Enzymes are considered to be a key soil component catalysing important transformations related to decomposition and nutrient turnover, and their activity in soil can be used as a measure of soil ...health. As part of the Síkfőkút DIRT (Detritus Input and Removal Treatments) Project in a temperate deciduous forest in northern Hungary, we examined the extent to which enzyme activity in soil is influenced by both the quality and quantity of plant detrital inputs. DIRT treatments include doubling of leaf litter and woody debris inputs as well as removal of litter and trenching to prevent root inputs. Our objective was to examine seasonal dynamics of soil phosphatase and β-glucosidase activities and to determine the effects of detrital manipulations on these dynamics. We found that the litter additions did not affect enzyme activities, but removal of roots caused significant decreases in enzyme activities. We conclude that plant-induced changes to soil enzyme activities are driven primarily by readily available, labile carbon provided by root turnover and root exudation rather than by aboveground detrital inputs. However, these results could also have been affected by changes in soil chemistry with detrital input removal: after only 6 years of litter removal, soil cation content decreased and soils became more acidic, both of which could inhibit enzyme activity. The soil phosphatase and β-glucosidase enzymes measured showed similar seasonal dynamics. Both enzymes showed the highest activities in spring coincident with high soil moisture and, presumably, high root activity. The minimal response of soil enzyme activity to dramatic litter additions suggests a level of resilience in ecosystem function in this forest, and suggests that aboveground litter is not a significant source of labile carbon to microbes in the mineral soil.
•Litter additions did not affect enzyme activities.•Detritus removal significantly reduced enzyme activities.•Root removal significantly reduced enzyme activities.•Enzyme activity are driven primarily by labile carbon.•Aboveground litter is not a significant source of labile carbon to microbes.
Grassland managers and scientists are increasingly interested in cost-effective alternative ways of grassland biodiversity conservation. Prescribed burning is a promising management tool which should ...be integrated in the planning of management efforts. In addition, small-scale prescribed burning is an effective fire suppression strategy to decrease the serious negative impacts of uncontrolled burnings on ecosystems and human life. Prescribed burning forms an integral part of the North-American grassland management practice, while in Europe it is rarely applied, despite the fact that uncontrolled burning occurs frequently in some regions. Our goal was to evaluate the use of prescribed burning as a promising but neglected management tool in European grasslands. We found that European studies on prescribed burning of grasslands are scarce and we conclude that annual burning is usually not an appropriate option for the conservation of species-rich grasslands. We reviewed burning studies from North-America to identify findings which might be adapted to the European grassland conservation strategy. In North-America, contrary to Europe, the application of burning is fine tuned in terms of frequency and timing, and usually combined with other restoration measures (grazing or seed sowing). Thus, we conclude that with the application of carefully designed prescribed burning, multiple conservation goals, e.g. invasion control and enhancing landscape-level heterogeneity, can be linked with an effective fire suppression strategy. We emphasize that for the application of prescribed burning in Europe, the general findings of carefully designed case studies should be combined with the practical knowledge of conservation managers concerning the local application circumstances to reach specific management objectives.
Graslandmanager und -wissenschaftler sind zunehmend an kostengünstigen Methoden des Biodiversitätsschutzes auf Grasländern interessiert. Kontrolliertes Abbrennen ist eine vielversprechende Methode, die bei der Planung von Managementmaßnahmen berücksichtigt werden sollte. Darüber hinaus ist kleinräumiges kontrolliertes Abbrennen ein effektives Mittel gegen die negativen Auswirkungen von Wildfeuern auf Ökosysteme und das menschliche Leben. Kontrolliertes Abbrennen bildet einen integralen Bestandteil der praktischen Graslandbewirtschaftung in Nordamerika, während es in Europa nur selten angewendet wird, obwohl unkontrollierte Brände in manchen Regionen häufig auftreten. Unser Ziel war, den Nutzen kontrollierten Abbrennens in Europa zu bewerten. Wir fanden, dass europäische Untersuchungen zum kontrollierten Abbrennen auf Grasländern selten sind, und wir schließen, dass jährliches Abbrennen gewöhnlich keine geeignete Option für den Schutz von artenreichen Grasländern darstellt. Wir werteten auch Feuerstudien aus Nordamerika aus, um Befunde, die an die europäische Strategie zum Graslandschutz angepasst werden könnten, zu identifizieren. In Nordamerika ist die Anwendung von Feuer im Gegensatz zu Europa, was Häufigkeit und Zeitpunkt anlangt, fein abgestimmt und normalerweise mit anderen Rekultivierungsmaßnahmen wie Beweidung oder Aussaat kombiniert. Wir schließen somit, dass mit der Anwendung von sorgfältig geplantem kontrolliertem Abbrennen zahlreiche Schutzziele (z.B. Kontrolle von invasiven Arten, Steigerung der Landschaftsheterogenität) mit einer effektiven Feuerschutzstrategie verbunden werden können. Wir betonen, dass für die Anwendung von kontrolliertem Abbrennen die allgemeinen Ergebnisse von sorgfältig geplanten Fallstudien mit dem praktischen Wissen von Naturschutzmanagern über die lokalen Anwendungsumstände kombiniert werden sollten, um spezifische Managementziele zu erreichen.
Grasslands used to be vital landscape elements throughout Europe. Nowadays, the area of grasslands is dramatically reduced, especially in industrial countries. Grassland restoration is widely applied ...to increase the naturalness of the landscape and preserve biodiversity. We reviewed the most frequently used restoration techniques (spontaneous succession, sowing seed mixtures, transfer of plant material, topsoil removal and transfer) and techniques used to improve species richness (planting, grazing and mowing) to recover natural-like grasslands from ex-arable lands. We focus on the usefulness of methods in restoring biodiversity, their practical feasibility and costs. We conclude that the success of each technique depends on the site conditions, history, availability of propagules and/or donor sites, and on the budget and time available for restoration. Spontaneous succession can be an option for restoration when no rapid result is expected, and is likely to lead to the target in areas with high availability of propagules. Sowing low-diversity seed mixtures is recommended when we aim at to create basic grassland vegetation in large areas and/or in a short time. The compilation of high-diversity seed mixtures for large sites is rather difficult and expensive; thus, it may be applied rather on smaller areas. We recommend combining the two kinds of seed sowing methods by sowing low-diversity mixtures in a large area and high-diversity mixtures in small blocks to create species-rich source patches for the spontaneous colonization of nearby areas. When proper local hay sources are available, the restoration with plant material transfer can be a fast and effective method for restoration.
The present and future of grassland restoration Török, Péter; Brudvig, Lars A.; Kollmann, Johannes ...
Restoration ecology,
April 2021, 2021-04-00, 20210401, Letnik:
29, Številka:
S1
Journal Article
Recenzirano
Odprti dostop
Grasslands contribute greatly to biodiversity and human livelihoods; they support 70% of the world's agricultural area, but are heavily degraded by human land use. Grassland restoration research and ...management receives less attention than forests or freshwater habitats, although grasslands are critical for sustaining ecosystems multifunctionality and capacity to support biodiversity. In this article, we introduce a Special Issue which considers major trends and prospects in grassland restoration. We identified three key topics: First, restoration must confront widespread seed and site limitations, and new monitoring methods, including remote sensing techniques, are critical for restoration projects. Second, we highlight that restored grasslands typically require ongoing disturbance management and that research is required to determine optimal approaches for implementing this management during restoration. Third, global and regional restoration agendas should be harmonized with site‐level goals, and syntheses of current knowledge and research needs must guide grassland restoration across scales. We also identify research gaps to be filled, and challenges which grasslands face in the future: (1) a need for careful target vegetation selection and climate‐adaptive restoration; (2) lack of knowledge in dynamics and restoration of several regions and grassland types, including drylands and (sub)tropical regions; (3) increased importance of species arrival sequence, and high stochasticity of species establishment; and finally (4) issues of post‐restoration management to guarantee long‐term sustainability of restored sites. A new generation of research and restoration projects to bridge these gaps is necessary to mitigate environmental challenges spanning localities to the globe as we commence the UN Decade on Ecosystem Restoration.
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•Air pollution is reflected by the Air Pollution Tolerance Index (APTI).•We compared APTI values of tree species across cities in 3 continents.•We found that APTI values reflect ...pollution in industrial, roadside and urban areas.•We found a strong positive correlation between APTI values and the size of cities.•We demonstrated that APTI is an especially useful tool for assessing urban health.
Air Pollution Tolerance Index (APTI) is used to assess how tolerant plant species are of air pollution; it also serves to identify tolerant plant species that can be useful for pollution removal. APTI is calculated from parameters that are affected by air pollutants, such as ascorbic acid content, total chlorophyll content, relative water content and pH of leaf extract. In this study we report APTI values of two common tree species (Celtis occidentalis and Tilia sp.) in Debrecen, Hungary. We also ran a meta-analysis to compare APTI values among various global cities and land use types (industrial, roadside and urban) using robust ANOVA. APTI’s relationship with city population and PM10 (particulate matter with aerodynamic diameter smaller than 10 μm) was analysed using regression modelling and Principal Component Analysis. We applied Random Forest Regression for statistical model building. We demonstrated that the tolerance of tree species is higher in industrial areas and in cities with high pollution levels than in control areas. We found a strong positive correlation between APTI and the size of cities. The cities showed a separation along the first principal component, which was also correlated with APTI and the size of cities. Our results show that APTI is an efficient tool in air pollution monitoring and in decision making during urban development and urban greening.
Environmental health is an essential component of the quality of life in modern societies. Monitoring of environmental quality and the assessment of environmental risks are often species based on the ...elemental concentration of deposited dust. Our result suggested that stomata size and distribution were the most important factors influencing the accumulation of air contaminants in leaves. We found that the leaves' surfaces of Acer negundo and Celtis occidentalis were covered by a large number of trichomes, and these species have proven to be suitable biomonitors for atmospheric pollution difficult; these can be overcome using bioindicator species. Leaves of Padus serotina, Acer campestre, A. negundo, Quercus robur and C. occidentalis were used to assess the amount of deposited dust and the concentration of contaminants in deposited dust in and around the city of Debrecen, Hungary. Samples were collected from an urban, suburban and rural area along an urbanization gradient. The concentrations of Ba, Cu, Fe, Mn, Ni, Pb, S, Sr and Zn were determined in deposited dust using ICP–OES. Scanning electron microscopy (SEM) was used to explore the morphological structure and dust absorbing capacity of leaves. We found significant differences in dust deposition among species, and dust deposition correlated with trichomes' density. Principal component analysis (PCA) also showed a total separation of tree.
•Dust is used as indicators of the accumulation of inorganic pollutants.•Scanning EM was used to explore the morphological structure of leaves.•Amount of dust deposited of leaves correlated with trichomes' density.•A. negundo, C. occidentalis and Q. robur are suitable to indicate air contaminants.•A. negundo and C. occidentalis are suitable to decrease the amount of dust in air.
Fragmented natural habitats within human-transformed landscapes play a key role in preserving biodiversity. Ants as keystone species are essential elements of terrestrial ecosystems; thus, it is ...important to understand the factors influencing their presence. In a large-scale multi-site study, we surveyed ant assemblages using sweep netting and D-vac sampling on 158 ancient burial mounds preserving grassland habitats in agricultural landscapes in East-Hungary. We asked the following questions: (1) How do habitat factors and landscape composition affect species richness and functional diversity of ants? (2) Which ant traits are affected by habitat factors and landscape composition? Despite their small sizes, mounds as permanent and relatively undisturbed landscape elements could provide safe havens for diverse ant assemblages even in transformed agricultural landscapes. The complex habitat structure of wooded mounds supported high species and functional diversity of ant assemblages. Ant species on wooded mounds had small or medium-sized colonies, enabling the co-existence of more species. The effect of landscape composition on ant assemblages was mediated by habitat factors: steep slopes buffered the negative effect of the cropland matrix and enabled higher ant diversity.
Land use changes have resulted in the loss and isolation of semi-natural habitats worldwide. In intensively used agricultural landscapes the remnants of natural flora only persist in small habitat ...islands embedded in a hostile matrix. In the steppe zone burial mounds, so-called kurgans, have the potential to preserve the natural flora and act as local biodiversity hotspots. Exploration of the factors driving biodiversity in isolated habitat fragments is crucial for understanding the ecological processes shaping their vegetation and for designing effective strategies for their protection. We sampled the vegetation of 44 isolated kurgans in East-Hungary and studied the effects of habitat area, slope, recent disturbance, past destruction and the level of woody encroachment on the species richness and cover of grassland specialist and problem species (competitor weedy species). We used model selection techniques and linear models for testing relevant factors affecting specialist species in grassland fragments. We found that the biodiversity conservation potential of kurgans is supported by their steep slopes, which provide adequate habitat conditions and micro-climate for steppic specialist plant species. Specialist species are threatened both by recent disturbances and encroachment of alien woody species, especially black locust. Factors supporting specialist species suppressed problem species by providing unfavourable environmental conditions and putting them at a competitive disadvantage. We identified that woody encroachment and current disturbances affect the vast majority of kurgans, posing a serious threat to grassland specialist species. Thus, there is an urgent need to integrate active conservation measures into the current passive protection of kurgans.
•We studied the vegetation of 44 isolated grassland fragments on kurgans.•We studied the effects of local environmental factors on their species composition.•Steep slopes of kurgans prevented ploughing and preserved several grassland species.•Grassland species were most threatened by disturbance and alien woody encroachment.•Improved measures are needed for the biodiversity conservation of kurgans.
Woody plants in water‐limited ecosystems affect their environment on multiple scales: locally, natural stands can create islands of fertility for herb layer communities compared to open habitats, but ...afforestation has been shown to negatively affect regional water balance and productivity. Despite these contrasting observations, no coherent multiscale framework has been developed for the environmental effects of woody plants in water‐limited ecosystems. To link local and regional effects of woody species in a spatially explicit model, we simultaneously measured site conditions (microclimate, nutrient availability and topsoil moisture) and conditions of regional relevance (deeper soil moisture), in forests with different canopy types (long, intermediate and short annual lifetime) and adjacent grasslands in sandy drylands. All types of forests ameliorated site conditions compared to adjacent grasslands, although natural stands did so more effectively than managed ones. At the same time, all forests desiccated deeper soil layers during the vegetation period, and the longer the canopy lifetime, the more severe the desiccation in summer and more delayed the recharge after the active period of the canopy. We conclude that the site‐scale environmental amelioration brought about by woody species is bound to co‐occur with the desiccation of deeper soil layers, leading to deficient ground water recharge. This means that the cost of creating islands of fertility for sensitive herb layer organisms is an inevitable negative impact on regional water balance. The canopy type or management intensity of the forests affects the magnitude but not the direction of these effects. The outlined framework of the effects of woody species should be considered for the conservation, restoration or profit‐oriented use of forests as well as in forest‐based carbon sequestration and soil erosion control projects in water‐limited ecosystems.
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