淤泥湖退化水生植被恢复及其在湖泊天然生态库中作用的研究

对淤泥湖水生植被的天然恢复过程、群落组成、结构、功能与动态等进行了定位研究（１９９２￣１９９５）。该湖水生植物共有２０科２９属４１种。４种生活型的植物种类在该湖均有分布,以沉水草本（１５种）和挺水草本（１３种）为多。８个分布区类型中世界广布成分１６种和东亚成分１０种。群落结构包括层次结构和层片结构。该湖共有８个群落类型;群落现存量３２０８．８ｇ·＾－２,全湖植被资源贮量为１６３６５．２ｔ。     

武汉东湖水生植被及其恢复途径探讨

１９９２～１９９３年对武汉东湖三个主要湖区（郭郑湖、汤林湖和牛巢湖）水生植被的调查表明,该湖区共有水生植物３２种,优势种为大茨藻、狐尾藻、苦草和菱。金鱼藻呈不断扩大的趋势。植被类型可分为１１个群丛,植被面积约为０．６５ｋｍ￣２,总生物量为１２３６．３９ｔ（湿重）,植被带状分布仅见于汤林湖北部和其他部分湖汊。汤林湖和牛巢湖水生植被正处于自然恢复演替阶段。     

1998年特大洪水后鄱阳湖自然保护区主要湖泊水生植被的恢复

鄱阳湖自然保护区的湖泊是相对独立于鄱阳湖主体湖的一个区域,是国际重要湿地。1998年的特大洪水导致湖泊中水生植物的地上部分大量毁灭。通过1999年和2001年的植被调查,并与历史资料比较,探讨了特大洪水干扰后的植被恢复动态。结果表明,1999年湖泊水生植物的种类和生物量均低于干扰前的水平;2001年物种种类已经恢复,苦草(Vallisneria spp．)和黑藻(Hydrialla verticillata)的生物量已超过干扰前的水平,但其它物种的生物量仍较低,尚处于恢复的初始阶段。据此推断,物种问恢复速度的差异主要与物种的无性繁殖方式有关。鄱阳湖自然保护区湖泊的植被恢复不同于温带和其它亚热带的湖泊,不经历轮藻(Chara spp．)作为先锋优势种的阶段,苦草和黑藻可以作为先锋种首先在湖泊中恢复。这可能与鄱阳湖作为通江湖泊其水位频繁波动、轮藻不易定居有关。研究显示,洪水导致的水生植物生物量下降和物种数目减少只是短期现象,湖泊水生植物能在几年内恢复到干扰前的水平。     

小兴凯湖的水生植被及其生态作用

本文论述了小兴凯湖水生植物的种类组成、植被类型、生物量及其在湖泊淤积和渔业中的作用。该湖属老年期湖泊,水生维管束植物共有25科56种,优势种为竹叶眼子菜、荇菜、芦、菰等。植被类型可划分为沉水植被、浮叶植被和挺水植被等三个亚型,包括12个主要植物群丛。全湖水生植物总生物量(湿重)为196380吨;以植物现存量计算,草食性鱼类的年生产力应为78.75吨。由于水生植物大量繁殖,为减缓湖泊的垫平作用,可适量放养草食性鱼类,控制住水生植物的过量繁殖;同时引种一些经济水生植物,压住水中杂草的生长。     

杭州西湖水生植被恢复的途径与水质净化问题

我国著名的风景湖泊——杭州西湖、南京玄武湖、北京昆明湖、武汉东湖和昆明滇池等,由于人类经济活动的影响,特别是由于生活污水的大量排入和渔业生产的影响,致使湖泊富营养化问题越来越严重,不仅降低了旅游价值,而且有害于沿湖居民的生活和健康,因此引起人们的极大关注。     

东湖围隔（栏）中水生植被恢复及结构优化研究

为重建湖泊水生植被 ,在武汉东湖无鱼的 2个大型围隔和 1个围栏中进行了水生植被自然恢复和人工结构优化试验 ,两年内 ,围隔 (栏 )中的植被均得以恢复 ,植物月生物量均值均高出对照区约 1倍 ,自然增加的维管束植物比对照区多 3～ 6种 ,漂浮植物易定殖 ,水绵和刚毛藻较易生长 ;自然恢复的植被常以穗花狐尾藻、野菱等为优势种 ,缺乏挺水层 ,群落结构不理想 ,通过合理选种植物 ,可较快地改善其结构 ,加快植被恢复进程 ,经初步实验 ,莲、芦苇、苦草、金鱼藻和穗花狐尾藻适应性较强 ,可作为重建东湖水生植被的先锋种 ,以沉水植物为主体的植被结构较优良 ,控制养鱼是恢复水生植被的前提     

退化红壤区植被恢复过程中灌木层主要种群的生态位特征

选择闽西典型退化红壤地区,对6个不同恢复阶段的封育马尾松群落灌木层主要种群的生态位特征进行了分析,结果表明,多数种群的生态位宽度较窄,对资源的利用不充分,生态位宽度较大的种群顺序与其重要值大小顺序存在一致性,同时种群间生态位重叠较为普遍,对资源的利用方式相对一致。这些结果与退化红壤区植被恢复过程中生境条件的变化密切相关,有助于理解植被恢复动态规律,指导运用人工措施以加快恢复进程。     

岷江上游退化植被不同恢复阶段群落小气候特征研究

按生态恢复的时间序列调查了6个不同类型的群落,测定了群落内光照强度、大气相对湿度、大气温度、土壤温度和土壤水分等参数。结果表明,随植被恢复时间的增加,群落内光照强度、地表温度和气温及其变动幅度逐渐减小;自然恢复群落和人工恢复群落相比较,前者有较高的群落气温和较低的大气相对湿度;随着恢复时间的增加,撂荒地各层的土壤含水量有所提高,人工恢复群落土壤上层(0-15cm)和中层(15—30cm)含水量随林龄增加而降低,而下层(30—45cm)则增加,自然恢复群落的土壤含水量高于其它群落。随之植被恢复的时间加长,群落内小气候向着稳定的方向发展,群落的环境逐渐得到改善。     

小良植被生态恢复的生态经济价值评估

应用生态经济学的核算方法,对中国科学院小良热带人工林生态系统定位站植被生态恢复系统的服务功能进行了定量评估。结果表明,小良恢复生态系统具有极高的生态经济价值。以20世纪90年代不变价计,小良植被生态恢复系统43a的累积服务功能价值超过621亿元人民币。其中直接使用价值为7．65亿元,占总生态经济价值的1．23％,间接使用价值为613亿元,占总生态经济价值的98．77％,间接使用价值远远大于直接使用价值。间接使用价值中净化环境服务功能的生态经济价值,仅以固C、释放O2、吸收SO2和滞尘计,就已达577亿元。与此同时,小良热带沿海台地的植被恢复通过复合农林经营等渠道促进了当地生态、经济与社会的协同发展。     

植被生态系统恢复及其在华南的研究进展

介绍了恢复生态学常用的理论,并指出恢复生态学研究大多涉及植被生态系统恢复。植被恢复的目标就是要恢复植被的合理结构、功能和动态过程,从而为人类提供生态系统服务。植被恢复可以把区域的地带性植被生态系统作为参考生态系统,但目前的植被恢复工作绝大部分只是恢复了植被生态系统的部分组成、结构和功能。植被生态系统恢复研究主要从退化的原因与过程、恢复的过程与机理,以及从生境恢复、种群恢复、群落恢复、生态系统和景观恢复等不同尺度上的恢复开展。在介绍华南地区的植被生态系统现存问题的基础上,对华南地区开展的植被生态系统恢复,尤其是华南植物研究所(园)开展的植被生态系统恢复研究进行了介绍。最后,提出了华南地区植被生态系统恢复的方向及发展趋势。     

高密度网围养鱼对水生植被的影响及生态对策探讨

研究了东太湖高密度网围养鱼实验区周围水生植被退化情况,影响范围半径＞６００ｍ,在中心带优势种微齿眼子菜为黑藻、金鱼藻和穗花狐尾藻所代替,并引起水绵严重发生,丧失了饲料生产能力．养鱼污染可导致水生植被退化,１４．３ｈｍ２网围面积上年Ｎ、Ｐ污染负荷量分别达２４２ｇ·ｍ（－２）·ａ（－１）和２７．４ｇ·ｍ（－２）·ａ（－１）．网围对风浪、水流的作用和水草收割的障碍效应是水生植被退化的另一重要原因．应对湖泊中网围养鱼的规模进行严格限制,并通过网围的小型、分散和短期化来减弱其环境效应的时空叠加,加强对网围周围水草的收割管理以防止植被退化和湖泊营养化．     

Applying remote sensing techniques to monitoring seasonal and interannual changes of aquatic vegetation in Taihu Lake,China

Knowledge of the composition and areal distribution of aquatic vegetation types, as well as their seasonal and interannual variations, is crucial for managing and maintaining the balance of lake ecosystems. In this study, a series of remotely sensed images with a resolution of 30 m (HJ-CCD and Landsat TM) were collected and used to map the distribution of aquatic vegetation types in Taihu Lake, China. Seasonal and interannual dynamics of aquatic vegetation types were explored and analyzed. The distribution areas of Type I (emergent, floating-leaved and floating vegetation) and Type II (submerged vegetation) were used to model their growing season phenology by double logistic functions. The resulting double logistic models showed, the area of Type I reached its peak in mid-August, and the maximum area for Type II occurred in mid-September. From 1984 to 2013, Type I area increased continuously from 59.75 km² to 148.00 km² (R² = 0.84), whereas the area covered by Type II first increased and then decreased, with a trend conforming to a significant quadratic curve (R² = 0.83). The eutrophication and stable state of Taihu Lake was assessed using a simple indicator which was expressed as a ratio of Type II area to Type I area. The results showed that the eutrophication in the lake might have been increasing in the area studied since 2000. Additionally, the results showed that air temperature had likely a direct effect on the growth of Type I (R² = 0.66) and a significant, but delayed, effect on the growth of Type II.     

惠州西湖富营养化现状评价及治理探讨

惠州西湖属于城市型浅水湖泊,本文通过历史和现状数据整理和分析,采用Carlson的营养状况指数(TSI)进行评判,表明惠州西湖处于富营养阶段。通过近几年的疏浚湖底沉积物、截流城市污水和换水等工程措施,惠州西湖水体总氮和总磷有所下降。目前西湖水生生态系统处于逆向演替的藻形湖泊时期,其水生植物受到严重破坏,湖水的透明度等指标没有得到改善。研究结果表明,今后惠州西湖应走生态修复途径,生态系统的恢复与重建和非点源污染控制是关键。     

Assessing the potential for recovery of lakeshore vegetation: species richness of sediment propagule banks

To assess the potential and develop appropriate techniques for the recolonization of lakeshore vegetation at sites where it had been completely lost, a pilot project was launched at Lake Kasumigaura, Japan. We investigated the species composition and density of the soil seed banks (propagule banks) of lake sediments at nine sites (total area, 65,200 m²) where lake sediments were spread thinly (∼10 cm) on the surfaces of artificial littoral zones. These zones were constructed in front of concrete levees and had microtopographic variations. In total, 180 species, including six endangered or vulnerable species and 12 native submerged plants that had disappeared from the aboveground vegetation of the lake, were recorded during the first year of restoration. The distribution of each restored species at the sites suggested the importance of microtopographic variation for recolonizing species-rich lakeshore vegetation. Furthermore, the origin of the source sediment affected the species composition of the established vegetation.     

Restoration of urban green environments based on the theories of vegetation ecology

Modern cities and industrial areas are standardized, built of non-biological materials such as iron, cement and petrochemicals. The most desirable life for citizens should be both mentally and physically sound, which are the basis of existence for all lives. A multistratal forest is estimated to have 25–30 times the green surface area monostratal grass. With underground organic compounds, multistratal forests also contribute to the reduction of CO₂. Building facilities can be completed in short term with economic backing. But it takes biological time to regenerate a multistratal forest using living green construction materials. It is urgent to start the restoration and reconstruction of native green environments immediately. To form green environments of multistructure using plants, it is necessary to systematize the data from field investigations and to follow the scientific scenario based on potential natural vegetation. We propose the restoration of native forests, which function as disaster-prevention and environmental-preservation forests in urban and pre-urban areas. Native forests grow well with no management. With the ecological technique 600 sites have been successfully revegetated in the Japanese Archipelago, in Malaysia, Melaka, Kuala Lumpur, and Bangkok in Southeast Asia, and in Belem, Brazil, and Concepcion, Chile in South America.     

The role of ecological factors in controlling vegetation dynamics on long temporal scales

Abstract

The pattern of change in the Holocene forests of Europe is outlined and discussed in the light of external and internal forcing factors. Forests are seen as non-linear, dynamic systems, that are, at any point in time, unique and changing. In the absence of human activity, potential forcing factors during the Holocene include (i) climate, (ii) soil development, and (iii) internal forest dynamics. Climate is influential through exerting control on the floristic pool from which forests developed. Current results indicate that the role of soil development is likely to have been minor, but may have slowed rate of invasion and increase of some mid- and late-Holocene forest dominants. Forest change following spread and increase then forces soil change. Internal processes of forest dynamics include competition among existing species, and interactions between existing species and potential invading species. The patterns of interaction may be detectable through rates of change and patterns of increase seen in pollen records. Such processes are seen as being the dominant influence on the pattern of change and the development of forest. Forested systems, such as those in Europe, are strongly influenced by historical events, such as the mid-Holocene decline of elm. Forest composition is likely to be similar, in the broadest terms, from one interglacial to another, but always to vary in detail. The interaction of individuals, populations and environmental variables ensures that, although deterministic, prediction of change will always be difficult.