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991.
Abstract: Introducing rare plants to new sites for conservation to offset effects of habitat destruction requires detailed knowledge of habitat requirements, plant demography, and management needs. We conducted a factorial experiment replicated at three coastal prairie sites to test the effects of clipping frequency and litter accumulation on seed germination, seedling survival, reproduction, and seedling recruitment of introduced populations of the endangered, tall-stature, annual forb, Holocarpha macradenia (DC.) E. Greene. Clipping favored H. macradenia , primarily by enhancing seed germination and flower production. Litter accumulation had no effect on seed germination, even after 5 years of treatments. Seedling recruitment was highly site specific with large numbers of recruits recorded at only one of three sites. Although recruitment of seedlings was higher in clipped plots for 2–3 years, by 4–5 years after introduction very few seedlings survived to reproduction in any treatment. We attribute this result to a combination of poor habitat quality, small population size, and lack of a seed bank. We were unsuccessful in introducing this relatively well-studied species of concern to apparently suitable habitat at multiple sites in multiple years, which suggests that translocating rare plant populations to mitigate for habitat destruction is an expensive and highly uncertain endeavor. 相似文献
992.
长江流域陆生植物资源的类型与开发利用 总被引:1,自引:0,他引:1
长江流域范围广大,大部分地区处于湿润,半湿润的亚热带区域,蕴藏着丰富的陆生植物资源。本文重点探讨了植物资源的类型,开发价值的评价,开发中存在的问题及其对策。 相似文献
993.
论贵州岩溶山区植物物种多样性的保护 总被引:2,自引:0,他引:2
严重玲 《长江流域资源与环境》1994,3(2):136-140
论述了植物物种多样性的概念及保护意义,针对贵州岩溶山区生态环境和植物资源现状,认为植物资源的开发和利用必须重视对植物物种多样性的保护,并提出了保护植物物种多样性的几点建议。 相似文献
994.
使火电厂锅炉燃烧后产生的烟气与冲灰水充分接触,可使水中PH降低,减少不体碱性污染;烟气中的SO2气体则在水中形成无污染的水溶性离子,从而减少了大气污染。 相似文献
995.
N. K. Panova V. Jankovska O. M. Korona E. V. Zinov'ev 《Russian Journal of Ecology》2003,34(4):219-230
Palynological, paleocarpological, and paleoentomological analyses of frozen peat deposits near Lake Pereval'noe, the Polar Urals, were performed to reveal the main stages of change in the pattern of vegetation over the period from the beginning of warming after the last Pleistocene glaciation to the late Holocene. Nine to four thousand years ago, the study region (at the present-day upper boundary of open larch forests) was covered with taiga forests, as the climate there was significantly warmer. These were larch–birch forests with an admixture of spruce and, later, spruce forests with larch and birch. 相似文献
996.
Macroalgal growth in nutrient-enriched estuaries: A biogeochemical and evolutionary perspective 总被引:1,自引:0,他引:1
Increased nutrient loading of a body of water leads to an increase in macroalgal growth. It is generally observed, however, that certain species thrive more than others, capitalising on the increased nutrient availability. These are usually small, fast-growing, ephemeral algae that often appear as nuisance blooms. This article discusses the correlation between nutrient increase and macroalgal bloom formation. From a historical perspective, the evolutionary history of nuisance macroalgae, and the habits available to them prior to anthropogenic influences on estuarine geochemistry are considered. The occurrence of macroalgal genera whose distribution is commonly related to estuaries with high nutrient loading is discussed, along with evidence suggesting that the ecophysiological traits of r-selected, ephemeral algae largely contribute to their ecological success and bloom-formation at nutrient-enriched sites. 相似文献
997.
大亚湾大鹏澳海域C、N、BSi的沉积记录研究 总被引:3,自引:0,他引:3
研究了大亚湾大鹏澳海域鱼类养殖区、贝类养殖区以及核电站附近3个站位50~78 cm的柱状沉积物中生物硅(BSi)、总有机碳(TOC)、总氮(TN)等生源要素的垂直变化,以揭示人类活动对海洋环境影响的沉积记录。位于近岸海水养殖区的两个沉积柱中,近年来TOC含量呈明显上升趋势,而核电站附近海域略有下降。从TOC/TN比值判断(三个沉积柱平均分别为9.54、7.42、7.9),该海域TOC是陆源和水生两种来源的混合物。此外,养殖区上表层沉积物中水生有机碳(TOCa)含量呈明显下降趋势,而TOC/TN比值则上升,说明养殖区水生初级生产力及其对总初级生产力的贡献下降;相反,陆源污染所造成的陆源有机碳(TOCt)含量明显增加。在核电站附近海域,TOCa含量明显上升,TOC/TN和TOCt值下降,表明核电站的运行使水体初级生产力上升,陆源有机碳输入则减少。BSi、BSi/TOCa的垂直分布表明,海水养殖区硅藻对总初级生产力的贡献逐年上升,而核电站海域硅藻的贡献则下降。 相似文献
998.
999.
1000.
It is less known whether and how soil metal lead (Pb) impacts the invasion of exotic plants.A greenhouse experiment was conducted to estimate the effects of lead on the growth and mycorrhizae of an invasive species(Solidago canadensis L.)in a microcosm system. Each microcosm unit was separated into HOST and TEST compartments by a replaceable mesh screen that allowed arbuscular mycorrhizal (AM) fungal hyphae rather than plant roots to grow into the TEST compartments.Three Pb levels(control,300,and 600 mg/kg soil)were used in this study to simulate ambient soil and two pollution sites where S. canadensis grows.Mycorrhizal inoculum comprised five indigenous arbuscular mycorrhizal fungal species (Glomus mosseae,Glomus versiform,Glomus diaphanum,Glomus geosporum,and Glomus etunicatum).The 15N isotope tracer was used to quantify the mycorrhizally mediated nitrogen acquisition of plants.The results showed that S. canadensis was highly dependent on mvcOrrhizae.The Pb additions significantly decreased biomass and arbuscular mycorrhizal colonization(root length colonized,RLC%) but did not affect spore numbers,N(including total N and 15N) and P uptake.The facilitating efficiency of mycorrhizae on nutrient acquisition was promoted by Pb treatments.The Pb was mostly sequestered in belowground of plant (root and rhizome).The results suggest that the high efficiency of mycorrhizae on nutrient uptake mightgive S. canadensis a great advantage over native species in Pb polluted softs. 相似文献