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721.
Supaporn Phanwilai Naluporn Kangwannarakul Pongsak 《Frontiers of Environmental Science & Engineering》2020,14(6):115
722.
David R. Stewart Zachary E. Underwood Frank J. Rahel Annika W. Walters 《Conservation biology》2018,32(1):183-194
Establishing protected areas has long been an effective conservation strategy and is often based on readily surveyed species. The potential of any freshwater taxa to be a surrogate for other aquatic groups has not been explored fully. We compiled occurrence data on 72 species of freshwater fishes, amphibians, mussels, and aquatic reptiles for the Great Plains, Wyoming (U.S.A.). We used hierarchical Bayesian multispecies mixture models and MaxEnt models to describe species’ distributions and the program Zonation to identify areas of conservation priority for each aquatic group. The landscape‐scale factors that best characterized aquatic species’ distributions differed among groups. There was low agreement and congruence among taxa‐specific conservation priorities (<20%), meaning no surrogate priority areas would include or protect the best habitats of other aquatic taxa. Common, wideranging aquatic species were included in taxa‐specific priority areas, but rare freshwater species were not included. Thus, the development of conservation priorities based on a single freshwater aquatic group would not protect all species in the other aquatic groups. 相似文献
723.
Effects of age and sex ratios on offspring recruitment rates in translocated black rhinoceros
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Jay V. Gedir Peter R. Law Pierre du Preez Wayne L. Linklater 《Conservation biology》2018,32(3):628-637
Success of animal translocations depends on improving postrelease demographic rates toward establishment and subsequent growth of released populations. Short‐term metrics for evaluating translocation success and its drivers, like postrelease survival and fecundity, are unlikely to represent longer‐term outcomes. We used information theory to investigate 25 years of data on black rhinoceros (Diceros bicornis) translocations. We used the offspring recruitment rate (ORR) of translocated females—a metric integrating survival, fecundity, and offspring recruitment at sexual maturity—to detect determinants of success. Our unambiguously best model (AICω = 0.986) predicted that ORR increases with female age at release as a function of lower postrelease adult rhinoceros sex ratio (males:females). Delay of first postrelease reproduction and failure of some females to recruit any calves to sexual maturity most influenced the pattern of ORRs, and the leading causes of recruitment failure were postrelease female death (23% of all females) and failure to calve (24% of surviving females). We recommend translocating older females (≥6 years old) because they do not exhibit the reproductive delay and low ORRs of juveniles (<4 years old) or the higher rates of recruitment failure of juveniles and young adults (4–5.9 years old). Where translocation of juveniles is necessary, they should be released into female‐biased populations, where they have higher ORRs. Our study offers the unique advantage of a long‐term analysis across a large number of replicate populations—a science‐by‐management experiment as a proxy for a manipulative experiment, and a rare opportunity, particularly for a large, critically endangered taxon such as the black rhinoceros. Our findings differ from previous recommendations, reinforce the importance of long‐term data sets and comprehensive metrics of translocation success, and suggest attention be shifted from ecological to social constraints on population growth and species recovery, particularly when translocating species with polygynous breeding systems. 相似文献
724.
转变增长方式,推行清洁生产 总被引:2,自引:0,他引:2
从我国资源承载力,环境污染的变化趋势及国际政治和国际贸易等方面,论述了维持我国经济持续发展,必须加速传统工业发展战略转移,走低消耗、低污染、高效益的发展道路。提出了经济增长与工业化战略及环保政策的思考和建议:加快产业结构转换和技术改造,大幅度降低单位产值的能耗物耗和污染物的排放:加速技术改造,推行工业清洁生产;增加环保投入,开辟资金来源。 相似文献
725.
汤安中 《中国人口.资源与环境》1992,(2)
本文从社会系统工程角度对人口、资源与环境三者的动态依存关系作了全面探讨。认为科技是转变这个系统运动性质的关键因素,人口问题的实质是自身的消耗接近于自身的供给,解决中国人口问题的根本途径是增加科技的投入。科技类似催化剂,可使潜在资源转化为现实资源,因而人均资源占有量不会绝对呈下降曲线。科技这一要素的大量介入,将使封闭的人口、资源与环境系统(就经济学意义而言)转变为一个全方位开放的、充满活力的耗散结构系统。 相似文献
726.
Richard R. Zavesky Alvin S. Goodman 《Journal of the American Water Resources Association》1988,24(6):1281-1287
ABSTRACT: This paper describes a new method of computing water-surface profiles, which does not require the assumption of hydrostatic pressure or of roughness coefficients. The method is based upon distributing entropy production values along a channel as uniformly as boundary conditions permit. The method requires a discharge capacity rating at a channel cross-section within the limits of the reach of the channel. A new theoretical relationship between the kinetic and momentum coefficients for the velocity profile is used, together with a dynamic programming technique for optimal distribution of energy losses along the channel. A computer model was developed and was used to verify the methodology for flood flow and channel data at four locations. 相似文献
727.
J. Büsch P. Huber E. Pflüger St. Miltenyi J. Holtz Professor Dr. A. Radbruch 《黑龙江环境通报》1994,14(12):1129-1140
For simple and effective isolation of fetal cells from peripheral maternal blood, we combined depletion of maternal cells and enrichment of fetal cells by high-gradient magnetic cell separation (MACS). First CD45+ and CD14+ cells were depleted from maternal peripheral blood mononuclear cells by MACS. From the depleted fraction, CD71+ erythroid cells were enriched up to 80 per cent by MACS. This ‘double-MACS’ procedure yielded an average depletion rate of 780-fold and an average enrichment rate of 500-fold, with approximate recovery rates of 40–55 per cent. For paternity testing, cells from unseparated blood and the various fractions were analysed for polymorphism of the HLA-DQ-A1 locus and D1S80 locus by the polymerase chain reaction (PCR). In CD45−/CD71+ sorted cells from maternal blood, but not in unfractionated cells from maternal blood or CD45−/CD14− cells, paternal alleles could be detected. In the CD45−/CD71+ fraction, the relative frequency of paternal alleles compared with maternal alleles ranged from 1 in 20 to 1 in 200 (determined by titration and depending on the quality of separation and biological variation). In 7 out of 11 cases, between weeks 12 and 25 of gestation, we could identify paternal alleles by PCR, either HLA-DQ-A1 or D1S80. This double-MACS procedure is simple, fast, efficient, and reliable for non-invasive prenatal diagnosis. 相似文献
728.
本文研究了孔雀绿与磷(砷)酸钼的离子对膜的形成条件。并依此与共存元素分离,进行痕量磷酸根、亚砷酸根和砷酸根的浮膜分光光度法测定。选用硫酸为介质,考察了25种共存离子对测定的影响。拟定了天然水中痕量磷酸根、亚砷酸根和砷酸根的分析方法.操作简便,结果令人满意。 相似文献
729.
Mehlich 1(M1), mehlich 3(M3) and CaCl2 DTPA have been used to predict the available micronutrient in soil. However, the forms of micronutrient extractable by these extractants are not known. In the present study, ten soils, collected from five provinces and the capital of China, representing a wide range of chemical and physical properties, were analyzed by sequential extraction to isolate five forms of cobalt and nickel, they are exchangeable, carbonate bound, Fe Mn oxide bound, organically bound and residual forms. The chemical forms extracted by M1, M3 and CaCl2 DTPA were also investigated. The results show strong correlation between the carbonate bound or organically bound forms of Co or Ni and the amounts of extractable by any of the above three extractants. The main forms extracted by these extractants are carbonate and organically bound forms. The ranking of these three extractants for extraction of Co and Ni are M1>M3=CaCl2 DTPA and M1=M3>CaCl2 DTPA, respectively. 相似文献
730.