Plants distributed in riparian regions experience frequent episodes of flooding and drought between years, and hence, riparian plants need to be flood- and drought-tolerant. Riparian plants possess various traits to s...Plants distributed in riparian regions experience frequent episodes of flooding and drought between years, and hence, riparian plants need to be flood- and drought-tolerant. Riparian plants possess various traits to survive flooding, while their sensitivity to drought has received less attention. To investigate the growth and photosynthetic responses of a riparian species （Bolboschoenus planiculmis） to flooding and drought, plants of this species were subjected to 60-d flooding or drought stress under greenhouse conditions. Growth and photosynthetic traits were measured at the end of the treatments. As well, we determined the efficiency of photosynthetic apparatus in mature leaves. Plants of B. planiculmis adequately adjusted their growth and photosynthetic traits under both flooding and drought conditions. Flooding did not affect the above-ground growth of B. planiculmis. Increased growth of roots and rhizomes and the generation of new tubers suggested a high ability of below-ground lateral growth by capturing resources under flooding conditions. Enhanced photosynthetic capacity, retained leaf pigment concentrations and chlorophyll a fluorescence capacity indicated photosynthetic adaptation to flooding. In contrast, drought significantly decreased the above-ground growth of B. planiculmis, especially the leaves, thereby minimizing water loss due to transpiration. Its increased root to shoot ratio and ＂phalanx＂ asexual propagation pattern might enhance soil water uptake ability. Although the functional leaves of B. planiculmis could retain their leaf pigment concentrations, as well as photosynthesis and chlorophyll a fluorescence, the total biomass of plants decreased, which may be a consequence of the reduced leaf area, suggesting adverse effects by drought. Therefore, both growth and photosynthetic responses of B. planiculmis are likely to contribute to the ability of this species to thrive in riparian regions, but remain susceptive to drought.展开更多
The dynamic environments in riparian zones support a variety of life-history strategies, which constitute a fundamental mechanism for development and maintenance of biodiversity in riparian forest ecosystems. To demon...The dynamic environments in riparian zones support a variety of life-history strategies, which constitute a fundamental mechanism for development and maintenance of biodiversity in riparian forest ecosystems. To demonstrate the effect of life-history strategies on biodiversity, we investigated community-level diversity and its relationship to environmental variability in the riparian Populus euphratica forests of the Ejina Oasis. Communities were divided into 14 associations on the basis of their species impor- tance values. The Simpson＇s index, Shannon-Wiener index, Pielou＇s evenness index and the regional Whittaker＇s index were applied to calculate community diversity. An ordination of the sample plots was carried out by correspondence analysis （CA）. Biodiversity was relatively low across the entire study area, but there was high community diversity （flw = 8.09） due to the spatial heterogeneity of habitats in different plots. In addition, we investigated the relationship between biodiversity and several environmental factors, such as water availability, community components and soil conditions. We conclude that the heterogeneity of soil and water availability drives community diversity patterns in riparian zones and that community-level diversity favors the maintenance of species diversity in the P euphratica forests in the Ejina Oasis.展开更多
Ecological surveys were carried out to investigate the distribution and characterization of riparian corridor plants along the Perai River,Penang,Malaysia from July 2007 to March 2008.Surveys were design to represent ...Ecological surveys were carried out to investigate the distribution and characterization of riparian corridor plants along the Perai River,Penang,Malaysia from July 2007 to March 2008.Surveys were design to represent horizon-tal sections of the river starting from the river mouth towards the upper reaches for 20 km.A total of 84 species of plants from 30 families were recorded.They consisted of 28 species of standing plants(plants with height of more than 1 m)and 56 species of weedy plants(plants with height of less than 1 m).Standing plants consisted of ferns,palms,herbs,shrubs and mangroves while weedy plants comprised of aroids,grasses,sedges and broad leaf weed.Species abundance and dominance for each zone were relatively different.Dominant species was determined using Important Species Index(ISI).Based on ISI,the important species of standing plants were Sonneratia alba,Acrostichum aureum,Nypa fruti-cans,Avicennia marina,Rhizophora apiculata,Acrostichum speciosum and Rhizophora mucronata.Weedy plants were dominated by Mikania micrantha,Cryptocoryne ciliata,Wedelia trilobata and Asystasia intrusa.The distribution of the corridor plant species was closely related to the pattern of river water salinity measurements.The distribution of mangrove species with tolerance and adaptation to seawater appeared as follows:Avicennia marina,Rhizophora apiculata,Rhizo-phora mucronata,Sonneratia alba,Nypa fructicans,Acrostichum aureum and Acrostichum speciosum.展开更多
In order to determine the contribution of aquatic macrophyte communities on nutrition to sustain the high primary productivity of an estuary aquatic community, we analyzed the process of phosphorus release from sedime...In order to determine the contribution of aquatic macrophyte communities on nutrition to sustain the high primary productivity of an estuary aquatic community, we analyzed the process of phosphorus release from sediments in aquatic macrophyte community in the estuary of the Chikugogawa River, South-Western Japan. Vertical profile of PD3-4 concentration and redox potential (Eh) of pore water in sediments were investigated within and outside the Phragmites australis community. Sediment horizon lower than 23 cm layer from the surface showed anaerobic (Eh australis community, whereas sediment was constantly oxic (Eh > 0 mV) up to 50 cm depth outside the P. australis community without organic matter accumulation. Non-vegetated sediment with organic matter accumulation showed anoxic profile as vegetated site. PD3-4 concentration in anaerobic parts of sediment showed higher than oxic parts, and higher PD3-4 concentration in sediment pore water corresponded to sulfur deposition in sediment. Sulfate ion supplied from the sea water is reduced under the anoxic condition and S2- reacts with water-insoluble phosphorus salts e.g. Fe3(PO4)2 or AlPO4 and Fe2S3 or Al2S3 precipitates. Thus PD3-4 was mobilized and released under anoxic sediments. P. australis supply organic litter to sediment and the sediment within the P. australis community showed anoxic after aerobic decomposition of organic substances in sediment. Incubation of sediments under N2 atmosphere accumulated PD3-4 in the medium corresponding to low Eh (3-4 was released under anaerobic condition. Estuary P. australis community has function for supplying PD3-4 to river water.展开更多
Riparian areas in dryland crop regions of the Intermountain Pacific Northwest have largely been converted to cropland or pasture during the last 140 years. Some formerly cultivated floodplains have become difficult to...Riparian areas in dryland crop regions of the Intermountain Pacific Northwest have largely been converted to cropland or pasture during the last 140 years. Some formerly cultivated floodplains have become difficult to farm;enrollment of these lands into conservation programs provides the opportunity to use them as wildlife habitat and as buffer areas near streams. Our objective was to evaluate plant community development on an USDA Conservation Reserve Enhan- cement Program site in northeastern Oregon from when the plant was planted in 1999 through 2008. The research was designed as a descriptive study. We established permanent line-transects to quantify vegetation establishment and changes in species composition through time. We collected data in 2000-2001 and 2007-2008. Vegetation cover in 2000-2001 was 100%, dominated by tall wheatgrass. Living plant material cover decreased from 98% in 2000-2001 to 33% in 2007 and 68% in 2008;dead plant residue significantly increased and tall wheatgrass cover decreased. Native species were present in similar percentages from 2000 to 2008, although there was a shift from target to nontarget species. The 1999 seeding can be judged a success because of the ground cover provided and the establishment of one target species, tall wheatgrass. However, the increased ratio of dead to living plant material and shift to non-target annual weed species suggests that more active management (i.e., fire, grazing, or mowing) of the tall wheatgrass stand is needed to maintain its productivity and/or a healthy mix of multiple species.展开更多
River restoration activities are challenging for the native vegetation and the colonization process. The development of invasive alien plant species (IAS) as well as the development of the pioneer vegetation cover and...River restoration activities are challenging for the native vegetation and the colonization process. The development of invasive alien plant species (IAS) as well as the development of the pioneer vegetation cover and seed bank were observed in one year prior to construction of a new river bed and within the first two years after construction, along the downstream section of the river Traisen in Austria. One year after completion of the new river channel, the occurrence of IAS above ground decreased while the occurrence of target species increased. Furthermore, no seeds of IAS were detected in the new river bed as a result of proper management of soil movement. Despite the positive impact on the abundance of IAS, the restoration project of the river Traisen shows that the fact that such a restoration activity is a disturbance event must be taken into consideration already during the planning process. Supporting the competitiveness of native plant species is an important tool for reducing the danger of establishment of invasive alien species.展开更多
城市河岸带是城市最具生态效能和活力的空间,创造近自然植物群落能够提高城市的生物多样性,形成万物共生的可持续生态景观。国内外相关研究学者在积极探寻城市河岸带植物群落构建的方法和标准,但这方面的综述文章寥寥无几。在web of sci...城市河岸带是城市最具生态效能和活力的空间,创造近自然植物群落能够提高城市的生物多样性,形成万物共生的可持续生态景观。国内外相关研究学者在积极探寻城市河岸带植物群落构建的方法和标准,但这方面的综述文章寥寥无几。在web of science和中国知网数据库中查新国内外相关文献50余篇,评述了国内外城市河岸带植物群落构建现状以及近自然植物群落构建途径两方面研究进展,以期梳理整合城市河岸带植物群落构建现状与趋势,拓宽城市河岸带植物群落新视野,为城市河岸带植物群落构建研究的体系框架提供研究思路。展开更多
基金supported by the Forestry Commonwealth Project (Grant No. 201004078)the National Science Foundation of China (Grant No.31200314)
文摘Plants distributed in riparian regions experience frequent episodes of flooding and drought between years, and hence, riparian plants need to be flood- and drought-tolerant. Riparian plants possess various traits to survive flooding, while their sensitivity to drought has received less attention. To investigate the growth and photosynthetic responses of a riparian species （Bolboschoenus planiculmis） to flooding and drought, plants of this species were subjected to 60-d flooding or drought stress under greenhouse conditions. Growth and photosynthetic traits were measured at the end of the treatments. As well, we determined the efficiency of photosynthetic apparatus in mature leaves. Plants of B. planiculmis adequately adjusted their growth and photosynthetic traits under both flooding and drought conditions. Flooding did not affect the above-ground growth of B. planiculmis. Increased growth of roots and rhizomes and the generation of new tubers suggested a high ability of below-ground lateral growth by capturing resources under flooding conditions. Enhanced photosynthetic capacity, retained leaf pigment concentrations and chlorophyll a fluorescence capacity indicated photosynthetic adaptation to flooding. In contrast, drought significantly decreased the above-ground growth of B. planiculmis, especially the leaves, thereby minimizing water loss due to transpiration. Its increased root to shoot ratio and ＂phalanx＂ asexual propagation pattern might enhance soil water uptake ability. Although the functional leaves of B. planiculmis could retain their leaf pigment concentrations, as well as photosynthesis and chlorophyll a fluorescence, the total biomass of plants decreased, which may be a consequence of the reduced leaf area, suggesting adverse effects by drought. Therefore, both growth and photosynthetic responses of B. planiculmis are likely to contribute to the ability of this species to thrive in riparian regions, but remain susceptive to drought.
基金supported by the National Natural Science Foundation of China (No. 30570332)the 11th Five-Year Plan of the National Scientific and Technological Support Projects (2008BADB0B05)
文摘The dynamic environments in riparian zones support a variety of life-history strategies, which constitute a fundamental mechanism for development and maintenance of biodiversity in riparian forest ecosystems. To demonstrate the effect of life-history strategies on biodiversity, we investigated community-level diversity and its relationship to environmental variability in the riparian Populus euphratica forests of the Ejina Oasis. Communities were divided into 14 associations on the basis of their species impor- tance values. The Simpson＇s index, Shannon-Wiener index, Pielou＇s evenness index and the regional Whittaker＇s index were applied to calculate community diversity. An ordination of the sample plots was carried out by correspondence analysis （CA）. Biodiversity was relatively low across the entire study area, but there was high community diversity （flw = 8.09） due to the spatial heterogeneity of habitats in different plots. In addition, we investigated the relationship between biodiversity and several environmental factors, such as water availability, community components and soil conditions. We conclude that the heterogeneity of soil and water availability drives community diversity patterns in riparian zones and that community-level diversity favors the maintenance of species diversity in the P euphratica forests in the Ejina Oasis.
基金supported by RESTORPEAT (European Commission Research Grant,304 /Pbio/650248/E104)
文摘Ecological surveys were carried out to investigate the distribution and characterization of riparian corridor plants along the Perai River,Penang,Malaysia from July 2007 to March 2008.Surveys were design to represent horizon-tal sections of the river starting from the river mouth towards the upper reaches for 20 km.A total of 84 species of plants from 30 families were recorded.They consisted of 28 species of standing plants(plants with height of more than 1 m)and 56 species of weedy plants(plants with height of less than 1 m).Standing plants consisted of ferns,palms,herbs,shrubs and mangroves while weedy plants comprised of aroids,grasses,sedges and broad leaf weed.Species abundance and dominance for each zone were relatively different.Dominant species was determined using Important Species Index(ISI).Based on ISI,the important species of standing plants were Sonneratia alba,Acrostichum aureum,Nypa fruti-cans,Avicennia marina,Rhizophora apiculata,Acrostichum speciosum and Rhizophora mucronata.Weedy plants were dominated by Mikania micrantha,Cryptocoryne ciliata,Wedelia trilobata and Asystasia intrusa.The distribution of the corridor plant species was closely related to the pattern of river water salinity measurements.The distribution of mangrove species with tolerance and adaptation to seawater appeared as follows:Avicennia marina,Rhizophora apiculata,Rhizo-phora mucronata,Sonneratia alba,Nypa fructicans,Acrostichum aureum and Acrostichum speciosum.
文摘In order to determine the contribution of aquatic macrophyte communities on nutrition to sustain the high primary productivity of an estuary aquatic community, we analyzed the process of phosphorus release from sediments in aquatic macrophyte community in the estuary of the Chikugogawa River, South-Western Japan. Vertical profile of PD3-4 concentration and redox potential (Eh) of pore water in sediments were investigated within and outside the Phragmites australis community. Sediment horizon lower than 23 cm layer from the surface showed anaerobic (Eh australis community, whereas sediment was constantly oxic (Eh > 0 mV) up to 50 cm depth outside the P. australis community without organic matter accumulation. Non-vegetated sediment with organic matter accumulation showed anoxic profile as vegetated site. PD3-4 concentration in anaerobic parts of sediment showed higher than oxic parts, and higher PD3-4 concentration in sediment pore water corresponded to sulfur deposition in sediment. Sulfate ion supplied from the sea water is reduced under the anoxic condition and S2- reacts with water-insoluble phosphorus salts e.g. Fe3(PO4)2 or AlPO4 and Fe2S3 or Al2S3 precipitates. Thus PD3-4 was mobilized and released under anoxic sediments. P. australis supply organic litter to sediment and the sediment within the P. australis community showed anoxic after aerobic decomposition of organic substances in sediment. Incubation of sediments under N2 atmosphere accumulated PD3-4 in the medium corresponding to low Eh (3-4 was released under anaerobic condition. Estuary P. australis community has function for supplying PD3-4 to river water.
文摘Riparian areas in dryland crop regions of the Intermountain Pacific Northwest have largely been converted to cropland or pasture during the last 140 years. Some formerly cultivated floodplains have become difficult to farm;enrollment of these lands into conservation programs provides the opportunity to use them as wildlife habitat and as buffer areas near streams. Our objective was to evaluate plant community development on an USDA Conservation Reserve Enhan- cement Program site in northeastern Oregon from when the plant was planted in 1999 through 2008. The research was designed as a descriptive study. We established permanent line-transects to quantify vegetation establishment and changes in species composition through time. We collected data in 2000-2001 and 2007-2008. Vegetation cover in 2000-2001 was 100%, dominated by tall wheatgrass. Living plant material cover decreased from 98% in 2000-2001 to 33% in 2007 and 68% in 2008;dead plant residue significantly increased and tall wheatgrass cover decreased. Native species were present in similar percentages from 2000 to 2008, although there was a shift from target to nontarget species. The 1999 seeding can be judged a success because of the ground cover provided and the establishment of one target species, tall wheatgrass. However, the increased ratio of dead to living plant material and shift to non-target annual weed species suggests that more active management (i.e., fire, grazing, or mowing) of the tall wheatgrass stand is needed to maintain its productivity and/or a healthy mix of multiple species.
文摘River restoration activities are challenging for the native vegetation and the colonization process. The development of invasive alien plant species (IAS) as well as the development of the pioneer vegetation cover and seed bank were observed in one year prior to construction of a new river bed and within the first two years after construction, along the downstream section of the river Traisen in Austria. One year after completion of the new river channel, the occurrence of IAS above ground decreased while the occurrence of target species increased. Furthermore, no seeds of IAS were detected in the new river bed as a result of proper management of soil movement. Despite the positive impact on the abundance of IAS, the restoration project of the river Traisen shows that the fact that such a restoration activity is a disturbance event must be taken into consideration already during the planning process. Supporting the competitiveness of native plant species is an important tool for reducing the danger of establishment of invasive alien species.
文摘城市河岸带是城市最具生态效能和活力的空间,创造近自然植物群落能够提高城市的生物多样性,形成万物共生的可持续生态景观。国内外相关研究学者在积极探寻城市河岸带植物群落构建的方法和标准,但这方面的综述文章寥寥无几。在web of science和中国知网数据库中查新国内外相关文献50余篇,评述了国内外城市河岸带植物群落构建现状以及近自然植物群落构建途径两方面研究进展,以期梳理整合城市河岸带植物群落构建现状与趋势,拓宽城市河岸带植物群落新视野,为城市河岸带植物群落构建研究的体系框架提供研究思路。
