Plant residues do not have an immediate impact on soil bacterial community composition and abundance

Plant residues are often used as soil amendments in laboratory experiments, but they can reportedly release compounds interfering with soil DNA extraction and subsequent molecular biological analyses. Theoretically, for accurate comparison of microbial community composition in soils with and without added plant residues after a period of incubation, no significant difference at the beginning of the experiment is required between the amended and unamended control soils. We mixed plant residue into soil and immediately (within 10 min) commenced DNA extraction, and then performed 16S rRNA gene sequencing and quantitative PCR (qPCR) to determine bacterial community composition and abundance. Soil without plant residue addition served as a control. Five commonly used DNA extraction kits, 16S rRNA gene primer pairs, and soils, and two types (rice straw and alfalfa shoots) and three addition rates (2%, 4%, and 6%; w/w) of plant residue, were tested. In all cases, we found no significant difference in measured bacterial community composition or abundance between the treatments with and without added plant residue.     

草原景观下昆虫群落及种群对生境破碎化的反应

生境破碎化是制约生物多样性重要的“瓶颈”之一。本研究在已有资料的基础上,论述了影响生物群落结构和种群动态过程的生境破碎化的生物反应特征,以及破碎化生境对生物多样性和种间关系的影响机理及基本理论假说,重点对草原景观下有关昆虫群落结构、丰富度、种群数量与动态、种间关系及群落次生演替等与生境破碎化关系的试验研究进行归纳总结, 提出了在草原环境下进行破碎化生境与昆虫群落和种群发生关系研究的问题及优势条件,指出了种间关系和次生演替与生境斑块格局的关系是草原生物多样性保护研究的关键之一。     

井陉县大青山野皂荚群落植物组成及多样性分析

为研究井陉县大青山地区野皂荚群落植物组成和多样性特征,以太行山中部井陉县低山区的野皂荚群落为研究对象,采用样方法,分析群落植物组成和多样性特征。结果表明,井陉县大青山地区野皂荚群落共有植物30种,隶属于19科28属;从植物组成来看,调查样地植物种类较多的是禾本科、豆科和菊科;植物优势种为鹅耳枥、野皂荚、荆条、中亚苔草和中华卷柏;从多样性指数来看,灌木层和草本层多样性指数、丰富度均高于乔木层;而乔木层的均匀度和优势度均高于灌木层和草本层。     

典型黄土残塬沟壑区啮齿动物群落分布格局及其时空动态

为研究典型黄土残塬沟壑区啮齿动物群落的分布格局及其对环境变化的响应,于1990—2020年对山西省隰县林草区、沟底作物区、塬面作物区和塬面果园区4种不同样区的啮齿动物群落进行调查,分析不同时间段啮齿动物的群落结构、多样性特征和空间生态位。结果显示,研究期间隰县啮齿动物整体密度呈高—低—高的趋势,由1990—1994年的12.71%逐步下降到2005—2009年的3.39%,之后又上升至2015—2020年的7.83%;作物区的啮齿动物群落多样性特征与林草区、塬面果园区的多样性特征有显著差异,而沟底作物区和塬面作物区的啮齿动物群落多样性特征无显著差异;不同啮齿动物间的Pianka空间生态位重叠指数显示啮齿动物对环境资源的需求和利用有一定的差异性。表明生境类型会影响啮齿动物群落的分布格局,而环境的变化是导致其格局变化的重要因素。     

社群丰容对圈养小熊猫区域分配的影响

为探索社群丰容对重庆动物园圈养小熊猫行为区域分配的影响,2014年1月—2015年2月,用目标动物取样法对比观察春季、夏季、秋季、冬季社群丰容前后圈养小熊猫区域分配。结果表明:社群丰容增加了小熊猫对栖架、树上的利用,减少了内室和裸露地面和近游客区域的利用。树上利用的最大占比值在夏季,丰容增加了11.1%;栖架的利用最大占比值在春季,丰容增加了2.8%;冬季对内室的利用占比值最高,丰容后,其利用占比减少了8.4%,从而相应增加了小熊猫户外停留时间;丰容后,小熊猫对裸露地面的最大利用占比值减少了3.7%,近游客区域最大占比值减少了5.6%。小熊猫对六大区域的最高利用占比,丰容前后没有变化,最高为树上,最少为裸露地面。     

欧亚温带草原东缘生态样带研究探讨

为揭示全球变化与欧亚温带草原东缘生态系统的关系,提出沿着从中国长城至俄罗斯贝加尔湖设置一条经向样带,主要表征欧亚大陆东缘经向热量梯度,反映受大陆性气候控制下的草原地带的生态系列.沿样带开展生物地球化学过程、能量交换、植被结构动态、气候—植被、放牧—草地—牧草驯化、土地利用格局与管理、模型模拟等研究工作,对于加深气候变化和人为影响对草原生态系统的发生、发展、利用及演变规律的影响的认识,增强对气候变化的减缓和适应能力,具有非常重要的意义.     

内蒙古草原与荒漠区的锦鸡儿属植物种群格局动态和种间关系 …

本文研究了内蒙古草原与荒漠区的锦鸡儿属植物随着年龄和植丛大小,表现出不同的人布格局。通常是幼小植丛多呈聚块分布,中等植丛趋向于均匀分布,大型植丛趋向于随机分布。     

穗花杉群落演替研究

采用固定样地的研究方法,对穗花杉Amentotaxus     

An analysis of structure of tree seedling populations on a Lahar

The structure of a tree seedling population is dependent on the interaction of several processes including seed dispersal, germination, survival, and competition on a physical landscape. Structural components (composition, size distributions, spatial distributions, age distributions, density, and history) of a tree seedling population on the Muddy River Lahar on the east side of Mount St. Helens were examined over a range of extents (1/10 m to 1000 m). Many of these component have rarely been examined at the larger extents listed here. Composition reflected distances to seed source and seed morphology. Seedling sizes are inversely proportional to depth to a buried soil if one existed. Spatial patterns indicated that seedling are clustered for tree seedlings less than 200 m apart, random for tree seedling from 200 m to 400 m and uniform for seedling greater than 400 m apart. This was confirmed by two measures of multidimensional spatial point pattern. Age distributions did not reflect the size distributions; old seedlings could be almost any size, young seedlings were constrained to be small in size. Densities appear to be typical for forests in the area. History of disturbance events (the lahar establishment, and successive ash, pumice, and erosion) has strongly influenced this tree seedling community.