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81.
Temporarily open/closed estuaries (TOCEs) are major ecosystems of the Indian Ocean coastal zones. Their functioning is tightly linked to climatic events such as monsoons and storms, and their mouth can close up for prolonged and variable periods of time, thus limiting their connectivity with the marine environment. Two types of genetic markers (i.e., mitochondrial cytochrome c oxidase I (COI) gene and microsatellites) were used to assess the genetic structure of 288 individuals of Terapon jarbua, a widely distributed fish species in the wider Gulf of Aden. Firstly, the hypothesis of panmixia was tested. Then, alternative hypotheses were investigated to explain the population genetic structure of T. jarbua: could it be shaped by (1) regional biogeographic barriers (i.e., Socotra Island vs. mainland Yemen) and/or (2) the particular functioning of TOCEs in relation to the species life cycle and particular physical ocean parameters? On one hand, the polymorphism of the COI inferred (1) a high haplotype diversity and a reduced nucleotide diversity over the whole data set and (2) a “star-like” shape of the haplotype network, thus suggesting a population expansion after local extinctions during the Pleistocene glaciations. On a second hand, the genotyping of eight microsatellites showed a significant genetic differentiation between T. jarbua populations in the wider Gulf of Aden (F ST = 0.035, p < 0.01), and thus, the panmixia hypothesis was rejected. Analyses of molecular variance results did not show any significant structure between Socotra Island and mainland Yemen and thus did not support the role of biogeographic barriers in structuring T. jarbua populations. Significant multi-locus deficits in heterozygotes at particular locations displaying high levels of F IS were recorded. It was suggested that a possible Wahlund effect took place in those TOCEs which could gather several cohorts of larvae stemming from different marine subpopulations over the sampled area. The present study emphasized the uniqueness of each TOCE as a potential reservoir of biodiversity and the urgent need for a better conservation program of those estuaries in the region, in order to avoid habitat fragmentation and permanent closure of those nursery areas by human activities.  相似文献   
82.
In the last years, the idea of using natural elements or nature-based solutions (NbS) to mitigate the impacts of cities on climate, biodiversity and citizens'' health became more popular in research and practice. Nevertheless, there are currently uncertainties in finding and selecting appropriate criteria and indicators for monitoring and evaluating the impact and performance of NbS and its co-creation processes. This paper proposes an easy-to-use and structured procedure for selecting appropriate criteria and indicators for monitoring and evaluating any kind of NbS project. The user is guided step by step in selecting meaningful metrics. The procedure is tested using a real case study from the Horizon 2020 research project CLEVER Cities as an example. The test shows that by following the indicated procedure, the criteria and indicator selection process is speeded up and reproducible.Supplementary InformationThe online version contains supplementary material available at 10.1007/s13280-022-01740-0.  相似文献   
83.
Phytoremediation, the use of plants for in situ contaminant cleanup, is gaining new appreciation as an aesthetically pleasing, sustainable method that naturally makes use of solar power. Hybrid poplars are widely used because they grow rapidly and have high transpiration rates, making them advantageous for hydraulic control of groundwater. However, the tendency for trees and other vegetation to uptake metals may be a disadvantage in some settings due to potential redistribution of metals from groundwater to the ground surface. Therefore, a pilot test in the upper midwestern United States was implemented to evaluate the applicability of poplars to groundwater withdrawal and metals transport. © 2009 Wiley Periodicals, Inc.  相似文献   
84.
Element distribution in a combined fly ash and bottom ash from combustion of copper chromate arsenate (CCA) treated wood waste was investigated by scanning electron microscopy (SEM/EDX) before and after electrodialytic extraction. The untreated ash contained various particles, including pieces of incompletely combusted wood rich in Cr and Ca, and irregular particles rich in Si, Al and K. Cr was also found incorporated in silica-based matrix particles. As was associated with Ca in porous (char) particles, indicating that Ca-arsenates had been formed during combustion. Cu was associated with Cr in the incompletely combusted wood pieces and was also found in almost pure form in a surface layer of some matrix particles - indicating surface condensation of volatile Cu species. In treated ash, Ca and As were no longer found together, indicating that Ca-arsenates had been dissolved due to the electrodialytic treatment. Instead particles rich in Ca and S were now found, indicating precipitation of Ca-sulphates due to addition of sulphuric acid in connection with the electrodialytic treatment. Cu and Cr were still found associated with incompletely combusted wood particles and incorporated in matrix particles. Chemical analyses of untreated and treated ash confirmed that most As, but only smaller amounts of Cu and Cr was removed due to the electrodialytic extraction. Overall metal contents in the original ash residue were: 1.4 g As, 2.76 g Cu and 2.48 g Cr, after electrodialytic extraction these amounts were reduced by 86% for As, 15% for Cu and 33% for Cr.  相似文献   
85.
This study examined how the species composition of an intertidal barnacle guild varied according to physical gradients in the environment at small scales governed by microclimates, medium scales of wave exposure and large scales of latitude. Barnacle distributions at small and medium scales were sampled in Ireland between 51°29′ and 52°44′N and 6°50′ and 10°08′W. Sampling on European shores spanned ~18° latitude from 37°05′ to 55°16′N. Barnacle surveys mainly took place in 2003–2004. An index of wave fetch was calculated along the wave exposure gradient using a digital coastline-based model that was supported by a biological exposure scale. A ‘dryness’ index was defined according to mean monthly wind speed, fetch along the average wind direction and mean monthly air or sea surface temperatures for 2 years (January 2001–December 2002) which is the period when the most recent adults in the barnacle community would have settled and grown to adulthood. The proportion of the dry-loving barnacle Chthamalus montagui Southward increased within the barnacle guild at all scales as the habitat became warmer and drier. Barnacle densities were high in all habitats, mean densities ranged from a minimum of 4.16 cm−2 on moderately exposed shores to a maximum of 6.27 cm−2 in sunlit or south-facing microclimates. Percentage cover of barnacles across the gradient of latitudes was usually >70%. The results suggest that the distribution and abundance of interacting barnacle species on European coasts is strongly controlled by abiotic factors, most likely temperature and desiccation.  相似文献   
86.
Summary. Recent economic and social changes in north Mediterranean regions have led to an important rural depopulation. Consequently, meadows developed on abandoned agricultural lands (characterized by high species richness) undergo reforestation. These former fields are mainly colonized by Pinus halepensis Miller, which is known to synthetize a wide range of secondary metabolites, among these, some could influence plant succession through allelopathy. The allelopathic potential of P. halepensis, was tested against two target species (Lactuca sativa L. and Linum strictum L.) with aqueous extracts obtained from different organs (root and needle) taking into account the individual age (±10, ±30 and > 60 years old). Root and needle extracts affected differently germination and growth of the two target species, the responses varying with concentration of extracts, age and organs tested. The strongest inhibitory effect was observed on the germination and growth of L. strictum, exposed to needle extracts of young P. halepensis (±10 years old), and root extracts of older P. halepensis (> 30 years old). These extracts contained several phenolic acids (e.g. 4-hydroxybenzoic acid and p-coumaric acid), which are known as allelochemicals and their concentrations vary with age and organ tested. Hence, P. halepensis could influence secondary succession through the release of potential allelochemicals in the environment by leaf leachates or root exudates.  相似文献   
87.
In studying the effect of employment‐relationship practices on employees, research has largely ignored individual differences, both cross‐culturally and within cultures. In this study, the authors examine the moderating effect of middle managers' traditionality, a within‐culture value orientation regarding submission to authority and endorsement of hierarchical role relationships, on their responses to an organization's employee–organization relationship practices. Based on social learning and social exchange theories, the authors expect the more traditional middle managers to respond less positively in terms of their performance and commitment to high levels of expected contributions and the associated psychological empowerment but respond more positively to high levels of offered inducements. Using a sample of 535 middle managers from 40 companies in China, the authors find support for all hypotheses except the moderating effect of traditionality on the relationship between offered inducements and performance. Additional analysis reveals that less‐traditional managers responded to economic rewards (but not developmental rewards) with higher job performance. The paper concludes with a discussion of implications for research and the practice of employment relationships. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
88.
For species that form multi-generational and territorial family groups, resource-rich areas are predicted to support family dynasties in which one genetic lineage continuously occupies an area and may even expand to occupy surrounding areas. Data from a long-term study of Tasmanian native hens (Gallinula mortierii) support this prediction. The reproductive success and dispersal patterns of 18 hen lineages were monitored for seven breeding seasons and over several generations. The founder group with the highest average territory quality produced the highest total number of fledged young and the highest number of fledged linear descendants, accounting for 24% of the combined reproductive output of these 18 lineages. In the space of 6 years, this single genetic lineage expanded from one territory to occupy 12 of the 47 territories present in the population. This rate of expansion was over four times the population average for the same period. A multivariate analysis revealed that the success of a genetic lineage depended only on the number of high-quality territories surrounding the founder group. These results further demonstrate the resource-dependent nature of reproductive success in this species, and also highlight the potential importance of family dynasties in other cooperative species with complex social dynamics and dispersal patterns.  相似文献   
89.
Cyclic hydroxamic acids and lactams are allelochemicals present in the common agricultural crops wheat, rye, and maize. The hydroxamic acids are mainly present in the plants as glucosides. Upon injury or insect attack or when exuded to the soil environment, the hydroxamic acids occur in their unstable agluconic form. In the first step in the transformation of hydroxamic acids, benzoxazolinones are formed spontaneously. It is necessary to elucidate the further microbial transformation of these compounds in the soil environment for a purposeful exploitation of the allelopathic properties of wheat, rye, and maize. In the present paper, the existing knowledge on microbial transformation products of benzoxazolin-2-one (BOA), 6-methoxy-benzoxazolin-2-one (MBOA), and 2-hydroxy-1,4-benzoxazin-3-one (HBOA) was reviewed. Three main groups of transformation products were identified: aminophenoxazinones, malonamic acids, and acetamides. Future research needs concerning the transformation of these chemicals in soil are discussed, when their properties for suppressing weeds and soil-borne diseases are going to be exploited.  相似文献   
90.
To understand which soil chemical properties are the best predictors of CH4 production in rice paddy soils, a model was developed with empirical data from nine types of rice soils collected around Japan and anaerobically incubated at 30 degrees C for 16 wk in laboratory conditions. After 1, 2, 4, 8, and 16 wk of incubation, CO2, CH4, and Fe(II) were measured to understand soil organic matter decomposition and iron (Fe) reduction. Available N (N ava) was also measured at the end of incubation. The results showed that decomposable C and reducible Fe are two key parameters that regulate soil CH(4) production (P CH4). There was a significant relationship between decomposable C and available N (N ava) (r2 = 0.975**). Except for a sandy soil sample, a significant relationship between total Fe (Fe total) and reducible Fe was found. From this experiment, a simple model of soil CH4 production was developed: P CH4 = 1.593N(ava) - 2.460Fe total/1000 (each unit was mg kg(-1) soil). After simulated CH4 production by two soil chemical properties as above, there was a significant consistency between model simulation and actual measurement (r2 = 0.831**).  相似文献   
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