黄河三角洲重盐碱地区园林灌木树种选择技术

指出在自然条件严酷的重盐碱地区,应根据地形、地貌、土壤和经济条件,合理运用"选树适地"、"改地选树"、"选树改地"和"选树选地"技术,既能保证树木成活,又能保证树木不受盐碱危害、生长旺盛,为打造出丰富多彩的园林景观,并实现其可持续发展提供基础资料。     

12种旱生灌木及其发芽特性的研究

初步探讨了果壳、浸种、发芽床对干旱地区荒漠灌木植物种萌发的影响。结果表明:12种灌木种子在不同 发芽方法所得出的发芽结果有着明显的不同,掌握了种子发芽初次计数和末次计数时间。     

Effects of fragmentation on cattle in African savannas under variable precipitation

Cattle move to access patches that vary in forage quantity and quality. Fragmentation can prevent animals from reaching patches. I used an integrative ecosystem model applied to three African landscapes to explore the sensitivity of cattle populations to fragmentation (here, changes in populations as parcel areas decreased) under different precipitation patterns. I hypothesized that low and high precipitation would yield populations relatively insensitive to fragmentation, intermediate precipitation would yield more sensitive populations, and more variable inter-annual precipitation would reduce sensitivity to fragmentation. Precipitation data were altered to yield averages of 100–1,000 mm year⁻¹ and inter-annual coefficients of variation of 0–60%. A 1,000 km² landscape in each area was divided into progressively smaller parcels and simulations conducted for each parcel. Rainfall at 100 mm year⁻¹ supported low populations that were insensitive to fragmentation. Populations peaked at rainfall levels similar to those observed, and declined under higher precipitation, due in-part to shrub expansion. Fragmenting landscapes caused up to a 62% decline in cattle. High inter-annual variation in precipitation reduced sensitivity to fragmentation when precipitation was above that observed. The pattern was opposite when precipitation was below what was observed. Cattle on the landscape with fine-scale heterogeneity were relatively insensitive to fragmentation, and those on the heterogeneous but coarse-grained landscape were extremely sensitive. Fragmentation in landscapes where populations are sensitive will require more intensive inputs to offset losses, and changes in the frequency of extreme weather associated with climate change will alter the sensitivity of some populations to fragmentation. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

高寒金露梅灌丛生物量及年周转量

采用样方调查与挖掘相结合的方法,以金露梅(Potentilla fruticosa)灌丛多年累积枝干、地下生物量和当年新生枝叶量及6-9月冠面长度、宽度和高度为参数进行线性回归分析,结合金露梅灌丛与草本植物在样地所占比例,估算其年净初级生产量及年净固碳量。结果表明:2004年金露梅灌丛地下实际周转量为53.7 g/m²,周转率为26%;当年新生枝叶量为41.0 g/m²,年净初级生产量94.7 g/m²;以草本植物与金露梅灌丛在样地所占比例为60%和40%进行估算,2004年金露梅灌丛草甸总净初级生产量为858.3 g/m²,固碳量481.9 g/m²。     

宁夏沙地立地分类评价和适地适树的研究

<正> 1.沙地立地分类的原则和系统1.1分类的原则a.多因子立地分类原则:在沙区不同地域的生态环境因子的组合是有差异的,这些因子包括气候、地质、地貌、土壤、水文以及沙丘的部位等均能决定各种植物的生存和发展,相似的生态因子产生相似的植物群体和生长量,即植物能反映生态条件量和质的特征,立地分类及评价原则正是以区别各种具有相似生态因子组合的不同地段划分类型,按     

共和地区灌木林的现状分析及保护对策

在分析共和地区灌木林的历史与现状的基础上,阐述了灌木林主要生态功能极其重要的生态地位,提出了恢复与发展灌木林的保护对策。     

乔灌草结合治理我国北方土地风沙化问题的研究进展

分析了土地风沙化的形成原因以及特点,介绍了植物治沙以及乔灌草结合的相关概念,指出乔灌草结合模式在治理北方土地风沙化中的必要性及应注意的问题,旨在优化乔灌草结合模式,使其在治理北方土地风沙化实践中发挥更加突出的作用。     

深圳市3种灌木单株蒸散量及作物系数的研究

[目的]测定深圳市3种常见灌木在不同灌水梯度下的蒸散量,并确定其作物系数,为深圳市园林灌木的合理灌溉提供理论依据。[方法]盆栽试验,4种灌水梯度分别为田间持水量的45%-30%、60%-45%、75%-60%和90%-75%。利用称重法测定4种灌水梯度下3种灌木的实际蒸散量,同时利用Makkink方法计算参考作物蒸散量,确定3种灌木的作物系数。[结果]3种灌木的蒸散量均随灌水梯度的增加而增加,灌水量多,蒸散量就多。金叶假连翘和龙船花的蒸散量曲线呈现单峰型,变叶木的蒸散量曲线呈现双峰型。3种灌木的蒸散量排列顺序为：金叶假连翘〉变叶木〉龙船花。变叶木、金叶假连翘、龙船花作物系数的变化范围分别为0.97-1.82、0.95-2.17、0.90-1.58。[结论]确定3种灌木在不同月份和不同灌水梯度下的蒸散量和作物系数。     

大通宝库林区灌木林在水源涵养中的效能

大通宝库林区是青海省省会城市西宁市最大的水源涵养林区,为西宁市工农业生产及生活年均供水量达2.22×108m3。而宝库林区森林资源主要以灌木林为主,本文就宝库林区主要种类灌木林分在水源涵养中的效能作了分析与评估。     

灌木层及主要灌木种在椴树红松林养分循环中的地位与作用

对原始椴树红松林中的灌木层及主要灌木种（毛榛子、溲疏和刺五加）的生物量、养分量、存留量、归还量、吸收量、循环速率等方面在林分的养分循环中的地位与作用进行了研究。研究结果表明：灌木层虽在林分的养分循环中处于次要地位,但具有促使林分养分步入良性生物循环的重要作用。毛榛子和溲疏是该林分灌木中的优势或亚优势种,在养分循环中起着重要的或突出的作用,是重点保护的灌木种。刺五加在养分循环中存留养分比较多,归还养分比较少,虽然消耗地力却是具有药用的灌木种,对它应既维持又要控制。