六盘山北侧叠叠沟小流域几种典型植被群落的水文功能研究

在宁夏六盘山北侧的半干旱区,研究了华北落叶松林、沙棘灌丛、虎榛子灌丛、草地植被类型的冠层截留与再分配、枯落物持水及土壤蓄水等水文功能。结果表明,不同植被类型的冠层截留能力相差较大,其中,沙棘灌丛的截留率最高（24.80%）,华北落叶松林略低（21.40%）,虎榛子灌丛最低（9.25%）;与此相反,树干茎流率以虎榛子灌丛为最高（33.18%）,超出大多数干旱半干旱区灌木树干茎流范围（2%～10%）。从季节变化上看,不同植被群落的截留率均为6月份最大,7—9月份持续下降,10月份出现回升;但截留量均为7月份最大。枯落物持水性能以华北落叶松林样地为最高,其次为虎榛子灌丛、沙棘灌丛和草地,这与各植被类型枯落物层贮存量的大小排序一致。1 m土 层的土壤容重以虎榛子样地为最小(1.03 g·cm^-3),然后依华北落叶松(1.07 g·cm^-3)、草地(1.08 g·cm^-3)、沙棘(1.16 g·cm^-3)的顺序增大。土壤总孔隙度、最大持水量以华北落叶松林样地为最高,毛管孔隙度、毛管持水量以虎榛子样地为最高,非毛管孔隙度以草地为最高;这几项指标均以沙棘样地为最低。综上所述,从林冠截持、枯落物持水性、土壤物理性质等总体来看,华北落叶松人工林的土壤存蓄水、调水能力最强,其次为虎榛子灌丛和草地,沙棘灌丛最差。     

六盘山四种典型森林生态水文功能的综合评价

为合理评价水源涵养林垂直结构改变对其水文功能的影响,在对宁夏六盘山香水河小流域内4种典型结构林分(华北落叶松+灌木复层林、华北落叶松纯林、稀植乔木的天然灌丛林、天然灌丛林)林冠层、枯落物层、土壤层的结构指标和功能指标测定的基础上,采用层次分析法建立了林分生态水文功能的层次结构模型,并用综合评分法对4种典型林分进行了评价。结果表明:林冠层生态水文功能以华北落叶松人工纯林最优,枯落物层以华北落叶松+灌木复层林最优,土壤层以稀植乔木的天然灌丛林最优。不同林分生态水文功能整体表现为华北落叶松+灌木复层林(0.902)>稀植乔木的天然灌丛林(0.893)>华北落叶松人工纯林(0.782)>天然灌丛(0.708),说明复层林的综合生态水文功能要好于单层林,表明在六盘山营林区对华北落叶松人工纯林进行林下补植灌木和对退化的天然灌丛稀植乔木等措施有助于林分生态水文功能的发挥。     

东北农牧交错带小流域不同林草植被类型水源涵养功能综合评价

以内蒙古赤峰市敖汉旗大五家流域内林草植被为研究对象,从林冠层、枯落物层、土壤层和林分生产力等方面选择评价指标,通过层次分析法确定评价指标的权重,应用主成份分析方法对不同林草植被涵养水源功能进行综合评价。旨在评价不同林草植被类型水源涵养功能的差异,为探寻低功能涵养水源型林草植被更新改造途径提供依据。研究结果表明:华北落叶松白榆混交类型涵养水源功能较高,其次是杨树柠条混交类型,油松沙棘混交类型涵养水源功能最差,在该流域应提倡营造针阔混交林。     

新疆荒漠区几种典型人工林生态服务功能综合评价

以新疆墨玉县人工林为例,应用经济学理论和生态系统自身的规律,采用层次分析法建立适用于荒漠区人工林生态服务功能的指标体系。该体系由4个准则层和12个指标层构成,通过建立的评价指标体系对墨玉县荒漠区几种典型人工林进行了生态服务功能评价。结果表明,生态服务功能综合评价：新疆杨>柽柳>沙枣>沙枣+柽柳>沙枣+新疆杨+桑树>沙枣+新疆杨,研究结果能为荒漠区人工林选择种植模式提供科学依据。     

基于云模型的宁南山区小流域土壤养分综合评价

土壤养分受到各因素的综合影响,也是植被生长繁衍的基础.为了解宁南山区小流域土壤养分状况,文中基于260个采样点0 ～20cm土层实测数据,分析了土壤养分含量特征,选取pH值、电导率(EC)、有机质(SOM)、全氮(TN)、全磷(TP)、全钾(TK)、碱解氮(AN)、速效磷(AP)和速效钾(AK)作为评价指标,运用熵权法...     

天山北坡4种栽培杨树的功能性状分析

植物功能性状可以用来推断植物生活史策略,反映生态系统功能。为了研究天山北坡4种栽培杨树适应环境的生态策略差异,对其主要功能性状进行比较分析。结果表明,4种杨树的叶片大小、叶片厚度、叶干物质含量、茎皮厚度、木材密度和根、茎、叶全N,P,K含量均差异显著;但4种杨树间比叶面积差异不显著;新疆杨单叶面积和干物质量最大,胡杨叶片厚度和木材密度最大,钻天杨茎皮厚度最大;4种杨树的叶片N含量均显著高于茎和根,茎和根的N和P含量差异均不显著,除胡杨外,其他3种杨树叶片P含量均显著高于茎和根,K含量在4种杨树的根、茎、叶器官中表现不一致;钻天杨根、茎、叶的N,P,K养分含量都相对较高,俄罗斯杨的根、茎、叶的N,P,K养分含量都相对较低。4种杨树功能性状不同反映了植物对环境的适应性差异。     

两种功能高分子材料对沙土物理性质影响的比较

采用SEM,透水系数法、加压板法等现代测试手段,观察与分析高分子吸水树脂、固沙植被多功能高分子复合材料表面微观结构形态,比较高分子吸水树脂与固沙植被多功能高分子复合材料改良沙土后沙土的透水、保水等特性及沙土水分的有效利用情况.实验结果证明固沙植被多功能高分子复合材料比高分子吸水树脂改良沙土的效果好,使沙土的气、液、固三相比有利植物的生长,能保持高的水有效利用率.本实验结果为固沙植被多功能高分子复合材料的应用提供了新的依据.     

Effect of sand-fixing vegetation on the hydrological regulation function of sand dunes and its practical significance

Soil water content is a key controlling factor for vegetation restoration in sand dunes. The deep seepage and lateral migration of water in dunes affect the recharge process of deep soil water and groundwater in sand dune ecosystems. To determine the influence of vegetation on the hydrological regulation function of sand dunes, we examined the deep seepage and lateral migration of dune water with different vegetation coverages during the growing season in the Horqin Sandy Land, China. The results showed that the deep seepage and lateral migration of water decreased with the increase in vegetation coverage on the dunes. The accumulated deep seepage water of mobile dunes (vegetation coverage<5%) and dunes with vegetation coverage of 18.03%, 27.12%, and 50.65% accounted for 56.53%, 51.82%, 18.98%, and 0.26%, respectively, of the rainfall in the same period. The accumulated lateral migration of water in these dunes accounted for 12.39%, 6.33%, 2.23%, and 7.61% of the rainfall in the same period. The direction and position of the dune slope affected the soil water deep seepage and lateral migration process. The amounts of deep seepage and lateral migration of water on the windward slope were lower than those on the leeward slope. The amounts of deep seepage and lateral migration of water showed a decreasing trend from the bottom to the middle and to the top of the dune slope. According to the above results, during the construction of sand-control projects in sandy regions, we suggest that a certain area of mobile dunes (>13.75%) should be retained as a water resource reservoir to maintain the water balance of artificial fixed dune ecosystems. These findings provide reliable evidence for the accurate assessment of water resources within the sand dune ecosystem and guide the construction of desertification control projects.     

Topographical and hydrological effects on meso-scale vegetation in desert steppe,Mongolia

This study investigated the seasonal variations of the normalized difference vegetation index(NDVI) and its relationships with climatic variables and topography in a small-scale(20 km×20 km) area(i.e., Tsogt-Ovoo village) within the desert steppe zone of Mongolia using in-situ observed climate data and satellite remote sensing data. We found that the topography is very important for vegetation growth in the desert steppe although the summer precipitation is the constraining factor. The unexpectedly high NDVI(up to 0.56), as well as the high aboveground biomass, in the valley bottom was primarily resulted from the topography-modulated redistribution of overland flow after relatively heavy precipitation events during the growing season. This makes the valley bottoms in desert steppes not only reliable feeding resources for livestock but also heavens for wild lives. But, the detected large standard deviation of annual maximum NDVI(NDVI_(max)) from 2000 to 2013 in the valley bottom in response to rather variable precipitation implies that the valley bottoms under desert steppe climates are more vulnerable to climatic change.     

Effects of vegetation types on soil water dynamics during vegetation restoration in the Mu Us Sandy Land,northwestern China

The arid and semi-arid northwestern China has been undergoing ecological degradation and the efforts to reverse the ecological degradation have been undertaken for many years. Some shifting dunes have been fixed and the vegetation has been partially recovered in certain areas and the Mu Us Sandy Land in the Ordos Plateau is an example of the success. The present study attempts to reveal the relationships between the vegetation restoration and ecohydrology in the Mu Us Sandy Land. We continuously measured soil water content at 10-min intervals under three vegetation types(i.e., shifting dune, shrub-dominated community, and herb-dominated community) in the Mu Us Sandy Land from April 2012 to October 2013. The results show the infiltration coefficient increased with increased rainfall amount and eventually reached a stable value. Infiltration coefficients were 0.91, 0.64, and 0.74 in the shifting dune, in the shrub-dominated community, and in the herb-dominated community, respectively. Cumulative infiltration and soil texture are two vital factors affecting the depths of rainfall penetration. Only rainfall events larger than 35.0 mm could recharge soil water at the 60–80 cm layer in the herb-dominated community. Our results imply that the expected forward succession of restored vegetation may be destined to deterioration after reaching the climax simply because of following two facts:(1) soil water is mainly retained at shallower layer and(2) plant fine roots mainly distribute in deeper layer in the herb-dominated community.     

不同植被覆盖下子午岭土壤养分状况研究

以黄土丘陵沟壑区的子午岭次生林区为研究区域,研究了不同植被覆盖对土壤养分状况的影响。结果表明:不同植被类型覆盖下,土壤有机质含量为乔木>灌木>草本>农田>弃耕地。土壤全氮含量为乔木≥草本>灌木>农田≥弃耕地;全磷含量变化不大,其中农田土壤全磷含量最高;全钾含量为乔木>灌木>草本>农田>弃耕地;土壤碱解氮含量为乔木>灌木≈草本≥农田>弃耕地;速效磷含量为乔木≈灌木≈农田>草本>弃耕地;速效钾含量为乔木≥草本>灌木≥农田>弃耕地。由此可见,随植被演替阶段的提高,不同植被覆盖下土壤的养分含量逐渐升高。因此,在黄土高原丘陵区,坡地退耕还林,恢复植被,可以有效改善土壤养分状况。     

Altitudinal changes of surface pollen and vegetation on the north slope of the Middle Tianshan Mountains,China

To provide information on vegetation patterns and altitudinal distributions of pollen assemblage in surface soil layers,their complicated relationships in a dryland mountain-basin system in northwestern China and a realistic basis for paleovegetational reconstruction,we investigated 86 vegetation quadrats and analyzed 80 soil samples from the surface soil layers along an altitudinal transect on the north slope of the Middle Tianshan Mountains from alpine cushion vegetation at 3,510 m near glacier to desert vegetation at 460 m in the Gurbantunggut Desert.According to surface pollen assemblages and the results of the detrended correspondence analysis,the transect can be divided into six major altitudinal pollen zones as alpine cushion vegetation,alpine and subalpine meadows,montane Picea forest,forest-steppe ecotone,Artemisia desert and typical desert,which basically reflect the characteristics of the mountainous vegetation patterns on the north slope of the Middle Tianshan Mountains.However,Picea pollen also exists outside the spruce forest,Chenopodiaceae and Artemisia pollen appeared above the elevation of 1,300 m,indicating that most of them might be introduced from lower elevations by upslope winds.Airborne pollen researches from three regions at different elevations further suggest that a high-frequency northwest anabatic wind has a remarkable influence on the transportation and dispersion of surface pollen in the area.     

宁夏六盘山水源区华山松次生林的生长季水量平衡与产流特征

为揭示典型森林生态系统对水文过程和产流功能的调控机制,文中在宁夏六盘山区,选择了华山松次生林样地,观测了2011年生长季(5月24日至10月20日)的水文过程,分析了水量平衡与产流特征。结果表明:2011生长季总降水量为724.3mm;华山松林分冠层截留量(率)为102.3mm(14.13%);林下降水量(率)为622.0mm(85.87%);枯落物层渗漏水量(率)为424.3mm(58.59%);0-30cm土层渗漏水量(率)为275.9mm(38.09%)。华山松林的生长季总蒸散为477.1mm,各蒸散分量(mm)对总蒸散的贡献表现为林木蒸腾(222.9)>林下蒸散(151.9)>植被截持(102.3)。水量平衡计算表明,该年生长季降水量可充分满足华山松林蒸散耗水需要,林地产水量(0-30cm土层的净流出量)为252.7mm。     

秦岭太白山植被的生态服务价值测评

生态系统服务功能的定量评价是当前生态学与生态经济学研究的热点课题。根据太白山植被类型及覆盖度的分布,利用生态经济学方法,定量测定各类植被的生态服务价值。结果表明:太白山区植被生态系统服务功能的总价值为12.52×108元/a,单位面积的生态服务价值平均为22041.09元/hm2.a。其中有机质生产价值为1.63×108元/a,涵养水源价值量为2.35×108元/a,植被保持土壤的经济价值为0.63×108元/a,固定CO2价值为2.99×108元/a,释放O2价值为3.18×108元/a,净化空气价值为1.74×108元/a。其中植被的固碳释氧价值最高,占总价值的49.3%,其次是涵养水源的价值,占18.8%。