西双版纳国家级自然保护区蚂蚁-树互作网络空间变异

网络分析(network analysis)可以同时分析群落中的物种多样性和种间关系, 为了解生态群落的稳定性机制提供了新的分析思路和方法。本研究从西双版纳国家级自然保护区的纳板河、勐仑和勐腊(补蚌)三个地点采集了树栖性蚂蚁及树木的种类和数量数据, 对蚂蚁-树组成的二分网络进行了分析, 探讨了3个采样点物种的多样性、网络指标以及群落指标之间的关系。我们采用零模型的方法比较了3个样点的标准化网络参数差异。结果表明: 蚂蚁和树木的物种数以及树的异质性指数(Shannon-Wiener多样性指数、Simpson多样性指数)都呈现出勐仑 > 纳板河 > 补蚌的趋势。树木-蚂蚁的灭绝曲线系数大小关系同样为勐仑 > 纳板河 > 补蚌, 灭绝曲线与树的物种数及异质性指数大小趋势一致, 而与蚂蚁的异质性指数并不吻合。根据Z值的绝对值来看, 网络参数(加权嵌套性、平均连接数、特化水平、模块性、连接度)与群落参数(灭绝曲线系数、生态位重叠)的大小趋势相同, 表现出勐仑 > 纳板河 > 补蚌的趋势。综上所述, 蚂蚁-树互作网络的稳定性(灭绝曲线系数)主要由树的数量和异质性指数决定。网络的加权嵌套性和网络中节点的平均连接数也能促进群落的稳定性。而在一个特化的(数值越大表示专性互作越多)和模块化(具有较多密切互作的节点单元)的网络中, 当低营养级物种灭绝时高营养级物种数量将迅速减少。     

区域水安全格局构建:研究进展及概念框架

随着全球变化背景下生态安全问题的日益严峻,生态安全格局研究成为宏观生态学关注的热点领域;水作为重要的自然生态要素,其安全格局的构建也是区域生态安全格局优化的重要组成部分,但目前其基本内涵、构建理论与方法、指标体系等尚未受到足够重视,缺乏系统梳理。在对比分析资源、环境与灾害等多学科视角下水安全概念异同的基础上,明晰了区域水安全格局的概念内涵,将其定义为保障区域水安全目标的土地利用空间格局;系统探讨了水安全格局构建历程与方法研究进展,指出水安全研究正由定量评价向空间管控转型,水环境安全格局构建严重滞后,缺乏水安全格局与自然生态过程、社会经济过程的耦合关联分析;最后,基于景观生态学格局-过程互馈理论和地理学区域综合视角,以GIS空间分析、In VEST模型等为技术支撑,构建了水资源安全、水环境安全和水灾害规避安全3个单一维度的水安全格局,并提出基于空间多准则分析模型的区域综合水安全格局构建概念框架,以期有效提升中国城市化进程的水安全格局保障。     

树干液流径向分布格局研究进展

树干液流径向分布的不均匀性是引起热技术估算单株乃至林分蒸腾误差的主要来源。因此, 了解树干液流径向分布格局并将其定量化, 成为利用热扩散和热脉冲技术准确估算森林蒸腾的必要条件。该文详细介绍了树干液流径向分布格局的研究方法, 总结了目前4种常见的树干液流的径向分布格局, 分析了影响树干液流径向分布格局的内部结构因素和外部环境因素, 阐明了树干液流径向分布格局的时间动态特征及其影响因素, 并提出目前研究中存在的问题和可能的解决方法。     

快速眼动睡眠剥夺对大鼠线索性恐惧消退再现的影响

目的：研究RSD对大鼠线索性恐惧消退再现的影响。方法：1d大鼠适应环境;2d进行恐惧条件化;3d恐惧消退训练并进行RSD;4d进行恐惧消退再现检测。结果：在恐惧条件化及消退训练阶段,0-6hRSD组、6—12hRSD组与各自对照组大鼠的僵直水平组间差异都无显著性;在恐惧消退再现检测阶段,0-6hRSD组大鼠的僵直水平显著高于对照组,6-12hRSD组与对照组大鼠的僵直水平组间差异无显著性。结论：RSD损害消退记忆的再现,并且依赖于睡眠剥夺的时段。     

重庆缙云山针阔混交林林隙树木更替规律研究

 研究了重庆缙云山大面积分布的亚热带次生性针阔混交林林隙树木更替规律,预测了该类型林林隙演替趋势。结果表明：马尾松(Pinus massoniana)种群表现出强烈的相互更替模式,四川大头茶(Gordonia acuminata)、四川山矾(Symplocos setchuanensis)等常绿阔叶树种自我更替与相互更替两种模式共存;林隙现实树木更替过程不能维持群落现有组成;Markov转移矩阵分析表明未来林冠层组成中马尾松种群将失去优势地位,整个群落将由针阔混交林向常绿阔叶林方向演替。     

太白山北坡小型兽类物种多样性垂直分布格局

物种多样性沿海拔梯度的垂直分布格局一直是生物多样性研究的热点问题,其中最为普遍的分布模式为中峰格局。为了解太白山北坡小型兽类物种组成和物种多样性垂直分布格局,本研究于2020和2021年两年的6至9月采用样线法、铗日法和陷阱法对太白山北坡小型兽类物种进行调查。在海拔780~3767.2 m之间,以200 m为梯度,设置采集样点15个,累计布置4150铗次,陷阱105个,样线8条。共记录小型兽类4目7科12属21种148只,阔叶林中的小型兽类物种多样性普遍高于针叶林,物种多样性在中海拔地区栓皮栎(Quercus variabilis)林、锐齿槲栎(Q.aliena)林最高,高海拔地区秦岭冷杉(Abies fargesii)林最低。小型兽类物种多样性垂直分布格局为左偏倚中峰格局,物种多样性在1500~2300 m海拔段内出现峰值。这种分布格局和林型中小型兽类东洋界与古北界、特有种与非特有种在太白山地区交汇有关,太白山北坡南北纵列的山脉-沟谷地貌为南北物种扩散和迁移提供了有利条件,在沟谷内气候和地理特征相似,形成了规律的林型垂直带谱,这使得小型兽类物种多样性垂直分布也具有相似的特点。     

三峡库区景观格局变化及其影响因素——以重庆市云阳县为例

从20世纪90年代中期至今是三峡库区生态-经济系统与景观格局发生重大变化的一段时期。论文通过对库区重庆市云阳县1994年与2002年遥感影像的解译,分析景观格局的变化,探讨生态建设、城镇化、基础设施建设、生态移民、农业产业结构调整等短时期内高强度的人类活动对该区域景观格局的影响。地形破碎、高差悬殊的山地特点以及在亚热带湿润气候主导下的山地立体气候分异等自然因素造成了景观格局的基本分异;有限的土地资源及其利用与分布状况是控制景观格局变化的主导因子;为保证三峡工程的顺利建设和安全运行而采取一系列生态经济建设活动成为促使景观格局变化的最重要的驱动因素;政治、经济和社会决策对景观格局变化具有重要影响。     

Implication of a pepper h-type thioredoxin in type I- and II-nonhost resistance to Xanthomonas axonopodis

Thioredoxins (TRXs) are distributed ubiquitously in prokaryotic and eukaryotic organisms. Plants have the most complex forms of TRXs. The functional roles of such TRXs have been studied in abiotic stress but their roles in plant defense responses against biotic stresses have been less well studied. Here, we identified an h-type TRX gene from pepper, CaTRXh1, and characterized its possible effect on Type II nonhost resistance, which entails localized programmed cell death in response to nonhost pathogens. Peptide sequences of CaTRXh1 showed a high degree of similarity with TRXhs from tobacco and Arabidopsis thaliana. Southern blot analyses revealed that CaTRXh1 was present as a single copy in the pepper genome. Intriguingly, leaf infiltration by Xanthomonas axonopodis pv. glycines 8ra, eliciting a visible type II nonhost hypersensitive response (HR), and its type III secretion-system null mutant 8–13, eliciting a type I nonhost non-HR, both induced CaTRXh1 at a level similar to that of pathogenesis-related protein 4, an HR marker gene in pepper. More surprisingly, expression of CaTRXh1 was significantly increased when X. axonopodis pv. vesicatoria race 3 infiltrated the leaf of a pepper cultivar containing a resistance gene, but not with infiltration of a susceptible pepper cultivar. Taken together, our study suggests that the expression of CaTRXh1 has a critical role in HR-mediated active defense responses in pepper. GenBank accession number: EF371503.     

HAUL-OUT PATTERNS, SITE FIDELITY AND ACTIVITY BUDGETS OF MALE HOOKER'S SEA LIONS (PHOCARCTOS HOOKERI) ON THE NEW ZEALAND MAINLAND

Diurnal and seasonal haul-out patterns, site fidelity and activity budgets of individually identified Hooker's sea lions were studied for two years at Papanui Beach, Otago Peninsula, New Zealand.
Fourteen male sea lions were identified. Lengths ranged from 1.65 m–2.28 m and estimated ages from 2-11 yr. The population consisted of four sexually and socially mature (potentially breeding), eight sexually mature but socially immature and two immature males. Most haul-outs (95.6%) were by nine identifiable individuals (Residents) returning on a regular basis, suggesting a high degree of site specificity. Emigration and recruitment were low in relation to the length of the study. Daily arrivals (mean = 0844 h, SD = 1.49) and departures (mean = 1802 h, SD = 1.18) indicate nocturnal feeding. During March 1986 sea lions spent 43.8% of each day ashore (= 78% of daylight hours). Numbers of sea lions hauled out declined in both breeding seasons; in 1986/87 this was due to a decrease in haul-out frequency of resident animals. All but one of these sea lions returned after the breeding season.
Sea lions preferentially selected the middle and the extreme ends of the beach as haul-out sites. During winter use was made of the grass dunes as haul-out areas.
There were significant differences in the frequencies of behavioral activities between summer and winter; more time was allocated to resting in summer.