Is the QBS-ar index a good tool to detect the soil quality in Mediterranean areas? A cork treeQuercus suberL. (Fagaceae) wood as a case of study

Assessing soil quality of Italian Western Alps protected areas by QBS-ar: impact of management and habitat type on soil microarthropods

Soil fauna has a crucial importance for the functioning of ecosystems and their conservation. Soil biota has a role in soil formation and distribution of organic matter, and groups like microarthropods can be used as indicators to assess soil quality and are often employed in monitoring programs. In the present study, the QBS-ar index, an index based on the presence/absence of microarthropod groups, was used to assess the level of soil quality in nine different sampling sites in the "Parco Naturale delle Alpi Marittime" and in the "Parco Naturale del Marguareis" (Cuneo, Piedmont). Forest soils, with different degree of management, and open environments (e.g., grasslands and peatlands) were analyzed comparatively, to investigate whether microarthropod fauna might be influenced by management and habitat type.The results show QBS-ar values are significantly higher in woodland soils compared to grasslands and peatlands (p < 0.05). The latter shows no significant difference between each other, although grasslands show a large range of values (108-214). Forest management does not seem to influence QBS-ar values (183-239), showing stable microarthropod communities both in the managed and unmanaged areas. In addition to this, QBS-ar values do not differ significantly in the different forest coenoses, confirming that woodlands have similar index values (p = 0.7).This study confirms that QBS-ar values in natural areas can vary depending on the environment. It is therefore important to consider clustering habitat types before assessing quality classes for QBS-ar values. Finally, sustainable forest management in the study area does not seem to affect significantly soil microarthropod presence in woodland sites.

Urban soil quality deteriorates even with low heavy metal levels: An arthropod-based multi-indices approach

Urban-induced habitat conversion drastically changes soil life in a variety of ways. Soil sealing, human disturbance, habitat fragmentation, industrial and vehicular pollution are the main causes of urban soil degradation. Soil arthropods, as one of the most abundant and diverse group of soil fauna, are involved in many soil processes that are of great importance in maintaining soil health and multifunctionality. Nevertheless, soil quality is still mainly characterized by physical, chemical, and microbiological parameters. Here, we assessed and compared the biological soil quality in woody (REF: reference forest, REM: remnant forest) and nonwoody (TURF: public turfgrass, and RUD: ruderal habitat) types of urban green spaces along a disturbance and management intensity gradient in the Budapest metropolitan area (Hungary), using community metrics and soil arthropod-based indicators. Vegetation cover and landscape characteristics of study sites were quantified through vegetation and urbanization indices, respectively. Basic soil properties, total and bioavailable concentrations of the main heavy metals (Cd, Co, Hg, Ni, Zn) were also measured. Acari, Collembola, and Hymenoptera (mainly Formicidae) were the most abundant groups. Litter-dweller taxa, particularly Protura, proved to be the most sensitive to urban disturbance. Representatives of Hemiptera, Diptera, Symphyla, and Pauropoda were common in low densities. The taxonomic diversity of soil arthropod assemblages in nonwoody and woody habitats was similar. Although the integrated faunal indices showed no differences among soil habitat types, they provided different responses and, consequently, different information. Our findings demonstrated that the biological quality and arthropod community structure of soils were strongly impacted by soil C/N and heavy metal contamination. We found that low and moderate levels of pollution have adverse effects on edaphic fauna, suggesting biological degradation of soils, even below pollution limits. Nevertheless, more disturbed urban green spaces have been shown to play a significant role in maintaining belowground biodiversity, thereby soil functions.

Soil Fauna of Ranibari Community Forest, Kathmandu, Nepal

Ranibari Community Forest (RCF) is the important forest patch present within the highly urbanized Kathmandu Valley with information gaps on soil fauna. This study aimed to explore the soil meso and macrofauna of the forest. Fourteen random quadrats (1 × 1 m2) were laid within seven blocks. Leaf litter samples and soil cores were collected, screened, sieved, and searched under a white sheet, once a fortnight from May to November 2019. The results showed that the diversity, abundance, and richness of soil fauna were the highest in the summer season (H´ = 2.897, abundance = 1,973, S = 84) dominated by Collembola. The Soil Biological Quality Index (QBS-ar) value was also found to be the highest in summer (QBS-ar = 417) and successively decreased in succeeding seasons. Soil fauna was diverse and evenly distributed in soil layers throughout the seasons, but the abundance was greater in leaf litters, particularly in summer. Fauna like Chilopoda, Diplopoda, Haplotaxida, and Isopoda were seen to be affected negatively by soil temperature in summer and autumn seasons. Soil moisture content was found to be positively correlated with immature insects, earthworms, and millipedes in the rainy and autumn seasons. Besides, the pH of the soil was seen to affect Diplura only in the autumn season. The relation of fauna with the physicochemical parameters (temperature, moisture, and pH) and also with other taxa showed their ecological roles and adaptation to a specific microclimate.

Soil Arthropods in the Douro Demarcated Region Vineyards: General Characteristics and Ecosystem Services Provided

Viticulture is one of the oldest and most profitable forms of agriculture; it is also one of the most intensive farming systems. As intensive cultivation threatens the environment, there is increasing interest in the concept of sustainability within the wine industry, as well as new business opportunities, as customers begin to pay more attention to environmental and sustainability issues. Recognizing the key role of soil quality in environmentally and economically sustainable viticulture makes it essential to understand better soil arthropod communities, given their crucial functions in maintaining soil quality and health. The ‘Douro Demarcated Region’ (DDR) in northern Portugal offers good potential, in regards to biodiversity, due to its significant areas of non-crop habitats. This work aims to compile information on soil arthropod communities (both soil surface and soil-living) collected in the DDR vineyard agroecosystems. A description of the ecosystem services provided by them, as a basis for the development and implementation of sustainable viticulture systems, is also an objective of this work. An important set of soil arthropods necessary for the delivery of vital ecosystem services for viticulture, with particular reference to supporting and regulating services, occurred in this ecosystem. Eight classes were chiefly represented in a sample of about 167,000 arthropod specimens: Arachnida, Chilopoda, Diplopoda, Entognatha, Insecta, Malacostraca, Pauropoda, and Symphyla. The most representative were Entognatha and Insecta in soil-surface arthropods, and Arachnida and Entognatha in soil-living arthropods. The presence of recognized groups as bioindicators in agroecosystems, such as soil quality indicators, is also revealed. This knowledge is expected to contribute to a more efficient and sustainable management of the viticultural ecosystem.

The influence of heavy metals on biological soil quality assessments in the Vaccinium myrtillus L. rhizosphere under different field conditions

The aim of this study was to determine the influence of heavy metals on biological soil quality assessments in Vaccinium myrtillus L. rhizosphere soil as well as in non-rhizosphere soil from different polluted sites. The presented study was also conducted in order to determine any differences in the soil physicochemical and biological properties between the Vaccinium rhizosphere soil and the non-rhizosphere soil. The content of heavy metals and their potential bioavailability, content of macronutrients, physicochemical soil properties, activity of six soil enzymes and microarthropod communities were determined. Soil organic matter, the levels of C, N and all the studied macronutrients and almost all enzyme activity were significantly higher in the rhizosphere soil than in the non-rhizosphere soil. At the most contaminated site, the content of heavy metals was also higher in the rhizosphere soil, but their bioavailability was lower than in the non-rhizosphere soil. The β-glucosidase and urease activity in the soil correlated most negatively with the examined metals. The levels of two enzymes were also strongly impacted by the organic matter-the C and N levels and pH. The number of microarthropods as well as the QBS (soil biological quality index) and FEMI (abundance-based fauna index) were higher in the rhizosphere soil. The bilberry rhizosphere soil had stronger correlation coefficient values between the measured parameters than the non-rhizosphere soil, which suggests that rhizosphere soil is more sensitive and could be used in the monitoring and assessment of forest ecosystems. β-glucosidase and urease were the most sensitive indicators of the adverse impact of Cd, Zn and Pb. The FEMI index seems to be a better indicator than the QBS for identifying differences in soil quality.

Soil Health and Arthropods: From Complex System to Worthwhile Investigation

The dramatic increase in soil degradation in the last few decades has led to the need to identify methods to define not only soil quality but also, in a holistic approach, soil health. In the past twenty years, indices based on living communities have been proposed alongside the already proven physical-chemical methods. Among them, some soil invertebrates have been included in monitoring programs as bioindicators of soil quality. Being an important portion of soil fauna, soil arthropods are involved in many soil processes such as organic matter decomposition and translocation, nutrient cycling, microflora activity regulation and bioturbation. Many studies have reported the use of soil arthropods to define soil quality; among taxa, some have been explored more in depth, typically Acari and Collembola, while generally less abundant groups, such as Palpigradi or Embioptera, have not been investigated much. This paper aims to evaluate and compare the use of different soil microarthropod taxa in soil degradation/quality studies to highlight which groups are the most reported for soil monitoring and which are the most sensitive to soil degradation. We have decided not to include the two most present and abundant taxa, Acari and Collembola, in this paper in consideration of the vast amount of existing literature and focus the discussion on the other microarthropod groups. We reported some studies for each taxon highlighting the use of the group as soil quality indicator. A brief section reporting some indices based on soil microarthropods is proposed at the end of this specific discussion. This paper can be considered as a reference point in the use of soil arthropods to estimate soil quality and health.

Long-term ecological effects of the red mud disaster in Hungary: Regeneration of red mud flooded areas in a contaminated industrial region

As one of the most severe ecological disasters ever to take place in Europe, the 2010 red mud accident has left behind long-term environmental impact, prompting the need for monitoring of soil biodiversity. Red mud (wet storage solution) can be regarded as a complex mixture of contaminants due to its extreme alkalinity and the presence of potentially toxic trace elements. After-effect investigations on soil properties and soil microarthropods were carried out in three distinct habitat types (agricultural land, grassland, woodland) in the red mud affected area. Soils in the red mud affected area were moderately to strongly alkaline (pH 7.5 to 8.5). Total content of trace metals Cd, Ni, Cr exceeded threshold concentrations for soil. Acari and Collembola were by far the most abundant taxa, while important groups like Pauropoda, Protura and Symphyla were completely absent from the samples of red mud affected plots. These observations were also reflected by the low values of the soil biological quality (QBS-ar) index. Independently of habitat types, total collembolan abundance tended to be lower in the contaminated area when compared with nearby control samples. Typical species distribution of Collembola communities in the contaminated area generally included one or two very common and abundant species and more, relatively rare species of low abundance. In the red mud affected open habitats, a distinct eudominance of Brachystomella parvula and Parisotoma notabilis was observed; whereas in contaminated woodland Parisotoma notabilis formed the bulk of the community with Sphaeridia pumilis, Folsomia manolachei and F. quadrioculata being subdominant. Species sensitive to alkalinity and red mud components (e.g. Hypogastrura vernalis, Lepidocyrtus tomosvaryi) were completely absent or were present only in limited numbers in the contaminated samples.

Does soil fauna like truffles just as humans do? One-year study of biodiversity in natural brûlés of Tuber aestivum Vittad

There are numerous aspects related to Tuber species, which have not been explored to date. Tuber aestivum Vitt. is an ectomycorrhizal fungus, that produces an area (called brûlé) around the host plant trunk, where the germination of other plants is inhibited. What happens inside this particular environment is still not sufficiently understood, especially in terms of soil fauna. A previous work showed that there were higher microarthropod abundances outside during the period of maximum activity of the mycelium. The genus Folsomia (Isotomidae Family; Order Collembola) showed higher abundance inside. The aim of this paper is to investigate the effects of brûlé, on soil parameters and soil fauna, during the annual biological cycle of T. aestivum. This study was carried out in nine spontaneous brûlés situated in Northern Italy (Emilia Romagna Region - Piacenza Province). Soil cores were collected in order to perform soil chemical and biological analysis. Moisture content, pH, organic matter content, total organic carbon were analyzed. Biodiversity and soil quality indices were applied. We found higher pH, lower carbon and organic matter content within the brûlé. Soil fauna community also showed some differences, seasonal and inside vs outside the brûlé. Some groups seem to be negatively affected by Tuber while Folsomia genus recorded almost always higher values inside. These results suggest that some organisms, such as some Collembola, might find a favorable environment inside the brûlé, while others - a negative one. However, these results should be compared by other analysis either on other Tuber species and on other soil organisms, such as nematodes and earthworms.

Impact of mechanical mowing and chemical treatment on phytosociological, pedochemical and biological parameters in roadside soils and vegetation

Many chemical and non-chemical strategies have been applied to control weeds in agricultural and industrial areas. Knowledge regarding the effects of these methods on roadside vegetation is still poor. A 2-year field experiment was performed along a road located near Livorno (Tuscany, central Italy). Eight plots/strips were identified, of which four were subjected to periodical mechanical mowing and the remaining four were treated with a chemical herbicide based on glyphosate (the producer's recommended rates were used for the selective control of broad-leaved weeds). Our results clearly showed that roadside soil and vegetation are a significant reservoir of anthropogenic activities which have a strong negative effect on several phytosociological, pedochemical and biological parameters. Compared with conventional mechanical mowing, chemical treatment induced (i) a significant increase in organic matter in the upper plot layers (+18%), and (ii) a marked reduction in weed height throughout the entire period of the experiment. Irrespectively of the kind of treatment, no significance differences were detected in terms of (i) biological quality of soil (the abundance and diversity of arthropod communities did not change), and (ii) plant elemental content (bulk concentrations of analysed trace elements had a good fit within ranges of occurrence in the "reference plant"). The glyphosate partially controlled broad-leaved weeds and this moderate efficacy is dependent upon the season/time of application. In conclusion, the rational and sustainable use of chemical herbicides may be a useful tool for the management of roadside vegetation.