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61.
The objectives of this study were to evaluate the allelopathic effects of Chinese privet (Ligustrum sinense Lour.) extract on native seeds and cuttings and to assess the survivability of native plants in a flooded riparian corridor. Field sites occupied the Trinity River floodplain in southeast Dallas County, Texas. Eight native species were evaluated. They were soapberry, red mulberry, persimmon, elderberry, beautyberry, coralberry, mustang grape, and heartleaf peppervine. From this study, we concluded that:
  • Truncating privet at ground level and applying equal parts of glyphosate and water to the stump effectively kills the plant;
  • Once removed, privet does not curtail establishment of native plants;
  • A 60‐day (d) flood killed most plants, with red mulberry being the most resilient;
  • A 1% leaf and berry extract from privet significantly reduced soapberry seed germination; and
  • A 1% extract from various parts of privet did not significantly affect root growth from cuttings.
  相似文献   
62.
Marine protected areas (MPAs) are the preferred tool for preventing marine biodiversity loss, as reflected in international protected area targets. Although the area covered by MPAs is expanding, there is a concern that opposition from resource users is driving them into already low-use locations, whereas high-pressure areas remain unprotected, which has serious implications for biodiversity conservation. We tested the spatial relationships between different human-induced pressures on marine biodiversity and global MPAs. We used global, modeled pressure data and the World Database on Protected Areas to calculate the levels of 15 different human-induced pressures inside and outside the world's MPAs. We fitted binomial generalized linear models to the data to determine whether each pressure had a positive or negative effect on the likelihood of an area being protected and whether this effect changed with different categories of protection. Pelagic and artisanal fishing, shipping, and introductions of invasive species by ships had a negative relationship with protection, and this relationship persisted under even the least restrictive categories of protection (e.g., protected areas classified as category VI under the International Union for Conservation of Nature, a category that permits sustainable use). In contrast, pressures from dispersed, diffusive sources (e.g., pollution and ocean acidification) had positive relationships with protection. Our results showed that MPAs are systematically established in areas where there is low political opposition, limiting the capacity of existing MPAs to manage key drivers of biodiversity loss. We suggest that conservation efforts focus on biodiversity outcomes and effective reduction of pressures rather than prescribing area-based targets, and that alternative approaches to conservation are needed in areas where protection is not feasible.  相似文献   
63.
Understanding the fundamentals of arsenic adsorption and oxidation reactions is critical for predicting its transport dynamics in groundwater systems. We completed batch experiments to study the interactions of arsenic with a common MnO2(s) mineral, pyrolusite. The reaction kinetics and adsorption isotherm developed from the batch experiments were integrated into a scalable reactive transport model to facilitate column-scale transport predictions. We then completed a set of column experiments to test the predictive capability of the reactive transport model. Our batch results indicated that the commonly used pseudo-first order kinetics for As(III) oxidation reaction neglects the scaling effects with respect to the MnO2(s) concentration. A second order kinetic equation that explicitly includes MnO2(s) concentration dependence is a more appropriate kinetic model to describe arsenic oxidation by MnO2(s) minerals. The arsenic adsorption reaction follows the Langmuir isotherm with the adsorption capacity of 0.053micromol of As(V)/g of MnO2(s) at the tested conditions. The knowledge gained from the batch experiments was used to develop a conceptual model for describing arsenic reactive transport at a column scale. The proposed conceptual model was integrated within a reactive transport code that accurately predicted the breakthrough profiles observed in multiple column experiments. The kinetic and adsorption process details obtained from the batch experiments were valuable data for scaling to predict the column-scale reactive transport of arsenic in MnO2(s)-containing sand columns.  相似文献   
64.
Vulnerability to climate variability and change in East Timor   总被引:2,自引:0,他引:2  
Barnett J  Dessai S  Jones RN 《Ambio》2007,36(5):372-378
This paper presents the results of a preliminary study of climate vulnerability in East Timor. It shows the results of projections of climate change in East Timor. The country's climate may become hotter, drier, and increasingly variable. Sea levels are likely to rise. The paper then considers the implications of these changes on three natural resources--water, soils, and the coastal zone--and finds all to be sensitive to changes in climate and sea level. Changes in the abundance and distribution of these resources is likely to cause a reduction in agricultural production and food security, and sea-level rise is likely to damage coastal areas, including Dili, the capital city.  相似文献   
65.
Databases have been compiled to derive parameter values relevant to the transfer of radionuclides from feedstuffs to domestic animal products to provide a revision to the IAEA Handbook on transfer parameters TRS 364. Significant new data inputs have been incorporated into the databases from an extensive review of Russian language information and inclusion of data published since the early 1990s. Fractional gastrointestinal absorption in adult ruminants presented in the revised handbook are generally similar to those recommended for adult humans by the ICRP. Transfer coefficient values are presented in the handbook for a range of radionuclides to farm animal products. For most animal products, transfer coefficient values for elements additional to those in TRS 364 are provided although many data gaps remain. Transfer coefficients generally vary between species with larger species having lower values than smaller species. It has been suggested that the difference is partly due to the inclusion of dietary dry matter intake in the estimation of transfer coefficient and that whilst dietary intake increases with size nutrient concentrations do not. An alternative approach to quantifying transfer by using concentration ratios (CR), which do not consider dietary intake, has been evaluated. CR values compiled for the handbook vary considerably less between species than transfer coefficient values. The advantage of the CR approach is that values derived for one species could be applied to species for which there are no data. However, transfer coefficients will continue to be used as few studies currently report CR values or give data from which they can be estimated.  相似文献   
66.
城市道路绿化带不同植物叶片附尘对大气污染的磁学响应   总被引:3,自引:1,他引:2  
隆茜  周菊珍  孟颉  达良俊 《环境科学》2012,33(12):4188-4193
对上海市金沙江路两侧绿化带内24个常绿植物叶片样品进行了磁性与重金属测试,以探讨城市道路绿化带不同植物叶片附尘对大气污染的磁学响应.结果表明,χ、SIRM值分别在(4~59)×10-8m3.kg-1和(496~6 114)×10-6Am2.kg-1之间变化,S-300 mT在89%~98%之间变动.所有植物样品中χARM/χ〈4,χARM/SIRM〈30×10-5mA-1.磁性参数表明,植物叶片附尘以亚铁磁性矿物为主,磁性矿物颗粒以假单畴(PSD)-多畴(MD)为主.重金属元素Zn、Cu、Pb含量与反映亚铁磁性矿物含量的χ、SIRM、χARM呈显著正相关,可以将磁性参数SIRM作为叶片重金属元素的替代指标.推荐在上海地区广泛种植的广玉兰作为道路植物污染的指示植物。  相似文献   
67.
68.
This essay comments and expands upon an emerging area of research, energy communication, that shares with environmental communication the fraught commitment to simultaneously study communication as an ordinary yet potentially transformative practice, and a strategic endeavour to catalyse change. We begin by defining and situating energy communication within ongoing work on the discursive dimensions of energy extraction, production, distribution, and consumption. We then offer three generative directions for future research related to energy transitions as communicative processes: analysing campaigns’ strategic efforts, critically theorizing energy’s transnational power dynamics, and theorizing the energy democracy movement.  相似文献   
69.
Investigating predator–prey relationships is an important component for identifying and understanding the factors that influence the structure and function of ecosystems. Mesopredators, defined as mid-level predators, have a profound effect on ecosystem structure by contributing an important link between apex predators and lower trophic levels. The diet of two elasmobranch mesopredators, Squalus acanthias and Mustelus antarcticus, was investigated in three locations in south-east Tasmania. Squalus acanthias consumed predominantly pelagic teleosts and cephalopods, while M. antarcticus predominantly consumed benthic crustaceans. As a result, there was low dietary and niche overlap between the two species. There was however evidence of intra-specific dietary variations between locations for both the species. This study has contributed to a better understanding of the top-down dynamics of the food web in coastal Tasmania, by providing important dietary information of two abundant mesopredators. In addition, the similar dietary patterns for S. acanthias and other Mustelus species over much of their global range suggest they may be consistent in their trophic roles across systems, with limited competition between these two sympatric mesopredators to be expected.  相似文献   
70.
Setting out from Jacques Derrida’s assertion that every act of naming is “a foreshadowing of mourning” ([2008. The animal that therefore I am. (M.-L. Mallet, Ed., D. Wills, Trans.). New York, NY: Fordham University Press], p. 20), this paper argues that the work of earthly coexistence is underwritten by the intertwined practices of naming and mourning. The paper demonstrates that names provide access to and shape our perceptions of earthly entities; that the act of naming prepares us for the work of mourning; that the proper names given to endlings provide poignant points of access to species on the edge of extinction; that species names disclose species as such and, thus, enable us to grieve not just particular living organisms but entire ways of life; and that the name given to the current geological epoch, the “anthropocene,” simultaneously reflects and engenders a mode of awareness which enables us to relinquish those ways of being human that no longer seem sustainable and carry forth those that promise to enrich earthly coexistence.  相似文献   
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