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Increased community compositional dissimilarity alleviates species loss following nutrient enrichment at large spatial scales

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Journal of Plant Ecology 2019年第2期12卷 376-386页

作者： Xiaolong Zhou Xudong Liu Pengfei Zhang Zhi Guo Guozhen Du Institute of Arid Ecology and Environment Xinjiang UniversityShengli Road No.666Urumqi 830046XinjiangChina Key Laboratory of Oasis Ecology Xinjiang UniversityShengli Road No.666Urumqi 830046XinjiangChina State Key Laboratory of Grassland and Agro-ecosystems School of Life SciencesLanzhou UniversitySouthern Tianshui Road No.222Lanzhou 730000GansuChina

Aims Anthropogenic activities have drastically increased nutrient availabil-ity,resulting in declines in species richness in many plant ***,most previous studies have explored only species-loss patterns and mechanisms over small sampling areas,so their results might overestimate species loss at larger spatial *** aim of this research was to explore species diversity change patterns and species-loss rates at multiple scales in alpine meadow communities following nutrient ***,we asked two closely related ques-tions:(i)do changes in species diversity and species-loss patterns differ among spatial scales?and(ii)how does community compositional dissimilarity and species turnover change among spatial scale?Methods This study was implemented in an alpine meadow community,which is regarded as one of the most sensitive and vulnerable ter-restrial ecosystems to anthropogenic nutrient *** conducted a fertilization experiment that involved the addition of nitrogen(N),phosphorus(P)and a mixture of both to a series of quadrats ranging from 1 to 16 m2 over 5 years to study the variations in the patterns of species diversity in response to nutrient additions at different spatial *** Findings Our results showed that the changes in species diversity and species loss were dependent on the type of fertilization and the spatial *** N and NP fertilization,species diversity significantly decreased at the small scale but not at the large scale,and the rate of species loss decreased as the spatial scale *** contrast,the differences between the P addition and control communities were negligible at both the small and large spatial scales.N fertilization caused species to be lost from the small sampling scale,but because different species were lost from dif-ferent samples,there was an increase in compositional dissimilarity at larger spatial scales,which reduced the total number of species lost when measured at

关键词： spatial scale species loss nutrient enrichment compositional dissimilarity

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nutrient enrichment and Saline Conditions Decreases Growth and Photosynthesis of the Mangrove Heritiera littoralis Dryand

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Open Journal of Marine Science 2016年第2期6卷 293-301页

作者： Mwita M. Mangora Institute of Marine Sciences University of Dar es Salaam Zanzibar Tanzania

Inundation associated with flooding and sea level rise is predicted to have major impacts on survival, growth and productivity of mangroves. A manipulative mesocosm experiment was conducted to assess whether nutrient enrichment enhances growth and photosynthesis of waterlogged and salinity stressed seedlings of the mangrove Heritiera littoralis Dryand. Seedlings were fertilized with a three-component granular farm NPK (Nitrogen-Phosphorous-Potassium, 20:20:20) at varied loads under waterlogging with four levels of salinity. Growth was assessed through biomass accumulation, and photosynthesis through photosynthetic quantum yield and leaf Chl content. When seedlings were exposed to both nutrient enrichment and increased salinity, a significant shift of biomass to roots was observed. Seedlings had low value of Chl a/b ratio and photosynthetic distraction resulting in mortality was high in the highest salinity and nutrient levels. These results are useful in explaining failure of regeneration in natural stands of riverine and freshwater bound mangroves following unprecedented flooding events that accrue land based nutrient loads into estuaries and deltas.

关键词： Heritiera littoralis Mangrove Seedlings nutrient enrichment Salinity Waterlogging

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Mechanisms and assessment of water eutrophication

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2008年第3期9卷 197-209页

作者： Xiao-e YANGt Xiang WU Hu-lin HAO Zhen-li HE MOE Key Laboratory of Polluted Environment Remediation and Ecological Health Zhejiang University Hangzhou 310029 China Zhejiang Provincial Key Laboratory of Subtropic Soil and Plant Nutrition Zhejiang University Hangzhou 310029 China Slnstitute of Food and Agricultural Sciences lndian River Research and Education Center University of Florida Fort Pierce FL 34945 USA

Water eutrophication has become a worldwide environmental problem in recent years,and understanding the mechanisms of water eutrophication will help for prevention and remediation of water *** this paper,recent advances in current status and major mechanisms of water eutrophication,assessment and evaluation criteria,and the influencing factors were *** eutrophication in lakes,reservoirs,estuaries and rivers is widespread all over the world and the severity is increasing,especially in the developing countries like *** assessment of water eutrophication has been advanced from simple individual parameters like total phosphorus,total nitrogen,etc.,to comprehensive indexes like total nutrient status *** major influencing factors on water eutrophication include nutrient enrichment,hydrodynamics,environmental factors such as temperature,salinity,carbon dioxide,element balance,etc.,and microbial and *** occurrence of water eutrophication is actually a complex function of all the possible influencing *** mechanisms of algal blooming are not fully understood and need to be further investigated.

关键词： Eutrophication mechanisms Influencing factors nutrient enrichment Assessment criterion Water quality

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Selenium,fibre,and protein enrichment of rice product:extrusion variables and product properties

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Food Quality and Safety 2019年第1期3卷 40-51页

作者： Pipat Tangjaidee Jiqian Xiang Hongqing Yin Xiaolong Wen Siew Young Quek Food Science School of Chemical ScienceUniversity of AucklandAuckland 1010New Zealand Enshi Tujia&Miao Autonomous Prefecture Academy of Agricultural Sciences Enshi CityHubei Province 445002P.R.China Riddet Institute Centre of Research Excellence for Food ResearchPalmerston North 4474New Zealand

Objectives:Rice has been identified as a high glycemic index(GI)food associated with obesity and *** study investigated the replacement of rice flour and its effect on product properties using extrusion *** and Methods:High selenium yam and konjac flours were used to increase fibre and selenium contents,whereas sorghum and soy protein were added to improve protein content as well as textural properties of *** following variables were optimized:yam flour(20%to 60%),feed moisture content(25%to 35%),and extrusion temperature(100°C to 120°C)by evaluating the breaking strength,firmness,colour,bulk density,and water absorption index(WAI)of the extruded ***:Results show that the extrusion temperature has a significant relationship with the products’breaking strength,WAI,and bulk density,whereas the feed moisture content influenced the WAI,bulk density,and firmness(Pnutrient enrichment via rice flour substitution.

关键词： extrusion nutrient enrichment rice product selenium fibre glycemic index

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Effects of experimental season of prescribed fire and nutrient addition on structure and function of previously grazed grassland

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Journal of Plant Ecology 2018年第4期11卷 576-584页

作者： Elizabeth H.Boughton Patrick J.Bohlen Julia H.Maki MacArthur Agro-ecology Research Center 300 Buck Island Ranch RoadLake PlacidFL 33852USA University of Central Florida Biology 4110 Libra DriveOrlandoFL 32816USA School of Natural Resources and Environment University of Florida103 Black HallPO Box 116455GainesvilleFL 32611USA

Aims Understanding the drivers of grassland structure and function fol-lowing livestock removal will inform grassland restoration and ***,we investigated the effects of fire and nutri-ent addition on structure and function in a subtropical semi-native grassland recently released from grazing in south-central *** examined responses of soil nutrients,plant tissue nutrients,bio-mass of live,standing dead and litter,and plant species composi-tion to experimental annual prescribed fire applied during different seasons(wet season *** season),and nutrient additions(N,P and N+P)over 9 *** Experimental plots were set up in a randomized block split-plot design,with season of prescribed fire as the main treatment and nutrient addition as the subplot *** cover data were collected annually from 2002 to 2011 and plant tissue and plant biomass data were collected in 2002-2006 and *** nutrients were analyzed in 2004,2006 and *** Findings Soil total phosphorus(P)levels increased substantially with P addition but were not influenced by prescribed *** of P and N led to increased P and N concentrations in live plant tissues,but prescribed fire reduced N in live *** of tissue N were higher in all plots at the beginning of the exper-iment,an effect that was likely due to grazing activity prior to removal of *** tissue N steadily declined over time in all plots,with annually burned plots declining faster than unburned *** fire was an important driver of standing dead and litter biomass and was important for main-taining grass biomass and percent *** addition was also important:the addition of both N and P was associated with greater live biomass and woody *** of grazing,lack of prescribed fire,and addition of N+P led to a reduction of grass biomass and a large increase in biomass of a woody *** prescribed fire promoted N loss from the system by reducing

关键词： grassland nutrient enrichment nutrient limitation prescribed fire productivity

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Seasonal Variability of Phytoplankton Community Structure in Relation to Different Nitrogen-Phosphorus Ratios in the Southern Coastal Waters of Zhejiang, China

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Journal of Ocean University of China 2013年第4期12卷 577-588页

作者： HUANG Wei ZHU Xuyu CHEN Quanzhen HE Qing LIAO Yibo DU Ping ZHANG Peng ZENG Jiangning Laboratory of Marine Ecosystem and Biogeochemistry Second Institute of Oceanography State Oceanic Administration College of Fisheries and Life Science Shanghai Ocean University Zhejiang Mariculture Research Institute

With the rapid development of economy and increase of population in the drainage areas, the nutrient loading has increased dramatically in the Changjiang estuary and adjacent coastal waters. To properly assess the impact of nutrient enrichment on phytoplankton community, seasonal microcosm experiments were conducted during August 2010-July 2011 in the coastal waters of Zhejiang Province. The results of the present study indicated that the chl a concentration, cell abundance, diversity indices, species composition and community succession of the phytoplankton varied significantly with different N/P ratios and seasons. Higher growth was observed in the 64：1 （spring）, 32：1 （summer）, 16：1 （autumn） and 128：1,256：1 （winter） treatments, respectively. The values of Shannon-Wiener index （H） and Pielou evenness index （J） were lower in the 8：1 and 16：1 treatments in autumn test, while H value was higher in the 128：1 and 8：1 treatments in winter test. A definite community succession order from diatoms to dinoflagel lares was observed in the autumn and winter tests, while the diatoms dominated the community throughout the culture in the spring and summer tests.

关键词： phytoplankton community succession nutrient enrichment Shannon-Wiener index Pielou evenness index nitrogen-phosphorus ratio

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Biomass allocation between leaf and stem regulates community-level plant nutrient resorption efficiency response to nitrogen and phosphorus additions in a temperate wetland of Northeast China

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Journal of Plant Ecology 2021年第1期14卷 58-66页

作者： Yun Zhang Gui-Sheng Yang Fu-Xi Shiu Rong Mao Key Laboratory of National Forestry Administration on Forest Ecosystem Protection and Restoration of Poyang Lake Watershed College of ForestryJiangxi Agricullural UniversityNanchang 330045China Wuyishanxipo Observation and Research Station of Forest Ecosystem Zixi 335300China Environment and Plant Protection Institute Chinese Academy of Tropical Agricultural ScienceHaikou 571101China

Aims nutrient resorption is a crucial component of plant nutrient use strategy,yet the controls on the responses of community-level nutrient resorption to altered nutrient availability remain ***,we addressed two questions:(1)Did leaf and stem nutrient resorption respond consistently to increased nutrient availability?(2)Was community-level plant nutrient resorption response after nutrient enrichment driven by the intraspecific plasticity in plant nutrient resorption or by altered species composition?Methods We investigated the changes in aboveground biomass,and leaf and stem nutrient resorption of individual species after 3-year nitrogen(N)and phosphorus(P)additions,and assessed community-level nutrient resorption response to 3-year nutrient additions in a graminoid-dominated temperate wetland,Northeast *** Findings For both leaves and stems,N and P additions did not affect nutrient resorption efficiency,but they decreased respective nutrient resorption ***,community-level N and P resorption proficiency declined with respective nutrient ***-level N and P resorption efficiency was reduced by N addition primarily due to altered community composition and declined leaf:stem *** results suggest that leaf and stem nutrient resorption processes exhibit consistent responses to increasing nutrient availability in the temperate *** findings highlight the importance of altered species composition and biomass allocation between leaf and stem in driving community-level nutrient resorption response to nutrient enrichment.

关键词： leaf:stem ratio nutrient enrichment nutrient resorption proficiency nutrient use strategy species composition

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Recent Trends of Zostera marina (Eelgrass) in a Highly Eutrophic Coastal Lagoon in the Mid-Atlantic Region (USA)

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Open Journal of Ecology 2016年第5期6卷 243-253页

作者： Michael J. Kennish Gregg P. Sakowicz Benjamin Fertig Department of Marine and Coastal Sciences Rutgers University New Brunswick USA Jacques Cousteau National Estuarine Research Reserve Tuckerton USA Ronin Institute for Independent Scholarship Montclair USA Department of Biology University of Maryland College Park Maryland USA

Spatial and temporal characteristics of Zostera marina (eelgrass) in the Barnegat Bay-Little Egg Harbor Estuary are compared before (2004-2011) and after (2012-2013) major fertilizer legislation (Fertilizer Law A2290) was enacted in New Jersey (USA) to reduce nutrient inputs from fertilizers to water bodies in the state. A significant decrease of Z. marina biomass and areal cover occurred in this eutrophic estuary between 2004 and 2011 concomitantly with increasing nitrogen and phosphorus loading from the watershed. The rate of decline in aboveground and belowground biomass was significantly sharper during 2004-2006 than during 2008-2010. In 2010, Z. marina biomass dropped to a very low level (mean aboveground biomass = 7.7 g dry wt mǄmean belowground biomass = 27.0 g dry wt mǄ), persisting through the last sampling period (October-November) in 2013. Biomass and areal cover of Z. marina decreased even further after Fertilizer Law A2290 was enacted in January 2012, with the lowest values recorded from August to November each year. These low values are the result of ongoing eutrophication of the system. More seagrass monitoring and research are necessary in future years to determine if the fertilizer law will have a positive effect on Z. marina condition in the estuary over the long term.

关键词： Barnegat Bay-Little Egg Harbor Estuary Coastal Lagoon nutrient enrichment Eutrophication Zostera marina Characteristics nutrient Reduction Regulation

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Water Quality Characterisation and Restoration Measures of University of Nottingham Malaysia Campus (UNMC) Lake

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Journal of Environmental Protection 2016年第4期7卷 481-489页

作者： Doris Ifeoma Ogueri Mohammed S. Gumsuri School of Geography University of Nottingham Malaysia Campus Semenyih Malaysia

nutrient enrichment has been identified as the major cause of University of Nottingham Malaysia Campus (UNMC) Lake’s water quality degradation. This study critically examines the nature, source and delivery of nutrients into the lake and observes that uncontrolled anthropogenic activities along the catchment area are the major sources. The chemical analyses of the water samples drawn from different sampling points were carried out in the laboratory and the total phosphorus readings were in the range of 20 to 55.7 μg/L with the inflow 1 recording the highest level. The chlorophyll a concentrations in the lake water were between 39 to 65 μg/L which exceeded Malaysian water quality standard. However, the silicate and nitrate levels were found to be in lower concentrations. Dissolved oxygen and pH readings obtained through in situ measurements in the lake water showed that there was oxygen depletion in the water during the night while it increased during the day, also the lake was acidic in the night and became alkaline in the day. All the findings were integrated to draw realistic restoration goals for the lake.

关键词： Lake Water Quality nutrient enrichment University of Nottingham Restoration Drainage Chlorophyll Malaysia

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Effects of Continuous Cropping of Panax notoginseng on the Properties of Rhizosphere Soil

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Agricultural Science & Technology 2017年第4期18卷 602-606页

作者： Kaiming LI Meixiang LIU Qianhui SUN Zilong ZHANG School of Life Science Beijing University of Chinese Medicine Beijing 100102 China School of Chinese Materia Medica Beijing University of Chinese Medicine Beijing 100102 China School of Basic Medical Science Beijing University of Chinese Medicine Beijing 100102 China

[Objective] This experiment aimed to investigate the effects of continuous cropping of Panax notoginseng on the properties of rhizosphere soil. [Method] A total of 12 rhizospheres oil samples were collected in the fields continuously cropped with P. notoginseng for different years and the soil properties including pH value, contents of available N, available K, available P,total N, total K, total P and organic matter were determined. [Result] With the increase in the number of years of continuous cropping, seven soli indices: soil pH value, organic matter content, total N, total P, total K, available P and available K gradually increased, while available N showed a gradual downward trend. The contents of organic matter content, total N, total P, total K,available P, available K and available N after three years of continuous cropping were increased by 74.93%, 65.85%, 123.82%,18.78%, 341.67%, 120.16% and-32.16%, respectively, indicating that continuous cropping of P. notoginseng resulted in nutrient enrichment in rhizosphere soils. The pH value and available N in IBC(soil inside the border check) and UBC(soil under the border check) were higher than that in BBC(soil beside the border check), suggesting that the soil was gradually alkalized due to the continuous cropping of P. notoginseng. [Conclusion] These results suggest that pH change and nutrient imbalance may be the obstacles to the continuous cropping of P. notoginseng.

关键词： Continuous cropping Correlation nutrient enrichment Panax notoginseng Soil properties

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