mining has led to a fragile ecological environment in the mining area, and it is urgent to solve the contradiction between coal development and ecological environmental protection. The Huainan mining area was selected as the research object, and the vegetation cover was extracted using 10-phase Landsat multispectral remote sensing images from 1989 to 2021 to analyze its spatial and temporal changes and driving forces to provide a scientific basis for the guided restoration of the ecological environment in the region. Combined with the image dichotomous model, regression slope, correlation coefficient, and standard deviation of vegetation cover grid points in different time series, standard deviation ellipse, and center of gravity migration, we analyzed the spatial and temporal variation pattern of vegetation cover for 33 years and revealed the responses of temperature, precipitation, population density, GDP, and afforestation area to vegetation cover. Results show the following: (1) from 1989 to 2021, the overall vegetation cover in the study area tended to decrease with 36.48% of the areas increasing and 63.52% of the areas decreasing, primarily in the very low and medium range; (2) the center of gravity of different types of vegetation cover generally shifted from north to south during 33 years; (3) climate and social activities had a substantial effect on the spatial heterogeneity of the vegetation cover in the study area. There is significant spatial heterogeneity in the effects of climate and social activities on the vegetation in the study area with human activities negatively correlating with vegetation cover. Mining activities are the primary driver of the evolution of regional vegetation cover, with climate change serving as a secondary driver.

Impacto de la cobertura vegetal en la erosión-deposición del suelo por efecto de escorrentía superficial

Introduction: In arid regions, soil losses are caused by torrential rainfall events and by the erosive energy of runoff. Objectives: To quantify the impact of the use of different types of vegetation cover on soil erosion and soil deposition caused by overland flow. Methodology: The experiment was carried out from July to September 2017 under a randomized block experimental design with three replications. The treatments evaluated were maize harvest residues and buffel grass (Cenchrus ciliaris L.) sowing (MHR + G), maize harvest residues (MHR), buffel grass sowing (G), and the control (C). Results: The MHR + G treatment reduced erosion by 44 % (26.3 t·ha-1) compared to the control (58.6 t·ha-1). Soil deposition was 47.6 and 51.7 t·ha-1 with MHR + G and G, respectively, while in C was 26.1 t·ha-1. Limitations of the study: The results found are valid for the soil and water conditions of this study Originality: There are few technical and scientific reports on the behavior of soil particle removal and deposition processes under runoff conditions. Conclusions: The layer thickness of soil removed and deposited, under overland flow conditions, depends on the type of soil cover. The MHR + G treatment significantly reduced soil erosion, making it a viable alternative.

Deep Subsoil Storage of Trace Elements and Pollution Assessment in Mountain Podzols (Tatra Mts., Poland)

Research highlights: this article refers to the deep storage of trace elements as a result of the podzolization process under different types of vegetation cover. This is also an attempt to trace differentiation in the distribution of trace elements in mountain soils under the podzolization process. Background and objectives: we focused on estimating whether the podzolization process of soils under various vegetation covers led to the deep storage of trace elements in the subsoil. Furthermore, the potential contamination of studied soils with trace elements using pollution indices was assessed. Materials and methods: in thirteen soil profiles under three different vegetation types, chosen chemical–physical properties, e.g., organically bonded and active forms of Al and Fe, podzolization indices, and trace element content (Cd, Pb, Zn, Cu, Cr, and Ni) were analyzed. Additionally, pollution indices, such as Geoaccumulation Index, Potential Ecological Risk, Pollution Load Index, and Contamination Security Index, were calculated. Results: the distribution of Al and Fe varied among the soil profiles, suggesting different rates of podzolization processes that were partially dependent on the type of vegetation. Exceptionally high values of Alo and Feo were noted in profiles P1 and P2 (1.53% and 2.52% for Alo, and 2.13% and 1.46% for Feo, respectively) in horizons Bs and BsC under Plagiothecio-Piceetum taricum. Some of the soils showed the expected distribution of trace elements as the result of the podzolization process revealed their accumulation in the spodic horizon. Moreover, four different patterns of trace element distribution were recognized. Often, the accumulation of trace elements occurred in Bs/BsC horizons, e.g., in case of Zn soils P8, P9, and P10, which reached 65.8, 68.0, and 72.30 mg∙kg−1, respectively. However, there were no large differences in trace element content in soils independent of the vegetation type. The pollution indices in most samples confirmed lack of contamination with trace elements. Only several soil horizons were moderately polluted and showed deterioration of soil quality or very low severity. Conclusions: in the majority of studied soils, the podzolization process resulted in the deep storage of trace elements, i.e., the accumulation of spodic horizon; however, in certain cases, it might have been related only to the different lithology, and appeared as anomalies not related to the dominant soil-forming process. Anomalies were characterized by a much higher content of trace elements in the BsC horizon compared to the upper O horizons. Obtained data of trace elements, as well as values of pollution indices, did not indicate pollution. This lack of pollution was related to localization of soils within a topographic barrier that protected them from the deposition of potential trace element–rich pollution.

Los recursos naturales de la finca El Morro, San Miguelito, Río San Juan, Nicaragua, 2013

This study was carried out at El Morro farm, San Miguelito municipality, Rio San Juan department, Nicaragua. The biophysical characteristics of the forest, wildlife, water and soil resources were evaluated. It was inventoried with a systematic sampling design according to the different types of vegetation cover, such as: open forest, tacotal (which is defined as uncultivated land covered with thick undergrowth) and scattered trees in pasture. Two circular plots were located, with a radius of 15 meters, separated at a distance of three km between them, the wild fauna was done simultaneously with the collection of floristic information. This study tries to know the floristic richness and the silvicultural state of the arboreal vegetation, the existing fauna, the quality of the water and the characterization of the soil, in order to contribute to decision-making in the implementation of good practices for the management of all existing resources on the farm.

Los recursos naturales de la finca El Morro, San Miguelito, Río San Juan, Nicaragua, 2013

Este estudio realizado en la finca El Morro, municipio de San Miguelito, departamento de Río San Juan, Nicaragua. Fueron evaluadas las características biofísicas de los recursos bosque, fauna silvestre, agua y suelo. Fue inventariado con diseño de muestreo sistemático de acuerdo a los diferentes tipos de cobertura vegetal, tales como: bosque abierto, tacotal y árboles dispersos en potrero. Se ubicaron dos parcelas circulares, con un radio de 15 metros, separadas a una distancia de tres km entre ellas, la fauna silvestre se hizo simultánea al levantamiento de la información florística. En este estudio se trata de conocer la riqueza florística y el estado silvicultural de la vegetación arbórea, la fauna existente, la calidad del agua y caracterización del suelo, con la finalidad de contribuir a la toma de decisiones en la implementación de buenas prácticas para el manejo de todos los recursos existentes en la finca

Influence of vegetation cover on the temperature dynamics of sandy soil

To study the temperature regime of soils, an autonomous atmospheric-soil temperature complex is used. The complex is installed at three sites with sandy soil and various kinds of vegetation cover: burnt areas, pine forest, and open sand. Observations are made from October 13, 2011 to August 16, 2019 in a soil profile from the surface to the 320 cm depth. An analysis of the temperature regime of sandy soil reveals main similarities and differences between the three sites with different types of vegetation cover. In summer, the sites with pine forest and burnt areas of pine forest warm up less intensively than the site with open sand. Due to the greater openness, this site is the warmest during the warm period. In winter, pine forest, due to its high vegetation, is a barrier to wind, reducing snow blowing, and prevents the radiation cooling of the surface. To a slightly lesser extent, these functions are performed by loose vegetation in the burnt areas. The influence of vegetation under different weather conditions (clear sky/overcast) is considered. Cloud cover, as well as vegetation, helps to reduce the variability of soil temperature. The results of the study show that after forest fire restoration of vegetation cover naturally contributes to the partial restoration of the soil temperature regime.

Attribution of the land surface temperature response to land-use conversions from bare land

Abstract Since the early 1980s, large-scale revegetation has been implemented in Northwest China and has been found to be useful in desertification prevention. However, it remains unclear, how land cover changes affect local meteorological conditions, such as land surface temperature. In this study, the land surface temperature response to land-use changes was comparatively evaluated using micrometeorological observations from a cropland site, a mixed forest site, a shrubland site, and adjacent bare land sites in the Heihe River Basin, Northwest China. The surface temperature changes (ΔTs) are decomposed into contributions from changes in radiative forcing, heat resistance, evapotranspiration, soil heat flux and air temperature based on the intrinsic biophysical mechanism (IBM) and the two-resistance mechanism (TRM). The results indicate that 1) the IBM attribution method is more applicable than the TRM method in these arid ecosystems; 2) the influence of different types of vegetation cover on the surface temperature exhibits temporal variance on the diurnal and seasonal time scales; 3) the dominant biophysical components in the daytime of the growing season are evaporative cooling in the cropland paired sites and heat resistance change in the mixed forest paired sites, but these two components are both at a moderate level in the shrubland paired sites. This study provides a useful reference for local climate impact assessments when implementing environmental protection projects in similarly arid areas.

Impacts of Vegetation on Quantity and Quality of Runoff from Green Roofs

As a key component of green roofs, vegetation may have significant impacts on both the quantity and quality of runoff. In this study, the effects of vegetation on both the quantity and quality of runoff from green roofs are investigated through monitoring the rainfall and runoff processes of green roofs with four different types of vegetation cover (Portulaca grandiflora, Sedum lineare, Festuca elata, and a non-vegetated bed as control) during 2017. The growth characteristics of the vegetation were also monitored, and the nutrients (NH4+-N, NO3--N, NO2--N, and PO43--P) and heavy metals (Cr, Cd, Cu, and Ni) in the rainwater and runoff were measured. The results show that the average rainfall event-based runoff reduction rates for the four green roof types were 51.3%, 41.5%, 36.3%, and 33.0%, respectively. Furthermore, the runoff reduction rates of the green roof planted with Portulaca grandiflora were significantly higher than both the Festuca elata green roof and the non-vegetated bed (P<0.05). The green roofs planted with Portulaca grandiflora and Sedum lineare both acted as sinks for the nutrients. The Portulaca grandiflora green roof, which had a higher biomass, provides higher nutrient load reduction rates (59.6%, 99.9%, 82.5%, and 25.7% for NH4+-N, NO3--N, NO2--N, and PO43--P, respectively) than the Sedum lineare green roof (52.5%, 89.3%, 75.3%, and 7.8%, respectively). The Festuca elata green roof and the non-vegetation bed acted as sinks for NH4+-N and NO2--N but were sources of NO3--N and PO43--P. All four of the green roofs were sinks for DCd, with pollution load reduction rates of 19.2%, 41.5%, 38.4%, and 31.1%, respectively. However, all the green roofs acted as the sources of DCr, DCu, and DNi.

Impacts of Vegetation on Hydrological Performances of Green Roofs Under Different Rainfall Conditions

Vegetation is an important component of green roofs and may affect their hydrological performance through the processes of rainwater interception and evapotranspiration. Based on the rainfall-runoff observations of green roofs with four types of vegetation covers (Portulaca grandiflora, Sedum lineare, Festuca elata, and bare substrate) located in Beijing during 26 rainfall events from April to October 2017, the impacts of vegetation cover on the hydrological performance of green roofs were investigated using runoff and peak discharge reduction rates and time-delay of runoff generation and peak discharge as indices. For the 12 green roofs, there was a significantly negative correlation (P<0.01) between runoff reduction rate and rainfall event volume. For low rainfall (<10 mm), the runoff reduction rates of all the green roofs were equal or close to 100%. When the rainfall volume increased to about 30 mm, the runoff reduction rates dropped to below 70%. For the heaviest rainfall event during the observation period (81.4 mm), the runoff reduction rates of all the green roofs were less than 55%. The impacts of vegetation on the hydrological performance of green roofs changed with rainfall conditions. The differences between runoff reduction rates of green roofs with different types of vegetation cover were largest for the heavy rainfall events. For the moderate rainstorm events, the differences were slightly lower. For light rainfall events, however, no significant differences were observed among the runoff reduction rates of green roofs with different types of vegetation cover, as little runoff was generated. Vegetation cover could enhance the hydrological performance of green roofs, as the runoff and peak discharge reduction rates and time-delay of runoff generation and peak discharge of green roofs covered with vegetation were all better than those of the bare substrate for all the groups of rainfall events except the light rainfall. Vegetation-covered green roofs with P. grandiflora performed the best, as the average height and aboveground biomass per unit area of P. grandiflora were the largest.

Organic farming favours bird communities and their resilience to climate change in Mediterranean vineyards

Farmland birds have suffered notable declines in Europe in recent decades, mainly due to agricultural intensification and climate change. Organic farming, which has been shown to enhance biodiversity, is increasingly being put into practice in European vineyards. Nevertheless, no previous studies have reported significant positive responses in avian communities to organic practices. On the other hand, cover cropping is a common practice in both organic and conventional vineyards and is thought to have positive effects on bird communities and, particularly, on insectivorous species that may help control pests in agroecosystems. In this work, we studied bird communities in Mediterranean vineyards in Catalonia (NE Iberian Peninsula) in both the breeding and wintering seasons, and tested the effects of two common management options – organic vs. conventional farming and herbaceous cover vs. bare soil – on bird communities. In particular, we focused on (a) insectivorous birds that may help control pests and (b) avian species negatively affected by climatic warming whose population fluctuations may reflect the resilience of these bird communities to future climate change. Organic farming had a positive effect on vineyard bird communities and, specifically, increased species richness and overall bird abundance. This farming technique also positively affected the abundance of both insectivorous species and species whose populations are declining due to climate change. The presence of inter-row herbaceous cover between vines also had positive effects on bird community parameters, specifically in spring and in organic vineyards, when herbaceous cover favours species richness and the abundance of insectivorous species. However, further investigations are still needed to better understand the effects of different types of vegetation cover - i.e. plant origin and composition (e.g. sown vs. spontaneous vegetation) and proportion of vegetation cover (full vs. partial vegetation cover) - when employed as tools in wildlife conservation. This work provides useful information regarding bird conservation, which will help mitigate the effects of climate change on bird populations.