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1.
基于分子生态学网络分析松嫩退化草地土壤微生物群落对施氮的响应 总被引:3,自引:1,他引:2
【目的】 氮素输入影响着全球草地生态系统的可持续性,关注施氮对土壤微生物群落的影响及其分子生态网络,为草地退化修复提供理论依据。【方法】 以松嫩退化羊草草地为研究对象,通过施氮和未施氮处理,利用高通量测序和随机矩阵网络构建理论构建土壤微生物群落分子生态网络。探讨氮素管理对退化羊草草地土壤微生物群落结构及网络的影响,氮添加条件下微生物网络结构中的关键微生物变化规律,以及该过程中微生物之间的互作关系,解析外源氮素添加条件下土壤细菌动态变化的关键结点和规律。【结果】 在门分类水平上施氮处理草地有细菌门22个,未施氮处理23个。7个菌门是施氮和未施氮处理草地的优势菌门,其中变形菌门(Proteobacteria)是含有OTU数量最多的门类,约占总序列的30.46%,酸杆菌门(Acidobacteria)是含有OTU数量次之的门类,约占总序列的30.15%,芽单胞菌门(Gemmatimonadetes)是含有OTU数量第3的门类,约占总序列的8.14%,放线菌(Actinomycete)约占总序列的6.15%,绿弯菌门(Chloroflexi)、拟杆菌门(Bacteroidetes)和硝化螺旋菌门(Nitrospirae)三者约占总序列的17.16%。施氮处理草地土壤微生物中的变形菌门、放线菌门、拟杆菌门的相对丰度均显著高于未施氮处理草地土壤(P<0.01);未施氮草地土壤中绿弯菌门、酸杆菌门、芽单胞菌门相对丰度显著高于施氮草地土壤(P<0.01),其他各门细菌施氮与未施氮处理间未呈现出显著差异。表征网络的正向连接比、平均路径长度、平均聚类系数和模块性均为施氮处理显著低于未施氮处理(P<0.001)。在土壤的分子生态网络中,未施氮处理有16个模块枢纽(Zi>2.5,Pi≤0.62),施氮处理有6个模块枢纽,均属于酸杆菌门、芽单胞菌门和放线菌门。施氮导致土壤微生物种间关系改变,进而改变土壤整体生态网络。【结论】 施氮降低了退化草地土壤网络结构的复杂程度和紧密性;降低了退化草地土壤中的酸杆菌门和绿弯菌门相对丰度,提高了变形菌门、放线菌门和芽单胞菌门相对丰度。土壤中微生物关键物种(OTU)由16个(未施氮)减少为6个,且二者土壤中均没有重叠OTU,这表明施氮调控微生物群落网络的关键物种,进而改变其分子生态网络结构。 相似文献
2.
郑书高 《畜牧兽医科学(电子版)》2021,(4):182-183
近年,畜牧养殖业蓬勃发展,过去的区域化散养已经基本不存在,养殖结构逐渐向集约化、一体化、规模化过渡,养殖规模也逐渐增大。养殖副产品肉、蛋、奶等极大满足了人们的生产生活,养殖中产生的尿液、粪污对生态环境造成极大影响。为促进规模化养殖实现绿色健康发展,该文分析规模化畜牧养殖对生态环境的破坏及防治措施。 相似文献
3.
以番茄品种罗拉为试材,设置5个处理,分别为:CK,定植密度33 300株·hm~(-2),留6穗果;T1,49 500株·hm~(-2),留4穗果;T2,66 000株·hm~(-2),留3穗果;T3,49 500株·hm~(-2),单株留2穗果与留6穗果相间;T4,66 000株·hm~(~(-2)),单株留2穗果与留4穗果相间,研究不同种植密度和留果方式对外保温覆盖大棚内番茄植株生长、产量、品质、群体微环境的影响。结果表明:T2和T1处理生育期平均温度、温度适宜度较高;T1和T3处理摘心前的叶片SPAD值显著高于对照;T1、T2处理的前期产量和总产量均显著高于对照;VC、可滴定酸、可溶性糖、番茄红素等果实品质以T1处理最优。综合产量、品质以及大棚内的温湿度和光照适宜度,T1处理种植风险较小,是外保温覆盖大棚中较为合适的种植方式。 相似文献
4.
中国竹类多样性及其重要价值 总被引:5,自引:5,他引:0
竹类属于禾本科Gramineae(Poaceae)、竹亚科Bambusoideae植物,全世界约1 500多种。中国竹类的自然分布广阔,横跨热带、亚热带和温带地区,涵盖包括台湾、香港在内的21个有竹子分布的省、自治区、直辖市和特区。中国是世界上竹类多样性最丰富的国家,也是世界上栽培竹类最丰富的国家,共有竹类植物753种(含22种引进种),约占世界总数的50%以上。同时,中国竹类在起源、遗传进化、内部构造、生态及林型等方面均具有十分丰富的多样性。中国竹类从宏观到微观所展现出的多样性特质,是大自然留给人类的宝贵遗产,对于人类认识自然、保护自然、从而更好的利用竹类资源服务于人类的长远利益,具有重要价值。文章从起源、生态、林型、物种、形态、遗传等方面概述了中国竹类的多样性,为进一步探讨竹类多样性提供基础信息。 相似文献
5.
以海南岛18个国家气象站1966—2019年的日观测数据为基础,对海南岛18个市(县)芒果单产的气象产量与其各生育期气温、降水、日照、相对湿度等做相关分析,选取花期平均气温、果实发育期平均气温、年≥10 ℃积温作为区划指标,同时考虑坡度因素的影响,采用集优法基于GIS开展了海南岛芒果种植精细化气候区划。结果表明,海南岛芒果种植气候适宜区主要分布在昌江、东方、乐东、三亚、陵水、万宁、琼海等西部南部和东部市(县)的沿海乡(镇),不适宜区主要分布在五指山大部、白沙南部、昌江南部、乐东东北部、三亚北部、陵水北部等市(县)地形陡峭的山地,其余为次适宜区。区划结果可为海南岛芒果种植布局规划和产业结构调整提供科学依据。 相似文献
6.
为提升香格里拉普达措国家公园的整体性和有效保护,对迪庆州范围内具有重要生态价值的区域,从国家代表性、生态系统重要性和管理可行性3个方面进行系统评估。适宜性分析结果认为,拟扩建区域山地植被垂直带谱典型完整,足以支撑地带性生物区系,区内多样的地貌构造以及珍贵、罕见的地质地貌景观和遗迹,具有十分重要的世界意义和保护价值,动植物区系较完整,能维持种群生存繁衍、生态功能稳定和生态系统健康,生态原真性十分突出。扩建后国家公园面积1030919.93 hm2,涉及香格里拉市的11个乡镇。综合评价认为,拟扩建区域资源具有国家代表性,生态系统突出,并具备管理可行性,全面符合建设国家公园的条件。提出将白马雪山、哈巴雪山、千湖山、红山、梅里雪山和碧罗雪山等6片区纳入普拉措国家公园扩建范围,并对扩建后国家公园更名、建立管理体制、运行机制等方面提出建议。 相似文献
7.
Fish functional diversity responses following flood pulses in the upper Paraná River floodplain 下载免费PDF全文
Matheus T. Baumgartner Anielly G. de Oliveira Angelo A. Agostinho Luiz C. Gomes 《Ecology of Freshwater Fish》2018,27(4):910-919
Flood pulses are the main force driving the dynamics of aquatic communities in floodplains. The responses of communities to environmental changes following flood pulses usually demand a time lag to appear and reach the climax. We assembled a data set of 16 years of fish samplings to assess the relationship between water level and four functional diversity measures, in the upper Paraná River floodplain. Specifically, we approached four aspects of each relationship between water level and functional diversity: nature (positive or negative), sensitivity (response intensity), responsiveness (response delay) and extent (response duration). The nature of the relationship between water level and functional diversity was positive in all cases. Functional richness (FRic) responded right after flood pulses, although with shorter extent. Abundance‐dependent functional measures (evenness—FEve; divergence—FDiv; and Rao's quadratic entropy—Rao's Q) presented delayed responses, reaching peaks more than 1.5 years after flood pulses. Significant effects of floods on fish functional diversity were observed for more than 3 years, although the highest functional diversity was observed with 1.8 years, on average. More importantly, flood pulses had no longer significant effects on functional diversity after 4 years. Regarding conservation strategies in regulated systems, flood events should occur every 2 or 3 years, with adequate timing (October‐November), intensity (up to 450 cm) and duration (at least 50 uninterrupted days). Intervals longer than 3 years or inadequate timing, intensity and duration could dramatically decrease functional diversity and compromise ecosystem services. 相似文献
8.
Linking small pelagic fish and cetacean distribution to model suitable habitat for coastal dolphin species,Delphinus delphis and Tursiops truncatus,in the Greek Seas (Eastern Mediterranean) 下载免费PDF全文
Marianna Giannoulaki Evangelia Markoglou Vasilis D. Valavanis Paraskevi Alexiadou Anna Cucknell Alexandros Frantzis 《水产资源保护:海洋与淡水生态系统》2017,27(2):436-451
- A large‐scale assessment of the summertime suitable habitat for Delphinus delphis (short‐beaked common dolphin) and Tursiops truncatus (common bottlenose dolphin) in Greek Seas (Eastern Mediterranean) was conducted using data from dedicated and opportunistic cetacean surveys and published data records.
- Using a presence/absence approach, generalized additive models were applied to define a suite of environmental, bathymetric and biotic factors that best describe common and bottlenose dolphin spatial distribution, during early (May, June, July) and late (August, September) summer.
- A geographic information system (GIS) was used to integrate sightings data with environmental characteristics, distance from the coast and sardine probability of presence. These variables were considered as good proxies for defining species‐suitable habitat within the study area's coastal environment.
- The final selected models were used to produce annual probability maps of the presence of the species in the entire Greek Seas, as a measure of habitat suitability. Based on the mean probability and standard deviation maps for the study period GIS techniques were subsequently used to determine the persistent (areas with high mean and low variation) and occasional (high mean and high variation) habitat of each species.
- Results showed that there was a high probability of common dolphin presence in areas with a high probability of sardine presence. For bottlenose dolphin, higher probability of the presence of species occurred in areas closer to the shore, with a high probability of sardine presence and with high concentrations of chlorophyll‐a.
- In both seasons, the North Aegean Sea and the Inner Ionian Sea Archipelago were indicated as the most suitable areas for common dolphin distribution. Persistent habitat areas of the bottlenose dolphin included enclosed seas, continental shelf waters, and waters surrounding islands. The indicated suitable areas are discussed along with deficiencies of the models and future implications for conservation.
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10.
Is behaviour in a novel environment associated with bodily state in brown trout Salmo trutta fry? 下载免费PDF全文
Energetic status and body size are inconstant bodily states often considered to have feedback effects on behaviour. Feedbacks can be negative, like starvation‐threshold feedbacks (lower state values = increased risk taking due to higher energy need, and vice versa), or positive, like state‐dependent safety feedbacks (higher state values = lower vulnerability when expressing risky behaviours, and vice versa). Few studies have investigated feedback effects during the early‐life survival bottleneck of territorial species, when rapid growth is particularly important to maintain competitive ability. We investigated effects of body size and energetic status on the emergence latency into an unknown environment in highly territorial brown trout fry. We manipulated energetic status using high and low food rations in different combinations over two consecutive periods. In contrast to results from other small‐sized fishes, no general behavioural effects of energetic state were detected, but larger fish had on average shorter emergence latency. Starvation‐threshold feedbacks were not supported, but the size effect favours the presence of a state‐dependent safety feedback. When individuals were split into clusters characterised by long (>34 s) and short (<34 s) emergence latency, a state‐dependent safety feedback, based on energetic status, was found in the short‐latency cluster. Positive state‐dependent feedbacks may reflect the high level of competition among wild trout fry during the first summer, particularly among the more active individuals (i.e., from the short latency cluster). High state levels could be utilised to gain advantages over lesser competitors (e.g., to establish territories), particularly if the overall risk of starvation is higher than the risk of predation. 相似文献