共查询到20条相似文献，搜索用时 375 毫秒
1.
乌拉特荒漠草原群落物种多样性和生物量关系对放牧强度的响应 总被引：1，自引：0，他引：1
以内蒙古乌拉特荒漠草原灌丛和草本植物群落为对象,研究这2种植物群落的物种组成、物种多样性及其与地上生物量关系对不同放牧处理(对照、中牧、重牧)的响应。结果表明:①随着放牧强度的增加,灌丛群落中红砂(Reaumuria songarica)和碱韭(Allium polyrhizum)的优势度增大,沙生针茅(Stipa glareosa)的优势度减小;重牧降低草本群落中沙生针茅的优势度,增加了蒙古韭(Allium mongolicum)和碱韭的优势度。②不同放牧处理显著降低了灌丛和草本群落的盖度、高度以及灌丛群落的密度,消除了灌丛和草本群落之间盖度的差异(P> 0. 05)。中牧降低灌丛群落的Pielou均匀度指数,重牧降低灌丛群落的物种丰富度,灌丛和草本群落的其他多样性指数在放牧处理之间无显著差异(P> 0. 05)。除物种丰富度外,其他多样性指数在灌丛和草本群落之间差异显著(P <0. 05)。③不同放牧处理降低了灌丛和草本群落的地上生物量和凋落物量,导致灌丛和草本群落之间地上生物量的显著差异(P <0. 05)。④地上生物量与Simpson优势度指数负相关,与Shannon-Wienner多样性指数和Pielou均匀度指数正相关;放牧处理下地上生物量与密度、物种丰富度正相关。放牧处理改变了荒漠草原植物群落组成、结构和功能,进而改变了群落结构和功能的重要关系。 相似文献
2.
The paper analyzes the hypothesis that the distribution of dominant plant species and characteristics of plant communities are related to groundwater depth. The results showed that variations of groundwater depth impacted distributions and characteristics of dominant plant communities. However, besides groundwater depth, the community composition and species diversity were also influenced by physiognomy of the habitat. Based on the similarity coefficient, the differences between dominant plant communities were significant at different groundwater depths. Compared with other results relating to desert vegetation and groundwater depth, variations of community distribution were similar at the large spatial scale. However, in this extremely arid region, there were significant differences in community type and community succession when compared with other arid regions, especially in relationship to deep groundwater depth. With groundwater depth from deep to shallow, communities transformed with the sequence of Alhagi communities, Tamarix spp. communities, Populus communities, Phragmites communities, and Sophora communities. At groundwater depth of less than 6.0 m, the community type and composition changed, and the species diversity increased. Among these dominant species, Tamarix exhibited the biggest efficiency in resource utilization according to niche breadth, which means it possessed the best adaptability to environmental conditions at the oasis margins. 相似文献
3.
选择古尔班通古特沙漠的北部(一号点)、中部(二号点)、南部(三号点)3个不同样点的裸沙和藻结皮、地衣结皮与苔藓结皮3种生物结皮类型,对比研究了草本植物多样性的差异性及其主要环境影响因素。结果表明:(1)不同生物结皮类型的土壤理化性质有明显差异,土壤有机质、全氮、全磷、全钾含量以及黏粒、粉粒和细沙的含量随生物结皮演替显著上升,而中沙和粗沙的含量呈显著下降趋势,在沙漠不同区域呈现明显的空间异质性,二号样点中裸沙和藻结皮的养分含量和pH明显低于一号点和三号点。(2)草本植物的物种丰富度和Shannon-Wiener指数随生物结皮发育呈明显上升趋势,草本植物的物种组成、群落结构在不同类型生物结皮和沙漠不同区域均具有显著差异。(3)在土壤理化特征中,有机质、速效P和全K含量,以及pH和粉粒含量是影响草本植物分布的关键因子。(4)不同类型生物结皮之间的微地形和种类组成差异、种子生物学特性以及生物结皮在不同尺度下的土壤环境异质性共同影响草本植物在生物结皮中的物种组成和丰度,最终导致草本植物群落结构在生物结皮中的演替变化。 相似文献
4.
Plant community structure responds strongly to anthropogenic disturbances, which greatly influence community stability. The changes in community structure, aboveground biomass(AGB), biodiversity and community stability associated with different management practices were studied with a three-year field investigation in a temperate steppe of Inner Mongolia, China. The species richness, Shannon-Wiener index, evenness, plant functional type abundance, AGB, temporal community stability, summed covariance, scaling coefficient and dominant species stability were compared among areas subjected to long-term reservation(R), long-term grazing(G), mowing since enclosure in 2008(M) and grazing enclosure since 2008(E). Site R had higher perennial grass abundance and lower species richness than sites G, M and E, although the AGB was not significantly different among the four sites. The species structure varied from a single dominant species at site R to multiple dominant species at sites G, M and E. The long-term reservation grassland had lower biodiversity but higher stability, whereas the enclosed grassland with/without mowing had higher biodiversity but lower stability. Different stability mechanisms, such as the compensatory dynamics, mean-variance scaling and dominant species stability were examined. Results showed that community stability was most closely related to the relative stability of the dominant species, which supports the biomass ratio hypothesis proposed by Grime. 相似文献
5.
不同季节土庄绣线菊根围丛枝菌根真菌群落差异性研究 总被引：1，自引：0，他引：1
土庄绣线菊(Spiraea pubescens)是内蒙古大青山干旱生态系统重要的护土灌木,研究季节变化对土庄绣线菊根围丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)群落的影响,有助于进一步探讨AMF在土庄绣线菊生长发育过程中发挥的作用。采用传统染色检测与Illumina Mi Seq测序相结合的方法,研究季节变化对内蒙古大青山土庄绣线菊AMF侵染率、孢子密度、丰富度、多样性和群落组成的影响。结果显示:在春季、夏季和秋季,AMF侵染率和丛枝丰度不存在显著差异,而孢子密度却存在显著差异。AMF丰富度和多样性在夏季显著低于春季和秋季,但在春季和秋季间差异并不显著;主成分分析(principal coordinate analysis,PCo A)和PERMANOVA分析表明,春季和秋季AMF群落组成与夏季存在显著差异,而在春季和秋季间差异并不显著。 相似文献
6.
荒漠草原不同放牧制度群落多样性研究 总被引：2，自引：0，他引：2
在内蒙古苏尼特右旗荒漠草原,通过划区轮牧与自由放牧的比较试验,研究不同放牧制度下群落α多样性和β多样性。结果表明:①对照区、轮牧区和自由放牧区的植物种类丰富度和多样性均较前一年均有所增加,优势度指数除对照区有所增加,轮牧区和自由放牧区基本不变化;均匀度指数轮牧区和自由放牧区均略有下降。②物种丰富度指数与均匀度指数呈负相关,荒漠草原植物群落多样性更多地受丰富度的影响。③对照区、轮牧区和自由放牧区群落β多样性指数随取样面积增加而降低;荒漠草原在不放牧、自由放牧和划区轮牧下,轮牧区β多样性指数最高,其次为对照区和自由放牧区;④2004年轮牧区与自由放牧区的相似性系数为最高,其次为轮牧区与对照区;自由放牧区与对照区差异最大。到了2005年,除轮牧区与自由区的相似性系数降低外,轮牧区与对照区、自由区与对照区的相似性系数均有所增加。 相似文献
7.
Species richness and abundance are two important species diversity variables that have attracted particular attention because of their significance in determining present and future species composition conditions.This paper aims to explain the qualitative and quantitative relationships between species diversity pattern and grain size(i.e.size of the sampling unit),and species diversity pattern and sampling area,and to analyze species diversity variability on active sand dunes in the Horqin Sandy Land,northeastern Inner Mongolia,China.A 50 m×50 m sampling plot was selected on the windward slope,where the dominant species was annual herb Agriophyllum squarrosum.Species composition and abundance at five grain sizes were recorded,and the species-area curves were produced for thirteen grain sizes.The range of values for species abundance tended to increase with increasing grain size in the study area,whereas,generally,species richness did not follow this rule because of poor species richness on the windward slope of active sand dunes.However,the homogeneity of species richness increased significantly.With the increase in sampling area,species abundance increased linearly,but richness increased logarithmically.Furthermore,variograms showed that species diversity on the windward slope of active sand dunes was weakly anisotropic and the distribution pattern was random,according to the Moran Coefficient.The results also showed that species richness was low,with a random distribution pattern.This conflicts with the results of previous studies that showed spatial aggregation in lower richness in a sampling area within a community and inferred that the physical processes play a more important role in species diversity than distribution pattern on active sand dunes.Further research into different diversity patterns and mechanisms between active sand dunes and interdune lowlands should be conducted to better understand biodiversity conservation in sand dune fields. 相似文献
8.
为明确外来入侵植物对本地湿地植物多样性的影响，在北京市湿地选择23个样地共245个样方进行物种多样性调查，并从不同植物性状数据库获取样方中所有植物的株高、叶长、叶宽、叶面积和比叶面积等10个功能性状数据，对比分析入侵群落与本地群落的物种多样性、系统发育多样性和功能多样性特征。结果显示，在北京市湿地共记录到26种外来入侵草本植物，隶属10科19属，其中，菊科外来入侵植物种类最多，有10种。除比叶面积、叶片碳含量和株高的系统发育信号显著外，其余7种植物功能性状的系统发育信号均不显著，表明大多数功能性状未表现出系统发育保守性。入侵群落所有物种的物种多样性指标Shannon-Wiener多样性指数、物种丰富度指数和Simpson优势度指数以及系统发育多样性指标谱系多样性和平均最近谱系发育距离均显著高于本地群落和入侵群落本地物种，而入侵群落本地物种的功能分散指数和Rao''Q二次熵指数均显著高于本地群落，表明外来物种入侵改变了湿地植物的生物多样性，且外来物种入侵后群落谱系多样性趋于发散，说明与本地植物亲缘关系越远的入侵物种越容易在湿地群落中建立种群，符合达尔文归化假说。 相似文献
9.
稻田捕食性节肢动物群落的种库与群落的重建 总被引：30，自引：1，他引：30
本文对稻田捕食性节肢动物群落的种库和群落的重建进行了初步的研究。害虫防治史、植被覆盖度、环境复杂性和气候因子等对种库都有不同程度的影响。种库的结构决定了群落的重建。重建群落的优势种、物种丰富度和群落多样性与种库呈正相关关系。生产上可采取适当的措施保护天敌群落的种库，促进天敌群落的迅速重建，充分发挥天敌对害虫的控制作用 相似文献
10.
克拉玛依植物群落结构和物种多样性研究 总被引：1，自引：0，他引：1
采用多样性指数,丰富度指数和均匀度指数对克拉玛依植物群落物种多样性进行了研究。结果表明:各群落类型的物种多样性指数的顺序为:梭梭+碱蓬>花花柴、胡杨>碱蓬+麻黄>柽柳>琵琶柴>猪毛菜>梭梭>芦苇>盐节木>白刺+柽柳;灌木和乔木群落多样性指数和丰富度指数大于草本群落,而均匀度指数在乔木,灌木和草本群落中则表现出多样化的趋势。 相似文献
11.
乌兰布和沙漠东北部几种白刺群落植物多样性研究 总被引：2，自引：0，他引：2
根据对乌兰布和沙漠东北部4种白刺植物群落的样地调查数据,采用物种丰富度指数S、Shannon-Wiener指数H'、Simpson指数D、Pielou均匀度指数J、Alatalo均匀度指数Ea、Whittaker指数βw、相异性系数CD、群落共有度Jaccard指数CP、Bray-Curtis指数CN等指标研究了该地区4种白刺群落分层的α多样性和β多样性。结果表明:这些α多样性和β多样性测度指标有效表征了干旱沙漠区同属不同植物群落内部在物种组成方面的差异、生境差异、群落间物种组成差异。四种白刺群落的草本层的物种丰富度指数都明显大于灌木层;唐古特白刺群落的物种丰富度指数最小,泡泡刺群落的物种多样性Shannon-Wiener指数H'和Simpson指数D最大,而且其群落均匀度也最大。唐古特白刺植物群落的Whittaker指数βw要比其它三种白刺群落要大,若仅考虑群落间共有物种数目多少,大白刺与泡泡刺在群落、灌木层与草本层间的相异性系数CD都最小,共有度Jaccard指数CP都最大;而西伯利亚白刺群落、灌木层和草本层与其余三种白刺的相异性系数CD都较大,Jaccard指数CP都较小。而数量数据指标Bray-Curtis指数CN变化与上述有所不同。采用植物盖度和相对盖度进行α多样性和β多样性对比分析,能够合理地说明不同白刺植物多样性特征。 相似文献
12.
Community structure and carbon and nitrogen storage of sagebrush desert under grazing exclusion in Northwest China 总被引：1，自引：0，他引：1
Overgrazing is regarded as one of the key factors of vegetation and soil degradation in the arid and semi-arid regions of Northwest China.Grazing exclusion(GE)is one of the most common pathways used to restore degraded grasslands and to improve their ecosystem services.Nevertheless,there are still significant controversies concerning GE’s effects on grassland diversity as well as carbon(C)and nitrogen(N)storage.It remains poorly understood in the arid desert regions,whilst being essential for the sustainable use of grassland resources.To assess the effects of GE on community characteristics and C and N storage of desert plant community in the arid desert regions,we investigated the community structure and plant biomass,as well as C and N storage of plants and soil(0-100 cm depth)in short-term GE(three years)plots and adjacent long-term freely grazing(FG)plots in the areas of sagebrush desert in Northwest China,which are important both for spring-autumn seasonal pasture and for ecological conservation.Our findings indicated that GE was beneficial to the average height,coverage and aboveground biomass(including stems,leaves and inflorescences,and litter)of desert plant community,to the species richness and importance values of subshrubs and perennial herbs,and to the biomass C and N storage of aboveground parts(P<0.05).However,GE was not beneficial to the importance values of annual herbs,root/shoot ratio and total N concentration in the 0-5 and 5-10 cm soil layers(P<0.05).Additionally,the plant density,belowground biomass,and soil organic C concentration and C storage in the 0-100 cm soil layer could not be significantly changed by short-term GE(three years).The results suggest that,although GE was not beneficial for C sequestration in the sagebrush desert ecosystem,it is an effective strategy for improving productivity,diversity,and C and N storage of plants.As a result,GE can be used to rehabilitate degraded grasslands in the arid desert regions of Northwest China. 相似文献
13.
14.
荒漠草原地区不同载畜率对功能群特征及其多样性的影响 总被引：6，自引：0，他引：6
采用随机区组试验研究了内蒙古高原荒漠草原亚带短花针茅(Stipa breviflora)草原群落不同载畜率对草原功能群特征及其多样性的影响,结果表明:不同载畜率水平下,功能群组成结构没有改变,功能群内物种组成及其群落学特征随着载畜率的增加发生了相应的变化。灌木类和多年生禾草特性比较稳定,多年生杂类草随着载畜率的增加物种组成下降幅度较大,使得群落结构和组成随载畜率的增加趋于简单化。丰富度指数和多样性指数重牧区最低,均匀度变化有所不同,因为中度放牧提高草地群落的植物多样性,更主要地是通过改变群落物种均匀性来实现的。 相似文献
15.
克拉玛依植物群落物种多样性研究 总被引：3，自引：0，他引：3
根据30个样地102个样方的调查资料,采用Simpson多样性指数、Shannon-Wiener多样性指数、Gleason丰富度指数[17]、Simpson优势度指数与Pielou均匀度指数[16]对克拉玛依植物群落进行研究。研究结果表明:克拉玛依植物群落结构简单、物种稀少,群落物种多样性水平较低,群落多样性指数的顺序为:胡杨群落﹥柽柳群落﹥梭梭群落﹥琵琶柴群落﹥芦苇群落﹥假木贼群落﹥猪毛菜群落﹥盐节木群落﹥碱蓬+麻黄群落﹥盐穗木群落。随着水分与土壤盐碱度的变化,群落物种多样性出现相应的变化趋势:乔木群落﹥灌木群落﹥草本群落。 相似文献
16.
As the increases of climatic aridity and grazing intensity,shrubs play an increasingly important role in grassland ecosystem in arid and semi-arid regions,and its abundance also generally increases.However,the effects of climatic aridity and grazing intensity on sexual reproduction of shrubs in grassland remain largely unclear.In order to understand the effects of grazing intensity and climatic drought stress,and their interaction on seed production of shrub species,we examined the seed number,seed weight and seed yield of Caragana stenophylla under three grazing intensities(fenced,mild grazing and severe grazing) across a climatic aridity gradient(semi-arid,arid,very arid and intensively arid zones) in the Inner Mongolia Steppe,northern China during 2012–2013.The seed number,seed weight and seed yield gradually increased from the semi-arid to the very arid zones,but decreased from the very arid to the intensively arid zones in fenced plots.The seed number and seed yield decreased from the semi-arid to the intensively arid zones in mild and severe grazing treatment plots,therefore,grazing enhanced the suppression effect of climatic aridity on seed production of C.stenophylla.The seed number and seed yield gradually decreased as grazing intensity increased.The seed weight was highest in severe grazing plots,followed by the mild grazing plots and then the fenced plots.Precipitation varied interannually during the study period.We observed that the seed number,seed weight and seed yield were lower in the low precipitation year(2013) than in the high precipitation year(2012).As climatic drought stress increased,the negative effects of grazing on seed production of C.stenophylla also gradually increased.Our results indicated that climatic drought stress may contribute to the encroachment of C.stenophylla shrub in arid zones by promoting its seed production.However,grazing had negative effects on sexual reproduction of C.stenophylla,and the combined effects of drought stress and grazing seriously suppressed sexual reproduction of C.stenophylla in the intensively arid zone. 相似文献
17.
在对江西南昌市梅岭景区6个典型景点中的蜘蛛多样性进行调查、鉴定并获得其蜘蛛资源详实分布名录的基础上,结合另文对其多样性的比较研究结果,通过将其39个未确定种的各科属级物种丰富度、景点物种多样性、群落结构多样性和捕食功能多样性共13个指数作为变量对其区域特色种作用因子进行主成分、相关性和聚类等统计分析,揭示其多样性形成原因和方式。结果表明:景点物种均匀度、景点物种丰富度、景点物种优势度、捕食功能均匀度、群落结构丰富度、捕食功能丰富度是区域特色种形成的6个主要作用因子,各因子间普遍相关,且生态和遗传因素各有侧重地作用于区域特色种的形成。 相似文献
18.
宁夏六盘山国家级自然保护区蝴蝶多样性调查 总被引：1，自引：0，他引：1
为明确宁夏六盘山国家自然保护区蝴蝶群落结构的多样性及其与季节变化特征的关系,采用样线法于2017年4—9月对该保护区内3种不同生境中的蝴蝶群落结构及其多样性时间动态进行调查,并对蝴蝶群落的多样性指数、丰富度指数、均匀度指数及优势度指数的变化进行分析。结果显示,在该保护区内共记录蝴蝶标本1 030号,隶属7科38属54种。在不同生境中,眼蝶科Satyridae为优势类群,相对多度为31.55%,绢蝶科Parnassiidae为稀有类群,相对多度为0.10%;蛱蝶科Nymphalidae蝴蝶群落的多样性指数、丰富度指数和均匀度指数均最高,分别为1.52、3.53和0.96;凤蝶科Papilionidae蝴蝶群落的优势度指数最高,为0.67;绢蝶科蝴蝶群落的丰富度指数、优势度指数和均匀度指数最低,均为0。在不同调查时间内,粉蝶科Pieridae蝴蝶群落的优势度指数和多样性指数均最高,分别为0.80和2.30;蛱蝶科蝴蝶群落的丰富度指数最高,为3.53;绢蝶科蝴蝶群落的均匀度指数最高,为1.00,但多样性指数、丰富度指数和优势度指数均最低,为0。6月记录到的蝴蝶个体数最多,为384只,9月记录到的个体数最少,仅21只。在物种的时间相似性方面,9月与其它各月的相似性最低,相似系数仅为0.13,处于极不相似水平;6月和7月的相似性最高,相似系数为0.57,处于中等相似水平,其它调查时间的相似性均处于中等不相似水平。表明不同生境和季节的蝴蝶优势种可以作为对生境状况进行评估的指示类群,生境差异性和干扰与蝴蝶群落的物种多样性密切相关,保护六盘山国家自然保护区植被的生境异质性和维持适度干扰是保护蝴蝶多样性的关键。 相似文献
19.
The role of community composition in grassland response to two methods of exotic forb removal 
下载免费PDF全文
下载免费PDF全文 Invasive plants can seriously threaten biodiversity and ecosystem function. Thus, controlling the abundance and mitigating the deleterious effects of invasive plants is imperative. The effectiveness of removal methods could vary based on potential damage to non‐target species and on the ecological context of invasion. For example, species‐poor communities might benefit disproportionately from invasive removal because they tend to be more heavily invaded than species‐rich communities. In this study, we tested the efficacy of two common methods of invasive plant control, hand removal and 2,4‐D herbicide application, against the invasive forb, Galium verum. We further tested whether the community response to G. verum removal varied across communities that differed in native grass richness (one, three or six species) and composition. Grass diversity did not interact with G. verum removal to influence any response. Instead, hand removal and herbicide application each reduced G. verum stem density by >50% relative to controls. Furthermore, hand removal of G. verum increased species richness by 25% relative to controls and herbicide‐sprayed plots. Despite this benefit, hand removal is labour‐intensive and impractical for large areas. These results also suggest that applying herbicide may control G. verum spread without substantially reducing forb diversity in invaded tallgrass prairie. Thus, herbicide application may be most suitable for grasslands with low native forb diversity, especially in managed grasslands and pastures where maintaining native forb diversity is a lower priority than maintaining high grass productivity. 相似文献
20.
Biological invasions are determined by interactions between resident plant communities and exotic plants. Time of invasion and species diversity of resident plant communities may greatly affect exotic plant invasions. We assembled low‐ and high‐diversity resident plant communities by sowing seeds of four and eight grassland species, respectively, and at each of three time periods (1, 4 and 7 weeks after sowing), the resident communities were invaded by Hydrocotyle vulgaris or not. We also constructed a plant community with H. vulgaris alone. Presence of H. vulgaris had no effect on biomass of the resident communities or biomass of each component species. Community age significantly affected biomass and evenness of the resident communities, and their competition with H. vulgaris, but the priority effect of the resident communities was slight. Increasing species richness did not change the interaction between H. vulgaris and the resident plant communities. These findings suggest a weaker competitive exclusionary effect of H. vulgaris on the resident communities with early germination, and H. vulgaris tended to have no significant impact on intact resident terrestrial plant communities. Thus, the potential risk of H. vulgaris invasion is low, especially in the communities with young age. 相似文献