典型草原自然演替过程中土壤理化性质动态变化

以内蒙古巴林右旗退化典型草原为研究对象,采用空间序列代替时间序列的方法,探讨围封条件下,退化典型草原自然恢复过程中土壤物理性质及养分的动态变化。结果表明:围封对典型草原土壤含水量产生深刻影响,土壤水分含量呈增加趋势,增加最明显的是土壤表层0~5 cm;典型草原群落自然恢复过程中,土壤有机质、全氮、速效氮、速效钾增加极显著(P<0.01),全磷和速效磷增加较为显著(0.01<P<0.05),同时,土壤养分有明显的表聚现象;典型草原群落去除放牧践踏的干扰后,土壤物理性状得以改善,恢复6年和10年的0~5 cm土层土壤容重分别为1.27和1.25 g/cm3,显著低于恢复初期的土壤容重(P<0.05)。     

避免曲轴提前报废修复技巧研究

通过对各种机型曲轴的磨损分析,确定曲轴磨损至极限尺寸时的相应对策及磨修技巧。     

自压喷灌技术在高寒干旱区草地植被恢复的应用浅析

针对高海拔、寒冷和干旱等恶劣气候环境地区草地植被恢复的瓶颈问题,结合可持续发展战略内涵,该研究系统地介绍了高寒干旱区草地自压喷灌技术,采用创新设计,设置围栏、围栏+喷灌、未围栏3个处理的初级生产效益对比分析试验。结果显示,围栏封育+自压喷灌样地植物平均高度比未围栏样地增加了155.77%,比仅围栏样地增加了76.71%;群落盖度比未围栏样地增加了152.69%,比仅围栏样地增加了35.96%;群落生产力比未围栏样地增加了110.00%,比仅围栏样地增加了24.10%。结果表明,自压喷灌技术在水源和地形条件具备的高寒干旱草地恢复中具备一定的示范和推广潜力,为西藏地区因地制宜,科学合理地利用水资源,为该区草地生态畜牧业的可持续发展提供了一条新思路。     

Do frugivorous birds assist rainforest succession in weed dominated oldfield regrowth of subtropical Australia?

Exotic plants often form the first woody vegetation that grows on abandoned farmland. If this vegetation attracts vertebrate frugivores which disperse the seeds of native plants, then native plants may recruit to such oldfield sites. However, there is debate about the extent to which exotic vegetation assists or suppresses the regeneration of native plants, and about its effects on faunal biodiversity. These issues were investigated in subtropical eastern Australia, where rainforests were cleared for agriculture in the 19th century, and where regrowth dominated by camphor laurel (Cinnamomum camphora, an exotic, fleshy-fruited tree) has become common on former agricultural land. The study assessed the assemblages of frugivorous birds, and the recruitment of rainforest plants, at 24 patches of camphor laurel regrowth. The patches were used by nearly all frugivorous birds associated with subtropical rainforest. Many of these birds (16 of 34 species) are considered to have a medium to high potential to disperse the seeds of rainforest plants, and eight of these were abundant and widespread in regrowth patches. Of 208 recorded plant species, 181 were native to local rainforest. The ratio of native to exotic species was higher amongst tree recruits than adult trees, both for numbers of species and individuals. Among native tree recruits, 79% of 75 species, and 93% of 1928 individuals, were potentially dispersed by birds. These recruits included many late-successional species, and there were relatively more individuals of late-successional, bird-dispersed native species amongst recruits than adult trees. The species richness, but not the abundance, of both frugivorous birds and of bird-dispersed rainforest trees decreased with distance from major rainforest remnants. Camphor laurel regrowth provides habitat for rainforest birds and creates conditions suitable for the regeneration of native rainforest plants on abandoned farmland. Careful management of regrowth dominated by fleshy-fruited exotic invasive trees can provide an opportunity for broadscale reforestation in extensively-cleared landscapes.     

坝上草原退耕地植被不同恢复处理土壤种子库研究

采用野外调查取样和室内实验相结合的方法,研究坝上草原退耕地土壤种子库的物种组成、密度和物种多样性等特征.结果表明:自然恢复、浅耕处理和深耕处理3种不同恢复措施下,土壤种子库物种丰富度(种)大小为浅耕处理(18)>自然恢复(15)>深耕处理(14);自然恢复处理、浅耕处理和深耕处理土壤种子库密度分别为23 949粒·m-2、15746粒·m-2和10600粒·m-2,浅耕处理和深耕处理分别比自然恢复处理减少34.3%和55.7%;不同恢复方式下土壤种子库与地上植被的物种密度的对应关系可用三次曲线来表示.土壤种子库间有较高的相似系数,但随着干扰程度的增加而减少.     

Spatial pattern and heterogeneity of soil properties in sand dunes under grazing and restoration in Horqin Sandy Land, Northern China

Applying a combination of classical and geostatistical methods, we identified soil properties and their spatial variation in a 5-year grazed sand dune (GSD5) and a 20-year recovered sand dune (RSD20) in Horqin Sandy Land, northern China. The paper assesses the effect of grazing, topography and vegetation restoration on spatial heterogeneity of soil properties. The results showed that soil organic carbon, total nitrogen, very fine sand (0.1–0.05 mm) content and their coefficients of variation were lower in GSD5 than in RSD20, while soil water contents (0–20 cm and 20–40 cm depths) were higher in GSD5 than in RSD20. Geostatistical analysis revealed that the spatial structured variance accounted for the largest proportion of total sample variance in soil properties at the measured scale under grazing and restoration. The spatial autocorrelation ranges were 66.30 m for soil organic carbon and 50.80 m for total nitrogen in GSD5 less than those in RSD20 (70.00 m and 76.10 m, respectively), while the spatial autocorrelation ranges of soil particle size fractions and soil water contents in RSD20 were less than those in GSD5. Kriging-interpolated maps also showed that the heterogeneity of soil organic carbon and total nitrogen and their degree of patch fragmentation were higher in GSD5 than in RSD20. These results suggested that continuous grazing resulted in an increase in spatial variability of soil nutrient and a decrease in spatial variability of soil particle size fractions and soil water content. Soil organic carbon and total nitrogen of sand dunes are associated closely with soil particle size fractions, relative height of sampling site and vegetation cover. Spatial patterns of soil properties are most strongly related to grazing, topography and plant-induced heterogeneity in sand dune ecosystems prone to wind erosion.     

退化喀斯特森林自然恢复评价研究

在研究贵州茂兰国家级自然保护区退化喀斯特森林自然恢复过程中群落组成、结构、功能的基础上,提出了退化群落恢复潜力度、恢复度和恢复速度３个评价指标和计算方法,分析了退化群落在自然恢复过程中群落高度、盖度、实生株／总株数、组成结构、显著度、生物量等特征指标的恢复潜力度、恢复度和恢复速度的变化,并进行综合评价。结果表明：低一级演替阶段群落向相邻更高一级演替阶段群落恢复的潜力度最高,群落自然恢复是由低级阶段     

城市景观水体的修复

对城市景观水体存在的问题和原因作了简单的分析,并对水景水体的修复提出解决的原理和方法,提出城市景观水体建设及治理应以体现生态、休闲、亲水、自然和突出文化内涵为指导思想和基本原则。结合南昌市近年“八湖二河”治理的实例,简述几种城市景观水体的修复方法。     

我国草原生态系统退化与恢复研究的进展与启示

草原生态系统是主要的陆地生态系统之一。近几十年来,草原地区生态系统退化现象越来越严重,草原生态系统的演替、退化、诊断、多样性保护等已成为热点研究领域。     

柠条的更新生态位及其与荒漠植被恢复的关系

更新生态位是一个新的成熟植物个体成功地代替另一个成熟个体所要求的可能生态位,其生活史早期阶段的一系列特点可以作为其更新生态位。对蝶形花科(Papilionaceae),锦鸡儿属(Caragana)落叶灌木柠条(Caraganaspp.)的种子萌发、幼苗生长、土壤种子库和营养繁殖等更新生态位特征及其与荒漠植被恢复的关系进行了综述,旨在为柠条的繁殖生物学和恢复生态学研究提供更新生态位方面的理论依据。