[Show abstract][Hide abstract] ABSTRACT: AimTo test the niche breadth hypothesis (NBH), which states that dominant species have broader environmental tolerances than rare species, focusing on oligarchic species distributions (1) along the gradients of edaphic and climatic individual variables, and (2) within the n-dimensional environmental frame defined by all edaphic and climatic variability.LocationAmazonian and Andean tropical rain forests along a ca. 3000 m elevation gradient, covering an area of 200 × 200 km in northwestern Bolivia.Methods
All woody plants with a DBH ≥2.5 cm were measured in 98 0.1-ha plots. We analysed 18 chemical properties of the soils in each plot. Climatic and topographic variables were obtained from available open-access databases. Three measures were calculated for each of the species found at each forest type: (1) regional-scale dominance based on frequency and local abundance, (2) niche breadth along each of the environmental variables, and (3) total niche size within the whole environment.ResultsOligarchic species showed broader niche breadths than the other species that constituted the community assembly in both Amazonian and Andean rain forests. The niche breadth of any species tended to be positively correlated with its degree of dominance. The Amazonian forest showed a stronger oligarchic pattern than the Andean forest, and the Amazonian common species showed larger niches overall. However, this pattern differed for some particular variables: Amazonian oligarchies had narrower niches along the variables related to organic matter and most climatic variables, whereas Andean oligarchies had narrower niches along several micronutrient factors and temperature variables.Conclusions
The results provide strong empirical support for the NBH in tropical rain forests. However, different patterns of dominance were found in the two habitats: oligarchic species ranged from narrow-niched species to very broad generalist species. Broad-niched oligarchic species have also been reported in other regions, suggesting an important role of niche size linking commonness at different scales. Oligarchic species exhibit relatively narrow niches with respect to soil factors if measured along wide gradients, regardless of the forest type studied. In contrast, the opposite pattern was found for many climatic variables, indicating higher sensitivity to climate in Amazonia compared to the Andes. Despite these differences, Amazonia has much larger total niche sizes for its common species than the Andes overall.
[Show abstract][Hide abstract] ABSTRACT: Six digestion procedures were tested to improve extraction methods for determination of trace elements in various organic amendments with high inorganic fractions. These procedures were tested in terms of pH, CaCO(3), organic matter, elemental analysis, BCR sequential extraction and X-ray diffraction analysis. Aqua regia extraction (ISO 11466), total digestion HF-HNO(3)-HClO(4) and four microwave-assisted digestions (i.e., HNO(3), HCl-HNO(3), HNO(3)-HF and HCl-HNO(3)-HF) were used. The effect of acid mixtures on microwave-assisted digestion of mineral fractions was assessed by Si and Al analysis and X-ray diffraction in the solid residues obtained. Microwave HF acid mixtures obtained highest trace element recoveries for all tested metals except Al. CaF(2) and CaAlF(5) precipitates were also detected using X-ray diffraction in the residues after microwave digestions with HF acid mixtures of amendments with high calcium content. A decision flowchart was suggested to determine the best acid mixture according to the amendment and the metals to be analyzed.
[Show abstract][Hide abstract] ABSTRACT: Total concentrations of chemical elements in soils may not be enough to understand the mobility and bioavailability of the elements. It is important to characterise the degree of association of chemical elements in different physical and chemical phases of soil. Another geochemical characterisation methodology is to apply sequential selective chemical extraction techniques. A seven-step sequential extraction procedure was used to investigate the mobility and retention behaviour of Al, Fe, Mn, Cu, Zn, Pb, Cr, Co, Ni, Mo, Cd, Bi, Sn, W, Ag, As and U in specific physical–chemical and mineral phases in mine tailings and soils in the surroundings of the abandoned Ervedosa mine. The soil geochemical data show anomalies associated with mineralised veins or influenced by mining. Beyond the tailings, the highest recorded concentrations for most elements are in soils situated in mineralised areas or under the influence of tailings. The application of principal components analysis allowed recognition of (a) element associations according to their geochemical behaviour and (b) distinction between samples representing local geochemical background and samples representing contamination. Some metal cations (Mn, Cd, Cu, Zn, Co, Cr, Ni) showed important enrichment in the most mobilisable and bioavailable (i.e., water-soluble and exchangeable) fractions due likely to the acidic conditions in the area. In contrast, oxy-anions such as Mo and As showed lower mobility because of adsorption to Fe oxy-hydroxides. The residual fraction comprised largest proportions of Sn and Al and to a lesser extent Zn, Pb, Ni, Cr, Bi, W, and Ag, which are also present at low concentrations in the bioavailable fractions. The elements in secondary mineral phases (mainly Fe, Mn, Cu, Zn, Cd, Pb, W, Bi, Mo, Cr, Ni, Co, As and U) as well as in organic matter and sulphides are temporarily withheld, suggesting that they may be released to the environment by changes in physico-chemical conditions.
[Show abstract][Hide abstract] ABSTRACT: The possibility of remediating contaminated soils though the use of high biomass-generating, native plant species capable of removing heavy metals is receiving increased attention. The cadmium (Cd) accumulation capacities of the native Mediterranean, perennial shrubs Atriplex halimus, Phyllirea angustifolia, Rhamnus alaternus and Rosmarinus officinalis were tested by growing transplanted specimens in a pine bark compost substrate (pH 5.6) contaminated with 100 mg Cd kg(-1). After 70 days, only R. alaternus showed reduced growth. The increase in biomass seen in all the test species enhanced the phytoextraction of Cd. However, the species behaved as metal excluders, except for the halophyte A. halimus, which behaved as an indicator plant. In this species the leaf Cd concentration reached 35 mg Cd kg(-1), with the shoot responsible for some 86% of total Cd accumulation. Atriplex halimus showed the highest bioconcentration factor (BCF) (0.36) and leaf Cd transport index (1.68); consequently, this species showed the highest Cd phytoextraction capacity.
International Journal of Phytoremediation 07/2011; 13(6):567-79. DOI:10.1080/15226514.2010.495152 · 1.74 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The ability of three composted materials to immobilize cadmium (Cd) was examined in order to assess their potential for recovering soils contaminated with this metal. Composted pine bark (PB) pH 5.6, spent mushroom compost (SM) pH 8.0, and composted pruning waste+biosolids (BS) pH 6.9 (containing 81%, 75% and 47% total organic matter, respectively) were characterized. FT-IR and CP-MAS (13)C NMR spectroscopy indicated the BS and SM to have a higher percentage of aliphatic and carboxyl groups than PB. The composts were artificially contaminated with Cd (80 and 200 mg kg(-1)) and, after 4 weeks incubation, subjected to sequential extraction. In column leaching experiments, the total Cd leached from the composts exposed to both Cd treatments was similar, but much less leached from the BS (0.2%) than the PB (4.0%) or SM (0.7%). The greater capacity of BS to immobilize Cd was attributed to the greater humification of its organic matter and higher content of inorganic components, particularly Fe.
[Show abstract][Hide abstract] ABSTRACT: Spanish juniper (Juniperus thurifera L.) grows optimally on high (1000–1100 m) Iberian moorland (Central Spain), in the French Alps, and in the High Atlas mountains of Morocco, where it must withstand adverse climatic conditions. These plants are characterized by their great resistance to the droughts and cold winter spells of the Mediterranean basin. Nowadays, the species is in clear decline due to intensive grazing and its slow growth rate; juniper plants are also susceptible to fire damage due to the resin in their leaves. To avoid soil degradation, however, the conservation of this species is essential. This paper reports the effect of temperature on the mineralogical composition and the dynamics of the soluble cations and anions in the organic horizon of a soil under this type of plant cover. The mineral components of this horizon and of the leaves of J. thurifera were determined, and their transformations recorded when subjected to different temperatures in the laboratory. Whewellite, a mineral that turns into calcite at around 400 °C was detected by X-ray diffraction in both the organic horizon and the leaves. Boehmite, goethite, CT opal, manganese oxide (birnessite), potassium sulphate and mixed sulphates of potassium and ammonium were also found in both types of sample at 300 °C. Maximum mineralogical transformation occurred between 200 and 300 °C. The dynamics of the soluble cations and anions largely explains the presence of calcite, birnessite and sulphates. The tendency of soluble phosphate anions to disappear with increasing temperature would lead to the reduced leaching of P. Nitrates accumulated with increasing temperature, meaning their losses through leaching might increase.
[Show abstract][Hide abstract] ABSTRACT: The congruence in floristic patterns between different life-forms of woody plants remains poorly understood in tropical rain forests. We explored whether the floristic patterns of woody plants, divided into small trees 2.5–10 cm dbh, large trees ≥10 cm dbh, and lianas ≥2.5 cm dbh were associated with each other or with patterns in soil properties, elevation, and geographical distances between sample plots. We also tested whether ecological amplitudes in relation to environmental variables differed among the plant groups. Trees and lianas were inventoried in 44 0.1-ha plots, distributed among three lowland and two submontane sites in the Madidi National Park, Bolivia. Soil samples were analysed for physico-chemical properties. Floristic differences between sites (as measured with each plant group separately) yielded significant Mantel correlations with each other, and with pH, Ca, Mg, elevation and geographical distance. Mantel correlations with edaphic distances were higher for large trees than small trees, but for Mantel correlations with geographical distance the situation was reversed. Environmental and geographical distances explained 31% of the variation in floristic differences for large trees, 22% for small trees, and 10% for lianas. The ecological amplitudes of lianas were wider than those of all trees for pH, Mg and elevation. The amplitudes of the two size classes of trees did not differ. In principal coordinates ordination, the three plant groups produced similar overall floristic patterns that were explainable by environmental factors.
[Show abstract][Hide abstract] ABSTRACT: The environmental impact of sewage sludges depends on the availability and phytotoxicity of their heavy metal. The influence of representative sludges (dewatered anaerobic, pelletization, and composted sludge) on the availability of heavy metals, and their effects on seed germination were compared. The total heavy metal concentrations were below the maximum permitted for land-applied waste and the differences among them were small. The DTPA-extracted metal concentrations were rather different. The sequential extraction of the compost showed a slight increase in Cd and Cu availability, and a decrease in the availability of Fe, Mn, Ni and Zn. Pelletization increased the availability of Ni and slightly reduced that of Cr. The dewatering sludge led to greater availability of Cr and Mn but reduced the concentration of Cd. The three different sludges also affected seed germination and root elongation in different ways. The most serious adverse effects were caused by the dewatered sludge extract.
[Show abstract][Hide abstract] ABSTRACT: This paper reports the effects of organic waste compost on Rosmarinus officinalis growth in pots containing degraded soil. Dried biosolid compost (B-C) and municipal solid waste (MSW-C) were mixed with soil at doses of 0, 20 or 40 Mg ha−1. The plants were harvested before anthesis and biomass production and rosemary oil production determined. The macronutrient, micronutrient and heavy metal contents of the aerial parts of the plant were analysed to determine nutritional status and heavy metal accumulation. All the biowaste treatments increased soil fertility. Biomass production increased significantly when plants were grown in the biowaste-treated soils. No significant differences were seen among the different treatments with respect to oil production. Plants grown on amended soils showed a general improvement in their macro- and micronutrient status, yet their heavy metal (Pb, Cr and Ni) contents did not increase significantly. The concentration of heavy metals found in the leaves would not significantly increase their transfer from the soil to humans via the food chain. Biowaste composts can be safely applied to degraded soils at a dose of 40 Mg ha−1 without the risk of adverse environmental effects. MSW-C is better applied at a dose of 20 Mg ha−1.
[Show abstract][Hide abstract] ABSTRACT: Se investigan los niveles de concentración de Pb, Cd, Cu, Ni y Zn así como la distribución de Pb en suelos de una zona cercana a una planta de reciclaje de baterías ácidas en Madrid (España) donde recientemente se produjo un grave episodio de muerte de ganado equino con evidentes síntomas de intoxicación por plomo. Las concentraciones totales de Pb y Cd en suelos disminuyeron con la distancia a la planta (5906 a 171 mg Pb/kg suelo y 11.0 a 1.58 mg Cd/kg suelo) en muestras tomadas de 40 a 400 m. respecto a la planta. El estudio de extracción secuencial química puso de manifiesto que en estos suelos el plomo aparece fundamentalmente en fracciones no residuales, representando más del 96 % del contenido total en los suelos más contaminados. El vertido de efluentes ácidos de la planta de reciclaje disminuyó drásticamente el pH de los suelos afectados (de aprox. 7.0 a 3.14) y elevó los contenidos de Pb en la fracción soluble ó intercambiable llegando a alcanzar el 37 % del contenido total de Pb en el suelo.
[Show abstract][Hide abstract] ABSTRACT: The diagnosis of lead poisoning in horses living on farmland in the vicinity of a battery recycling plant was based on clinical signs as well as on laboratory findings. Chemical analysis of six surface soils (0-15 cm) and herbage samples taken at different distances to the recycling plant showed very high total lead levels in the closest sites to the facility and a clear decrease with distance. Total lead levels in soil samples ranged from 127 to 5657 mg kg(-1), with more than 70% of lead extractable by EDTA in the most polluted soils. Lead levels in the aerial part of herbage samples were in the range of 113-4741 mg kg(-1). A water washing pre-treatment of the vegetal samples considerably diminished the concentration of lead, suggesting that airborne lead particles from the facility emissions were fixed on the shoots. The analysis of samples taken from six dead horses showed lead concentrations, expressed as mg kg(-1) (d.w.), as follows: blood: 0.20-0.89; liver: 2.5-15; kidney: 1.70-6.75. Lead intake levels, estimated according to the ingestion rate of Grammineae forage, illustrates that the apported lead through the ingestion of vegetation growing in the closest sites to the recycling plant was approximately 99.5 mg Pb/kg body weight/day surpassing the fatal dosage for horses of 2.4 mg Pb/kg body weight/day reported by Hammond and Aronson, Ann NY Acad Sci, 1964; 111: 595-611.
Science of The Total Environment 06/2002; 290(1-3):81-9. DOI:10.1016/S0048-9697(01)01066-X · 4.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Se estudian las modificaciones de los contenidos y la distribución de metales pesados en suelos y en partes constitutivas de Thymus zygis desarrollados en parcelas experimentales de un área degradada del sur de Madrid, bajo ambiente semiárido, al año de la aplicación de biosólido (B) y residuo sólido urbano (RSU) sobre el suelo a tasas de 0 y 80 Mg ha-1. Se apreció un incremento generalizado de los contenidos totales de metales pesados sobre todo en el nivel superficial (0 ¿15 cm) del suelo tratado, así como el incremento de las fracciones más lábiles obtenidas mediante procedimiento de extracción secuencial química. Asimismo se observó el aumento considerable del porte de la vegetación autóctona (Thymus zygis) en las parcelas tratadas, que mostraban concentraciones ligeramente superiores en Cd, Cu y Zn en las raíces y en Zn en la parte área con respecto a las plantas testigo si bien en ningún caso alcanzaban los límites considerados como tóxicos para plantas herbáceas.
[Show abstract][Hide abstract] ABSTRACT: Digested biosolid (SS) and municipal solid waste (MSW) were surface-applied to a degraded carbonated soil, under semi-arid environment, at rates of 0 and 80 Mg/ha, to determine the changes in organic matter and in the distribution of heavy metals in the topsoil, 1 year after its application. Waste application slightly increased the organic matter content and improved the composition of humic fractions in the treated soils, mainly in the MSW amended plots. A sequential extraction method (Tessier et al., 1979) was used to determine the distribution of Cd, Cr, Cu, Ni, Pb and Zn in both the waste and the amended.soils. Waste application had little effect on the total concentration of Ni and Cr in the treated soils as a consequence of the low availability of these metals in the wastes. A considerable increase of Cd, Cu, Pb and Zn was observed as a consequence of the high content and/or high availability of these metals in the wastes. The more labile fraction (exchangeable fraction) of all metals studied increased slightly (< 1.5 mg/kg) when SS and MSW were added. However, a remarkable increase in the Fe/Mn oxide fraction of Cd, Cu and Pb and in the organic fraction of Zn were noted in treated plots, this increase being higher in the MSW treated soils.
Science of The Total Environment 06/2000; 255(1-3):29-44. DOI:10.1016/S0048-9697(00)00444-7 · 4.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We studied the mineralogical and chemical modifications in four soils in Spain produced by a forest fire: two of the soils developed under Quercus pyrenaica and two under Juniperus oxycedrus. Samples were taken 2 and 8 months after the fire. Increases in soil pH, electrical conductivity, exchangeable-bases and total Ca occurred in both soils, but were more evident under Juniperus oxycedrus. The presence of calcite and alteration of vermiculite, were observed in soils beneath Juniperus oxycedrus, but not Quercus pyrenaica. This was due to lower temperatures reached during the fire in the mineral soil under this species. By heating plant and soils samples in the laboratory to 300, 400 and 500°C, the formation of calcite during the burning of Quercus pyrenaica (500°C) and Juniperus oxycedrus (300°C) was confirmed. According to the chemical and mineralogical modifications observed in-vitro, the temperature in the mineral soil under Juniperus oxycedrus reached during the fire was close to 300°C.
Science of The Total Environment 09/1997; 204(1-204):89-96. DOI:10.1016/S0048-9697(97)00173-3 · 4.10 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The influence of copper sorption by iron hydroxides with different degrees of crystallization in clay fractions of several alluvial cultivated soils of the fertile lowlands of the Manzanares river (Madrid) has been studied. Mineralogical study of the
Science of The Total Environment 11/1995; 172(2):245-249. DOI:10.1016/0048-9697(95)04819-7 · 4.10 Impact Factor