黄土丘陵区天然和人工植被类型对土壤理化性质的影响

不同植被类型对黄土高原土壤质量的改善作用存在较大差异。研究天然和人工植被类型对土壤性状的影响差异对于深入认识黄土高原植被恢复与土壤环境演化的关系,准确评价不同植被恢复模式生态环境效益具有重要意义。该研究以黄土丘陵区燕沟流域为例,选择研究区广泛分布的11种天然和人工植被类型为研究对象,系统分析了该区天然和人工植被类型对土壤性状的影响。结果表明:天然和人工植被类型对土壤性状的影响差异明显。200cm土层土壤含水率大小为农田>天然草地>人工乔木林地>果园>人工灌木林地>天然灌木林地。与农田相比,天然灌木林地和天然草地土壤体积质量降低最为明显,人工乔木林地、人工灌木林地和果园土壤体积质量下降差别不明显。天然灌木林地、天然草地和人工灌木林地土壤有机质、全氮都有明显提高,人工乔木林地和果园土壤有机质和全氮提高不明显。不同植被类型土壤有机质、全氮总体随土层加深呈下降趋势,农田、果园和人工乔木林地土壤有机质和全氮垂直变化较小,而天然灌木林地、天然草地和人工灌木林地变化较大。不同植被类型土壤全磷含量差异较小,且垂直变化不明显。总体看来,天然植被类型对该区土壤性状改善作用优于人工植被类型,而人工灌木林的改善作用优于人工乔木林。     

The Isotopic Composition of Anthropogenic Pb in Soil Profiles of Northern Germany: Evidence for Pollutant Pb from a Continent-wide Mixing System

Seventy-five samples of six soil profiles from forests on different substrates plus one next to a motorway were analyzed for the variation of Pb concentration and isotopic composition with depth. A substantial fraction of the anthropogenic Pb (peak concentrations between 74 and 300 ppm) is still stored in the organic top soil, and seldom penetrates deeper than 20–30 cm. In (²⁰⁸Pb/²⁰⁶Pb) vs. (²⁰⁷Pb/²⁰⁶Pb)-diagrams the Pb in the uppermost layers of the profiles plots on an excellent correlation line (R = 0.99) indicating essentially a two-component mixing system. Values for the dust on Scottish plants, Norwegian and Swiss bogs as well as for aerosols collected over the North Atlantic (data from the literature) plot on the same correlation line showing that the Pb was deposited from a continent-wide mixing system with two apparent end members: The radiogenic one is similar to geogenic Pb and could consist of contributions from certain European ore deposits and from different soil components (e.g. silicates and Fe-oxides), power plants and cement factories. The less radiogenic component must contain or consist of Pb from Proterozoic or even Archaic ore deposits. However, the sources of this Pb remain somewhat elusive. In any case, this isotopic pattern is so consistent all over Europe that the correlation line may serve as a line of reference for quasi normal or European Standard Lead Pollution (ESLP). The gasoline derived Pb in the soils is swamped by Pb of other provenances.     

黄土坡面不同土地利用方式对土壤有机碳流失的影响

坡面土地利用方式与产流、产沙及土壤有机碳的流失具有密切关系。对延安燕沟流域的坡耕地、草地、刈割草地、灌木地、刈割灌木以及刺槐林地径流小区的径流、泥沙及有机碳流失量进行了分析。结果表明：在不同土地利用方式下,产流、产沙量与植被覆盖度呈负相关关系;随径流流失的可溶性有机碳量表现为：坡耕地〉刈割草地〉草地〉刈割灌木地〉灌木地〉刺槐林地小区,随泥沙流失的有机碳量表现为：坡耕地〉草地〉灌木〉刺槐林地。随泥沙流失的土壤有机碳占总流失量的主要部分,而随径流流失的有机碳只占很少的比例。因此,增加黄土坡面植被覆盖度是控制产流、产沙量和有机碳流失的重要途径。     

The effect of land cover/vegetation on soil water dynamic in the hilly area of the loess plateau,China

Severe soil and water loss has lead to widespread land degradation in China's loess plateau. During the past decades, a great deal of effort was made on vegetation restoration to reduce soil and water loss in the loess plateau. However, due to water shortage the efficiency of vegetation restoration was not as satisfactory as expected. As part of a vegetation restoration project, we conducted research aiming to understand the relationship between vegetation pattern and soil water dynamics. The goal was to find vegetation types appropriate for the loess plateau with scarce water resources. In 1986, fifteen plots of land were planted with five vegetation types: pine woodland, shrubland, sloping cropland, alfalfa and semi-natural grassland. Soil water content, runoff, soil erosion were measured for each plot. Environmental variables, such as rainfall, evaporation and temperature, were recorded simultaneously by an automated meteorological station. The relationship between land cover pattern and soil water dynamic was evaluated by using statistical models. We found that: (1) soil water loss occurred during the growing season, and it reached the maximum in the second half of July; (2) soil water was not fully replenished from rainfall during the rainy season; (3) pine woodland induced the largest water loss to surface runoff, followed by sloping cropland, alfalfa, semi-natural grassland and shrubland; the poor capability of pine woodland for water conservation may be attributed to soil compaction and poor ground coverage under the tree; (4) in most cases, soil water of the five vegetation types was low except for shrubland and semi-natural grassland where it was moderate-high during a few periods. These conditions inhibit sustainable vegetation growth in the semi-arid loess hilly area of the loess plateau, China.     

Biomonitoring of Trace Elements in Air and Soil Compartments Along the Major Motorway in France

The impact on the environment of Cd, Pb and Zn emissions from the A1 motorway, one of the busiest in France, was based on a simultaneous analysis of lichens, fungi and soil.The study was conducted in 12 rest areas located along a 55 kmstretch of the motorway. Cd, Pb and Zn concentrations in the top soil horizon (0–10 cm) largely exceeded their concentrations at the control site.The Cd-, Pb- and Zn levels in fruiting bodies of fungi Armillaria mellea, Coprinus comatus, Marasmius oreades and Paxillus involutus were highly variable between sites. The contamination degree of transplanted thalliof Parmelia caperata was well correlated to the cumulated traffic on the western side. On the eastern side, heavy metals originated from the traffic but also from neighbouring sources (urbanization and agricultural practices). Although lead levels are decreasing, leaded petrol is still on offer and lead remains an indicator of vehicle pollution.     

Species-specific barrier effects of a motorway on the habitat use of two threatened forest-living bat species

It is generally recognized that roads can adversely affect local animal populations but little is known how roads affect bats. In particular, no study compared the response of bats that differ in foraging ecology to motorways that cut through the breeding habitat. As bats are key species in conservation, such data are urgently needed for designing management plans. Using radio-telemetry, mist netting, and mark-recapture data we investigated the effects of a motorway with heavy traffic on the habitat use of two threatened forest-living bats. We compared barbastelle bats (Barbastella barbastellus), which forage in open space, to Bechstein’s bats (Myotis bechsteinii), which glean prey from the vegetation. Five of six radio-tracked barbastelle bats crossed the motorway during foraging and roost switching, flying through underpasses and directly over the motorway. In contrast, only three of 34 radio-tracked Bechstein’s bats crossed the motorway during foraging, all three using an underpass. Bechstein’s bats, unlike barbastelle bats, never crossed the motorway during roost switching. Moreover, only in Bechstein’s bats individuals foraging close to the motorway had smaller foraging areas than individuals foraging further away, whereas other forest edges had no such effect. Our data show that motorways can restrict habitat accessibility for bats but the effect seems to depend on the species’ foraging ecology and wing morphology. We suggest that motorways have stronger barrier effects on bats that forage close to surfaces than on bats that forage in open space, and discuss the implications of our findings for bat conservation during road construction.     

卧龙泉河流域土壤重金属污染的模糊评价

运用模糊评价模型对卧龙泉河流域土壤-植物重金属污染现状进行了评价,结果表明,卧龙泉河上游和中游地区土壤-植物重金属污染严重。其中,卧龙泉河上游土壤污染因子为Cu、Pb,水稻和玉米分别为Pb、Cu、C r、A s和Pb、C r、Hg;王家崴子地区土壤的污染因子主要为A s、Pb、Cd、Zn,水稻和玉米分别为Pb、Cu、Cd、C r、A s和Pb、C r、A s、Hg;氰化厂旱田土和靠山屯林地土为轻污染,污染因子分别为Pb、Zn、Cu、Hg和Hg、Pb;卧龙泉河下游万福旱田土和王家崴子西山坡林地土无污染。王家崴子和万福地区的韭菜Pb、Zn、Hg污染严重。同一地区不同植物的污染因子不同,不同地区水稻或玉米的的污染因子也不同。     

The effect of landscape-scale environmental drivers on the vegetation composition of British woodlands

Assessment of factors influencing woodland vegetation composition across Britain was made using multivariate techniques to analyse data gathered during the 1971 National Woodland Survey. Indirect gradient analysis (unconstrained ordination using detrended correspondence analysis) suggested a gradient strongly associated with nutrient availability and pH. Direct gradient analysis (constrained ordination using canonical correspondence analysis) and variation partitioning were used with over 250 ecophysiologically relevant variables, including climatic, geographical, soil and herbivore data, to model the response of woodland vegetation. Although there was a high degree of multicollinearity between environmental variables, analysis revealed the vegetation composition of surveyed woodlands to be primarily structured by geographical, climatic and soil gradients, in particular rainfall, soil pH and accumulated temperature. The woods have recently been resurveyed. The results of this analysis therefore provide a baseline against which species dynamics can be assessed under a series of conservation threats, such as land use and climate change.     

托木尔峰自然保护区台兰河上游不同植被类型的水源涵养功能

为了研究托木尔峰自然保护区生态系统的水源涵养功能,选择台兰河上游为研究区域,采用野外观察与室内试验相结合的方法,分别对该区域具有代表性的雪岭云杉林、灌木林、草地植被,从林冠层、枯枝落叶层和土壤层3个层次及综合性的水源涵养能力进行了定量分析。结果表明:研究区云杉林林冠截留能力优于灌木林,穿透降雨量及林冠截留量平均值均大于灌木林。除草地外,各样地枯枝落叶未分解层平均厚度均大于半分解层,云杉林枯枝落叶层的厚度和蓄积量明显大于灌木林,不同植被类型枯枝落叶半分解层的自然持水率、最大持水率均高于未分解层,云杉林枯枝落叶层自然持水率、最大持水率均高于灌木林,灌木林和云杉林的枯枝落叶未分解层有效拦蓄量均高于半分解层。不同植被类型平均土壤容重大小表现为草地灌木林云杉林,土壤孔隙度的平均值大小则与之相反;不同植被类型的土壤自然含水率、饱和含水量及非毛管持水量均表现为云杉林灌木林草地,而不同植被类型30cm深土层的蓄水能力变化则存在差异。研究区不同植被类型的水源涵养能力在181.06~237.63mm,综合、有效水源涵养能力均表现为云杉林灌木林草地,其中土壤层的涵养贡献率最大,总有效蓄水量远小于总持水量。综上所述,台兰河上游云杉林和灌木林具有较好的涵养水源能力,放牧强度和人为干扰是影响研究区不同植被类型尤其是生境脆弱的草地植被水源涵养功能的重要因素。     

黄土高原丘陵沟壑区生态用水资源利用研究

对黄土高原丘陵沟壑区不同植被地连续10a的试验调查发现,人工草地和沙棘、油松林地土壤水分在长系列年内变化上基本一致,1m土层含水量处于100～140mm,生长期土壤水分基本上处于亏缺状态;而荒坡草地土壤含水量年内均比人工草地高约40mm,土壤水分一直处于适宜、稳定的水平。林地沙棘和油松均表现出适应该地气候特点的生长的状况,但从土壤水文循环状况看,土壤水分长时期处于亏缺状态不利于植被的再生长和生态效益的发挥。径流试验研究表明,人工草地、油松林地年内平均径流深分别为1.45mm和1.27mm,径流系数为0.08和0.07;荒坡草地和沙棘林地在年内基本上不发生大的径流,且多为清流。因此,植被恢复在治理措施上应当注重植被的自然修复和保护,并充分利用径流资源补充土壤水分,使其朝着利于植被生长的方向发展。     

南方红壤丘陵区马尾松林下水土流失现状、成因及防治

马尾松林下水土流失已经成为南方红壤丘陵区水土流失治理一个亟待解决的问题。在分析南方红壤丘陵区马尾松林下水土流失现状及特点的基础上,从马尾松林下植被状况、人为干扰、地形、降雨侵蚀力、土壤性状等方面综合探讨了马尾松林下水土流失的成因。认为:林下植被匮乏是造成马尾松林下水土流失最主要和最直接的原因;掠夺性人为干扰是造成马尾松林下水土流失的根本原因;破碎的地形、较高的降雨侵蚀力和土壤可蚀性则为林下水土流失的发生提供了有利条件。同时总结了诸如微地形改造、林下补植、封禁保护等马尾松林下水土流失治理的成功经验,以期为今后马尾松林下水土流失治理提供参考。     

大黑山生态修复区不同植被类型土壤颗粒的分形特征

运用土壤粒径质量分布原理与分形理论,对大黑山生态修复区6种不同植被类型土壤颗粒分形特征进行研究。结果表明：1）不同植被类型土壤颗粒粒径的质量分数分布差别很大,土壤黏粒和粉粒含量林地比荒草地高87.47%和89.94%,砂粒含量和细砾与粗砾含量林地比荒草地低25.09%和19.19%;土壤粉粒和黏粒含量黑桦＋山杨混交林、蒙古栎和山榆等天然次生林地明显高于山杏和油松等人工林地。2）有林地土壤颗粒分形维数明显大于荒草地,天然次生林土壤颗粒分形维数大于人工林,且以天然次生混交林最大。3）不同植被类型土壤颗粒分形维数与土壤粒径〈0.05 mm的黏粒含量和粒径0.05-0.25 mm之间的粉粒含量呈明显的线性正相关关系,土壤的颗粒越小,细粒含量越高,分形维数越大。4）不同植被类型土壤颗粒分形维数与土壤不均匀系数呈较好的线性负相关关系,随着土壤不均匀系数的降低,土壤颗粒分形维数增大。除荒草地外,大黑山生态修复区其他5种植被类型土壤均为不均匀性良好的土壤,以天然次生林土壤粒径分布结构较好,尤其是以天然次生混交林的最好,其次是人工林的。     

Predictors of fine-scale spatial variation in soil mite and microbe community composition differ between biotic groups and habitats

Soils support highly diverse communities, but due to the great spatial complexity at very fine scales and small size of soil organisms, our knowledge of what structures belowground communities remains limited. We used a spatially nested sampling regime (distances between samples of 0.06–122 m) to develop an understanding of the relationship between soil mite and microbial community composition and properties of vegetation and underlying soil within two habitats: birch woodland and heather moorland. We found that variation in community composition of all four biotic groups investigated (Oribatida, Mesostigmata, fungi and bacteria – thus representing multiple trophic levels) was related to variation in soil properties and vegetation, but also space. These three factors (i.e. vegetation, soil properties and space) accounted for 17–36% of the variation in community composition of the biotic groups. The remaining, rather large, proportion of unexplained variation in community composition (64–87%) is likely to represent either random variation or variation related to unmeasured variables that are not spatially auto-correlated. Soil properties generally explained more variance in belowground communities than could vegetation composition. This should not be interpreted as evidence that soil properties exert a greater influence on belowground communities than vegetation composition per se, as the vegetation composition within a habitat is likely to vary at a larger spatial scale than the soil properties we measured. Vegetation composition had stronger explanatory power in the birch woodland and was more strongly related to fungal community composition than that of any other biotic group, particularly in heather moorland. This relationship may reflect the strong association between plants and their fungal symbionts and pathogens. We conclude that both vegetation composition and variation in soil properties influence belowground communities. However, the relative importance of these two factors depends on both habitat and the type of organism being studied.     

左云县店湾镇春季不同植被条件下土壤含水量研究

为了研究左云县店湾镇春季不同植被条件下0—600 cm深度范围内土壤垂直剖面水分变化特征,分别对该区乔木（白榆和小叶杨）林地、灌木（柠条和沙棘）林地和草地5种不同植被条件下土壤水分进行了研究。结果表明:研究区不同植被条件下土壤剖面含水量变化规律不同。左云县矿区春季各土层平均含水量草地最高,柠条林地次之,白榆林地最少。其中草地各土层平均含水量比柠条林地高0.3%,比白榆林地高3.8%。该区各植被条件下土壤水分主要呈难效水状态。且各植被条件下土壤在200—400 cm深度范围内都存在干层,有轻度干层、中度干层和重度干层发育。该区水循环主要是地表水循环,地下水循环基本不存在,形成了土壤—植物—大气的水分循环模式,属于异常水分循环类型。     

重庆岩溶地区不同土壤类型的土地利用多样性分析

以重庆岩溶地区为例，探讨岩溶地区土壤类型的多样性与不同土壤类型上土地利用方式的多样性。结果表明重庆市岩溶区黄壤、石灰土和黄棕壤是本区主要土壤类型，土壤景观的多样化和空间异质化程度不高，但各类景观分布比例不均匀，土壤景观嵌块体呈现出复杂的几何形状。除了山地草甸土以林地和草地、棕壤以林地为主要景观外，另外的9种土壤类型上都是以耕地和林地为主要的景观，农、林用地在景观空间格局的结构和功能中起主导作用。由于各类土壤性质和分布特点的不同，耕地和林地在各类土壤上的分配比例存在着明显的差异，以及人类活动使得耕地的嵌块体数急剧增多和居民工矿用地、林地、未利用地的嵌块体数目增加。     

长期处于植被条件下香港土壤中氮的矿化

This research examined nitrogen mineralization in the top 10 cm of soils with a vegetation gradient in Hong Kong at sites where fire has been absent for 0, 1, 3, 6 and 17 years (at the time of the study), and the relationships between N mineralization and successional development of vegetation in the absence of fire. The sites including a newly burnt area (S1), short grassland (S2), tall grassland (S3), mixed tall grassland and shrubland (S4), and woodland (S5) were selected, with the in situ core incubation method used to estimate nitrogen mineralization. Throughout the 60-day incubation in four periods, more nitrogen was mineralized at the S3 and S4 sites, the predominantly grassland sites, which contained the highest levels of soil organic matter (SOM) and total Kjeldahl nitrogen (TKN), than the S1 site, while immobilization occurred at the S2 and S5 sites. Leaching loss decreased with successional development of the vegetation, in the order of S1 > S2 > S3 > S4 > S5. The pattern of nitrogen uptake with ecological succession was less conspicuous, being complicated by the immediate effect of fire and possibly the ability of the woodland species to extract nitrogen from the deeper ground. In the absence of fire for 3 to 6 years, the build-up of SOM and TKN was accompanied by active mineralization, thus paving the way for the invasion of shrub and tree species. A close relationship existed between nitrogen mineralization and ecological succession with this vegetation gradient. Inherent mechanisms to preserve nitrogen in a fire-prone environment including immobilization and uptake and the practical relevance of nitrogen mineralization to reforestation are discussed.     

Soil seed banks in the Arasbaran Protected Area of Iran and their significance for conservation management

The Arasbaran Protected Area is an important but little studied nature reserve in NW Iran. In the past habitat heterogeneity and biodiversity have been threatened by over-exploitation; in the future depopulation may lead to partial abandonment. The soil seed bank was examined to see whether there are sufficient species represented as persistent seeds to reconstitute the vegetation in the event of habitat deterioration. There were differences between seed banks from different soils and vegetation types but essentially all soil seed banks contained few species and low densities of seed. Moreover, the species in the seed bank were unrepresentative of the vegetation. During future periods of changing land use it will be important to maintain the existing vegetation. There are however indications of successful recent conservation management. Annuals are abundant in the woodland seed bank but absent from the vegetation. The forest is recovering from the disturbance of collecting fire-wood.     

Changes in soil properties across a chronosequence of vegetation restoration on the Loess Plateau of China

Soil fertility is important for vegetation growth and productivity. The relationship between vegetation and soil fertility is important for both scientific and practical reasons. However, the effects of soil fertility on vegetation development and succession are poorly documented on the Loess Plateau. In this study, we compared soil properties of the Yanhe Watershed in northern Shaanxi across five different land uses (shrubland, farmland, natural grassland, woodland and artificial grassland) and a chronosequence of soils undergoing restoration for 5, 10, 15, 20, 25, 30, 35, 40 and 45 years. We found that revegetation had a positive effect on soil bulk density decrease, total porosity and capillary porosity increase in the surface soil layers but not in the subsurface layer. Additionally, soil organic matter, total nitrogen, available nitrogen and available potassium were greater at shrubland and woodland sites compared with other land uses. Total phosphorus and available phosphorus were greater at farmland sites. Results of the study indicate that revegetation on eroded soil can produce important increases in soil fertility on older plantations and in areas with natural succession.     

Regional and local patterns of soil nutrients at Rocky Mountain treelines

The soils across treeline should vary because of direct effects of biological differences of coniferous subalpine forest and the herbaceous alpine tundra in Colorado. In addition, the change in life form may indirectly affect soils because of interactions of the vegetation and wind-driven deposition processes. This is particularly important as nitrogen (N) saturation is a growing concern in high elevation ecosystems, and treeline is predicted to be a deposition hotspot. The vegetation transition at treeline provides an opportunity to test the effects of vegetation, topography, and external inputs on soils at three spatial scales. First, a regional evaluation of soils at eleven abrupt treeline sites was made comparing sites on east and west aspects both east and west of the Continental Divide (CD). Second, soils were compared in the adjacent forest and tundra. Finally, edge effects were assessed along transects spanning treeline. At the regional scale, total soil N was higher east of the CD and on east aspects while exchangeable calcium was higher on east aspects and at sites west of the CD. Higher lead (Pb) concentration in the forest organic horizon was associated with lower ²⁰⁶Pb/²⁰⁷Pb ratios, an indication of greater anthropogenic Pb inputs. However, the spatial pattern in soil Pb suggests a different source area or transport mechanism than N. Within individual sites, the soils differed between the forest and tundra in almost every measured variable, but edge effects were minimal on both sides of these abrupt treelines. While a direct link between the observed soil patterns to deposition of external inputs cannot be made based on the study design, the observed soil patterns suggest that the impacts of acid deposition are amplified or attenuated by processes such as dust deposition.     

Soil respiratory activity in relation to motor vehicle pollution

Soil respiratory activity was measured at various distances from two busy roadsides in South East England. Wide variation in the level of respiration between sites was observed. Soil respiration showed a reduction in soils collected from sites located 0.5 m from A40 compared with levels of respiration measured at a control site away from the direct influence of motor vehicle pollution. At the M3 site, a depression in soil respiration was observed up to 100 m from the motorway compared to the control site for the area. Measurements of soil levels of Pb, Cd, Ni, and Zn were made at the same sites as those used for respiratory activity experiments. Subsequent regression analysis on these data and soil respiration failed to show any consistent relationship between the level of soil pollution and soil respiration for both sites. The findings indicated that soil type is the dominant factor influencing the general level of soil microbiological activity at these two roadsides. The evidence implicating soil heavy metal levels as agents initiating a reduction in microbiological activity was inconclusive.