高寒草甸不同植被土壤微生物数量及微生物生物量的特征

用稀释平板法和氯仿熏蒸法研究了藏嵩草草甸、小嵩草草甸、矮嵩草草甸、禾草草甸、杂类草草甸及金露梅灌丛土壤的微生物数量、生物量及有机质的变化特征.结果表明:0～40 cm土层细菌和放线菌数量、微生物生物量碳和土壤有机质含量均以藏嵩草草甸最高,其微生物生物量及土壤有机质显著高于其它5种植被;真菌数量以金露梅灌丛最高;由表层到深层,随着土壤深度的增加以上各项指标均呈下降趋势.通径分析表明:土壤各生物环境因子之间存在着不同程度的相关性;土壤微生物数量、生物量及土壤有机质含量均与土壤水分含量存在显著的相关关系,说明土壤水分是调节高寒草甸生态系统土壤微生物代谢及物质转化的关键因子.     

青海省海北州典型高寒草甸土壤质量评价

以青海省海北州的典型高寒草甸(金露梅灌丛草甸、矮嵩草草甸、高山嵩草草甸)为研究对象,以7种土壤微生物活性指标和10种土壤理化性质指标组成的土壤生物肥力性质为评价指标,对不同利用方式下草甸的土壤质量进行主成分分析(PCA).结果表明:高寒草甸土壤综合质量可用3个主成分(PC)来表征,其中PC1上有13个指标的载荷较高,PC2上有3个指标的载荷较高,PC3上只有全磷的载荷较高.结合Norm值的方法,筛选出微生物生物量碳、脲酶、碱性磷酸酶、蛋白酶、有机碳、全氮、有效氮、有效磷、有效钾、容重和阳离子交换量(CEC)等11项指标,建立了海北高寒草甸土壤综合质量评价的最小数据集(MDS).通过主成分和对应的权重系数分析,对3种草甸的土壤综合质量进行排序,0～10 cm层为矮嵩草草甸＞金露梅灌丛＞高山嵩草草甸;10～20 cm层为金露梅灌丛＞高山嵩草草甸＞矮嵩草草甸.     

两种生境下鹅绒委陵菜无性系形态的比较

以调查统计的方法研究了矮嵩草草甸和金露梅灌丛两种生境下鹅绒委陵菜无性系的形态特性,研究结果表明：矮嵩草草甸内的鹅绒委陵菜无性系绝大多数特征参数大于金露梅灌丛内,形态可塑性较显著,这与不同生境下的资源异质性特征密切相关。研究为生境适应假说提供又一例证。     

青海高寒区域金露梅灌丛草甸灌木和草本植物固碳量的比较

以青海海北高寒区域金露梅（PotentillafruticosaLinn.）灌丛草甸为研究对象,分析了6月至9月金露梅灌丛草甸灌木和草本植物不同部位的生物碳量,并据此对灌木及草本植物的年净初级生产碳量进行了比较。结果显示：金露梅灌丛草甸灌木植物地上部和地下部不同层次的生物量和碳含量均有明显差异,根据生物量所占比例确定其地上部和地下部的平均碳含量分别为0.50和0.48。依据不同月份灌丛冠面最大长度、最小宽度和最大高度,采用方程“Wij=e〔aln（A·B·H）＋b〕”计算灌木地上当年新生生物碳量、地上多年累积生物碳量和地下多年累积生物碳量,相关性均极显著（P〈0.01）,表明利用该方程评估金露梅灌丛草甸灌木不同部位的生物碳量是可行的。不同月份金露梅灌丛草甸灌木地上当年新生生物碳量、地上多年累积生物碳量和地下多年累积生物碳量分别为9.36-21.15、78.07-90.12和74.37-101.22g·m-2,差异不明显;其地上部和地下部净初级生产碳量分别为33.20和26.85g·m-2,总计为60.05g·m-2。金露梅灌丛草甸草本植物地上部和地下部净初级生产碳量分别为111.41和445.41g·m-2,总计为556.82g·m-2。如果根据草本和灌木占地面积78%和22%进行加权计算,则金露梅灌丛草甸当年的总净初级生产碳量为447.53g·m-2,其中灌木的净初级生产碳量仅占2.95%,且金露梅灌丛草甸地下部与地上部净初级生产碳量的比值为3.75。研究结果显示：青海高寒区域金露梅灌丛草甸以草本固碳为主,且地下部净初级生产碳量明显高于其地上部。     

藜的光合特性研究

5月中旬选取典型晴天用L I-6400便携式光合仪对藜从第一片完全展开叶倒数第3~5片功能叶进行有关光合参数的测定.结果表明:藜的光合日变化呈双峰型,有明显的“午休”现象,第1个峰值出现在8:30左右,P n达到9.34μm o l CO2.m-2.s-1;第2个峰值出现在16:00左右,P n为4.26μm o l CO2.m-2.-s 1.造成光合午休的主要原因是受气孔调节.在400μm o l.m o-l 1CO2浓度下藜的光饱和点(LSP)为1 350μm o l CO2.m-2.-s 1左右,光补偿点(LCP)为22.5μm o l CO2.m-2.-s 1左右;表观量子效率(AQY)为0.035μm o l CO2.m o-l 1photons.二氧化碳饱和点(CSP)在976μm o l CO2.m o-l 1左右,二氧化碳补偿点(CCP)在40μm o l CO2.m o-l 1左右,羧化效率(CE)为0.113 2μm o l CO2.m-2.-s 1.说明藜是一种具有较强耐荫能力的C3型阳性植物.     

高寒草甸不同草地群落物种多样性与生产力关系研究

生态系统的结构和功能、生物多样性与生产力的关系问题是近年来群落生态学中研究的中心问题,其中,生态系统生产力水平是其功能的重要表现形式,用4种不同草地类型探讨自然群落的物种多样性与生产力关系.结果表明,矮嵩草草甸、小嵩草草甸和金露梅灌丛群落中物种多样性与生产力的关系呈线性增加关系,藏嵩草沼泽化草甸群落中线性增加关系不显著,这表明群落生产力除受物种多样性的影响外,也受物种本身特征和环境资源的影响.不同的环境资源和环境异质性是形成群落结构特征、物种多样性分布格局差异的主要原因之一.     

北固山湿地虉草光合日变化的研究

采用便携式L I-6400光合测定仪,在晴朗的天气,对鬲艹鸟草成熟叶片净光合速率(Pn)以及光合有效辐射(Par)、气孔导度(Cond)、细胞间CO2浓度(C i)、叶温(T l)、叶周围气温(T a)和蒸腾速率(T r)等影响因子进行田间测定,研究艹鬲鸟草的光合日变化。结果表明:鬲艹鸟草净光合速率日变化呈双峰曲线,主峰出现在10¨00,次峰出现在15¨00,光合“午休”现象明显,非气孔限制是产生“午休”的主要原因。净光合速率变幅为5.86~20.64μm o l.m-2.-s 1,蒸腾速率变幅为2.8~6.22 mm o l.m-2.s-1,光补偿点为40μm o l.m-2.s-1,光饱和点为2 100μm o l.m-2.-s 1(自然状态下达不到),表观光量子效率为0.056 5 m o l.m o-l 1,暗呼吸速率为2.26μm o l.m-2.-s 1,水分利用效率为2.31~3.65μm o l.mm o-l 1。数据显示,鬲艹鸟草是一种高光效植物,对于其资源的合理利用及其对湿地生态系统的稳定意义重大。     

青海海北地区高山蒿草草甸植物群落生物量动态及能量分配

 对青海海北地区高山草甸主要植物群落小嵩草(Kobresia pygmaea)草甸、矮嵩草(K．humilis)草甸、藏嵩草(K．tibetica)沼泽化草甸地上生物量动态和能量分配的研究结果表明,不同植物群落年地上净生产量及其年际动态和主要植物类群生物量季节动态具明显的差异,其生物量季节动态可由如下模型表示： Wi＝Ki/(1+exp(Ai-Bit)) 植物群落地上、地下生物量的垂直分布呈典型的金字塔和倒金字塔模式。小嵩草草甸、矮嵩草草甸和藏嵩草沼泽化草甸的地上净生产量依次为368.4g·m-2·a-1、418.5g·m-2·a-1和518.4g·m-2·a-1,所固定的太阳能值依次为6655.16kJ·m-2·a-1、7610.09kJ·m-2·a-1、9488.77kJ·m-2·a-1。光能利用率分别为0.1097％、0.1256％、0.1568％。     

镇江北固山湿地芦苇光合日变化的研究

用便携式L I-6400光合测定仪,在晴朗的天气,对芦苇成熟叶片净光合速率(Pn)以及光合有效辐射(Par)、气孔导度(G s)、细胞间CO2浓度(C i)、叶温(T l)、叶周围气温(T a)和蒸腾速率(T r)等影响因子进行田间测定,研究芦苇的光合日变化。结果表明:芦苇净光合速率日变化呈双峰曲线,主峰出现在10:00,次峰出现在15:00,光合“午休”现象明显,且气孔限制是产生“午休”的主要原因。净光合速率日均为20.01μm o l.m-2.s-1,蒸腾速率日均为6.15 mm o l.m-2.-s 1,光补偿点为98μm o l.m-2.-s 1,光饱和点为2 125μm o l.m-2.-s 1(自然状态下达不到),表观光量子效率为0.060 4 m o l.m o-l 1,暗呼吸速率为2.91μm o l.m-2.-s 1,CO2补偿点为53μm o l.m o-l 1,饱和点为1 368μm o l.m o-l 1,羧化效率为0.064 7。数据显示,芦苇是一种高光效阳性植物,对于其资源的合理利用及其对湿地生态系统的稳定意义重大。     

高山草甸土壤过氧化氢酶活性的研究

土壤过氧化氢酶活性与土壤呼吸作用强度和土壤微生物的生命活动相关,它在一定程度上反映了土壤微生物学过程的强度。本文系作者于1986年8月在青海省海北高寒草甸生态系统定位站,对4种植被类型土壤的过氧化氢酶活性进行研究的初步结果。研究方法1.土壤样品的采集样品采自海北高寒草甸生态系统定位站,植被类型分别为:矮嵩草(Kobresis humilis)草甸,金露梅(Dasiphora fruticosa)灌丛,垂     

Lentic Meadows and Riparian Functions Impaired After Horse and Cattle Grazing

Perennially and intermittently available water in lentic, spring-fed herbaceous meadows supports wetland plants that build and maintain absorbent soil organic matter, capture sediment, prevent erosion, and thereby sustain riparian ecosystems. Enhanced forage and available water attract a diversity of wildlife and grazing animals that can degrade riparian vegetation through prolonged overuse. We tested novel monitoring methods and adapted existing methods to obtain quantified vegetation data that have been consistently linked to riparian functionality and compared these data to ungulate species use. We quantified ungulate use with time-lapse cameras at 10 Nevada spring-fed herbaceous meadows where core greater sage-grouse (Centrocercus urophasianus) habitat, public land grazing allotments, and free-roaming horse (Equus caballus) herd management areas (Bureau of Land Management) or territories (U.S. Department of Agriculture Forest Service) overlapped. Free-roaming horses used most study sites over longer periods and grazed more intensely than cattle or domestic sheep. Native ungulate grazing intensity was comparatively negligible. Free-roaming horses selected spring-fed meadow sites on average 51 (±33 [SE]) times more than the surrounding rangelands, and cattle selected them 30 ± 23 times more. Within the wettest area of a site, study sites with longer duration of use and higher intensity of use had more soil alteration and bare ground. Riparian ecosystem degradation occurred where meadows had limited rest or recovery time from grazing during the growing season. At all sites we noted loss of riparian function, especially within the hydric areas with the highest potential to grow abundant cover of stabilizing wetland plant species. Transects for monitoring soil alteration and vegetation cover in this hydric location can provide a leading indicator of riparian recovery or degradation and help in adjusting free-roaming horse population levels or livestock management strategies. © 2021 The Wildlife Society.     

Soil Carbon and Nitrogen Storage in Upper Montane Riparian Meadows

Though typically limited in aerial extent, soils of high-elevation riparian wetlands have among the highest density of soil carbon (C) and nitrogen (N) of terrestrial ecosystems and therefore contribute disproportionally to ecosystem services such as water retention, forage production, wildlife habitat, and reactive N removal. Because much soil C and N is stored in labile forms in anaerobic conditions, management activities or environmental changes that lead to drying cause mineralization of labile soil organic matter, and loss of C and N. Meadows are focal points of human activities in mountain regions, often with incised stream channels from historically heavy grazing exacerbated by extreme runoff events. To quantify soil C and N stores in montane riparian meadows across hydrologic conditions, 17 meadows between 1950- and 2675-m elevation were selected in the central Sierra Nevada Range, California, that were classified using the proper functioning condition (PFC) system. Results indicate that C and N density in whole-solum soil cores were equivalent at forest edge positions of properly functioning, functioning at-risk, and nonfunctioning condition. Soils under more moist meadow positions in properly functioning meadows have at least twice the C, N, dissolved organic C, and dissolved organic N (DON) than those under nonfunctioning meadows. Densities of total N and DON, but not C, of functioning at-risk meadows are significantly lower (P < 0.05) than those of properly functioning meadows at mid-slope and stream-bank positions, suggesting accelerated loss of N early in degradation processes. Though variable, the soil attributes measured correspond well to the PFC riparian wetland classification system.     

芦芽山亚高山草甸的数量分类与排序研究

芦芽山亚高山草甸是在华北地区最典型的山地草甸之一,该草甸在水土保持、生态旅游资源开发和生物多样性保护等方面发挥着重要作用。应用双向指示种分析法（TWINSPAN）和除趋势对应分析（DCA）相结合的方法,对山西芦芽山亚高山草甸进行数越分类和排序,将该草甸划分为13个群丛类型,分别位于不同的海拔高度。分类结果很好地反映了植物群丛类型与环境梯度之间的关系,并在DCA二维排序图上得到较好的验证。DCA排序轴反映了海拔、土壤湿度和坡向的梯度变化,表明海拔高度、水热条件和地形是影响植物群丛变化的主要生态因子。     

Trophic Transfers from Seagrass Meadows Subsidize Diverse Marine and Terrestrial Consumers

In many coastal locations, seagrass meadows are part of a greater seascape that includes both marine and terrestrial elements, each linked to the other via the foraging patterns of consumers (both predators and herbivores), and the passive drift of seagrass propagules, leaves, roots and rhizomes, and seagrass-associated macroalgal detritus. With seagrasses declining in many regions, the linkages between seagrass meadows and other habitats are being altered and diminished. Thus, it is timely to summarize what is known about the prevalence and magnitude of cross-habitat exchanges of seagrass-derived energy and materials, and to increase awareness of the importance of seagrasses to adjacent and even distant habitats. To do so we examined the literature on the extent and importance of exchanges of biomass between seagrass meadows and other habitats, both in the form of exported seagrass biomass as well as transfers of animal biomass via migration. Data were most abundant for Caribbean coral reefs and Australian beaches, and organisms for which there were quantitative estimates included Caribbean fishes and North American migratory waterfowl. Overall, data from the studies we reviewed clearly showed that seagrass ecosystems provide a large subsidy to both near and distant locations through the export of particulate organic matter and living plant and animal biomass. The consequences of continuing seagrass decline thus extend far beyond the areas where seagrasses grow.     

新疆博斯腾湖地区芦苇沼泽及草甸植被资源的利用和保护

博斯腾湖(简称博湖)又名喀喇赤湖,汉书《西城传》称为“焉耆近海”,位于新疆焉耆盆地东南,是开都河尾闾之区,又是孔雀河的河源地,是我国内陆干旱区中第一大淡水湖泊。河湖沿岸发育了大面积的芦苇沼泽及其草甸植被,水、土、生物条件十分优越,是农林牧发展的重要基地。由于苇产资源丰富,已成为我国造纸工业原料供给的地区。随着本     

Diazotrophy in Alluvial Meadows of Subarctic River Systems

There is currently limited understanding of the contribution of biological N₂ fixation (diazotrophy) to the N budget of large river systems. This natural source of N in boreal river systems may partially explain the sustained productivity of river floodplains in Northern Europe where winter fodder was harvested for centuries without fertilizer amendments. In much of the world, anthropogenic pollution and river regulation have nearly eliminated opportunities to study natural processes that shaped early nutrient dynamics of large river systems; however, pristine conditions in northern Fennoscandia allow for the retrospective evaluation of key biochemical processes of historical significance. We investigated biological N₂ fixation (diazotrophy) as a potential source of nitrogen fertility at 71 independent floodplain sites along 10 rivers and conducted seasonal and intensive analyses at a subset of these sites. Biological N₂ fixation occurred in all floodplains, averaged 24.5 kg N ha⁻¹ yr⁻¹ and was down regulated from over 60 kg N ha⁻¹ yr⁻¹ to 0 kg N ha⁻¹ yr⁻¹ by river N pollution. A diversity of N₂-fixing cyanobacteria was found to colonize surface detritus in the floodplains. The data provide evidence for N₂ fixation to be a fundamental source of new N that may have sustained fertility at alluvial sites along subarctic rivers. Such data may have implications for the interpretation of ancient agricultural development and the design of contemporary low-input agroecosystems.     

划破草皮对高寒草甸植物多样性和生产力的影响

本研究探讨了高寒草甸在不同划破强度下植被组成、多样性、功能群和生产力的变化.结果表明:垂穗披碱草等对土壤通透性和资源空间要求较高的物种,竞争力随划破强度的增加而上升,而对土壤通透性和资源空间要求相对较低的物种则相反;轻度划破干扰对提高物种丰富度具有一定的促进作用,但多样性指数则总体上表现为随划破强度的增加而呈下降的趋势;划破干扰对植被功能群的影响表现为以垂穗披碱草为代表的禾草类组分随干扰强度的增加而显著上升,莎草类和杂类草组分随干扰强度的增加而显著下降;划破干扰对草地初级生产力的提升具有显著的促进作用,且可显著增加植物总量中优质牧草的比重;划破干扰可独立作为高寒草甸类草地恢复与改良的有效措施,在定向培育垂穗披碱草型割草场的技术组合中具有核心和基础性的地位.     

Transplanting Sedges (Carex spp.) in Southwestern Riparian Meadows

Abstract The success of revegetation efforts in southwestern U.S. riparian meadows has been limited because natural recolonization is often poor and little is known about establishment of transplanted native meadow species such as sedges. To evaluate their potential use in riparian restoration, the survival and growth of transplanted wildlings of three sedge species, Carex lanuginosa (woolly sedge), C. nebrascensis (Nebraska sedge), and C. rostrata (beaked sedge), were assessed. Transplanting occurred during two seasons (summer and fall) using two transplant sizes (295 and 680 cm³) at seven montane meadow sites in Arizona. Survival was similar among species, but shoot numbers were greater for C. lanuginosa (12.7 shoots/wildling) compared with C. nebrascensis (5.5 shoots/wildling) and C. rostrata (7.9 shoots/wildling). Survival was significantly greater for the summer transplant season (55.1%) versus fall (24.1%). Survival and growth were greater for the larger transplant size (46.1% large vs. 33.0% small; 8.1 shoots/wildling large vs. 6.4 small). Wildling survival was related to depth to groundwater for each species. Survival was highest for C. lanuginosa (78.6%), C. nebrascensis (88.2%), and C. rostrata (64.3%) where the groundwater depth was ?48 to ?60, ?28 to ?47, and ?8 to ?27 cm, respectively. These results suggest that restoration will be most successful if transplanting occurs in summer, using large wildling transplants when under stressful conditions such as waterlogged or dry soils, and when species are planted at appropriate groundwater depths.     

Effects of Traditional Flood Irrigation on Invertebrates in Lowland Meadows

Lowland meadow irrigation used to be widespread in Central Europe, but has largely been abandoned during the 20^th century. As a result of agri-environment schemes and nature conservation efforts, meadow irrigation is now being re-established in some European regions. In the absence of natural flood events, irrigation is expected to favour fauna typical of lowland wet meadows. We analysed the effects of traditional flood irrigation on diversity, densities and species composition of three invertebrate indicator taxa in lowland meadows in Germany. Unexpectedly, alpha diversity (species richness and Simpson diversity) and beta diversity (multivariate homogeneity of group dispersions) of orthopterans, carabids, and spiders were not significantly different between irrigated and non-irrigated meadows. However, spider densities were significantly higher in irrigated meadows. Furthermore, irrigation and elevated humidity affected species composition and shifted assemblages towards moisture-dependent species. The number of species of conservation concern, however, did not differ between irrigated and non-irrigated meadows. More variable and intensive (higher duration and/or frequency) flooding regimes might provide stronger conservation benefits, additional species and enhance habitat heterogeneity on a landscape scale.