高山森林溪流凋落叶冬季水溶性碳含量动态

凋落物分解过程中水溶性碳是高山森林溪流生态系统碳的重要来源,其在溪流中的流动转移不仅会影响下游水质环境,而且其含量动态受冬季季节性雪被形成及消融过程的深刻影响,但缺乏必要关注.因此,采用凋落叶分解袋法,以川西高山森林典型乔木(四川红杉Larix mastersiana、方枝柏Sabina saltuaria)和灌木(高山杜鹃Rhododendron lapponicum、康定柳Salix paraplesia)凋落叶为研究对象,根据凋落叶自然分解规律,研究冬季不同时期(冻结初期、冻结期、融化期)河流、溪流、河岸带以及林下凋落叶水溶性碳以及可溶性组分含量格局的动态变化特征.结果表明:在冬季的分解过程中,冻结初期河流与溪流中凋落叶水溶性碳与可溶性组分含量显著降低,而至冻结期与融化期含量均无明显变化.各时期,林下凋落叶水溶性碳和可溶性组分含量显著高于其他生境,表现为从河流、溪流、河岸带至林下逐渐增加的变化趋势.相关分析表明,高山森林凋落叶分解过程中水溶性碳和可溶性组分含量与平均温度、正积温、负积温以及流速均呈极显著负相关关系,同样也受到PO3-4和p H等水环境因子的影响.可见,高山森林凋落叶冬季水溶性碳和可溶性组分在分解过程中易随水体的流动而向下游生态系统输出,这为深入认识高山森林-流域水体间的生态联系提供了一定的科学依据.     

论龙须草的开发价值及在我国的利用现状与展望

龙须草(Eulaliopsis binata)是中国、印度等亚洲少数国家特有的野生资源植物,在我国西南山区极富有开发价值。本文从龙须草的经济效益、生态效益、社会效益诸方面详细论述了龙须草在促进山区人民脱贫致富、解决山区剩余劳动力、缓解造纸原料短缺现状、增加纸张品种与品位、治理水土流失、恢复生态平衡等方面的独特作用;分析了我国开发利用龙须草资源的现状,指出“建立全国性生产、供销、科学研究一体化协作组织”、“开展驯化龙须草为栽培作物的系统研究”、“开展国际学术交流”等为当前龙须草开发与应用急需解决的7大课题。     

青藏高原高寒牧区聚落用地适宜性评价及其重构——以藏北那曲县为例

本文建立了适用于高寒牧区的聚落布局适宜性评价体系,利用自组织神经网络（SOFM）对青藏高原藏北地区那曲县展开聚落布局适宜性评价,并评估其现状聚落布局的合理性,在此基础上提出其聚落未来重构的思路。结果表明:（1）那曲县对于聚落布局的适宜性整体较低,适宜性水平高于一般适宜的区域零散分布在海拔较低、地势低缓的河谷地区,仅占全县面积的12%。其他适宜性较低的区域占全县面积的88%,分布相对集中。不同乡镇对于聚落布局的适宜性差异显著。（2）那曲县现有的聚落空间占全县总面积的0.47%,为7594 hm²,其中分布在一般适宜及以上等级区的面积占聚落总面积的86.47%,而较不适宜、不适宜和禁建区内的聚落占比高达13.53%。那曲县聚落空间布局倾向于较高级别的适宜区,聚落用地适宜性条件较好的乡镇其布局合理性越高。那曲县局部聚落布局不合理的原因包括:缺失空间布局指引、村级行政区划欠佳、藏民对神山的宗教信仰和历史遗存的地域环境认同。（3）聚落的空间重构可推动生态移民、适度“村庄化”等要素的整合来实现。聚落的经济重构要建设由特色产业为基础的村镇系统、充分利用“点—轴”结构的辐射效应等结构要素的重组来实现。聚落的社会重构需要通过合理安排基础设施、增强藏族社会关系组织程度、提倡藏区优秀文化传承等优化功能的措施来实现。     

岷江上游水体中DOM光谱特征的季节变化

川西北高原湿地和高山峡谷区是岷江等河流重要集水区,地表水体中溶解性有机质(DOM)更多受环境背景影响,DOM来源与结构特征对认识流域有机碳输出通量及模式有重要意义.本文对岷江上游在4月(枯水期末)和10月(丰水期末)分别进行沿程地表水采样并测定了DOM三维荧光光谱(EEM),结合平行因子模型(PARAFAC)分析岷江上游水体DOM沿程和季节变化特征.结果表明,DOM荧光峰(类腐殖峰A、C和类蛋白峰B、T)沿程波动趋势和程度不同;枯水期末(4月)A、C峰强而丰水期末(10月)B、T峰强.PARAFAC识别出3个荧光组分,即C1(250~260/380~480 nm,类腐殖质,占比48.68%~65.02%),C2(300~330/380~480 nm,类腐殖质,占比23.17%~29.83%)和C3(270~280/300~350 nm,类蛋白质,占比11.83%~21.53%);枯水期末(4月)组分沿程波动更明显,其中C1沿程波动最显著.荧光指数(FI)均值在1.4~1.9之间,说明不同季节DOM均有内外源混合特征;枯水期末(4月)DOM腐殖化、芳香性和疏水性高,表明DOM陆源贡献更大,而丰水期末(10月)DOM自生源贡献比枯水期更高.CDOM浓度[a(355)]与类腐殖质浓度[Fn(355)]极显著正相关,这也证实岷江上游水体中DOM的陆源输入.C1、C2在枯水期末(4月)相关性极显著而丰水期末(10月)相关性未达到显著性水平,进一步表明岷江上游水体中DOM的外源性及季节性差异.     

新疆高山地区冰川阻塞湖引起的突发性洪水灾害

我国新疆地区经常发生冰川阻塞湖引起的突发性洪水灾害.通过对叶尔羌河、昆马力克河和四棵树河三条典型河流的研究,发现可预报洪水序列与阻塞湖库容量有正相关关系.结合分析阿尔泰山、祁连山和西藏地区的地理环境特点,认为塔里木盆地周边地区是冰湖洪水的突发区.     

有机酸对潮褐土和红壤吸附Cu(II)的影响及其机制

采用吸附平衡法,研究了有机酸(草酸、柠檬酸)对潮褐土和红壤吸附Cu2+的影响及机制。结果表明,潮褐土、红壤对Cu2+吸附明显有异,潮褐土对Cu2+吸附量是红壤对Cu2+吸附量的5倍多。潮褐土对Cu2+的竞争吸附率随有机酸浓度升高而降低,当草酸、柠檬酸浓度为10 mmolL-1时,Cu2+吸附率均分别比对照的降低40%和70%以上。在低浓度条件下,红壤对Cu2+的竞争吸附率随有机酸浓度的提高而增加,当草酸、柠檬酸浓度分别超过1 mmolL-1和0.05 mmolL-1时,又随有机酸浓度的升高而降低。两种土壤对Cu2+次级吸附率随有机酸浓度升高而变化的规律与竞争吸附的一致。在相同有机酸浓度下,土壤对Cu2+的次级吸附率均比竞争吸附率的高。     

黄河源区退化高寒草地土壤种子库:种子萌发的数量和动态

对青藏高原黄河源区不同退化程度高寒草地的土壤种子库土样用土壤分析筛进行浓缩,并以萌发法分析土壤种子库萌发种子数量和动态.结果表明,孔径0.25~2 mm的土壤分析筛分离土样中萌发种子可达萌发种子总量的85%~97%,而小于0.25 mm的土样中未发现种子.因此,用0.25 mm孔径大小的土壤筛对高寒草地土壤种子库土样进行大规模浓缩是一种方便、可靠的方法.4种不同退化程度高寒草地(A:未退化草甸;B:轻度退化草甸;C:中度退化草甸;D:重度退化草甸)的土壤种子库在实验室条件下萌发的种子数量分别为:A 1 194~3 744粒/m2,平均2 421.3粒/m2;B 5 376~1 0912粒/m2,平均7 786.7粒/m2;C 2 304~1 3216粒/m2,平均8 695.5粒/m2;D 4 768~12 352粒/m2,平均8 125.9粒/m2.除样地A外,其它3个样地的可萌发种子数量差异不大.单子叶植物种子在培养到d 10左右开始萌发,双子叶植物在5~7 d内开始萌发,前者3 wk后基本不再萌发,后者5 wk左右停止萌发.4个样地土壤种子库种子萌发主要集中在第2~3周,并表现出近似单峰型格局.图1表3参39     

Ecological Effectiveness of Agri-Environment Schemes in Different Agricultural Landscapes in The Netherlands

Abstract:  Agri-environment schemes are an instrument used by western European countries to counteract the negative effects of contemporary agriculture on biodiversity, but not much is known about their effectiveness. We investigated the ecological effects of Dutch agri-environment schemes aimed at promoting botanical diversity or meadow birds, and we tested whether the effectiveness of the schemes depends on landscape type or structure. In three different types of landscape, we surveyed plants, birds, bees, and hover flies on 78 paired fields that either had agri-environment schemes or were managed conventionally, and we collected data on a range of different environmental variables. Neither plant species richness nor abundance of meadow birds was higher on fields with agri-environment schemes. Landscape type had a significant effect on both species groups, but the effects of the schemes were independent of landscape type. Neither the diversity of plants nor the abundance of birds was related to any of the environmental variables. Agri-environment schemes designed to promote plant species richness or bird abundance did have positive side-effects because they enhanced the species richness of bees and hover flies, irrespective of the type of landscape. Furthermore, landscape type, groundwater level (hover flies), and area of wooded edges (bees) significantly affected both species groups. The failure of the schemes to promote the target species may be related to the high intensity of land use in The Netherlands. Simple conservation measures taken by farmers may not be sufficient to counteract the impact of factors that are often controlled at the landscape level (e.g., hydrology). Similar studies in other countries are needed to place the results of our study into a European context.     

垃圾肥在潮土上对花生的增产效果

在潮土上施用垃圾肥对花生产量和品质影响的研究结果表明，在较贫瘠的土壤上，垃圾肥单独或与Ｎ、Ｐ化肥配合施用，都有明显的增产效果：单独施用比对照增产率为９．３％～２９．１％，与化肥配合施用增产率为１０．８％～２０．５％。垃圾肥施用量在１５～３０ｔ／ｈｍ２时可获较高的增产效益。施用垃圾肥对花生仁中的粗蛋白质、粗脂肪和全磷含量有一定的提高。尽管所施用垃圾肥中含有一定量的有害元素，如Ｃｄ、Ｐｂ、Ｃｒ等，但花生仁中这些元素含量并不高，说明施垃圾肥是安全的。试验结果还表明；施用垃圾肥能提高土壤有机质、全氮以及有效Ｎ、Ｐ、Ｋ的含量。特别是有效微量元素含量提高幅度较大，Ｚｎ、Ｃｕ、Ｂ各处理平均是对照的２～１０倍，Ｆｅ、Ｍｎ、Ｍｏ比对照提高１７％～３８％。     

Human use and conservation planning in Alpine areas of Northwestern Yunnan,China

Alpine areas in northwestern Yunnan, China possess globally significant levels of biodiversity and are important locally for livelihood activities such as livestock grazing and medicinal plant collection. Because local land use has important impacts on alpine conditions and communities have significant capacity to manage alpine resources, we emphasized local collaboration during the initial stages of conservation planning. Our collaboration with local communities investigated how livelihood strategies affect the condition of alpine resources in northwestern Yunnan and how future conservation efforts can be compatible with local livelihoods. We sampled three livestock herding sites, each within a different alpine sub-region, using open-ended interviews and maximum variation sampling. According to interviewees, livestock grazing within the alpine zone currently does not appear to be negatively impacting the availability of forage. Medicinal plant collection, however, is showing unsustainable trends. Tourism is as yet a nascent industry, but is seen as having great potential by those interviewed. It is clear that with increases in population, access to regional markets, and tourism, northwestern Yunnan’s rich alpine resources will require careful management. In addition to the data collected, we found that the methodology used may be widely applicable to organizations with limited resources that wish to engage local communities during the formative stages of regional-level conservation planning.