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Diversity, Abundance, Richness, and Birds of Conservation Interest in Nyando Sugar Belt, Muhoroni Sub-County, Lake Victoria Basin, Western Kenya 预览
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作者 Daniel Mokaya Mogaka Shadrack Muya +1 位作者 Francis Ndwigah Paul Ndang’ang’a 《动物科学期刊(英文)》 2019年第3期268-285,共18页
Thus far, no expedition has comprehensively surveyed the composition of bird species in the dilapidated habitats of Nyando sugar belt, Western Kenya. This has made it difficult unearthing equilibrium between agricultu... Thus far, no expedition has comprehensively surveyed the composition of bird species in the dilapidated habitats of Nyando sugar belt, Western Kenya. This has made it difficult unearthing equilibrium between agricultural growth and bird species conservation. In response, we conducted bird assessment by stratifying the expedition area into farmlands and shrub-land. We then sampled birds by the standard point count method and opportunistic counts within a 30 m radius parcel of land. We exhaustively observed 1450 birds of 122 species. The farmland recorded a density of 2.065 ± 1.11 birds per hectare whereas the shrub-land had a density of 1.644 ± 0.70 birds per hectare. Nyando sugar belt was a diverse community with a Shannon diversity index value (H’) of 3.225 regardless of the birds being constrained in certain habitats. The magnitude of the disparity in true diversity indicated that the farmland was 4 times more diverse than the shrub-land. The facts promoted by this research validate the incorporation of bird conservation in the farmland and formulation of avian conservation strategies. 展开更多
关键词 DIVERSITY ABUNDANCE Richness BIRDS Nyando CONSERVATION Migration Forest DEPENDENCY Kenya
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Population Density, Diversity and Abundance of Antelope Species in Kainji Lake National Park, Nigeria 预览
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作者 Olajesu Sunday Oladipo Akinyemi Abiodun Folorunso +1 位作者 Lateef Funmilayo Lewiska Lameed Gbolagade Akeem 《生态学期刊(英文)》 2019年第4期107-116,共10页
Habitat degradation and fragmentation are eating deep into conservation areas and this is a serious threat to species diversity and abundance. Species like the antelopes have a sedentary and docile nature which makes ... Habitat degradation and fragmentation are eating deep into conservation areas and this is a serious threat to species diversity and abundance. Species like the antelopes have a sedentary and docile nature which makes them highly vulnerable to habitat degradation or human intrusion. The effect becomes complex as the remaining flora and fauna communities can be significantly impacted by changes in ecosystem structure and function. Population density, diversity and abundance of fauna species will either increase or decrease over time depending on the quality of the environment/habitat and the level of human interference or disturbance. Hence an updated checklist of species diversity and abundance is necessary to enable management and other stakeholders make pragmatic plans and policy towards sustainable species conservation. With the aid of a Global Positioning System (GPS), a 5 km transect was established per site and censured for Antelope species using the King Census method of enumeration. Descriptive statistics and ANOVA was used to analyze the data. Seven (7) species of Antelopes were recorded. Kobs (Kobus kob) were the most abundant (2019), while Reedbuck (Redunca redunca) was the least abundant with twenty-five (25) individuals. Kob is the most observed species in Oli Complex with 24.13%, ranking about 50% of kob in proportion. This was followed by roan antelope (Hippotragus equinus), and Red Flanked duiker, 4.02% and 3.63% respectively. Kobs had the highest density of 40.38 per square km followed by roan antelope (3.32) and RF duiker (2.36). Relative density followed a similar trend. The least encounter rate was observed in Sylvicapra grimmia (0.02) and increse further to Hippotragus equinus (0.4), Redunca redunca (0.06) and Alcelaphus buselaphus (0.09) respectively. It was low amongst Tragelaphus scriptus (0.2), and moderate, while it was very high amongst the kobs (5.0). The rate of encountering an antelope in the park is very high at a rate of 6.2 animals per kilometer. Species of antelopes are almost not 展开更多
关键词 Kainji LAKE National PARK ANTELOPES Density DIVERSITY ABUNDANCE
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Avian Abundance, Diversity and Conservation Status in Etago Sub-County Kisii County Kenya 预览
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作者 Mokono M. Isaac Shadrack M. Muya +1 位作者 Winnie Kiiru Muchane Muchai 《生态学期刊(英文)》 2019年第5期157-170,共14页
Bird’s species diversity and abundance are being threatened due to agricultural activities and anthropogenic practices which causes habitat destruction and fragmentation. Understanding how avian species respond to ha... Bird’s species diversity and abundance are being threatened due to agricultural activities and anthropogenic practices which causes habitat destruction and fragmentation. Understanding how avian species respond to habitat destruction is important towards development of effective measures to ensure that the environment is protected. A study on avian abundance, diversity and conservation status was conducted in Etago Sub-County, Kisii County Kenya from September 2018 to February 2019. Point counts and time species counts were used to carry out birds’ survey to determine their abundance and diversity in the secondary forest, sugarcane plantations, human settlement and mixed firms. A total of 4992 individuals were observed and recorded in the entire study area. The human settlement had the highest density of 1.664 ± 0.18 birds/ha followed by sugarcane plantation with 1.092 ± 0.16 birds/ha and Nyangweta secondary forest was third with 0.0819 ± 0.13. Mixed firms had the least density of 0.95 ± 0.017 bird/ha. Further Dunn’s multiple comparisons test showed that Mixed farming and forest had no significant difference and had mean rank difference of 11.37. In mixed farming vs human settlement there was a significant difference with a mean rank difference of 57.38;in mixed farming vs sugarcane farms there was no significant difference;in the four habitats, 114 species of birds were cumulatively recorded. Out of these, 106 species were recorded in the secondary forests, 98 human settlement and 87 species in the sugarcane plantations and 55 in mixed farms. There was a significant difference in bird diversity in the four habitats where Secondary forest had the highest diversity of 3.85 and sugarcane plantations had a diversity of 3.71 while human settlement and mixed firms had lower diversities of 2.6 and 2.5 respectively (df1 = 2, df2 = 0.0 F = 0.00001, P = 0.00001). 展开更多
关键词 Density SIMILARITY DIVERSITY ABUNDANCE Richness
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Relative importance of long-term changes in climate and land-use on the phenology and abundance of legume crop specialist and generalist aphids
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作者 Martin Luquet Maurice Hulle +3 位作者 Jean-Christophe Simon Nicolas Parisey Christelle Buchard2 Bruno Jaloux 《昆虫科学:英文版》 SCIE CAS CSCD 2019年第5期881-896,共16页
Abstract Insect populations are prone to respond to global changes through shifts in phenology, distribution and abundance. However, global changes cover several factors such as climate and land-use, the relative impo... Abstract Insect populations are prone to respond to global changes through shifts in phenology, distribution and abundance. However, global changes cover several factors such as climate and land-use, the relative importance of these being largely unknown. Here, we aim at disentangling the effects of climate, land-use, and geographical drivers on aphid abundance and phenology in France, at a regional scale and over the last 40 years. We used aerial data obtained from suction traps between 1978 and 2015 on five aphid species varying in their degree of specialization to legumes, along with climate, legume crop area and geographical data. Effects of environmental and geographical variables on aphid annual abundance and spring migration dates were analyzed using generalized linear mixed models. We found that within the last four decades, aphids have advanced their spring migration by a month, mostly due to the increase in temperature early in the year, and their abundance decreased by half on average, presumably in response to a combination of factors. The influence of legume crop area decreased with the degree of specialization of the aphid species to such crops. The effect of geographical variation was high even when controlling for environmental variables, suggesting that many other spatially structured processes act on aphid population characteristics. Multifactorial analyses helped to partition the effects of different global change drivers. Climate and land-use changes have strong effects on aphid populations, with important implications for future agriculture. Additionally, trait-based response variation could have major consequences at the community scale. 展开更多
关键词 ABUNDANCE CLIMATE warming degree of specialization land-use change LEGUME APHIDS PHENOLOGY
浙江水源地水库浮游动物丰度和生物量与水质参数的通径分析 预览
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作者 李共国 徐杭英 +2 位作者 于海燕 俞建 韩明春 《水生生物学报》 CAS CSCD 北大核心 2019年第1期165-172,共8页
为探明浙江水源地水库浮游动物群落特征及与环境因子的关系,达到用浮游动物群落参数监测水源地水库水质的目的。于2014年1月至2016年10月,对10个饮用水源地水库(K1—K10)展开了水质参数、浮游动物丰度和生物量的季节调查。采用多元逐步... 为探明浙江水源地水库浮游动物群落特征及与环境因子的关系,达到用浮游动物群落参数监测水源地水库水质的目的。于2014年1月至2016年10月,对10个饮用水源地水库(K1—K10)展开了水质参数、浮游动物丰度和生物量的季节调查。采用多元逐步回归与通径分析的方法,研究了浙江水源地水库环境因子与浮游动物群落之间的相互关系和作用过程。结果表明,2014—2016年水库浮游动物平均密度97.5ind./L,主要由桡足类无节幼体(占36.3%)、轮虫(28.4%)和剑水蚤(20.0%)组成。平均生物量289.3μg/L,主要由枝角类(占39.3%)、剑水蚤(29.0%)和哲水蚤(14.5%)组成。Chl.a含量是春、夏季水库浮游动物丰度的决策因子,TP含量是秋、冬季群落丰度波动的限制因子,春季TN通过N﹕P比率影响群落丰度。DO含量是冬季和夏季水库浮游动物生物量发展的决策因子,冬季DO通过降低N﹕P比促进群落生物量发展。水库浮游动物现存量受到了TP含量消长、N﹕P比率变化,以及最终反映的水体Chl.a含量共同影响。 展开更多
关键词 水库 浮游动物 丰度 生物量 水质参数 通径分析
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青藏高原维管植物物种丰富度分布的情景模拟
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作者 范泽孟 白茹玉 岳天祥 《地理学报:英文版》 SCIE CSCD 2019年第10期1625-1636,共12页
For quantitatively explaining the correlations between the vascular plant species abundance(VPSA) and habitat factors, a spatial simulation method has been developed to simulate the distribution of VPSA on the Qinghai... For quantitatively explaining the correlations between the vascular plant species abundance(VPSA) and habitat factors, a spatial simulation method has been developed to simulate the distribution of VPSA on the Qinghai-Tibet Plateau. In this paper, the vascular plant type, land cover, mean annual biotemperature, average total annual precipitation, topographic relief, patch connectivity and ecological diversity index were selected to screen the best correlation equation between the VPSA and habitat factors on the basis of 37 national nature reserves on the Qinghai-Tibet Plateau. The research results show that the coefficient of determination between VPSA and habitat factors is 0.94, and the mean error is 2.21 types per km~2. The distribution of VPSA gradually decreases from southeast to northwest, and reduces with increasing altitude except the desert area of Qaidam Basin. Furthermore, the scenarios of VPSA on the Qinghai-Tibet Plateau during the periods from 1981 to 2010(T0),from 2011 to 2040(T2), from 2041 to 2070(T3) and from 2071 to 2100(T4) were simulated by combining the land cover change and the climatic scenarios of CMIP5 RCP2.6, RCP4.5 and RCP8.5. The simulated results show that the VPSA would generally decrease on the Qinghai-Tibet Plateau from T0 to T4. The VPSA has the largest change ratio under RCP8.5 scenario, and the smallest change ratio under RCP2.6 scenario. In general, the dynamic change of habitat factors would directly affect the spatial distribution of VPSA on the Qinghai-Tibet Plateau in the future. 展开更多
关键词 spatial simulation method vascular plant species ABUNDANCE SPATIO-TEMPORAL distribution SCENARIO analysis Qinghai-Tibet PLATEAU
长期施肥对稻田不同土层反硝化细菌丰度的影响 预览
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作者 陈娜 刘毅 +5 位作者 黎娟 袁婧 葛体达 吴金水 孙志龙 徐华勤 《中国环境科学》 EI CAS CSCD 北大核心 2019年第5期2154-2160,共7页
为了探讨长期施肥对稻田不同土层关键反硝化功能种群丰度的影响及核心驱动因子,以湖南宁乡长期施肥定位试验田为平台,选取不施肥(CK)、全量化肥(NPK)和秸秆还田(ST)3个处理,结合实时荧光定量PCR(q PCR)技术,系统分析了稻田不同土层(0~10... 为了探讨长期施肥对稻田不同土层关键反硝化功能种群丰度的影响及核心驱动因子,以湖南宁乡长期施肥定位试验田为平台,选取不施肥(CK)、全量化肥(NPK)和秸秆还田(ST)3个处理,结合实时荧光定量PCR(q PCR)技术,系统分析了稻田不同土层(0~10,10~20,20~30,30~40cm)关键反硝化功能基因(narG、nirK和nirS)的丰度及其与土壤理化性质的内在联系.结果表明,相比于不施肥处理(CK),施肥处理(NPK和ST)在0~40cm土层土壤SOC、TN、NO3^--N、NH4^+-N和Olsen-P分别显著增加了2.2%~83.6%,3.5%~58.3%,70.8%~222.1%,0.9%~83.7%和16.5%~94.5%,pH值下降了0.31~0.67个单位;长期施用化肥和秸秆使narG、nirK和nirS基因丰度分别增加0.75~7.18倍,1.57~3.02倍和0.53~3.81倍,其中秸秆还田对反硝化细菌数量的影响比单施化肥更显著;稻田narG、nirK和nirS反硝化型细菌的丰度随土层深度增加而逐渐降低,具有明显的垂直分布特征;RDA分析结果显示,土壤养分如SOC和TN是影响水稻土narG、nirK和nirS反硝化型细菌垂直分布的关键因子,而pH值是调控反硝化细菌在稻田底土分布的核心驱动因子.研究结果可为提升稻田土壤肥力和减少稻田氮素损失和温室气体排放提供理论依据. 展开更多
关键词 水稻土 长期施肥 不同土层 反硝化细菌 种群丰度
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绿潮暴发对浮游动物群落结构影响研究 预览
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作者 于洋 孟娜 +3 位作者 王建勇 王尽文 刘迎迎 王珍珍 《海洋开发与管理》 2019年第3期57-63,共7页
本调查于2016年和2017年的5月、8月,对日照近岸海域浒苔暴发区进行了4个航次的浮游动物断面调查。4个航次中,2016年和2017年5月航次获得的种类数要明显低于同年8月航次,而平均丰度和湿重生物量均高于同年8月航次。造成这种情况的原因可... 本调查于2016年和2017年的5月、8月,对日照近岸海域浒苔暴发区进行了4个航次的浮游动物断面调查。4个航次中,2016年和2017年5月航次获得的种类数要明显低于同年8月航次,而平均丰度和湿重生物量均高于同年8月航次。造成这种情况的原因可能是调查海域8月浒苔暴发结束,浒苔的消亡过程会大量消耗营养盐,导致水体中营养盐含量下降,进而影响到其他浮游植物和浮游动物的生长。应用PRIMER软件中的单变量分析得到群落种数(S)、丰富度(d)、香农-威纳指数(Shannon-Weaner index)(H′)和均匀度(J),从多样性指数分析可以看出,5月航次的生物多样性均劣于同年8月航次。不同年度相同季节航次中出现的优势种极其相似,而不同季节航次出现的优势种则大不相同。 展开更多
关键词 绿潮 浮游动物 丰度 生物量 多样性 优势种
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Patterns of Species Richness and Abundance in Badingilo National Park in South Sudan 预览
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作者 Thomas Francis Lado David Gwolo Phanuel Mogga Richard Angelo Lado Benjamin 《动物研究(英文)》 2019年第1期27-32,共6页
The study was carried out to determine patterns of birds’species richness,alpha and beta diversities;and abundance in Badingilo national park using a 10 m fixed-radius point count method.A total of 2670 individuals w... The study was carried out to determine patterns of birds’species richness,alpha and beta diversities;and abundance in Badingilo national park using a 10 m fixed-radius point count method.A total of 2670 individuals were recorded from 182 points in the park.The highest expected number of species(Jack1 estimator)was observed in the Riverine habitat and least was in the Agriculture and Human settlement habitat type.The total number of species observed in the park was 63;however Jack1 estimator indicated that there were 68 species in the park.The majority of the birds observed during the study were resident species,few migratory and Palaearctic bird species.Few birds observed in the park were abundant.The most abundant species was the village weaver(381 individuals),and the rarest species were black-bellied bustard,barn owl,black scimitar bill and tree pipit(one individual each). 展开更多
关键词 Habitat types Jack1 estimator Rarefaction curves Rank abundance curves South Sudan
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Pyrosequencing of nirS gene revealed spatial variation of denitrifying bacterial assemblages in response to wetland desertification at Tibet plateau
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作者 GU Yun-fu LIU Ting +3 位作者 BAI Yan XIANG Quan-ju ZHANG Xiao-ping CHEN Qiang 《山地科学学报:英文版》 SCIE CSCD 2019年第5期1121-1134,共14页
Amplicon sequencing of functional genes is a powerful technique to explore the diversity and abundance of microbes involved in biogeochemical processes. One such key process, denitrification, is of particular importan... Amplicon sequencing of functional genes is a powerful technique to explore the diversity and abundance of microbes involved in biogeochemical processes. One such key process, denitrification, is of particular importance because it can transform nitrate(NO3-) to N2 gas that is released to the atmosphere. In nitrogen limited alpine wetlands, assessing bacterial denitrification under the stress of wetland desertification is fundamental to understand nutrients, especially nitrogen cycling in alpine wetlands, and thus imperative for the maintenance of healthy alpine wetland ecosystems. We applied amplicon sequencing of the nirS gene to analyze the response of denitrifying bacterial community to alpine wetland desertification in Zoige, China. Raw reads were processed for quality, translated with frameshift correction, and a total of 95,316 nirS gene sequences were used for rarefaction analysis, and 1011 OTUs were detected and used in downstream analysis. Compared to the pristine swamp soil, edaphic parameters including water content, organic carbon, total nitrogen, total phosphorous, available nitrogen, available phosphorous and potential denitrification rate were significantly decreased in the moderately degraded meadow soil and in severely degraded sandy soil. Diversity of the soil nirS-type denitrifying bacteria communities increased along the Zoige wetland desertification, and Proteobacteria and Chloroflexi were the dominant denitrifying bacterial species. Genus Cupriavidus(formerly Wautersia), Azoarcus, Azospira, Thiothrix, and Rhizobiales were significantly(P<0.05) depleted along the wetland desertification succession. Soil available phosphorous was the key determinant of the composition of the nirS gene containing denitrifying bacterial communities. The proportion of depleted taxa increased along the desertification of the Zoige wetland, suggesting that wetland desertification created specific physicochemical conditions that decreased the microhabitats for bacterial denitrifiers and the denitrification related g 展开更多
关键词 Wetland DESERTIFICATION AMPLICON sequencing nirS bacteria Differential ABUNDANCE analysis
Impacts of El Nino on the somatic condition of Humboldt squid based on the beak morphology 预览
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作者 HU Guanyu YU Wei +4 位作者 LI Bai HAN Dongyan CHEN Xinjun CHEN Yong LI Jianhua 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第4期1440-1448,共9页
The Humboldt squid Dosidicus gigas has a short life span, and environmental variability plays a significant role in regulating its population dynamics and distribution. An analysis of 1 096 samples of D. gigas collect... The Humboldt squid Dosidicus gigas has a short life span, and environmental variability plays a significant role in regulating its population dynamics and distribution. An analysis of 1 096 samples of D. gigas collected by the Chinese commercial fishing vessels during 2013, 2014, and 2016 off the Peruvian Exclusive Economic Zone, was conducted to evaluate the impacts of El Nino events on the somatic condition of D. gigas. This study indicates that the slopes of all beak variables in relation to mantle length (ML) for females were greater than those of males during 2013, 2014, and 2016, and slopes of the upper crest length and the lower rostrum length significantly differed between females and males in 2013 (P<0.05). Variation in the slopes for beak variables among years was studied;no significant difference was observed (ANCOVA, P>0.05). The Fulton's condition coefficients (K) of females and males in 2013 and 2014 were significantly greater than those in 2016 (P<0.01). The K values of females were greater than those of males in 2013, 2014, and 2016, and K values significantly differed between females and males in 2013. In normal years, the chlorophyll a (Chl a) concentration showed an N-shaped variability from January to December. However, in the El Nino period, it tended to weaken the upwelling coupled with warm and low Chl a concentration waters. We suggest that the poor somatic condition of D. gigas during the El Nino year was resulted from the low Chl a concentration in the waters, and the abundance of D. gigas would decrease due to the unfavourable environment and the lack of prey items in the El Nino year. 展开更多
关键词 El Nino event Dosidicus GIGAS SOMATIC CONDITION abundance BEAK MORPHOLOGY
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不同利用方式对内蒙古羊草草原氨氧化微生物丰度的影响 预览
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作者 朱蕊 陈清 +1 位作者 马成仓 王中良 《草地学报》 CAS CSCD 北大核心 2019年第2期437-442,共6页
草地利用方式变化会显著改变草地的氮素循环,进而影响草原生态系统功能。土壤硝化作用是土壤氮素循环的重要环节,由氨氧化微生物驱动的氨氧化过程是硝化作用的限速步骤,在土壤氮素可利用性等方面起着关键作用。目前,土壤氨氧化微生物对... 草地利用方式变化会显著改变草地的氮素循环,进而影响草原生态系统功能。土壤硝化作用是土壤氮素循环的重要环节,由氨氧化微生物驱动的氨氧化过程是硝化作用的限速步骤,在土壤氮素可利用性等方面起着关键作用。目前,土壤氨氧化微生物对于羊草(Leymus chinensis)草原利用方式变化响应的研究仍然欠缺。本研究应用定量PCR的方法,对内蒙古羊草草原不同利用方式(放牧和围封)下氨氧化微生物丰度及其与硝化潜势的关系进行研究。结果表明:放牧和围封样地的氨氧化古菌(Ammonia-Oxidizing Archaea,AOA)丰度均明显高于氨氧化细菌(Ammonia-Oxidizing Bacteria,AOB)丰度,土壤AOA-amoA和AOB-amoA基因丰度范围分别为每克干土(1.82~3.40)×10^8个拷贝数和(1.05~1.17)×10^6个拷贝数;长期围封后,AOA丰度显著下降,下降了46.5%,AOB丰度则无显著变化;长期围封后,羊草草原的硝化潜势显著降低,硝化潜势与AOA丰度呈显著正相关关系,与AOB丰度没有显著性相关。与AOB相比,AOA丰度对于草地利用方式的改变更敏感,可能是影响土壤硝化潜势的优势种群。该研究为理解内蒙古羊草草原硝化过程的微生物机制提供科学依据。 展开更多
关键词 羊草草原 放牧 围封 氨氧化微生物 丰度 硝化潜势
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气候变化对鲑鱼丰富度和繁殖影响的研究进展 预览
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作者 王志萍 李家薰 +2 位作者 Dave Fillion 霍耀明 周文慧 《海洋科学》 CAS 北大核心 2019年第4期98-104,共7页
鲑鱼是人类重要的食品来源之一,具有巨大的经济价值。同时,鲑鱼资源通过输送营养物质对维持溪流和陆地生态系统的结构、功能和过程等有重要作用。而鲑鱼是对温度极为敏感的冷水性鱼类,对气候变化的反应尤为明显。作者通过文献综述法梳... 鲑鱼是人类重要的食品来源之一,具有巨大的经济价值。同时,鲑鱼资源通过输送营养物质对维持溪流和陆地生态系统的结构、功能和过程等有重要作用。而鲑鱼是对温度极为敏感的冷水性鱼类,对气候变化的反应尤为明显。作者通过文献综述法梳理相关研究,从气候变化引起的温度变化、淡水和海洋环境的变化以及鱼病传播4个方面探讨对鲑鱼丰富度和繁殖的影响,并提出研究展望。研究显示:温度变化对鲑鱼的产卵和迁徙有较大影响;溪流和河流流量的改变会影响鲑鱼的迁徙和幼年鲑鱼的存活数量;温度和二氧化碳浓度的变化使海洋食物供应减少,鲑鱼丰富度降低;水温的升高使病原体增加,鲑鱼死亡率增加。本研究成果可为鲑鱼种群应对气候变化的研究及管理提供一定的理论支持。 展开更多
关键词 鲑鱼 气候变化 丰富度 繁殖
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刈割干扰和养分添加条件下Epichlo?内生真菌感染对羽茅所在群落多样性和生产力的影响
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作者 吴曼 李娟娟 +2 位作者 刘金铭 任安芝 高玉葆 《植物生态学报》 CAS CSCD 北大核心 2019年第2期85-93,共9页
Epichlo?内生真菌感染能够影响宿主植物的种内和种间竞争力,但目前关于内生真菌感染对宿主植物所在群落多样性和生产力影响的研究较少。该研究以感染(E+)和不感染(E–)内生真菌的羽茅(Achnatherum sibiricum)及其原生境中常见的5种植物... Epichlo?内生真菌感染能够影响宿主植物的种内和种间竞争力,但目前关于内生真菌感染对宿主植物所在群落多样性和生产力影响的研究较少。该研究以感染(E+)和不感染(E–)内生真菌的羽茅(Achnatherum sibiricum)及其原生境中常见的5种植物构建人工群落,探究在不同养分水平和刈割条件下内生真菌对宿主植物群落的影响。结果表明:内生真菌对宿主植物群落多样性的影响同刈割与否有关。在无刈割条件下,内生真菌感染对宿主群落多样性无显著影响;在刈割条件下,内生真菌感染显著增加了宿主群落的多样性,其原因在于内生真菌感染显著增加了群落中多度较小的冰草(Agropyron cristatum)和大针茅(Stipa grandis)等的多度,而显著降低了优势种羊草(Leymus chinensis)的多度。内生真菌感染对群落生产力未见显著影响。研究发现养分添加对内生真菌作用的影响只出现在宿主植物水平,而对宿主植物所在群落未产生显著影响,内生真菌对宿主羽茅的促进作用只出现在养分添加条件下。 展开更多
关键词 内生真菌 羽茅 群落多样性 生产力 多度
厦门湾海滩微塑料污染特征 被引量:2
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作者 刘启明 梁海涛 +2 位作者 锡桂莉 胡欣 葛健 《环境科学》 EI CAS CSCD 北大核心 2019年第3期1217-1221,共5页
以厦门湾6个典型海滩为工作区,分析海滩微塑料的污染特征.结果表明:①厦门湾6个海滩的微塑料丰度数据范围介于(28. 1±9. 4)~(312. 7±35. 2) n·kg-1之间.②厦门湾海滩微塑料分为碎片类、发泡类、薄膜类和纤维类等4种类型... 以厦门湾6个典型海滩为工作区,分析海滩微塑料的污染特征.结果表明:①厦门湾6个海滩的微塑料丰度数据范围介于(28. 1±9. 4)~(312. 7±35. 2) n·kg-1之间.②厦门湾海滩微塑料分为碎片类、发泡类、薄膜类和纤维类等4种类型.各站位点均以碎片类和发泡类为主,占总数量的80%左右,薄膜类和纤维类所占比例较少.③厦门湾海滩粒径<1 mm的微塑料占最大比例,超过60%.粒径为1~3 mm和3~5 mm的微塑料所占比例较小.④通过红外光谱分析,确认厦门湾海滩微塑料碎片类和纤维类的主要成分是聚乙烯,发泡类和薄膜类的主要成分是聚苯乙烯.⑤通过扫描电镜观测,大部分微塑料表面粗糙、凹凸不平,带有明显裂痕.整体而言,厦门湾海滩微塑料污染处于中等偏下的程度,陆源污染是厦门湾海滩微塑料污染的最主要来源. 展开更多
关键词 厦门湾 海滩 微塑料 丰度 污染
鄱阳湖枯水期延长背景下越冬水鸟群落结构、丰富度及其空间分布格局 预览
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作者 张娜 李言阔 +5 位作者 单继红 涂小斌 张育慧 李跃 汪凌峰 应钦 《湖泊科学》 EI CAS CSCD 北大核心 2019年第1期183-194,共12页
鄱阳湖是我国最大的淡水湖,也是具有国际意义的候鸟越冬地.本研究于2015和2016年越冬期对鄱阳湖越冬水鸟的群落结构、丰富度和空间分布进行了系统的调查,分别记录到水鸟494033和388017只,隶属于6目13科68种.雁形目和鸻形目鸟类种类最多... 鄱阳湖是我国最大的淡水湖,也是具有国际意义的候鸟越冬地.本研究于2015和2016年越冬期对鄱阳湖越冬水鸟的群落结构、丰富度和空间分布进行了系统的调查,分别记录到水鸟494033和388017只,隶属于6目13科68种.雁形目和鸻形目鸟类种类最多,其次是鹳形目和鹤形目;从生态型来看,游禽32种,涉禽36种.雁鸭类相对丰富度最高,是鄱阳湖越冬水鸟的优势类群,其次是鸻形目鸟类,而2015和2016年鹤形目鸟类数量仅占当年总数量的2.6%和1.4%.在鄱阳湖湿地的不同区域,越冬水鸟种类组成差异较大.从空间分布来看,越冬水鸟主要集中在鄱阳湖自然保护区、九江湿地和南昌湿地.开展鄱阳湖越冬水鸟的种群数量调查,摸清越冬水鸟群落结构和种群丰富度现状,对于有针对性地开展越冬水鸟保护具有重要意义. 展开更多
关键词 鄱阳湖 越冬水鸟 丰富度 多样性 分布
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用于海洋沉积物中厌氧氨氧化细菌分子生态学研究的引物比较 预览
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作者 付璐璐 李思琦 +1 位作者 甄毓 米铁柱 《中国海洋大学学报:自然科学版》 CAS CSCD 北大核心 2019年第9期77-88,共12页
为比较厌氧氨氧化细菌16SrRNA基因的2对特异性引物(Amx368F/Amx820R、Brod541F/Amx820R)在其分子生态学研究方面的优点与不足,本研究采用高通量测序和qPCR技术对长江口及其邻近海域沉积物中厌氧氨氧化细菌细菌的群落组成、多样性和丰度... 为比较厌氧氨氧化细菌16SrRNA基因的2对特异性引物(Amx368F/Amx820R、Brod541F/Amx820R)在其分子生态学研究方面的优点与不足,本研究采用高通量测序和qPCR技术对长江口及其邻近海域沉积物中厌氧氨氧化细菌细菌的群落组成、多样性和丰度进行比较分析,结果表明,引物Amx368F/Amx820R特异性较高,能够较为完整地反映沉积物中厌氧氨氧化细菌的多样性信息,且其覆盖的厌氧氨氧化细菌丰度与功能基因hzo丰度正相关(P<0.01);而引物Brod541F/Amx820R特异性较低,覆盖部分厌氧氨氧化细菌及其他多个门的细菌,其量化的厌氧氨氧化细菌与功能基因hzo丰度无明显相关关系(P>0.05)。因此,引物Amx368F/Amx820R能够更加真实地反映厌氧氨氧化细菌在海洋沉积物中的群落特征,在其分子生态学研究中更具优势。 展开更多
关键词 厌氧氨氧化细菌 16SRRNA基因 群落结构 丰度
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沼渣施肥对桉树人工林土壤氨氧化古菌丰度和群落结构的影响 预览
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作者 秦文弟 韦长江 +8 位作者 李鸣 蒋湖波 黄凌志 夏金亮 叶勇卫 彭健 伍琪 李金怀 徐铁纯 《西部林业科学》 CAS 北大核心 2019年第2期30-36,共7页
针对沼渣在桉树集约化经营中的合理利用,为了解桉树人工林种植在氮素生物地球化学循环中的作用,在尾巨桉人工林地布设了沼渣、桉树专用肥和对照CK共3组施肥试验,采用实时荧光定量和变性梯度凝胶电泳方法研究沼渣施肥对桉树人工林土壤氨... 针对沼渣在桉树集约化经营中的合理利用,为了解桉树人工林种植在氮素生物地球化学循环中的作用,在尾巨桉人工林地布设了沼渣、桉树专用肥和对照CK共3组施肥试验,采用实时荧光定量和变性梯度凝胶电泳方法研究沼渣施肥对桉树人工林土壤氨氧化古菌(ammonia-oxidizing archaea,AOA)丰度和群落结构的影响。结果表明,尾巨桉人工林土壤施用沼渣后对AOA的丰度和群落结构均产生了一定的影响。施用沼渣显著促进了AOA的生长,土壤总氮、有机碳和硝态氮含量均与AOA丰度呈显著正相关(P﹤0.05),与土壤pH和铵态氮以及尾巨桉树高、胸径和材积相关不显著(P﹥0.05)。施用沼渣的尾巨桉人工林土壤AOA的群落结构多样性要比施用桉树专用肥的AOA的群落结构多样性好。 展开更多
关键词 沼渣 桉树专用肥 尾巨桉 桉树人工林土壤 氨氧化古菌 丰度 群落结构
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基于约束非负矩阵分解的高光谱图像解混
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作者 方帅 王金明 曹风云 《激光与光电子学进展》 CSCD 北大核心 2019年第16期14-23,共10页
光谱解混可以有效提升高光谱图像的利用效率。非负矩阵分解(NMF)常用于寻找非负数据的线性表示,可以有效解决混合像元问题。基于丰度的稀疏性和图像局部不变性提出一种高光谱解混算法。对丰度采取稀疏性约束和基于拉普拉斯矩阵的图正则... 光谱解混可以有效提升高光谱图像的利用效率。非负矩阵分解(NMF)常用于寻找非负数据的线性表示,可以有效解决混合像元问题。基于丰度的稀疏性和图像局部不变性提出一种高光谱解混算法。对丰度采取稀疏性约束和基于拉普拉斯矩阵的图正则项约束,构造了一个新的目标函数,端元和丰度在经过若干次迭代后取得了较好的解混合结果。该算法在模拟和真实数据上都进行了有效性验证,实验结果证明所提算法具有良好的解混性能。 展开更多
关键词 图像处理 光谱解混合 非负矩阵分解 端元 丰度
Is Nitrous Oxide Reduction Primarily Regulated by the Fungi-to-Bacteria Abundance Ratio in Fertilized Soils?
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作者 MA Shutan WANG Jinyang YAN Xiaoyuan 《土壤圈:英文版》 SCIE CAS CSCD 2019年第5期569-576,共8页
The production of nitrous oxide (N2O) is a widespread trait in fungi and is of interest because denitrifying fungi lack the N2O reductase gene (nosZ) that regulates N2O reduction to nitrogen gas (N2). The adaptive abi... The production of nitrous oxide (N2O) is a widespread trait in fungi and is of interest because denitrifying fungi lack the N2O reductase gene (nosZ) that regulates N2O reduction to nitrogen gas (N2). The adaptive ability of soil fungi is better than that of bacteria in acidic soils. We investigated the N2O reduction potential, described by the N2O product ratio (Nn2O), N2O/(N2O+N2), in soils of different types of fields under crop cultivation with different fertilizer inputs and a bare fallow field with no fertilization as a control. The fungi-to-bacteria abundance ratio (Rf/b) was negatively correlated (P < 0.01) with the natural pH of the soil;however, the high value of Rp/b measured in vineyards was due to the large inputs of manure. When the denitrification potential was measured at natural pH values of soils, Nn2O was negatively correlated (P < 0.01) with soil pH. When the denitrification potential was measured after short-term modifications of soil pH, however, no significant correlation was found between Nn2O and the modified pH. Based on stepwise multiple regression analysis, soil pH and residual nitrate (NO3) were the key factors regulating N2O reduction in soils at natural pH values (R^2 = 0.8& P < 0.001), whereas the key factor was the soil residual NO, alone (R^2 = 0.83, P < 0.001) when the soil pH was modified. When the effect of the soil chemical properties was weakened, a high Rf/b value had the potential (P < 0.01) to affect N2O reduction;however, the role of fungi was offset by the presence of denitrifying bacteria. These results provide evidence that compared to the indirect effects of Rf/b、the direct effects of the soil chemical properties have a greater effect on N2O reduction in fertilized soils. 展开更多
关键词 DENITRIFICATION potential denitrifying bacteria denitrifying fungi fertilizer input manure application microbial ABUNDANCE SOIL ACIDIFICATION SOIL pH SOIL residual nitrate
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