Rotifer Nervous System Visualized by FMRFamide and 5-HT Immunocytochemistry and Confocal Laser Scanning Microscopy

The characteristic ecology of floodplain lakes is in part due to their relatively strong water-level fluctuations. We analyzed the factors determining water-level fluctuations in 100 floodplain lakes (during non-flooded conditions) in the active floodplains of the Lower Rhine in the Netherlands. Furthermore, we explored the relationship between water-level fluctuations and macrophyte species richness, and analyzed the suitability of artificially created lakes for macrophyte vegetation. During non-flooded conditions along the Rhine, lake water-level fluctuations are largely driven by groundwater connection to the river. Hence, water-level fluctuations are largest in lakes close to the main channel in strongly fluctuating sectors of the river and smallest in isolated lakes. Additionally, water-level fluctuations are usually small in old lakes, mainly due to reduced groundwater hydraulic conductivity resulting from accumulated clay and silt on the bottom. Species richness of floating-leaved and emergent macrophytes was reduced at both small and large water-level fluctuations, whereas species richness of submerged macrophytes was reduced at small water-level fluctuations only. In addition, species richness of submerged macrophytes was higher in lakes that experienced drawdown, whereas no similar pattern was detected for floating-leaved and emergent macrophytes. The decline in amplitude of lake water-level with lake age implies that the number of hydrologically dynamic lakes will decrease over time. Therefore, we suggest that excavation of new lakes is essential to conserve the successional sequence of floodplain water bodies including conditions of high biodiversity. Shallow, moderately isolated, lakes with occasional bottom exposure have the highest potential for creating macrophyte-rich floodplain lakes along large lowland rivers. The water-level regime of such lakes can in part be designed, through choice of the location along the river, the distance away from the river and the depth profile of the lake.     

湿地生态系统健康研究进展

湿地作为一个生态系统 ,具有多种功能和价值 ,是人类最重要的环境资本之一 ,被称为“自然之肾”。湿地在蓄洪防旱、调节气候、控制土壤侵蚀、促淤造陆、降解环境污染等方面起着极其重要的作用。湿地拥有丰富的野生动植物资源 ,是众多野生动植物特别是珍稀水禽的繁殖和越冬地。不仅如此 ,湿地向人类提供大量的生产和生活资料 [1] 。然而 ,近些年来一些地区的湿地状况令人担忧 ,具体表现城市化、工业化、路基建设、农业开发及废物处理等造成湿地面积的缩小 ;水利、灌溉、水库蒸发、河流及地下水过度提取 ,沼泽地排水、挖渠、土地开荒、筑堤造…     

Invertebrate DNA metabarcoding reveals changes in communities across mine site restoration chronosequences

Invertebrate biomonitoring can reveal crucial information about the status of restoration projects; however, it is routinely underused because of the high level of taxonomic expertise and resources required. Invertebrate DNA metabarcoding has been used to characterize invertebrate biodiversity but its application in restoration remains untested. We use DNA metabarcoding, a new approach for restoration assessment, to explore the invertebrate composition from pitfall traps at two mine site restoration chronosequences in southwestern Australia. Invertebrates were profiled using two cytochrome oxidase subunit 1 assays to investigate invertebrate biodiversity. The data revealed differences between invertebrate communities at the two mines and between the different age plots of the chronosequences. Several characteristic taxa were identified for each age within the chronosequence, including springtails within the youngest sites (Order: Collembola) and millipedes within the oldest and reference sites (Order: Julida). This study facilitates development of a molecular “toolkit” for the monitoring of ecological restoration projects. We suggest that a metabarcoding approach shows promise in complementing current monitoring practices that rely on alpha taxonomy.     

喀斯特槽谷区土地石漠化与综合治理技术研发

深入揭示流域尺度水-土-生资源格局和研发因地制宜的水-土-生治理技术是"十三五"石漠化治理工程的主要瓶颈。国家重点研发计划——"喀斯特槽谷区土地石漠化过程及综合治理技术研发与示范"项目(2016YFC0502300)针对槽谷区特点,锁定两个关键科学问题和五个关键技术,从过程机理研究-技术研发-应用示范3个层面解剖区域水/土/生物资源分布格局与地质地貌之间的关系,阐明石漠化过程中的相关生态变化机理,因地制宜地研发水土资源高效利用、土壤地上/下流/漏失阻控与生态恢复技术;研发野生砧木及经济树种互作效应与优化配套技术,构建槽谷区可持续的生态系统和生态产业模式并示范推广,为区域生态改善和贫困问题解决提供科技支撑。     

上海城市近自然森林的重建动态

近自然森林作为城市植被恢复的重要模式,已在我国多地开展了实践,并衍生了新的造林模式。为评估不同近自然森林建设模式的群落恢复进程,本研究以上海城市裸地上重建的近自然森林为对象,通过长期监测两处分别应用原"宫胁法"与新"异龄复层落叶—常绿混交林"种植模式的近自然森林重建过程,从物种组成、垂直结构、生活型组成和目标恢复物种4个方面解析恢复动态。结果表明:两种造林模式恢复的近自然森林,随恢复进程其物种组成逐渐趋同,在十多年内已形成了落叶—常绿垂直混交结构;"异龄复层落叶—常绿混交林"造林模式可更好地促进常绿阔叶树种的恢复,尤其是常绿建群种红楠与小叶青冈。本研究证实了近自然森林恢复技术可以缩短亚热森林群落向演替后期发展的时间,以及新造林模式的有效性,为近自然森林技术的应用与实施提供了科学依据。     

Comparisons of population density and genetic diversity in artificial and wild populations of an arborescent coral,Acropora yongei: implications for the efficacy of “artificial spawning hotspots”

We are developing techniques to restore coral populations by enhancing larval supply using “artificial spawning hotspots” that aggregate conspecific adult corals. However, no data were available regarding how natural larval supply from wild coral populations is influenced by fertilization rate and how this is in turn affected by local population density and genetic diversity. Therefore, we assessed population density and genetic diversity of a wild, arborescent coral, Acropora yongei, and compared these parameters with those of an artificially established A. yongei population in the field. The population density of wild arborescent corals was only 0.27% of that in the artificial population, even in a high‐coverage area. Genetic diversity was also low in the wild population compared with the artificial population, and approximately 10% of all wild colonies were clones. Based on these results, the larval supply in the artificial population was estimated to be at least 1,400 times higher than that in wild A. yongei populations for the same area of adult population.     

六盘山叠叠沟小流域典型坡面土壤水分的植被承载力

确定土壤水分的植被承载力是我国北方半干旱地区合理调控土壤水分和植被生长关系、科学恢复林草植被的核心问题。我国北方半干旱地区的土壤水分主要来自大气降水, 作为土壤水分限制型生态系统的坡面植被, 植物种类和植被密度等结构特征与降水量紧密相关。根据六盘山石质山区的特点, 基于水量平衡原理, 建立了阴坡华北落叶松(Larix principis-rupprechti)和阳坡草地的土壤水分植被承载力数学模型, 即由4~10月的生长季降雨量(P)计算得到可承载的叶面积指数(Leaf area index, LAI)公式: LAI_tree= exp((0.773 1×P-186.12)/146.46)和LAI_grass= exp((0.511 2×P-345.93)/227.89), 并提出了考虑坡面水分再分配影响的不同坡位的土壤水分植被承载力计算方法。阴坡华北落叶松的植被承载力(用LAI表示)从坡顶的1.45升高到坡中的4.83, 然后稳定在3.0~3.3。对于阳坡草地, 土壤水分可承载的LAI从坡顶的0.37上升到坡中的0.46, 然后在0.41~0.47之间变动, LAI的计算值与实测值较为接近, 计算结果比较合理。     

生态退耕与植被演替的时空格局

综述了多重尺度上生态退耕的时空格局及其对植被演替时空变异影响的研究进展,提出了生态退耕与植被演替的时空格局研究方向.在自然和人文等因子的驱动下,全球兴起了生态退耕的热潮,生态退耕类型正在由人工恢复为主向自然弃耕为主发展.尽管国内外很多学者开始关注不同尺度上生态退耕的时空格局及其影响因子,但是生态退耕的时空变异性研究仍然比较薄弱,尤其缺乏多重尺度上生态退耕时空格局及其驱动因子的综合研究,在很大程度上限制了研究结果外推.研究表明,受到多因子的综合影响,生态退耕后植被演替呈现出复杂多样的时空变化特征;退耕植被演替研究从植物群落结构特征分析为主向群落功能分析发展,从传统的演替过程规律分析转向退耕植被演替的时空变异性分析;相对来说,生态退耕后植被演替的时空分异、影响因子和机制方面的研究比较薄弱.加强多重尺度上生态退耕时空格局与植被演替时空变异的综合研究是将来的研究重点.     

川西亚高山针阔混交林乔木层生物量、生产力随海拔梯度的变化

川西亚高山针阔混交林是该地区云冷杉暗针叶林大规模采伐后自然恢复形成的主要次生林类型之一,是由采伐迹地向顶极暗针叶林演替过程中的重要阶段。采用样地调查与异速生长模型相结合的方法,研究了川西亚高山林区4个海拔梯度(A:2900—3050m;B:3150—3300m;C:3300—3450m;D:3450—3550m)40a生针阔混交林的生物量与生产力变化。结果表明,林分乔木层生物量、生产力随海拔上升而不断下降,分别由A梯度的157.07t/hm2、3.43t·hm-·2a-1下降到D梯度的54.65t/hm2、1.36t·hm-·2a-1,气温的海拔间差异以及林分密度的递减是影响林分生物量、生产力变化的主要原因;阔叶类树种单株平均生物量、生产力随海拔升高而显著下降,由A梯度的200.55kg、4.96kg/a下降到D梯度的47.86kg、1.19kg/a;而针叶类树种单株平均生物量、生产力则逐渐上升,由A梯度的51.57kg、1.28kg/a上升到D梯度的73.88kg、1.84kg/a,但未达显著水平,阔、针叶类树种生物量、生产力变化分异是物种的生物学特性和林分环境共同作用的结果。相关分析显示,该地区阔叶类树种对海拔梯度的响应比针叶树种更为敏感和显著。