三江平原沼泽湿地污水处理的实地模拟研究

现场模拟发现，沼泽湿地生态系统对污水中N、P的净化速度随时间的延长呈指数规律下降，初期净化效果与污水中N、P的含量为正相关关系。毛果苔草（Carex lasiocarpa）生态系统和乌拉苔草（Carex meyeriana）生态系统对N、P的去除量大于纯沼泽水，毛果苔背系统又高于乌拉 苔草，表明植物各类和重量、泥炭土厚度等都影响净化效率。通过统计显示，毛果苔草生态系统不同组分对N的净化能力大小的排列次序为：茎叶＞泥炭＞根系＞枯落物；对P的净化能力排列次序为：根系＞泥炭＞茎叶＞枯落物。按单位质量组分对P的去除量由小到大对比，泥炭：茎叶：枯落物：根第为1.00:1.81:2.95:3.84；而对N的净化效果由小到大对比，泥炭：枯落物：根系：茎叶为1.00:1.62:2.00:5.11。毛果苔果地上部分单位干重对N的吸附量是地下部分的大约2.6倍，表现出N具有从根系向茎叶传递积累的特性；相反，毛果苔草地下部分单位干重对P的吸量是地上部分的大约2.1倍，显示P主要积累于毛苔草的根系中。     

鄱阳湖典型苔草湿地生物量季节变化及固碳功能评价

为进一步评估鄱阳湖湿地碳平衡，量化湿地固碳功能，于2009年9月～2011年5月，在鄱阳湖南矶湿地国家级自然保护区，选择以灰化苔草为建群种的洲滩湿地，采取收获法测定了灰化苔草4个生长季的地上、地下生物量及净初级生产力(NPP)。结果表明：1）苔草地上、地下生物量均具有明显的季节变化模式，变化范围分别为14608～1 77067 、1 80627～4 03256 g/m2；地下生物量与地上生物量的比例变化范围为208～1744，平均值为519。2）苔草地上地下生物量、NPP均表现为春季高于秋季。3）受洲滩淹水时间影响，苔草生物量、NPP具有显著的年际差异， 2010～2011年度苔草NPP仅相当于2009～2010年度的625%；NPP的下降地上部分较地下部分更明显。4）鄱阳湖湿地苔草固碳潜力巨大，2个年度固碳量分别为1 92383，1 23121 gC/m2     

植物对沼泽湿地生态系统N2O排放的影响

利用静态暗箱/气相色谱法连续3个生长季(2003-2005年)对三江平原小叶章草甸和毛果苔草沼泽N2O排放通量进行野外对比观测试验.结果表明,植物不同生长阶段对湿地生态系统N2O排放通量的影响不尽相同.植物的参与促进了湿地生态系统N2O的排放,2003-2005年生长季小叶章草甸土壤-植物系统N2O排放通量分别是土壤表观N2O排放通量的1.58倍、2.09倍和2.34倍,同期毛果苔草沼泽土壤-植物系统N2O排放通量分别是土壤表观N2O排放通量的1.86倍、1.50倍和1.33倍.3个生长季小叶章草甸N2O排放通量均大于毛果苔草沼泽,这主要是由土壤理化性质的空间变异性以及水文情况的差异造成的.     

模拟增温效应对西藏苔草繁殖生态的影响

通过采用国际冻原计划模拟增温对植物影响的方法,从繁殖生态学角度研究了西藏苔草（Carex thibetica Franch）种群的物候期、分蘖数、生物量和种群繁殖对增温的响应。结果表明：暖棚内气温、土壤表层温度分别了1.17℃和1.50℃;物候期提前或延迟,生长期延长;增温可以提高西藏苔草的生殖产量,但不提高其种子发芽率;增温可提高西藏苔草分蘖数和生物量;西藏苔草繁殖对策趋于营养繁殖。     

长白山区沟谷乌拉苔草Carex meyeriana沼泽湿地气候效应

通过对长白山区沟谷沼泽典型乌拉苔草湿地土壤温度、乌拉苔草群落相对湿度、叶片温度、风速、光量子通量密度以及蒸腾速率的日变化和蒸腾速率的季节变化的研究,初步揭示沟谷乌拉苔草沼泽湿地的气候效应。结果表明长白山沟谷沼泽湿地具有三江平原沼泽同样的冷湿效应。土壤化通时间比三江平原化通时间提前1个多月,蒸腾速率日变化不同季节趋势基本一致,不同层次叶片的蒸腾速率日变化趋势基本一致,最大值在7至8月份蒸腾速率(H2O)达到100~140 mol.m-2.s-1。光量子通量密度与温度成正比,与湿度成反比,大气温度日变化和叶片温度日变化趋势基本相同,相对湿度的日变化趋势和大气温度的变化趋势正好相反,和光量子通量密度的变化趋势相反。沟谷湿地的同样具有小气候效应。     

Genetic Effects of Habitat Fragmentation on Common Species of Swiss Fen Meadows

Abstract:  The area of Caricion davallianae alliance in Switzerland has been considerably reduced and fragmented during the last 150 years. We assessed the genetic variability, inbreeding level, and among-population differentiation of two common habitat-specific plant species, Carex davalliana SM. and Succisa pratensis Moench, in 18 Caricion davallianae fen meadows subjected to fragmentation. We used a spatial field design of fen systems (six systems total), each consisting of one large habitat island and two small habitat islands. We used allozyme electrophoresis to derive standard genetic parameters ( A, P, H_O, H_E, F_IS, F_ST ). In Carex we identified a consistently lower A in isolated habitat islands; furthermore, H_E was lower in small habitat islands than in large habitat islands. In Succisa we identified a lower H_O in small habitat islands than in larger ones. Small habitat islands were marginally significantly differentiated (  F_ST ) from large islands for Succisa . For both species, no effects were evident for F_IS ; therefore, we argue that genetic drift rather than inbreeding is the main cause of the observed differences. The genetic structure of Carex and Succisa in small habitat islands differed from that in large habitat islands, but differences were small. It appears that the observed differences in genetic variability among fen meadows correspond to observed differences in fitness and demographic traits. We show that habitat fragmentation affects not only the rare species in an ecosystem but also reduces the survival probabilities of common species. One of the main goals of conservation should be to mitigate fragmentation of natural habitats in order to increase population sizes and connectivity.     

Nitrogen mediates above-ground effects of ozone but not below-ground effects in a rhizomatous sedge

Ozone and atmospheric nitrogen are co-occurring pollutants with adverse effects on natural grassland vegetation. Plants of the rhizomatous sedge Carex arenaria were exposed to four ozone regimes representing increasing background concentrations (background-peak): 10-30, 35-55, 60-80 and 85-105 ppb ozone at two nitrogen levels: 12 and 100 kg N ha⁻¹ yr⁻¹. Ozone increased the number and proportion of senesced leaves, but not overall leaf number. There was a clear nitrogen × ozone interaction with high nitrogen reducing proportional senescence in each treatment and increasing the ozone dose (AOT40) at which enhanced senescence occurred. Ozone reduced total biomass due to significant effects on root biomass. There were no interactive effects on shoot:root ratio. Rhizome tissue N content was increased by both nitrogen and ozone. Results suggest that nitrogen mediates above-ground impacts of ozone but not impacts on below-ground resource translocation. This may lead to complex interactive effects between the two pollutants on natural vegetation.     

落新妇地下部分挥发油化学成分GC—MS分析

利用水蒸汽蒸馏法提取落新妇地下部分的挥发油,测得含量为0．10％;采用气相色谱－质谱联用技术（GC—MS）对落新妇的挥发性成分进行了分离鉴定,分离出57种成分,鉴定了其中50种;运用峰面积归一法确定了各成分的相对含量,检出率为87．71％。落新妇地下部分挥发油的主要成分为邻苯二甲酸二丁酯、十六甲基八环硅氧烷。     

三江平原典型环型湿地主要植物群落枯落物的热值变化

研究了小叶章(Calamag rostis angustifolia)、毛果苔草(Carex lasiocarpa)和漂筏苔草(Carex pseudocuraica)群落枯落物在1个生长季内的分解热值变化特征,并初步探讨其影响因素。环型湿地3种植物群落由于各自的微环境不同致使其枯落物热值变化有所差异。6月至10月,小叶章群落枯落物热值呈现逐渐下降趋势,而毛果苔草群落和漂筏苔草群落由于所处环型湿地位置不同而形成不同于小叶章群落的湿地水热条件,从而造成其枯落物热值的总体变化趋势是先下降再上升,最后又下降。同时,同一群落不同深度枯落物热值变化也不同。0—10、10—20和20—30 cm土层热值变化相似,而30—40 cm土层热值变化规律不明显。     

土壤动物对三江平原典型毛果苔草湿地枯落物分解的影响

采用尼龙网分解袋法，从枯落物的分解量、组分含量和分解残留物的热能值3方面，研究了土壤动物对三江平原毛果苔草（Carex lasiocarpa）湿地枯落物分解的影响。结果表明，土壤动物加速了枯落物的分解，大中型土壤动物的分解作用大于小型土壤动物；土壤动物增加了枯落物中腐殖酸、纤维素和木质素等物质含量以及C／N比值的变化幅度，促进了枯落物组分的释放；土壤动物影响枯落物分解过程中的能量流动；但土壤动物并未影响枯落物分解的总体变化趋势，土壤动物对枯落物分解不起决定性作用。