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51.
52.
在现代社会中,人类的经济建设以与自然过程相竞争的规模进行着,所造成的生态影响不仅表现在地区生态系统的结构和功能上,也表现在生物圈中,而且还从地球化学循环中显示出来。这种情况,使得现代社会的经济管理,必然由传统的经济管理逐步转变成生态经济管理。 相似文献
53.
The major developments in the field of nuclear activation analysis, from 1936 to 1989, are discussed. The developments are
grouped into five consecutive time periods. The impact of various scientists on the development of the field in the first
35 years is also discussed. 相似文献
54.
黄连木五倍子的生态研究与利用 总被引:1,自引:0,他引:1
一、产地自然概况黄连木五倍子最早发现于河南省南部信阳市郊贤山脚下(东经114°0′,,北纬32°10′)。该地为低山丘陵,海拔90一320m,南部紧连鸡公山厂傍依南湾水库和狮河。 相似文献
55.
旱地作物生态工程的设计 总被引:1,自引:1,他引:0
旱地作物生态工程是运用生态学和系统科学的原理和方法而设计和组建的旱地作物生产工艺体系。它把作物及其环境作为一个系统,统筹兼顾,相互协调,全面安排,综合利用。其最终目标是建立高效的,相对平衡的旱地作物生态系统。工程的最大特点在于它的整体性和综合性。它是作物先进生产技术的科学组装 相似文献
56.
以往研究流域开发战略问题,多从流域内资源的开发利用方面考虑,而衡量其方案的优劣也多以经济效益的大小为准绳。现在,环境污染与生态危机已威胁着人类的生存与发展,因此在研究流域战略问题时,必须开拓思路, 相似文献
57.
Species boundaries,phylogenetic relationships,and ecological differentiation inAnthriscus (Apiaceae)
Krzysztof Spalik 《Plant Systematics and Evolution》1996,199(1-2):17-32
Species boundaries and phylogenetic relationships of 17 taxa ofAnthriscus (Apiaceae), with special emphasis on the critical sect.Cacosciadium, were explored using morphological data with principal component analysis, phenetics, and phylogenetics. The analyses did not provide satisfactory resolution of taxa from sect.Cacosciadium and only four species were retained. The total number of species was reduced to nine. Sect.Cacosciadium is distinguished by only two synapomorphies while sects.Anthriscus andCaroides are better supported. Present geographic and ecological variation suggests that the radiation ofAnthriscus occurred through divergence of peripheral isolated populations adapting to different habitats: high montane meadows and screes, shady climax forests, and seasonally dry habitats at lower altitudes. The adaptive significance of particular morphological traits is discussed. 相似文献
58.
谷蠹生态学特性的研究 总被引:3,自引:0,他引:3
谷蠹Rhyzoperthadominica(F.)生态学特性的试验结果表明,温度、湿度、粮食含水量对其各发育历期影响非常显著;食物影响不显著。 相似文献
59.
Kirsty Barr Henrik Moller Emma Christmas Philip Lyver Jacqueline Beggs 《Oecologia》1996,105(2):266-270
An introduced social wasp Vespula vulgaris may compete with native birds for honeydew and invertebrates in New Zealand forests. Experimentally hidden mealworms (Tenebrio molitor) persisted longer at two sites following wasp poisoning that at two sites where wasps were not poisoned. Mealworms persisted longer in the morning than in the afternoon within all study sites. An unusually low mealworm removal rate during a morning trial before wasp poisoning heavily influences the results of this experiment but we have no ecological reason to ignore it. Wasps may therefore be having a heavy impact on invertebrate abundance on very short time scales (within a day following dawn emergence). They may also remove cached food items that would otherwise be retrieved by the South Island robin (Petroica australis australis) during cold or dark feeding conditions. 相似文献
60.
Uncultivated plants growing on disturbed sites may be useful for assessing the bioavailability of some metals in soils, and thus the potential for metal mobilization up the terrestrial food chain, an important element in ecological risk assessment. A planted chicory cultivar (Cichorium intybus L. var. foliosum Hegi.) and the uncultivated plants horseweed (Canada fleabane) (Erigeron canadensis L.) and dogfennel (Eupatorium capillifolium (Lam.) Small) were evaluated for their ability to act as index plant species for soil Cd, Cr, Ni, and V at two field sites where these metals had been applied five yr previously to two highly weathered sandy Ultisols. Soil Cd was available to all analyzed plant tissues of all three plant species at both sites, particularly on the sandier Blanton soil. Chicory was an effective index plant for Cd on the finer textured Orangeburg soil but functioned as an indicator plant (toxicity symptoms were observed) on the sandier Blanton soil. Horseweed and dogfennel were effective index plants for Cd in both contaminated soils. Soil Cr, Ni, and V were less bioavailable than soil Cd and plant metal uptake was more sensitive to residual soil Cr, Ni, and V than was soil extraction with double acid. Horseweed and chicory may have potential as index plants for soil Cr. Chicory may have potential as a Ni index plant. Chicory and dogfennel may have potential as V index plants. 相似文献