厦门市大屿岛主要乔木种生态位特征分析          下载免费PDF全文

黄晓敏  杨盛昌  郑志翰  黄含玥  张琳婷  肖兰 《应用海洋学学报》2019,38(2):239-245

通过样方法对福建省厦门市大屿岛主要乔木种生态位特征进行分析。结果表明:整个岛屿乔木树种物种多样性较低,其中Shannon-Wiener物种多样性指数为1. 26,Margalef丰富度指数为1. 44,Simpson生态优势度指数为0. 54,Pielou均匀度指数为0. 57。乔木层优势物种是台湾相思(Acacia confusa),其重要值达53. 84%。其次是马尾松(Pinus massoniana)、柠檬桉(Eucalyptus citriodora)和潺槁木姜子(Litsea glutinosa)。生态位特征分析表明台湾相思生态位宽度最大,其Levins和Shannon生态位宽度值分别为19. 00和2. 84。生态位宽度较大的还有马尾松,潺槁木姜子和柠檬桉。台湾相思和马尾松的生态位重叠值最高,为0. 673,其次为台湾相思和潺槁木姜子,其生态位重叠值为0. 633。台湾相思、马尾松、柠檬桉和潺槁木姜子的胸径和冠幅在空间分布中变化趋势相似。综上可知厦门大屿岛乔木树种多样性较低,植物种类简单,优势种相对明显,生态位特征值较小的植物对生境要求较高,整个生态系统较为脆弱。  相似文献   

干旱区植物水分生态位适宜度的数学模型及其过程数值模拟试验研究   总被引：22，自引：4，他引：18  

李自珍  施维林  唐海萍  王新平 《中国沙漠》2001,21(3):281-285

在干旱地区水分是影响植物生长的限制因子。文章分析了沙地植物的水分利用状况,通过扩展经典生态位理论的内涵,用数学抽象方法定义植物水分生态位适宜度为其水分最适生态位点与现实生态位点的贴近度,建立了响应数学模型及数值模拟方法,依据试验观测结果进行了植物水分生态位适宜度过程的计算分析,所获结果具有较高的精度。文中有关数值模拟试验研究结果为干旱区无灌溉条件下人工植被的营建提供了新的理论模式和定量依据。  相似文献   

The southernmost Quaternary niche glacier system in Great Britain          下载免费PDF全文

STEPHAN HARRISON  JASPER KNIGHT  ANN V. ROWAN 《第四纪科学杂志》2015,30(4):325-334

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New insights on the trophic ecology of bathyal communities from the methane seep area off Concepción,Chile (~36° S)     

Germán Zapata‐Hernández  Javier Sellanes  Andrew R. Thurber  Lisa A. Levin  Frédéric Chazalon  Peter Linke 《Marine Ecology》2014,35(1):1-21

Studies of the trophic structure in methane‐seep habitats provide insight into the ecological function of deep‐sea ecosystems. Methane seep biota on the Chilean margin likely represent a novel biogeographic province; however, little is known about the ecology of the seep fauna and particularly their trophic support. The present study, using natural abundance stable isotopes, reveals a complex trophic structure among heterotrophic consumers, with four trophic levels supported by a diversity of food sources at a methane seep area off Concepción, Chile (~36° S). Although methanotrophy, thiotrophy and phototrophy are all identified as carbon fixation mechanisms fueling the food web within this area, most of the analysed species (87.5%) incorporate carbon derived from photosynthesis and a smaller number (12%) use carbon derived from chemosynthesis. Methane‐derived carbon (MDC) incorporation was documented in 22 taxa, including sipunculids, gastropods, polychaetes and echinoderms. In addition, wide trophic niches were detected in suspension‐feeding and deposit‐feeding taxa, possibly associated with the use of organic matter in different stages of degradation (e.g. from fresh to refractory). Estimates of Bayesian standard ellipses area (SEA_B) reveal different isotopic niche breadth in the predator fishes, the Patagonian toothfish Dissostichus eleginoides and the combtooth dogfish Centroscyllium nigrum, suggesting generalist versus specialist feeding behaviors, respectively. Top predators in the ecosystem were the Patagonian toothfish D. eleginoides and the dusky cat shark, Bythaelurus canescens. The blue hake Antimora rostrata also provides a trophic link between the benthic and pelagic systems, with a diet based primarily on pelagic‐derived carrion. These findings can inform accurate ecosystem models, which are critical for effective management and conservation of methane seep and adjacent deep‐sea habitats in the Southeastern Pacific.  相似文献   

三门湾海域主要底上动物生态位及种间联结性*     

孟周  王晓波  韩庆喜 《海洋与湖沼》2022,53(5)

为探究三门湾海域物种间的资源利用情况及生态关系,在该海域进行了底拖网生物调查。根据2017年和2018年夏季在浙江省三门湾海域进行的大型底上生物研究结果,运用优势度(Y)、生态位宽度、生态位重叠、方差比率法(VR)、检验、联结系数(AC)、共同出现百分率(PC)对生态位和种间联结性进行了研究。结果表明:2017~2018年间三门湾海域共捕获大型底上动物53种,包括两年共有种,即主要底上动物22种。其中优势种3种,包括哈氏仿对虾(Mierspenaeopsis hardwickii)、中华栉孔虾虎鱼(Ctenotrypauchen chinensis) 和棒锥螺(Turritella terebra),这三个物种属中生态位种;三门湾主要底上动物依据生态位宽度值划分为3组,即广生态位种、中生态位种和窄生态位种;种对间生态位重叠值总体差异性较大,其与种对的食性、栖息环境密切相关;根据总体联结性分析得主要底上动物总体呈显著正关联,群落结构较为稳定; 检验、联结系数(AC)和共同出现百分率(PC)表明种对间联结性较弱,趋近于相互独立。三门湾大型底上动物的群落结构比较稳定,但种对间的关联性在逐渐下降。  相似文献   

人工鱼礁区三种习见肉食性软体动物营养生态位研究     

张智鹏  薛久亮  王鸣岐  刘海英  史奇让  宋静静  赵文溪 《海洋通报》2022,(5)

以小黑山岛人工鱼礁区为研究区,利用稳定同位素技术分析该海域三种习见肉食性软体动物长蛸（Octopus minor）、短蛸（Octopus fangsiao）和脉红螺（Papana venosa）的营养生态位,进而判断物种种间关系。分析结果显示食物来源范围由大到小依次为长蛸、脉红螺、短蛸,其中长蛸食物来源包含短蛸食物来源范围,但脉红螺与两种蛸类食物来源无交叉;营养级由高到低依次为长蛸、短蛸、脉红螺。长蛸与短蛸营养生态位重叠比例较高,存在明显的竞争关系,与短蛸相比,长蛸营养级更高,食物来源范围更广,在竞争中处于优势地位;脉红螺的营养生态位与两种蛸类无重叠,其营养级比两种蛸类更低,且无捕食或竞争关系。  相似文献   

基于稳定同位素方法的东海中南部海域主要饵料生物营养生态位季节变动的研究          下载免费PDF全文

张琥顺  宋普庆  郑新庆  刘世刚  李渊  王雪华  林龙山 《应用海洋学学报》2022,41(3):375-385

饵料生物在海洋生态系统中处于承上启下的关键地位,为准确评估东海中南部海域饵料生物的营养关系,基于2018年11月和2019年4月两个航次调查中收集的饵料生物的碳氮稳定同位素数据,对其营养生态位的季节变动特征及种间竞争关系进行了研究。结果表明：该海域饵料生物的碳氮稳定同位素比值跨度较大,海域整体食源多样性水平较高,营养结构较稳定;饵料生物δ13C和δ15N值存在明显的季节差异,春季饵料生物的营养级显著低于秋季;浮游动物的营养生态位在两个季节间未发生明显的偏移,但其他饵料生物的生态位的位置和重叠度发生了一定变化,这或许与饵料生物摄食选择的季节差异有关;鱼类、虾类和头足类的营养生态位在不同采样时期分别表现出不同的重叠和分化特征,证明了不同饵料生物对食物选择的差异性。相关研究结果可为类似海域生物营养生态位的研究提供参考,也可为东海海域渔业资源的可持续开发利用和生态环境的保护提供科学资料。  相似文献   

GIS-based stratification of malaria risk zones for Zimbabwe     

Isaiah Gwitira  Amon Murwira  Mhosisi Masocha  Fadzai M. Zengeya  Munyaradzi Davis Shekede  Joconiah Chirenda 《国际地球制图》2013,28(11):1163-1176

Abstract

Malaria burden has considerably declined in the last 15 years mainly due to large-scale vector control. The continued decline can be sustained through malaria risk stratification. Malaria stratification is the classification of geographical areas according to malaria risk. In this study, ecological niche modelling using the maximum entropy algorithm was applied to predict malaria vector habitat suitability in terms of bioclimatic and topographic variables. The output vector suitability map was integrated with malaria prevalence data in a GIS to stratify Zimbabwe into different malaria risk zones. Five improved and validated malaria risk zones were successfully delimited for Zimbabwe based on the World Health Organization classification scheme. These results suggest that the probability of occurrence of major vectors of malaria is a key determinant of malaria prevalence. The delimited malaria risk zones could be used by National Malaria Control programmes to plan and implement targeted malaria interventions based on vector control.  相似文献   

Modeling the Probability of Niche Employment: Exploring Workforce Segmentation in Metropolitan Atlanta     

《Urban geography》2013,34(6):528-559

This paper examines employment concentrations (commonly called niches) in the Atlanta Metropolitan Area. Concentration ratios (created from 1990 5% Public Use Microdata Samples) reveal niches characterized by gender, race, and ethnicity. White workers of both sexes commonly hold niches in white-collar occupations and non-Whites (Blacks, Mexicans, Koreans, Chinese, and Asian Indians) primarily occupy niches as blue-collar, or secondary service workers. Chinese, Korean and Asian Indian males are the only groups of non-Whites to hold jobs in a significant number of white-collar employment niches. Generally, non-White niches pay very little and for women, especially, niche employment is generally not very lucrative. Logistic regression models explore predictors of niche employment and indicate that the social constructs of ethnicity and race have the most substantial impact upon an individual's odds for niche employment. Human capital measures alone do not sufficiently account for niche employment, and segmentation theory best explains the phenomenon.  相似文献   

基于改进遗传算法的Holt-Winters模型在采空沉陷预测中的应用     

彭帅英  李广杰  彭文  马建全  王雪冬  秦胜伍 《吉林大学学报(地球科学版)》2013,43(2):515-520

针对遗传算法存在的缺陷,提出了用小生境方法改进遗传算法。为了提高采空沉陷预测精度,借助Holt-Winters模型的预测功能,应用改进遗传算法求解和优化Holt-Winters模型组合参数,形成了改进遗传算法-Holt-Winters模型组合算法。将组合算法应用于长平高速公路采空区路段沉陷预测,计算表明：改进遗传算法弥补了传统遗传算法易早熟、局部寻优能力弱的缺陷;改进遗传算法-Holt-Winters模型组合算法克服了按梯度试算法搜索质量差和精度不高的缺点,输出稳定性好,预测结果相对误差在2%以内,预测精度显著提高;在采空沉陷中长期预测的相对误差小于0.79%,该算法可用于中长期采空沉陷预测。  相似文献