Spatial evaluation of the ecological importance based on GIS for environmental management: A case study in Xingguo county of China

How to assort with the relationship between the urban construction and the maintenance of ecological security is a hot issue during the process of urbanization. The purpose of this study is to identify the key ecological land maintaining ecological security and to put forward some measures for environmental management. Based on the GIS technology, from the view of water security, biodiversity conservation, disaster protection, natural recreation security, and human disturbance, an integrated index is put forward to evaluate the ecological importance of regional space. Then, a GIS-based approach for evaluating ecological importance was created, with Xingguo county of China as a case study. The results show that the area of core eco-space in the study area accounts for 30% of the total area. These areas mainly consist of the core areas of regional river systems, wetlands, nature reserves, forest parks, and scenic spots and the endangered and protected zone of geological hazards. According to the spatial characteristics of ecological importance for different regions, this study proposes some zoning regulations and measures for environmental management.     

Systems ecological accounting for wastewater treatment engineering: Method,indicator and application

Wastewater treatment facility is vital for sustainable urban development. In the course of removing contaminants and discharging ready-for-reuse water, wastewater treatment consumes resources and triggers environmental emission during its lifetime. A comprehensive framework to analyze the embodied ecological elements as natural resources and environmental emissions of wastewater treatment is presented in this work. The systems method as a combination of process and input–output analyses is applied and a set of indicators are accordingly devised. Two representative ecological elements, i.e., greenhouse gases emissions and solar emergy of alternative wastewater treatment systems, i.e., a traditional activated sludge wastewater treatment plant and a constructed wetland have been taken into consideration. For each ecological element, five indicators have been calculated and compared to assess the impact on climate change and resources utilizing style of the case systems. The framework raised in this paper is fully supportive for optimal decision-making among different wastewater treatment technologies, and could be transplanted to be applied to systems ecological accounting for other production systems.     

The influence of biological and environmental factors on metallothionein concentration in the blood

The concentration of metallothionein (MT), a low-molecular-weight protein, is regulated by many factors, primarily metals (zinc, cadmium, copper), cytokines, glucocorticoides and free radicals. These factors are determined by such aspects of human biology as gender, pregnancy and age, as well as by environmental factors including the use of oral contraceptives and cigarette smoking, all which may affect MT levels in the body.The aim of this study was to investigate the influence of these biological and environmental factors on MT concentrations in erythrocyte lysate and in plasma.MT concentrations were determined by a two-step direct enzyme-linked immunosorbent assay. Evaluation of exposure to cigarette smoking was performed by checking cotinine levels in the plasma of subjects.The studies showed higher MT concentrations in both the erythrocyte lysate and plasma of women when compared to men. Furthermore, pregnancy causes an increase of MT concentration in plasma, while oral contraceptives cause an elevated concentration of MT in erythrocyte lysate. Age impacts plasma MT concentrations in men, whereas it does not affect concentrations of MT in erythrocyte lysate.     

Facultative parthenogenesis and sex-ratio evolution

Summary Phenotypic models of selection are used to determine the effect of facultative parthenogenesis on the production of males in a spatially variable environment when (i) sex determination is under strict genetic control, and (ii) when sex may be environmentally determined. The results show that when sex is under strict genetic control and there is some chance of maturing in isolation, selection favors a female-biased sex ratio. When sex can be environmentally induced by cues which indicate high density, selection favors a mixture of genetic and environmental control, such that half the individuals always become female and the other half become females when isolated and become males when not isolated.     

Changes in gas exchange characteristics and water use efficiency of mangroves in response to salinity and vapour pressure deficit

Summary Measurements were made of the photosynthetic gas exchange properties and water use efficiency of 19 species of mangrove in 9 estuaries with different salinity and climatic regimes in north eastern Australia and Papua New Guinea. Stomatal conductance and CO₂ assimilation rates differed significantly between species at the same locality, with the salt-secreting species, Avicennia marina, consistently having the highest CO₂ assimilation rates and stomatal conductances. Proportional changes in stomatal conductance and CO₂ assimilation rate resulted in constant and similar intercellular CO₂ concentrations for leaves exposed to photon flux densities above 800 mol·m^-2·s^-1 in all species at a particular locality. In consequence, all species at the same locality had similar water use efficiencies. There were, however, significant differences in gas exchange properties between different localities. Stomatal conductance and CO₂ assimilation rate both decreased with increasing salinity and with increasing leaf to air vapour pressure deficit (VPD). Furthermore, the slope of the relationship between assimilation rate and stomatal conductance increased, while intercellular CO₂ concentration decreased, with increasing salinity and with decreasing ambient relative humidity. It is concluded from these results that the water use efficiency of mangroves increases with increasing environmental stress, in this case aridity, thereby maximising photosynthetic carbon fixation while minimising water loss.Contribution No. 459 from the Australian Institute of Marine Science     

北京地区大葱和玉米根际VA菌根的季节变化及其与环境因子之间的关系

1986-1987年连续两年系统调查了北京地区大葱(Allium fistulosum L.)和玉米(Zeamays L.)根际 VA 菌根侵染百分率及菌根真菌孢子密度的季节变化。分析了菌根和菌根真菌的发生与几种土壤因子(土壤硝态氮、铵态氮、速效磷和有机质含量,土壤 pH 值)和气候因子(气温、积温、土温、光照、降水量,相对湿度等)之间的关系。结果表明:大葱和玉米的侵染百分率随作物生育期的增长而增加,并以6月和9月的增长速度最快。一年中,植物根际菌根真菌的孢子密度有二个高峰,分别在6-7月和10月。在北京的同一地区,一年中,几种测定的土壤因子变化很小,因此,认为气候因子对菌根发生的季节变化具有更大的影响。用线性相关和关联度分析的结果表明:一年中,菌根的发生与积温的关系最为密切。     

A new null hypothesis for measuring the degree of plant community organization

An attempt is made to derive a measure for the degree of plant community organization, which would not be based on species co-occurrence and co-abundance. The use of the independent random distribution hypothesis (IRDH) is suggested for this purpose. The hypothesis is expected to be valid, if no deterministic phytosociological-structure-generating mechanism is present. If structural variability is used as a statistic for testing the hypothesis, deviances from the conditions of IRDH (species distributions are independent from each other, environmental gradients are lacking) will be attributable either to species interactions (smaller structural variability than expected), or to environmental heterogeneity (greater structural variability than expected). Structural variability is evaluated as the variance of species diversity, the indexN=exp(H') is used for measuring diversity. The precise measure of the degree of community organizationW is computed as the shift between two empirical distributions:D ^* (VN) or Bootstrap distribution of variance of diversity in the community, andD ^o (VN) or the random community variability distribution, which is evaluated after simulating the IRDH conditions.A satisfactory interpretation can be given to the results of evaluatingW for 11 data sets of 10 relevés each.Abbreviation IRDH Independent random distribution hypothesis     

The amnesic shellfish poison domoic acid enhances neurotoxicity by excitatory amino acids in cultured neurons

Summary A recent episode of human intoxication by cultured mussels containing a rare excitatory amino acid named domoic acid, received particular attention for its neurological implications. The intoxication produced neurological problems, such as headache, confusion, and loss of memory, particularly severe at times. Neuronal damage was found in the hippocampus and amygdala of four patients. We now report that in neuronal cultures the neurotoxicity of a domoic acid-containing mussel extract is the result of domoic acid potentiation of the excitotoxic effect of glutamic acid and aspartic acid present in high amounts in mussel tissue. Moreover, we show that subtoxic concentrations of domoic acid are sufficient to potentiate glutamic acid and aspartic acid neurotoxicity. We present evidence suggesting that the neurotoxic synergism may be due to a reduction of Mg^{+ +} block at the NMDA receptor-associated channel, following activation of NON-NMDA receptors by domoic acid.     

Models of seasonal growth of the equatorial carp Labeo dussumieri in response to the river flood cycle

Synopsis The phenology of Labeo dussumieri, an omnivorous carp common to South Asia, was investigated in a population inhabiting a flood plain anabranch of the Mahaweli Ganga, Sri Lanka. The Mahaweli Ganga exhibited a bimodal discharge pattern typical of many equatorial rivers, with a minor peak during the S.W. monsoon and a major peak during the N.E. monsoon. Seasonal changes in several lotic variables were measured in an attempt to correlate changes in environmental conditions to reproduction and growth in L. dussumieri. The onset of gonad recrudescence and spawning were synchronized with the increased river discharge during the S.W. and N.E. monsoons: gonad development followed one monsoonal discharge peak and spawning took place at the beginning of the other. Most fish spawned at the beginning of the major discharge peak in October and November, following the September dry season. Increased discharge was concomitant with a fall in temperature, light intensity, pH and conductivity. Growth was shown to be seasonal, exhibiting an annual bimodal pattern with peaks coincident with S.W. and N.E. monsoonal rains. Seasonal changes in growth were expressed by two models in terms of: (a) change of somatic weight or fork length with time, (b) change of specific growth rate in response to river discharge, modified by somatic weight. Gonad recrudescence and spawning stress did not appear to influence growth rate.     

Distribution,biology and hybridization of Scaphirhynchus albus and S. platorynchus in the Missouri and Mississippi rivers

Synopsis Scaphirhynchus albus and S. platorynchus were studied in Missouri during 1978–1979 to assess their distribution and abundance, to obtain information on their life histories, and to identify existing or potential threats to their survival. S. platorynchus was collected in substantial numbers (4355 specimens) at all 12 sampling stations in the Missouri and Mississippi rivers, while only 11 S. albus were captured from 6 stations. Twelve specimens identified in the field as hybrids between the two species were captured from 4 stations. Morphometric and meristic comparisons of presumed hybrids with the parent species, using cluster and principal components analyses, demonstrated intermediacy of most specimens identified in the field as hybrids. Aquatic insects comprised most of the diet of S. platorynchus and S. albus, but S. albus and the hybrids had consumed considerable quantities of fish. S. albus grew more rapidly than S. platorynchus, while the growth of hybrids was intermediate. Hybridization appears to be a recent phenomenon, resulting from man-caused changes in the big-river environment. Hybridization may be a threat to survival of S. albus in the study streams.