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Hydrological alteration and biodiversity change along the river network caused by anthropogenic activities and climate variability

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Ecological Processes 2022年第1期11卷 189-205页

作者： Farshid Zolfagharpour Bahram Saghafian Majid Delavar Department of Civil Engineering Science and Research BranchIslamic Azad UniversityTehranIran Department of Water Resources Engineering Tarbiat Modares UniversityTehranIran

Background:Population growth and intensified human activities in conjunction with climate variability continue to affect the hydrologic cycle,aquatic and terrestrial flora and *** this regard,understanding interactions among ecosystem functions,impacts of anthropogenic interventions and those of climate variability is vital for projecting future ecosystem responses to human activities and climate *** objectives of this study are to determine the ecological flow state via eco-flow index based on discharge hydrograph,to model the ecological diversity through the shannon diversity index,and to assess the degree of hydrologic alteration using indicators of hydrologic alteration and range of variability approach in six hydrometric stations along the Zayandeh-Rud River in central *** river drains into Gavkhuni ***,the streamflow-induced potential changes for Capoeta damascina(a cyprinid fish species of the genus Capoeta),Petroleuciscus esfahani(a small cyprinid fish)and Aphanius isfahanensis(a Cyprinodontid fish)are *** outcome is expected to assist managers with understanding the effects of anthropogenic activities and climate variability on Gavkhuni aquatic ecosystems so that management options that enhance species resilience and adaptability are ***:Human activities,a primary factor influencing the natural flow regime,caused a significant increase in the minimum flow,July to March streamflow,low pulse number,and the number of reversals in most studied *** the contrary,some other hydrologic indices declined in *** impoundment,the most prominent factor among human interventions,resulted in an overall alteration degree of 74.8%in *** variability impacted the natural flow regime in the range of low degree hydrologic alteration(27.3%).In addition,the biodiversity of the study basin,as modeled by the shannon diversity index,had strong relevance to the annual eco-surplus and was more sensitive

关键词： Eco-flow shannon diversity index Human activity Indicators of hydrologic alteration Natural flow regime Range of variability Zayandeh-Rud River

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Thinning intensity affects microbial functional diversity and enzymatic activities associated with litter decomposition in a Chinese fir plantation

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Journal of Forestry Research 2018年第5期29卷 1337-1350页

作者： Wenya Xiao Fei Fei Jiaojiao Diao Bin J.W.Chen Qingwei Guan Department of Ecology College of Biology and the EnvironmentNanjing Forestry University Collaborative Innovation Center for Sustainable Forestry in Southern China of Jiangsu Province Nanjing Forestry University

Microbial functional diversity and enzymatic activities are critical to maintaining material circulation during litter decomposition in ***,an important and widely used silvicultural treatment,changes the microclimate and promotes forest ***,how thinning affects microbial functional diversity and enzymatic activities during litter decomposition remains poorly *** conducted thinning treatments in a Chinese fir plantation in a subtropical region of China with four levels of tree stem removal（0,30,50,and 70%）,each with three replicates,and the effects of thinning on microbial functional diversity and enzymatic activities were studied 7 years after treatment by collecting litter samples four times over a 1-year *** functional diversity and enzymatic activities were analyzed using Biolog Ecoplates（Biolog Inc.,Hayward,CA,USA）based on the utilization of 31 carbon *** microbial abundance during litter decomposition was lower after the thinning treatments than without *** functional diversity did not differ significantly during litter decomposition,but the types of microbial carbon-source utilization did differ significantly with the thinning *** cellulase and invertase activities during litter decomposition were significantly higher under the thinning treatments due to changes in the litter carbon concentration and the ratios of carbon and lignin to *** present study demonstrated the important influence of thinning on microbial activities during litter ***-intensity thinning may maximize vegetation diversity and,in turn,increase the available substrate sources for microbial organisms in litter and promote nutrient cycling in forest ecosystems.

关键词： Biology technology Litter decomposition Microbial enzymatic activities shannon diversity index

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Spatial pattern of tree diversity and evenness across forest types in Majella National Park,Italy

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Forest Ecosystems 2015年第4期2卷 304-313页

作者： Mohammad Redowan Department of Forestry and Environmental Science Shahjalal University of Science and Technology

Background： Estimation of tree diversity at broader scale is important for conservation planning. Tree diversity should be measured and understood in terms of diversity and evenness, two integral components to describe the structure of a biological community. Variation of the tree diversity and evenness with elevation, topographic relief, aspect, terrain shape, slope, soil nutrient, solar radiation etc. are well documented. Methods： Present study explores the variation of tree diversity （measured as shannon diversity and evenness indices） of Majella National Park, italy with five available forest types namely evergreen oak woods, deciduous oak woods, blacWaleppo pine stands, hop-hornbeam forest and beech forest, using satellite, environmental and field data. Results： Hop-hornbeam forest was found to be most diverse and even while evergreen Oak woods was the lowest diverse and even. diversity and evenness of forest types were concurrent to each other i.e. forest type which was more diverse was also more even. As a broad pattern, majority portion of the study area belonged to medium diversity and high evenness class. Conclusions： Satellite images and other GIS data proved useful tools in monitoring variation of tree diversity and evenness across various forest types. Present study findings may have implications in prioritizing conservation zones of high tree diversity at Majella.

关键词： Tree diversity Tree evenness Forest type shannon diversity index shannon evenness index Neural network Kappa statistic

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Exotic Plant Alnus trabeculosa Alters the Composition and diversity of Native Rhizosphere Bacterial Communities of Phragmites australis

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Pedosphere 2016年第1期26卷 108-119页

作者： CHEN Xueping ZHANG Xuanxuan ZHU Xi'e ZHANG Hui LIANG Xia LEI Yanru HE Chiquan School of Environmental and Chemical Engineering Shanghai University Shanghai Key Laboratory of Bio-Energy Crops Shanghai University

Alnus trabeeulosa, a rhizobia-nodulating tree, was introduced into the Chongxi tidal wetland in the Yangtze River estuary of China to increase the biodiversity of plants and restore tidal wetland functions. However, the effect of the introduced plant on soil bacterial communities and restoration outcomes remains unknown. In this study, the rhizosphere bacterial community structure and diversity were compared between Phragrnites australis monospecific community and A. trabeculosa-P, australis mixed communities, aiming to assess whether A. trabeculosa influenced the rhizosphere bacterial communities of P. australis and to investigate whether different taxonomic groups within a soil community may respond similarly to the presence of an introduced exotic plant. Among the 14 phylogenetic phyla detected, Proteobacteria and Acidobacteria were the dominant bacterial taxa in the rhizosphere. Phylogenetic analysis of the predominant Proteobacteria showed that the clones from the rhizosphere soils of A. trabeculosa and P. australis in A. trabeculosa-P, australis mixed communities were more diverse than those in the rhizosphere soil of P. australis in P. australis monospecific community. The rhizosphere community in the wetland potentially included active microbial community related to carbon, nitrogen, and sulfur cycling in the Yangtze River estuary. The rhizosphere soil of P. australis in A. trabeculosa-P, australis mixed communities exhibited the highest shannon diversity index （Hr） and Simpson diversity index （l/D）（H = 4.52, 1/D = 253）. Correspondence analyses revealed that the bacterial community structures were altered after A. trabeculosa was introduced.

关键词： clone library phylogenetic group restoration outcomes rhizosphere soil microbial index shannon diversity index Simpson diversity index 16S rRNA gene wetland restoration

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