拉萨半干旱河谷植被对地表节肢动物多样性的影响

调查不同植被恢复措施下拉萨半干旱河谷地表节肢动物类群多样性以及群落结构,为揭示地表节肢动物多样性对植被恢复措施的响应具有重要意义。采用陷阱法对青藏高原半干旱河谷砂生槐灌丛、人工杨树林和藏沙蒿灌丛样地地表节肢动物群落组成、类群多样性以及功能群结构进行调查,计算各处理地表节肢动物类群相对多度、类群丰富度、多样性指数、Cody指数和S9rensen指数。共采集半干旱河谷地表节肢动物个体数738,隶属5纲15目51科。砂生槐灌丛样地收集节肢动物40科,占所有类群78.4%,杨树人工林和藏沙蒿灌丛样地调查到土壤节肢动物类群为30和23科,分别占总科数的58.8%和45.1%。各植被恢复类型在目的分类单元下,双翅目、膜翅目和弹尾目类群相对多度较高,而在科的分类单元下,驼跳科、蚁科和漏斗网蛛科为拉萨半干旱河谷优势地表节肢动物类群。砂生槐灌丛节肢动物类群丰富度和多样性指数最高,人工杨树林最低。砂生槐灌丛和藏沙蒿灌丛地表节肢动物营养功能群均以捕食性为主。不同植被群落间群落相似性也有差异,砂生槐与藏沙蒿灌丛间相似性较高,而人工杨树林与藏沙蒿之间较低。不同植物群落组成和结构影响土壤理化特性、地表凋落物数量、质量和微生境条件,进而影响地表节肢动物群落组成、数量和营养功能群。砂生槐灌丛样地具有较高节肢动物类群丰富度和捕食性动物类群,有利于拉萨半干旱河谷地区地表节肢动物多样性维护。     

皖北石灰岩山地植被对地表节肢动物组成及多样性的影响

调查皖北石灰岩山地退化生态系统不同植被恢复类型地表节肢动物群落组成、类群多样性以及功能群组成,揭示退化生态系统植被恢复进程中土壤地表节肢动物群多样性变化规律及其影响因素,为石灰岩山地植被恢复成效评价提供科学依据。采用陷阱法对皖北石灰岩山地侧柏+构树混交林、酸枣+牡荆灌丛和荩草+牡荆草灌丛样地地表节肢动物群落组成、多样性以及功能群进行调查。共采节肢动物个体数11601,隶属8纲14目44科。酸枣+牡荆灌丛样地采集到节肢动物37科,占所有类群的84.1%,荩草+牡荆草灌丛和侧柏+构树混交林采集到土壤节肢动物类群为35和26科,分别占总科数的79.6%和59.1%。在目的分类单元下,直翅目、等足目和鞘翅目类群相对多度较高,而科的分类单元下,潮虫科、金龟甲科、蚁科和蟋蟀科为皖北石灰岩山地优势地表节肢动物类群。酸枣+牡荆灌丛节肢动物类群丰富度和荩草+牡荆草灌丛多样性指数最高,侧柏+构树混交林两者均最低。3个样地地表节肢动物营养功能群均以植食性为主。不同植被恢复类型间群落相似性也有变化,酸枣+牡荆灌丛和荩草+牡荆草灌丛间相似性较高,而侧柏+构树混交林与其他2种类型之间相似度均较低。研究结果表明石灰岩山地生境不同植被群落组成、数量和结构及其驱动形成的土壤理化特性、表层的凋落物数量、质量和微生境条件的变异,引起地表节肢动物群落组成、结构和多样性和营养功能群的不同。     

东北黑土区耕作措施对地表节肢动物多样性的影响

【目的】调查不同耕作措施下东北黑土地表节肢动物群落类群多样性以及营养功能群结构, 有利于揭示地表节肢动物多样性对土地管理措施的响应。【方法】本研究于2012年7－9月在黑龙江海伦中国科学院海伦农田生态系统国家野外科学观测研究站采用陷阱法对东北典型黑土区免耕、 少耕、 平翻、 旋耕和组合5种耕作措施长期定位试验区的地表节肢动物群落组成、 类群多样性以及功能群结构进行调查, 计算各处理地表节肢动物类群相对多度、 类群丰富度、 Shannon Wiener多样性指数、 Pielou均匀度指数、 Simpson优势度指数、 Cody指数和Srensen指数。【结果】本次调查共收集黑土农田地表节肢动物个体数为2 942, 隶属7目18科。免耕样地收集节肢动物15科, 占所有类群83.34%; 少耕和组合样地均为11科, 占61.12%。所有耕作措施下鞘翅目和蜘蛛目类群相对多度最高, 步甲科为黑土农田优势地表节肢动物类群。免耕样地节肢动物类群丰富度和多样性指数最高, 少耕样地最低。除旋耕样地外, 其他耕作样地地表节肢动物功能群均以捕食性为主。群落相似性指数分析表明, 不同耕作措施间群落相似性不同, 免耕与组合之间相似性较高, 而平翻与组合之间较低。【结论】步甲科是黑土农田地表节肢动物群落中的优势类群。不同耕作措施影响近地表土壤以及植被微生境, 进而影响地表节肢动物群落组成、 数量和营养功能群。免耕样地具有较高节肢动物类群丰富度和捕食性动物类群, 有利于维持黑土农田地表节肢动物多样性。     

不同演替阶段热带森林地表凋落物和土壤节肢动物群落特征

为了解不同演替阶段热带森林土壤节肢动物群落结构特征及其与地表凋落物的关系, 2001年9月采用样线调查法对西双版纳23年次生林、35年次生林、季节雨林地表凋落物及其中的土壤节肢动物进行了调查。所获数据表明, 地表凋落物数量(现存量干重)和质量(N和C/N)总体上表现为35年次生林最好, 23年次生林次之; 蜱螨目和弹尾目为3林地地表凋落物土壤节肢动物群落优势类群, 膜翅目蚂蚁、马陆目、鞘翅目、双翅目和半翅目为常见类群。土壤节肢动物个体密度和个体相对密度均表现为35年次生林>季节雨林>23年次生林。群落的丰富度指数以季节雨林最高, 多样性和均匀度指数显示为23年次生林最高, 35年次生林的优势度指数最高, 3林地土壤节肢动物群落类群组成相似性达到较好水平。相关分析表明, 3种不同演替阶段热带森林土壤节肢动物个体密度与林地地表凋落物现存量呈正相关, 而现存凋落物N元素储量与土壤节肢动物的相关性仅表现在23年次生林和季节雨林。研究认为, 热带森林土壤节肢动物群落的发展与森林植被演替密切相关, 其群落个体数量和多样性受森林地表凋落物数量、质量的调控, 但其他环境因素如捕食效应、人为干扰等影响亦不可忽视。     

辽东山区次生林与人工林大型地表节肢动物多样性

采用陷阱法在地表节肢动物活动高峰期(7—8月)对辽东山区蒙古栎(Quercus mongolica)林、胡桃楸(Juglans mandshurica)林和阔叶混交林3种次生林以及红松(Pinus koraiensis)人工林和落叶松(Larix spp.)人工林地表节肢动物群落进行了调查。共捕获地表节肢动物5135头,隶属于7纲18目66个类群,优势类群为蚁科(20.4%)、葬甲科(19.5%)、蜣螂科(17.2%)和步甲科(14.5%);地表节肢动物的功能群丰度依次为:腐食性杂食性捕食性植食性;系统聚类分析表明,地表节肢动物群落和地表甲虫群落均显示红松人工林、落叶松人工林和胡桃楸林群落结构聚为一类,蒙古栎林和阔叶混交林群落聚为一类;冗余度分析表明,凋落物厚度、植被盖度与树高因子可以解释地表节肢动物及地表甲虫群落差异的85.9%和81.9%。研究结果表明,研究区森林植被及凋落物状况、人为干扰是影响研究区大型地表节肢动物群落多样性的重要因素。     

大兴安岭重度火烧迹地地表土壤节肢动物群落特征

火是生态系统的主要干扰因子之一,直接影响地表土壤动物群落多样性。为了解大兴安岭火烧迹地地表土壤动物群落恢复状况,于2016年6月和8月,选取松岭区南瓮河国家级自然保护区内2006年落叶松白桦混交林重度火烧迹地为实验样地、未受干扰的混交林为对照样地,采用陷阱法研究地表土壤节肢动物群落组成与多样性。本研究共捕获地表土壤节肢动物17 460只,隶属5纲14目57科85属。其中大型土壤节肢动物隶属4纲11目36科55属,优势类群为铺道蚁属（Tetramorium）;中小型土壤节肢动物隶属2纲3目18科30属,优势类群为球角跳属（Hypogastrura）。整体而言,重度火烧迹地地表土壤节肢动物总个体数多于对照样地,而总类群数低于对照样地,但仅大型地表土壤节肢动物个体数明显低于对照样地（P < 0.05）。研究时段,8月份中小型土壤节肢动物的个体数明显高于6月份（P < 0.05）。群落多样性分析表明,重度火烧迹地与对照样地的地表土壤节肢动物群落多样性指数差异性不显著（P > 0.05）,其中6月份中小型地表土壤节肢动物Shannon-Wiener指数、Pielou均匀度指数与Margalef丰富度指数明显低于8月份（P < 0.01）,而6月份Simpson优势度指数高于8月份（P < 0.01）。火烧迹地与对照样地土壤节肢动物群落相似性系数为0.78,不同月份之间地表土壤节肢动物群落相似性均为0.43,表明地表土壤节肢动物群落总体变化较小,但地表土壤节肢动物群落随时间发生改变。地表土壤节肢动物对研究区域资源的利用存在明显的差异（P < 0.01）,重度火烧迹地可共同利用资源增多,对照样地可共同利用资源少而优势现象明显。重度火烧迹地地表主要土壤动物类群因可利用资源增加而导致生态位重叠指数增加。典型判别分析显示,地表土壤节肢动物群落受火烧干扰影响,且存在明显的季节变化。     

祁连山国家公园煤矿修复对地表节肢动物多样性的影响

高寒山区煤矿覆土回填和种植草本植物能够快速改善环境,强烈影响地表节肢动物多样性及其生态功能,地表节肢动物对煤矿修复的响应还会因海拔及放牧扰动强度的变化而异。选择祁连山国家公园甘肃片区中部西营河和东大河保护站煤矿修复区和毗邻草地(对照区)为研究对象,利用陷阱法调查煤矿修复区及对照区地表节肢动物的种类组成和数量变化,解析地表节肢动物群落及关键类群对煤矿修复的响应模式,确定影响地表节肢动物多样性变化的关键要素。结果表明,煤矿修复缩小了修复区和对照区地表节肢动物群落差异,但煤矿修复区和对照区地表节肢动物群落组成明显不同并存在地域差异。西营河煤矿修复显著提高了地表节肢动物活动密度,而东大河保护站煤矿修复导致地表节肢动物活动密度略有降低,地表节肢动物类群丰富度、多样性和均匀度指数变化与活动密度相反。主要地表节肢动物科对煤矿矿区修复的响应模式不同并存在区域差异,西营河保护站煤矿修复显著提高了平腹蛛科、微蛛亚科和隐翅虫科的活动密度,但显著降低了硬体盲蛛科和象甲科的活动密度;东大河保护站煤矿修复显著提高了步甲科活动密度,但降低了蚁科和狼蛛科的活动密度。pRDA排序结果表明,海拔高度和全氮含量解释了西营河...     

石家庄市菜用大豆田节肢动物群落结构及多样性

为明确河北省石家庄市菜用大豆田节肢动物群落结构特点及其多样性,应用马来氏网,对该地区菜用大豆田的节肢动物进行采集及种类鉴定,并对其群落结构组成、主要类群发生动态进行研究。结果表明：石家庄市菜用大豆田中共诱集到各类节肢动物3纲11目94科255种6927头,其中唇足纲45头,弹尾纲31头,昆虫纲6851头。在昆虫纲中,数量从大到小顺序为：半翅目＞双翅目＞鞘翅目＞缨翅目＞鳞翅目＞膜翅目＞脉翅目＞直翅目＞蜻蜓目。主要类群包括叶蝉科、蚜科、蓟马科、夜蛾科、薪甲科、瓢甲科、蚜蝇科。叶蝉、蚜虫、蓟马、夜蛾和叶甲为优势害虫种群。蚜蝇、瓢虫为主要天敌。该地区菜用大豆田的节肢动物种类和个体数量均远多于其他地区大豆地块。多样性分析表明,石家庄市菜用大豆田的节肢动物群落结构多样性指数、均匀度指数和丰富度指数均较高,说明该地区节肢动物群落具有较高稳定性。     

北京市海淀区土壤节肢动物群落特征

掌握城市土壤节肢动物的群落结构和物种组成对保护城市物种多样性具有重要意义.用手拣法和干漏斗法对北京市土壤节肢动物进行调查,共得土壤节肢动物样本4 984个,隶属6纲16目,共36个类群,其中蜱螨目、蚁科和弹尾目是优势类群,分别占个体总数的32.60%,27.83%,26.91%.不同功能区土壤节肢动物群落特征不同,平均密度为公园＞机关单位＞校园＞工业区＞交通干线＞住宅区,丰富度为公园＞交通干线＞校园＞工业区＞机关单位＞住宅区.不同地表植被状况下,土壤节肢动物的平均密度、丰富度和多样性指数排序均为林地＞草地＞行道树＞裸地.另外土壤节肢动物的个体数和类群数随着土层的加深而减少.北京市土壤节肢动物群落组成与同地带森林生态系统土壤节肢动物群落组成基本相同.     

黄河下游农业景观中不同生境类型地表节肢动物优势类群

生物多样性是连接景观异质性与生态系统服务的桥梁。在区域尺度上,以指示类群代替地表节肢动物类群,可以有效的开展生物多样性的保护工作。但是,在黄河下游农业景观中,关于地表节肢动物指示类群的研究报道较少。以黄河下游农业景观中4种生境类型(农田、林地、树篱和沟渠)为研究样地,且在农田生境中划分不同尺度(尺度1,3.6 hm2、尺度2,14 hm2和尺度3,28 hm2),通过调查不同生境中地表节肢动物分布及其多样性,结合地表节肢动物优势类群的辨识,分析了优势类群和地表节肢动物多样性的相关性,确定了研究区内地表节肢动物多样性的指示类群。结果发现:研究区内地表节肢动物优势类群为膜翅目、鞘翅目和蜘蛛目。树篱和林地生境的地表节肢动物多样性指示类群是膜翅目,农田生境中地表节肢动物多样性指示类群是鞘翅目,沟渠生境中地表节肢动物多样性指示类群是蜘蛛目。农田生境中优势类群间无相关性(P0.05);林地、沟渠和树篱生境中鞘翅目与蜘蛛目之间存在显著正相关(P0.01);林地和沟渠生境中,鞘翅目与膜翅目之间存在正相关(P0.05)。在农田生境中优势类群之间的相关性存在尺度依赖性,随着空间尺度的增大,相关性有一定的增强。在尺度2和尺度3上膜翅目和鞘翅目均存在正相关(P0.05),并且随着尺度增加而呈上升趋势。研究表明,黄河下游农业景观中不同生境类型地表节肢动物多样性的指示类群差别较大,其中树篱和林地生境具有较高的相似性,而农田生境地表节肢动物优势类群相关性存在尺度依赖性。在黄河下游农业景观中,以优势类群多样性代替地表节肢动物类群的多样性,可以在条件不足、时间紧迫的情况下更加有效的开展生物多样性的保护工作。     

Structure of ground-dwelling arthropod assemblages in vegetation units of Área Natural Protegida Península Valdés,Patagonia, Argentina

Knowing the spatial variation of insect and arachnid assemblages and their relationship with habitat variables is critical to understand the structure and dynamics of these communities in arid environments. The aim of this paper was to analyze the variation in ground-dwelling arthropod assemblages across three representative vegetation units of the Área Natural Protegida Península Valdés (Patagonia, Argentina). We asked whether environmental differences among representative vegetation units were associated to distinct arthropod assemblages. We selected three plant communities: grass, dwarf-shrub, and shrub steppes, and established three sampling sites within each of them. We measured variables of vegetation structure and soil characteristics and collected the arthropods using 10 pitfall traps per site. We analyzed the structure of arthropod assemblages at both family and ant species taxonomic levels. Each plant community displayed a distinctive assemblage, with differences in diversity, taxa abundance, trophic structure and functional groups of ants. Vegetation variables explained a higher proportion of the variation in the structure of the ground-dwelling arthropod assemblages than the soil variables. This work highlights the importance of the different vegetation units for the conservation of ground-dwelling arthropod biodiversity in Península Valdés.     

人工固沙植被恢复对地表节肢动物群落组成及多样性的影响

人工绿洲是干旱区主要的自然景观之一,为了维护绿洲稳定而营建的防护林强烈改变地表生态水文过程,进而影响着地上和地下生物多样性。然而,以往的研究对地上植被关注较多,而对土壤动物研究较少。以张掖绿洲外围人工固沙植被群落和天然固沙植被群落为研究对象,探讨人工固沙植被恢复对荒漠地表节肢动物群落组成及多样性的影响及不同动物类群对植被变化的响应模式。研究表明,天然固沙植被群落转变为人工固沙植被群落显著降低了地表节肢动物数量,但提高了地表节肢动物类群丰富度和多样性,这在5月份表现尤为明显。植被类型对地表节肢动物群落的影响不同,8月人工柽柳林群落地表节肢动物活动密度、类群丰富度和多样性均显著高于人工梭梭林群落。人工固沙植被恢复显著降低了适应荒漠环境的拟步甲科甲虫,而蚁科和部分蜘蛛的数量显著增加,它们对人工固沙植被恢复的响应模式不同决定了群落结构及多样性的变化规律。此外,研究还发现一些地表节肢动物类群对不同生境具有强烈的指示作用,如拟步甲科等可指示荒漠生境,潮虫科等可指示梭梭林生境,而蠼螋科和狼蛛科等可指示柽柳林生境。综上所述,人工栽植固沙灌木形成的固沙植被群落导致了一些适应荒漠环境的地表节肢动物类群的数量降低,但也为更多的地表节肢动物类群提供了适应栖居环境和充足的食物资源等,从而提高了地表节肢动物的多样性。     

Declines in a ground-dwelling arthropod community during an invasion by Sahara mustard (Brassica tournefortii) in aeolian sand habitats

Sahara Mustard (Brassica tournefortii; hereafter mustard), an exotic plant species, has invaded habitats throughout the arid southwestern United States. Mustard has reached high densities across aeolian sand habitats of southwestern deserts, including five distinct sand habitats in the eastern Coachella Valley, California. We examined trends in ground-dwelling arthropod community structure concurrent with mustard invasion in 90 plots within those habitats from 2003 to 2011 (n = 773 plot·years). We expected arthropod communities to respond negatively to mustard invasion because previous work documented significant negative impacts of mustard on diversity and biomass of native plants, the primary resource base for many of the arthropods. Arthropod abundance and species richness declined during the study period while mustard cover increased, and arthropod metrics were negatively related to mustard cover across all plots. When controlling for non-target environmental correlates (e.g. perennial frequency and precipitation) and for potential factors that we suspected of mediating mustard effects (e.g. native cover and sand compaction), negative relationships with mustard remained statistically supported. Nevertheless, arthropod richness’s relationship decreased slightly in strength and significance suggesting that mechanistic pathways may be both direct (via habitat structure) and indirect (via native cover suppression and sand compaction). However, mechanistic pathways for mustard effects, particularly on arthropod abundance, remain unclear. Most arthropod taxa, including most detritivores, decreased through time and were negatively related to mustard cover. In contrast, many predators were positively related to mustard. In total, our study provides substantial evidence for a negative effect of Sahara mustard on the structure of a ground-dwelling arthropod community.     

小兴安岭阔叶红松林地表甲虫Beta多样性

Beta多样性用来衡量集群内物种组成的变异性,可以被分解为空间物种转换和物种集群镶嵌两个组分,是揭示群落构建机制的重要基础。目前开展了较多的地上生态系统beta多样性研究,然而地下生态系统beta多样性进展缓慢。以小兴安岭凉水和丰林自然保护区为研究地区,于2015年8、10月采用陷阱法对阔叶红松林进行调查,揭示地表甲虫(步甲科、隐翅虫科、葬甲科)的beta多样性。结果表明:(1)凉水共发现39种、856只地表甲虫,丰林共发现43种、1182只地表甲虫。8月凉水明显具有较高的全部甲虫(三个科的总和)物种多样性和丰富度,10月正好相反。(2)凉水和丰林之间地表甲虫beta多样性的差异仅发现于8月的步甲科和葬甲科之间。(3)凉水和丰林地表甲虫的beta多样性主要由空间物种转换组成,物种集群镶嵌对beta多样性的贡献很小,说明地表甲虫物种组成变异主要由本地物种之间较高的转换引起。研究表明小兴安岭阔叶红松林地表甲虫的beta多样性主要由空间物种转换组成,在揭示群落构建机制过程中,其内部物种交换和环境调控不容忽视。     

An invasive plant-fungal mutualism reduces arthropod diversity

Ecological theory holds that competition and predation are the most important biotic forces affecting the composition of communities. Here, we expand this framework by demonstrating that mutualism can fundamentally alter community and food web structure. In large, replicated field plots, we manipulated the mutualism between a dominant plant ( Lolium arundinaceum ) and symbiotic fungal endophyte ( Neotyphodium coenophialum ). The presence of the mutualism reduced arthropod abundance up to 70%, reduced arthropod diversity nearly 20%, shifted arthropod species composition relative to endophyte-free plots and suppressed the biomass and richness of other plant species in the community. Herbivorous arthropods were more strongly affected than carnivores, and for both herbivores and carnivores, effects of the mutualism appeared to propagate indirectly via organisms occurring more basally in the food web. The influence of the mutualism was as great or greater than previously documented effects of competition and predation on arthropod communities. Our work demonstrates that a keystone mutualism can significantly reduce arthropod biodiversity at a broad community scale.     

Effect of Argentine ant invasions on ground-dwelling arthropods in northern California riparian woodlands

Although the Argentine ant (Linepithema humile) is a widespread invasive species that displaces native ants throughout its introduced range, the effects of these invasions on arthropods other than ants remain poorly known. This study documents the consequences of Argentine ant invasions on ants and other ground-dwelling arthropods in northern California riparian woodlands. Baits and unbaited pitfall traps were used to sample different components of the arthropod communities at five pairs of uninvaded and invaded sites. Sites occupied by Argentine ants supported almost no native epigeic ants except for the winter-active Prenolepis imparis. Sites with Argentine ants averaged four to ten times more ant workers than did sites with native ants, but ant worker biomass did not differ between uninvaded and invaded sites. Argentine ants recruited to baits in invaded areas, on average, in less than half the time of native ants in uninvaded areas. Despite the loss of epigeic native ants, higher Argentine ant worker abundance, and faster recruitment by Argentine ants at invaded sites, pitfall trap samples from uninvaded and invaded areas contained similar abundances and diversities of non-ant arthropods. These findings suggest that Argentine ants and the native ants they displace interact with the ground-dwelling arthropods of these habitats in a similar manner. Received: 24 February 1997 / Accepted: 9 November 1997     

热带次生林、旱稻种植地和火烧迹地土壤节肢动物群落结构特征及季节变化

通过模拟刀耕火种过程 ,对刀耕火种前后的次生林、旱稻地 (第 2年 )和火烧迹地 (火烧后直接撂荒地第 2年 )土壤节肢动物群落结构特征及季节变化进行了调查研究。结果显示 :3块样地土壤节肢动物群落的优势类群组成相同 ,均为蜱螨目、膜翅目和弹尾目 ,但不同生境样地中各优势类群所占群落总数的比例不同 ,并且 3样地常见和稀有类群的组成差异较大 ;土壤节肢动物类群数、个体数和 DG多样性指数表现为次生林高于其它 2块样地 ,而旱稻地和火烧迹地则无较大差异 ,但一些类群在旱稻地、火烧迹地的数量分布与次生林具有差异 ,且在土壤层的表现较为突出 ;3块样地土壤节肢动物群落具有较好相似性 ,其中旱稻地与火烧迹地达到极相似水平 (D、DS>0 .9)。3种不同类型生境土壤节肢动物群落在类群数、个体数和多样性指数的季节变化总体呈现出雨量少的干季或雨季初末期高于雨量最大的雨季中期 ,与当地降雨量和气温变化有密切关系 ,同时各样地土壤节肢动物群落因生境条件不同及人为活动干扰强弱而形成各自的季节消长特点。研究表明刀耕火种后的旱稻种植对土壤节肢动物群落的恢复和发展在一定限制条件 (面积、周围次生林和坡度 )下无破坏性影响 ,但植被改变、农事活动等对直接撂荒地和旱稻地土壤节肢动物群落的季节消长产生     

Shrubs and species identity effects on the distribution and diversity of ground-dwelling arthropods in a Gobi desert

Disentangling the relationship between shrub vegetation and ground-dwelling arthropods at multiple levels of taxonomic resolution is essential to developing a suitable management strategy for the conservation of shrub-associated arthropod biodiversity in shrubland ecosystems. Using Gobi desert (dominated by shrub species Nitraria sphaerocarpa and Reaumuria soongorica) occurring widely in inland arid areas of northwest China as a model system, we sampled ground-dwelling arthropods by pitfall trapping method under canopies of both shrubs and in intershrub bare areas during spring, summer and autumn. Our aim was to determine whether the presence and species identity of shrubs influence the distribution of ground-dwelling arthropods and whether the influence of shrub presence and species identity differs among trophic and taxonomic groups. At the community level, total arthropod abundance and species richness were significantly greater under shrubs than in intershrub bare habitats, whereas more arthropods were captured under N. sphaerocarpa than under R. soongorica. At the trophic group level, the abundance of predator and decomposer arthropods was significantly greater under shrubs than in intershrub bare habitats, whereas herbivore and decomposer arthropods were more abundant under N. sphaerocarpa than under R. soongorica. At the family level, the abundance of Carabidae, Gnaphosidae, Karschiidae, Tenebrionidae and Thomisidae was consistently much greater under shrubs than in intershrub bare habitats, whereas that of Formicidae, Philodromidae and Tettigoniidae did not differ between the shrub microhabitats and the intershrub bare habitats. However, the abundance of Curculionidae under R. soongorica and the abundance of Geotrupidae under N. sphaerocarpa were significantly lower than that in intershrub bare habitats. N. sphaerocarpa was commonly preferred by arthropods in the families of Curculionidae and Tenebrionidae, whereas R. soongorica was commonly preferred by arthropods in the family Geotrupidae, but shrub species identity did not affect the abundance of the remaining families. Our results suggest that shrubs and species identity play important roles in structuring ground-dwelling arthropod communities, but the response of arthropods differed among trophic or taxonomic groups. This study may have important implications for the conservation of invertebrate biodiversity in Gobi desert ecosystems.     

Plant genotypic diversity and environmental stress interact to negatively affect arthropod community diversity

Many studies have found positive relationships between plant diversity and arthropod communities, but the interactive effects of plant genetic diversity and environmental stress on arthropods are not well documented. In this study, we investigated the consequences of plant genotypic diversity, watering treatment, and its interaction for the ground-dwelling arthropod community in an experimental common garden of quaking aspen (Populus tremuloides Michx.). We found that varying plant genotypic diversity and watering treatment altered multivariate arthropod community composition and structure. Arthropod biodiversity and richness showed a distinct response to the plant diversity × watering treatment interaction, declining sharply in water-limited genotypic mixtures. Abundance of arthropod functional groups did not show any response to diversity or the plant diversity × watering treatment interaction, but varied in their response to watering treatment, with predator and detritivore abundance increasing and parasitoid abundance decreasing in well-watered blocks. Our results conflict with most previous studies, and suggest that environmental stress can substantially change the nature of the plant-arthropod diversity relationship. Additionally, we suggest that the plant-arthropod diversity relationship is dependent on the type of plant and arthropod species sampled, and that the association between tree diversity and ground-dwelling arthropods may be much different than more commonly studied grassland species and herbivorous arthropods.