The form of the species richness-productivity relationship (SRPR) is both theoretically important and contentious. In an effort to distill general patterns, ecologists have undertaken meta-analyses, within which each SRPR data set is first classified into one of five alternative forms: positive, humped (unimodal), negative, U-shaped (unimodal), and no relationship. Herein, I first provide a critique of this approach, based on 68 plant data sets/studies used in three meta-analyses published in Ecology. The meta-analyses are shown to have resulted in highly divergent outcomes, inconsistent and often highly inappropriate classification of data sets, and the introduction and multiplication of errors from one meta-analysis to the next. I therefore call on the ecological community at large to adopt a far more rigorous and critical attitude to the use of meta-analysis. Second, I develop the argument that the literature on the SRPR continues to be bedeviled by a common failing to appreciate the fundamental importance of the scale of analysis, beginning with the confusion evident between concepts of grain, focus, and extent. I postulate that variation in the form of the SRPR at fine scales of analysis owes much to artifacts of the sampling regime adopted. An improved understanding may emerge from combining sampling theory with an understanding of the factors controlling the form of species abundance distributions and species accumulation curves.
Waste electrical and electronic equipment (WEEE) is one of the fastest growing waste streams, worldwide. In addition to the increasing amount, WEEE consists of numerous toxic, precious and scarce metals which makes its recycling and safe disposal an important environmental issue. Switzerland has a well-established recycling system operating since 1992. With 15 kg of WEEE collected per inhabitant in 2011, Switzerland is one of the leading countries in collection. However, small electronic devices and IT and telecommunication equipment that do not constitute a significant mass in overall WEEE pose greater challenges to collection and recycling due to their size and dissipative structure. Among these categories, laptops and mobile phones stand out with increasing penetration rate, decreasing lifetime, and complex composition with high concentrations of precious metals in relatively small volumes. This study investigated the recycling of WEEE in Switzerland with particular focus on material flows of laptops and mobile phones as well as copper, silver, gold, and palladium originated from these products in 2011. Material flow analysis revealed collection rate for laptops and mobile phones as 35 and 37% and treatment rates as 28% and 15%, respectively. The overall recycling rates for copper, silver, gold, and palladium in laptops were estimated as 21, 13, 14, and 14%, respectively. As a result of lower treatment rate for mobile phones the recycling rates were found as 12% for copper, 7% for silver 8% for gold and palladium. In addition to the quantitative assessment of the recycling programme’s performance, Structural analysis was carried out to understand the underlying socio-economic, technical, and political elements that are influential in this case. The results suggest that external factors such as metal prices and criticality of metals have large influence on material flows. By coupling stakeholders' conceptualization of the system with material flows, this study strives to provide a comprehensive interpretation of the system for strategic management of WEEE in Switzerland.
► Fifty-three emerging pollutants measured in sewage, surface and drinking water. ► Nineteen compounds detected in sewage at median values higher than 0.1 μg L. ► Eleven of them not properly eliminated and still higher than 0.1 μg L in effluent. ► Pharmaceuticals, UV filters and organoP flame retardants prevail in surface water. ► BP-4, TnBP, TCEP and several organoP diesters found in drinking water at 10–100 ng L . A monitoring programme was carried out on wastewater, surface and drinking water on the NW area of Spain during the four seasons of a year period (November 2007–September 2008). This study covered a series of emerging pollutants of different classes, including pharmaceuticals, neutral and acidic organophosphorus flame retardant/plasticizers (OPs), triclosan, phenoxy-herbicides, insect repellents and UV filters. From the total set of 53 compounds, 19 were found in raw wastewater with median concentrations higher than 0.1 μg L . Among them, salicylic acid, ibuprofen and the UV filter benzophenone-4 (BP-4) were the most concentrated, exceeding the 1 μg L median value. Subsequently, 11 of these contaminants are not efficiently enough removed in the small WWTPs tested and their median concentrations in effluents still surpassed the 0.1 μg L , so that they can spread through surface water. These chemicals are the pharmaceuticals naproxen, diclofenac and atenolol; the OPs tri(2-chloroethyl) phosphate (TCEP), tri(chloropropyl) phosphate (TCPP), tri- -butyl phosphate (TnBP), diphenyl phosphate (DPhP) and diethylhexyl phosphate (DEHP); and the sulphonate UV filters BP-4 and 2-phenylbenzimidazole-5-sulphonic acid (PBSA). These OPs were then the dominant emerging pollutants occurring in surface and drinking water, where they are detected in the 20–200 ng L range. Pharmaceuticals and UV filters are typically below the 10 ng L level. Finally, herbicides were only detected in the last sampling campaign under the 100 ng L drinking water European Union limit.
1. Senescence is usually viewed as increased age-specific mortality or decreased age-specific fecundity due to the declining ability of natural selection to remove deleterious age-specific mutations with age. In herbaceous perennial plants, trends in age-specific mortality are often confounded by size. Age-indeterminate senescence, where accumulated physiological damage varies strongly with environment, may be a better model of senescence in these species. 2. We analysed trends in size and fertility in Plantago lanceolata, using a long-term demographic census involving > 10 years and > 8000 individuals in four cohorts. We used elasticity and pairwise invasion analysis of life-history function parameterized age × stage matrices to assess whether the force of natural selection declined with age. Then, we used reverse age analysis of size and fertility to assess whether age-indeterminate senescence occurred. Reverse age analysis uses longitudinal data for individuals that have died to look at trait patterns as a function of both age and remaining time to death. We hypothesized that (i) the strength of natural selection would decline strongly with age, and (ii) physiological condition would deteriorate for several years prior to death. 3. Both elasticity and invasion analyses suggested that the strength of natural selection through mortality declined strongly with age once size was accounted for. Further, reverse age analyses showed that individuals shrank for 3 years prior to death, suggesting physiological decline. Inflorescence production declined with age, and also declined in the 3 years prior to death regardless of overall age. 4. Synthesis. The hypothesis that plants escape senescence generally assumes that plants can continue to grow larger and increase reproduction as they get older. The results here show that size and reproduction decline with age and the rates of these declines towards death are life span- and age dependent. Further research is needed to delineate the importance of age-determinate vs. age-indeterminate factors in senescence patterns across species.
Research investigating interactions between aboveground (AG) and belowground (BG) herbivores has been central to characterizing AG-BG linkages in terrestrial ecosystems, with many of these interactions forming the basis of complex food webs spanning the two subsystems. Despite the growing literature on the effects of AG and BG herbivores on each other, underlying patterns have been difficult to identify due to a high degree of context dependency. In this study, we present the first quantitative meta-analysis of AG and BG herbivore interactions. Previous global predictions, specifically that BG herbivores normally promoted AG herbivore performance and AG herbivores normally reduced BG herbivore performance, were not supported. Instead, the meta-analysis identified four factors that determined the outcome of AG-BG interactions. (1) Sequence of herbivore arrival on host plants was important, with BG herbivores promoting AG herbivore performance only when introduced to the plant simultaneously, whereas AG herbivores had negative effects on BG herbivores only when introduced first. (2) AG herbivores negatively affected BG herbivore survival but tended to increase population growth rates. (3) AG herbivores negatively affected BG herbivore performance on annual plants, but not on perennials, and these effects were observed more consistently in laboratory than field studies. (4) The type of herbivore was also important, with BG insect herbivores belonging to the order Diptera (i.e., true flies) having the strongest negative effects on AG herbivores. Coleoptera (i.e., beetles) species were the most widely investigated BG herbivores and had positive impacts on AG Homoptera (e.g., aphids), but negative effects on AG Hymenoptera (e.g., sawflies). The strongest negative outcomes for BG herbivores were seen when the AG herbivore was a Coleoptera species. We found no evidence for publication bias in AG-BG herbivore interaction literature and conclude that several biological and experimental factors are important for predicting the outcome of AG-BG herbivore interactions. The sequence of herbivore arrival on the host plant was among the most influential.
► Fish, meat, dairy products, eggs and fat/oils were analyzed for persistent organic pollutants (POPs) followed by per capita intake calculations. ► The highest levels of PCDD/F, PCB, PBDE, HBCD and chlorinated pesticides were found in the fish/fish products. ► The levels and intake of different POPs from food of animal origin in the market basket of 2005 seem to have decreased since the market basket study in 1999. Based on consumption data statistics, food items from four regions in Sweden were sampled in a so-called market basket study. Food items from five food groups, i.e. fish, meat, dairy products, eggs and fat/oils, were analyzed for persistent organic pollutants (POPs) followed by per capita intake calculations. The highest levels of PCDD/F, PCB, PBDE, HBCD and chlorinated pesticides were found in the fish/fish products. The estimated market basket per capita intake of PCDD/F and dl-PCB was 0.7 pg WHO-TEQ kg bw d (TEFs from 1998). The intake of ∑PCB was estimated to 4.9 ng kg bw d and fish was found to be the major contributor with 64%. The intake of ∑PBDE was found to be 0.7 ng kg bw d . Fish (38%) and dairy products (31%) were the largest contributors to the total PBDE intake. The intake of HBCD was estimated to 0.14 ng kg bw d . HBCD mainly came from fish (65%), but also dairy products (24%) and meat (10%) contributed. Also regarding the chlorinated pesticides, fish was found to be the major contributor, with 51% of the ∑DDT coming from fish. The intake of ∑DDT, ∑HCH and HCB was 4.0, 1.0 and 1.1 ng kg bw d , respectively. Most of the ∑HCH and HCB originate from dairy products (43% and 55%, respectively). This study shows that the levels, and intake, of different POPs from food of animal origin in the market basket of 2005 seem to have decreased since the market basket study in 1999.
Lanthanum (La) modified bentonite is being increasingly used as a geo-engineering tool for the control of phosphorus (P) release from lake bed sediments to overlying waters. However, little is known about its effectiveness in controlling P across a wide range of lake conditions or of its potential to promote rapid ecological recovery. We combined data from 18 treated lakes to examine the lake population responses in the 24 months following La-bentonite application (range of La-bentonite loads: 1.4–6.7 tonnes ha ) in concentrations of surface water total phosphorus (TP; data available from 15 lakes), soluble reactive phosphorus (SRP; 14 lakes), and chlorophyll (15 lakes), and in Secchi disk depths (15 lakes), aquatic macrophyte species numbers (6 lakes) and aquatic macrophyte maximum colonisation depths (4 lakes) across the treated lakes. Data availability varied across the lakes and variables, and in general monitoring was more frequent closer to the application dates. Median annual TP concentrations decreased significantly across the lakes, following the La-bentonite applications (from 0.08 mg L in the 24 months pre-application to 0.03 mg L in the 24 months post-application), particularly in autumn (0.08 mg L to 0.03 mg L ) and winter (0.08 mg L to 0.02 mg L ). Significant decreases in SRP concentrations over annual (0.019 mg L to 0.005 mg L ), summer (0.018 mg L to 0.004 mg L ), autumn (0.019 mg L to 0.005 mg L ) and winter (0.033 mg L to 0.005 mg L ) periods were also reported. P concentrations following La-bentonite application varied across the lakes and were correlated positively with dissolved organic carbon concentrations. Relatively weak, but significant responses were reported for summer chlorophyll concentrations and Secchi disk depths following La-bentonite applications, the 75th percentile values decreasing from 119 μg L to 74 μg L and increasing from 398 cm to 506 cm, respectively. Aquatic macrophyte species numbers and maximum colonisation depths increased following La-bentonite application from a median of 5.5 species to 7.0 species and a median of 1.8 m to 2.5 m, respectively. The aquatic macrophyte responses varied significantly between lakes. La-bentonite application resulted in a general improvement in water quality leading to an improvement in the aquatic macrophyte community within 24 months. However, because, the responses were highly site-specific, we stress the need for comprehensive pre- and post-application assessments of processes driving ecological structure and function in candidate lakes to inform future use of this and similar products.
Natural and artificial radionuclides and heavy metals in the surface soil of the uranium mining area of Tongliao, China, were measured using gamma spectrometry, flame atomic absorption spectrophotometry, graphite furnace atomic absorption spectrophotometry and microwave dissolution atomic fluorescence spectrometry respectively. The estimated average activity concentrations of U, Th, Ra, K and Cs are 27.53±16.01, 15.89±5.20, 12.64±4.27, 746.84±38.24 and 4.23±4.76 Bq/kg respectively. The estimated average absorbed dose rate in the air and annual effective dose rate are 46.58±5.26 nGy/h and 57.13±6.45 μSv, respectively. The radium equivalent activity, external and internal hazard indices were also calculated and their mean values are within the acceptable limits. The heavy metal concentrations of Pb, Cd, Cu, Zn, Hg and As from the surface soil were measured and their health risks were then determined. Although the content of Cd is much higher than the average background in China, its non-cancer and cancer risk indices are all within the acceptable ranges. These calculated hazard indices to estimate the potential radiological health risk in soil and the dose rate are well below their permissible limit. In addition the correlations between the radioactivity concentrations of the radionuclides and the heavy metals in soil were determined by the Pearson linear coefficient.
Aim of the present study was to assess impact of urban drains over river water and sediments by physico-chemical and metal analysis. Metal speciation (Sequential Extraction Procedure) and elemental composition analysis (SEM–EDS) was used to quantify metal pollution load in river sediments. Metal speciation analysis showed dominance of available and labile fractions of all heavy metals (Cr, Ni, Cu, Zn, Cd and Pb) except Mn and Fe which were dominant in residual forms. Cluster analysis (CA), Principal Components Analysis (PCA) and Partial Least Square Regression (PLSR) were applied as source receptor modeling for pollutants. Results classified river stretch into three zones i.e. moderately, severely and extremely polluted, on the basis of pollutant concentration released from anthropogenic sources. SEM–EDS study revealed the elemental composition percentage in river sediments. Pollution Load Index (PLI) varied from 1.8 (S1)–3.9 (S15). The Geo accumulation index (GAI) was found highest for Cd (6.88–8.97) and Pb (2.41–3.24).
Many studies indicated that industrialization and urbanization caused serious soil heavy metal pollution from industrialized age. However, fewer previous studies have conducted a combined analysis of the landscape pattern, urbanization, industrialization, and heavy metal pollution. This paper was aimed at exploring the relationships of heavy metals in the soil (Pb, Cu, Ni, As, Cd, Cr, Hg, and Zn) with landscape pattern, industrialisation, urbanisation in Taiyuan city using multivariate analysis. The multivariate analysis included correlation analysis, analysis of variance (ANOVA), independent-sample T test, and principal component analysis (PCA). Geographic information system (GIS) was also applied to determine the spatial distribution of the heavy metals. The spatial distribution maps showed that the heavy metal pollution of the soil was more serious in the centre of the study area. The results of the multivariate analysis indicated that the correlations among heavy metals were significant, and industrialisation could significantly affect the concentrations of some heavy metals. Landscape diversity showed a significant negative correlation with the heavy metal concentrations. The PCA showed that a two-factor model for heavy metal pollution, industrialisation, and the landscape pattern could effectively demonstrate the relationships between these variables. The model explained 86.71% of the total variance of the data. Moreover, the first factor was mainly loaded with the comprehensive pollution index (P), and the second factor was primarily loaded with landscape diversity and dominance (H and D). An ordination of 80 samples could show the pollution pattern of all the samples. The results revealed that local industrialisation caused heavy metal pollution of the soil, but such pollution could respond negatively to the landscape pattern. The results of the study could provide a basis for agricultural, suburban, and urban planning.