首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
    
Environmental variations are rapidly altering plant species and functional composition, which may have consequent influences on ecosystem functioning. We measured species and functional diversity of macrophyte community as well as environmental variables in 1,008 plots in 24 freshwater lakes across Yunnan–Guizhou plateau and Yangtze River in south China. We used generalized multilevel path models to test how the environmental effects on macrophytes productivity directly and indirectly through changes in species and functional diversity. We found distinct species and functional responses to the four groups of environmental variables:water quality, heterogeneity, climate, and topography. Macrophyte communities tended to be high richness and dominated by species with high‐stem dry mass content and long flowering duration at eutrophic, heterogeneous, high altitude, or deepwater habitats. Submersed and annual species with high‐specific leaf area dominated in heterogeneous and high altitude conditions, whereas species with high shoot and leaf dry mass content as well as thin stem and lamina dominated in heterogeneous and low‐altitude conditions. Functional dispersion (FDis) decreased in heterogeneous and high‐altitude habitats and increased at deepwater. These changes in functional composition have subsequently significant influences on community productivity, involving the opposite pathways of positive effects of community‐weighted mean (CWM) traits and negative effects of FDis, ultimately contributing to the observed invariable macrophytes productivity along the tested environmental gradients. Our results provide strong evidences that both species and functional composition mediate the cascading effects of environments on macrophytes productivity.  相似文献   

3.
    
Functional diversity is increasingly recognized by microbial ecologists as the essential link between biodiversity patterns and ecosystem functioning, determining the trophic relationships and interactions between microorganisms, their participation in biogeochemical cycles, and their responses to environmental changes. Consequently, its definition and quantification have practical and theoretical implications. In this opinion paper, we present a synthesis on the concept of microbial functional diversity from its definition to its application. Initially, we revisit to the original definition of functional diversity, highlighting two fundamental aspects, the ecological unit under study and the functional traits used to characterize it. Then, we discuss how the particularities of the microbial world disallow the direct application of the concepts and tools developed for macroorganisms. Next, we provide a synthesis of the literature on the types of ecological units and functional traits available in microbial functional ecology. We also provide a list of more than 400 traits covering a wide array of environmentally relevant functions. Lastly, we provide examples of the use of functional diversity in microbial systems based on the different units and traits discussed herein. It is our hope that this paper will stimulate discussions and help the growing field of microbial functional ecology to realize a potential that thus far has only been attained in macrobial ecology.  相似文献   

4.
城市自生草本植物的物种多样性和功能多样性直接影响城市生态系统的功能和稳定性,但目前相关研究依然很缺乏。以深圳市为例,基于建成区600个1hm2样地的现场调查数据,分析自生草本植物的群落结构、物种多样性、群落功能特征及功能多样性。结果显示:(1)调查共记录自生草本植物61科178属273种,其中多年生草本占54.6%,乡土植物占65.6%。(2)占明显优势的功能特征有中小型叶(91.85%)、草质叶(42.59%)、纸质叶(32.96%)、叶片无毛或近无毛(56.67%)、中等密度绒毛(40.37%)、叶面较粗糙(52.59%)、花期4—6个月(50.78%)、果期4—6个月(49.22%)、干果(86.03%)。(3)群落类型间功能丰富度FDp、功能离散度Rao二次熵差异极显著(P<0.01)、功能均匀度FEve差异显著(P<0.05)。(4)公园绿地的物种多样性指数明显高于其他三类绿地;不同绿地类型间的功能丰富度和功能离散度在滞尘、降噪、降温增湿及生物多样性保护方面都有极显著差异(P<0.01),功能均匀度只在滞尘及生物多样性保护方面差异极显著(P<0.01)。(5)各功能多样性指数均与Margalef指数、Simpson指数及Shannon-Wiener指数呈极显著正相关关系(P<0.01)。研究结论和方法为维护城市生态系统稳定性、建设生态宜居城市、促进城市可持续发展提供理论依据。  相似文献   

5.
为了探讨观光木当年生枝条生物量的分配规律和叶片功能性状的变化规律及其影响因素,该研究以濒危物种观光木(Michelia odora)为对象,测定了广西地区5个不同纬度上观光木当年生小枝及叶片功能性状.结果表明:(1)随着纬度的增加小枝总重和总叶重总体呈异速生长关系,其生物量更多趋于对小枝的构建.(2)观光木叶功能性状呈...  相似文献   

6.
  总被引:1,自引:0,他引:1  
The ability to explain why multispecies assemblages produce greater biomass compared to monocultures, has been a central goal in the quest to understand biodiversity effects on ecosystem function. Species contributions to ecosystem function can be driven by two processes: niche complementarity and a selection effect that is influenced by fitness (competitive) differences, and both can be approximated with measures of species’ traits. It has been hypothesised that fitness differences are associated with few, singular traits while complementarity requires multidimensional trait measures. Here, using experimental data from plant assemblages, I show that the selection effect was strongest when trait dissimilarity was low, while complementarity was greatest with high trait dissimilarity. Selection effects were best explained by a single trait, plant height. Complementarity was correlated with dissimilarity across multiple traits, representing above and below ground processes. By identifying the relevant traits linked to ecosystem function, we obtain the ability to predict combinations of species that will maximise ecosystem function.  相似文献   

7.
    
The arbuscular mycorrhizal (AM) symbiosis is a key plant–microbe interaction in sustainable functioning ecosystems. Increasing anthropogenic disturbance poses a threat to AM fungal communities worldwide, but there is little empirical evidence about its potential negative consequences. In this global study, we sequenced AM fungal DNA in soil samples collected from pairs of natural (undisturbed) and anthropogenic (disturbed) plots in two ecosystem types (10 naturally wooded and six naturally unwooded ecosystems). We found that ecosystem type had stronger directional effects than anthropogenic disturbance on AM fungal alpha and beta diversity. However, disturbance increased alpha and beta diversity at sites where natural diversity was low and decreased diversity at sites where natural diversity was high. Cultured AM fungal taxa were more prevalent in anthropogenic than natural plots, probably due to their efficient colonization strategies and ability to recover from disturbance. We conclude that anthropogenic disturbance does not have a consistent directional effect on AM fungal diversity; rather, disturbance equalizes levels of diversity at large scales and causes changes in community functional structure.  相似文献   

8.
    
Classical old‐field succession studies focused on vegetation changes after the abandonment of annual croplands or on succession after the elimination of cultivated crops. Perennial‐crop‐mediated succession, where fields are initially covered by perennial crops, reveals alternative aspects of old‐field succession theories. We tested the validity of classical theories of old‐field succession for perennial‐crop‐mediated succession. We formulated the following hypotheses: (1) functional diversity increases with increasing field age; (2) resource acquisition versus conservation trade‐off shifts toward conservation at community level during the succession; (3) the importance of spatial and temporal seed dispersal decreases during the succession; and (4) competitiveness and stress‐tolerance increases and ruderality decreases at community level during the succession. We studied functional diversity, trait distributions and plant strategies in differently aged old‐fields using chronosequence method. We found increasing functional richness and functional divergence, but also unchanged or decreasing functional evenness. We detected a shift from resource acquisition to resource conservation strategy of communities during the succession. The role of spatial and temporal seed dispersal was found to be important not only at the initial but also at latter successional stages. We found an increasing stress‐tolerance and a decreasing ruderality during succession, while the competitiveness remained unchanged at the community level. Despite the markedly different starting conditions, we found that classical and perennial‐crop‐mediated old‐field successions have some similarities regarding the changes of functional diversity, resource acquisition versus conservation trade‐off, and seed dispersal strategies. However, we revealed also the subsequent differences. The competitive character of communities remained stable during the succession; hence, the initial stages of perennial‐crop‐mediated succession can be similar to the middle stages of classical old‐field succession. Moreover, the occupied functional niche space and differentiation were larger in the older stages, but resources were not effectively utilized within this space, suggesting that the stabilization of the vegetation requires more time.  相似文献   

9.
10.
11.
强烈扰动和环境胁迫对植物群落的物种多样性(SD)和功能多样性(FD)有重要影响, 但SD和FD随时间的变化模式及其关系至今少有研究。该研究通过对高寒矮生嵩草(Kobresia humilis)草甸为期7年(2007-2013年)的刈割(3个水平: 不刈割、留茬3 cm和留茬1 cm)和施肥(2个水平: 施肥和不施肥)控制实验探讨了SD和FD随时间的变化模式及其关系。研究结果显示: (1)刈割显著增加了SD和FD, 施肥处理则降低了SD, 对FD增加仅有微弱影响; (2)各处理群落的SD随着时间而下降, FD则随时间增加; (3)随着刈割强度的增加, SD(x)-FD(y)关系由正线性相关变为无相关, 斜率大小为slopel ≥ slopem > slopeh (下标l、m和h分别表示轻度、中度和重度扰动强度), 施肥并不会改变此关系形式和斜率; (4)刈割与施肥对SD和FD的互作效应都不显著, 且不施肥群落SD(x)-FD(y)关系的斜率也为slopel ≥ slopem > slopeh。上述结果说明, 刈割并不一定导致植物功能性状的趋同构建, 也能引发趋异构建, 而施肥引起的强烈种间竞争也并未显著增强趋异构建过程, 这与植物群落构建理论的预测不完全一致。与施肥相比, 刈割扰动是决定群落中SD-FD时间关系形式的主要因素, 并决定着SD-FD关系斜率的变化。  相似文献   

12.
何淑嫱  李伟  程希平  谭芮  松卫红 《生态学报》2019,39(6):2063-2070
高寒草甸具有重要的生态服务功能,然而固有脆弱性使其极易遭受气候变化和人为干扰等多重因素的影响。作为滇西北旅游资源中重要的组分之一,高寒草甸吸引了大批游客前往开展徒步旅行活动,但伴随着的践踏干扰作用会不可避免地对高寒草甸生态系统带来负面影响。然而,目前关注践踏干扰对滇西北高寒草甸植被的影响,特别是植被功能性状和功能多样性如何发生变化方面的研究还十分欠缺。以云南省香格里拉市碧塔海自然保护区内的典型高寒草甸生态系统为研究对象,采用实验践踏的方式(一共5种不同强度的践踏处理)来模拟旅游活动对草甸植被的干扰作用,并以草甸植被的茎叶性状特征为切入点,重点探讨践踏干扰对茎叶性状的平均大小和变异程度的影响,以及物种丰富度(以物种形态分类为基础)和功能丰富度(以功能性状为基础)之间的关系。研究结果显示,随着践踏强度的增加,植株高度和叶片大小的平均值,而不是茎叶性状的变异程度,出现明显下降趋势。此外,物种丰富度和功能丰富度均随践踏强度的增强而减小,且两者之间呈现显著正相关关系。然而,较之轻度践踏实验组,重度践踏实验组中的功能均匀度和功能分离度水平均有所增加,表明践踏干扰可能会在短期内打破优势种对资源的绝对占有格局和减少物种间的生态位重叠程度。尽管高寒草甸对人类践踏活动有一定的承受能力,但气候变化和人为干扰等多重因素势必会改变和影响高寒草甸群落的结构和功能可持续性,这也对高寒草甸的保护与管理工作提出了更加紧迫的要求。  相似文献   

13.
    
Environmental stressors and disturbances can cause changes in an ecosystem's community structure, which can be reflected in its functional diversity. As grazing intensity increases, this causes changes in the environment that inevitably lead to changes in the community structure, which can especially affect rodents due to their sensitivity to the environment. The effects of grazing prohibition and overgrazing on the functional diversity of desert rodent communities in Alxa were studied in April, July, and October of 2018–2020. The trap-day method was used to study rodent communities in disturbed habitats. Five functional traits were selected and quantified: nutrition, life history, physiology, morphology, and activity rhythm. The results showed that: (1) The species composition of rodent communities in the Alxa Desert in spring and autumn was significantly correlated with the functional traits of the hibernation, reproductive cycle, and feeding habits. The species composition in the summer was only significantly correlated with the functional traits of reproductive cycle and diet. (2) The effects of overgrazing on the functional diversity of rodents in desert areas have significant temporal and spatial characteristics. (3) In spring and summer, overgrazing made the Functional Richness index of the rodent community lower than that of areas where grazing is prohibited, but the Functional Evenness index was higher than that of grazing-prohibition areas. In autumn, overgrazing increased the Functional Richness index of the rodent community and decreased the Functional Evenness index. The Functional Divergence index was higher in overgrazing areas than in grazing-prohibited ones. These results suggest that, in spring and summer, overgrazing reduced the ecological space utilization ability of rodent communities; however, the impact on the degree of utilization of community resources is more comprehensive. In autumn, overgrazing increases the ability of rodent communities to use ecological space but reduces resource efficiency. Overgrazing makes the niche differentiation of rodent communities higher, the degree of overlap lower, and the competition between species weaker. Therefore, overgrazing will affect the functional diversity of the community through the utilization of ecological space, resource utilization, interspecific competition, and niche.  相似文献   

14.
    
  1. This study assessed the hypothesis that spatial and environmental drivers of river macrophyte diversity and community composition differ in relative importance in calcareous river systems located in warm regions of America versus Africa.
  2. We collected aquatic vegetation and spatio‐environmental data, during 2006–11, from >200 hardwater rivers, and associated floodplain waterbodies, located up to 30° north or south of the Equator, in México, Trinidad, Brazil, Argentina, U.S.A. (Florida), South Africa, Botswana and Zambia.
  3. Species rarefaction procedures were used to assess the impacts of differing sampling effort in the two continents upon estimation of γ‐diversity (“species pool”). We then used a cluster analysis approach (two‐way indicator species analysis: TWINSPAN) to classify samples into groups based upon species composition. Variation in species richness, community composition and six spatial and environmental variables, among samples making up these groups, were compared using ANOVA and Kruskal–Wallis procedures. Regression trees and redundancy analysis were used to infer the relative importance of spatial and environmental drivers in explaining variation in local species richness and species community composition between the two continents. Sorensen's index (Cs) was calculated to estimate species turnover (β‐diversity) between African and American samples.
  4. In total, 378 macrophyte taxa were recorded, with no significant difference in mean macrophyte α‐diversity between African and American sites, but with evidence for high species turnover between the two continents (Cs = 0.17). Rarefaction analysis confirmed the existence of a larger macrophyte species pool in the hardwater rivers sampled in Africa compared to America. TWINSPAN classification identified seven sample end‐groups, only one of which contained a mix of sites from both continents. PERMANOVA and non‐metric multidimensional scaling ordination analysis confirmed significant differences in community composition present in these sample‐groups. There were substantial differences between the sample‐groups for α‐diversity, and for spatial and environmental variables.
  5. The high species turnover between Africa and America may be accounted for by geographical segregation, along with differences in aquatic habitat characteristics, and varying long‐distance dispersal capacities of individual species. The relative importance of spatial and physicochemical drivers (latitude, pH, altitude, alkalinity and electrical conductivity but not flow) differed between the continents in influencing variation in both macrophyte diversity and community composition. Latitude was a significant, although nonlinear and rather complex, spatial driver of macrophyte α‐diversity in both American and African hardwater rivers. Water chemistry variables varied in relative importance as drivers of macrophyte α‐diversity for African and American sites individually, and for all sites combined, but pH and/or electrical conductivity were more important than alkalinity in each case. In all three cases, altitude was consistently the third most important driver of α‐diversity. Spatial and environmental variables played important roles in structuring macrophyte community composition in warm‐water calcareous rivers in both America and Africa, with latitude being the strongest individual driver. Thus, this spatial variable, which is a surrogate for numerous enviro‐climatic variables, appears to be of importance in determining macrophyte distributions at large spatial scales, for the ecosystem type examined here.
  相似文献   

15.
16.
17.
    
Tropical montane forests comprise heterogeneous environments along natural gradients of topography and elevation. Human‐induced edge effects further increase the environmental heterogeneity in these forests. The simultaneous effects of natural and human‐induced gradients on the functional diversity of plant leaf traits are poorly understood. In a tropical montane forest in Bolivia, we studied environmental gradients associated with elevation (from 1900 m to 2500 m asl), topography (ridge and gorge), and edge effects (forest edge vs. forest interior), and their relationship with leaf traits and resource‐use strategies. First, we investigated associations of environmental conditions (soil properties and microclimate) with six leaf traits, measured on 119 woody plant species. Second, we evaluated changes in functional composition with community‐weighted means and functional structure with multidimensional functional diversity indices (FRic, FEve and FDiv). We found significant associations between leaf traits and soil properties in accordance with the trade‐off between acquisition and conservation of resources. Functional composition of leaf traits shifted from the dominance of acquisitive species in habitats at low altitudes, gorges, and forest interior to the dominance of conservative species in habitats at high altitudes, ridges, and forest edges. Functional structure was only weakly associated with the environmental gradients. Natural and human‐induced environmental gradients, especially soil properties, are important for driving leaf traits and resource‐use strategies of woody plants. Nevertheless, weak associations between functional structure and environmental gradients suggest a high redundancy of functional leaf traits in this tropical montane forest.  相似文献   

18.
19.
  总被引:1,自引:0,他引:1  
Litter decomposition is a key process of nutrient and carbon cycling in terrestrial ecosystems. The decomposition process will likely be altered under ongoing climate change, both through direct effects on decomposer activity and through indirect effects caused by changes in litter quality. We studied how hydrological change indirectly affects decomposition via plant functional community restructuring caused by changes in plant species’ relative abundances (community‐weighted mean (CWM) traits and functional diversity). We further assessed how those indirect litter quality effects compare to direct effects. We set up a mesocosm experiment, in which sown grassland communities and natural turf pieces were subjected to different hydrological conditions (dryness and waterlogging) for two growing seasons. Species‐level mean traits were obtained from trait databases and combined with species’ relative abundances to assess functional community restructuring. We studied decomposition of mixed litter from these communities in a common “litterbed.” These indirect effects were compared to effects of different hydrological conditions on soil respiration and on decomposition of standard litter (direct effects). Dryness reduced biomass production in sown communities and natural turf pieces, while waterlogging only reduced biomass in sown communities. Hydrological stress caused profound shifts in species’ abundances and consequently in plant functional community composition. Hydrologically stressed communities had higher CMW leaf dry matter content, lower CMW leaf nitrogen content, and lower functional diversity. Lower CWM leaf N content and functional diversity were strongly related to slower decomposition. These indirect effects paralleled direct effects, but were larger and longer‐lasting. Species mean traits from trait databases had therefore considerable predictive power for decomposition. Our results show that stressful soil moisture conditions, that are likely to occur more frequently in the future, quickly shift species’ abundances. The resulting functional community restructuring will decelerate decomposition under hydrological stress.  相似文献   

20.
香溪河水生昆虫功能性状及功能多样性空间格局   总被引:1,自引:0,他引:1       下载免费PDF全文
蒋万祥  何逢志  蔡庆华 《生态学报》2017,37(6):1861-1870
近年来,生物多样性研究已从群落物种多样性拓展至功能多样性层面,使用功能性状表征功能组成及功能多样性是当前底栖动物生态学研究的热点之一。物种功能性状对环境变化敏感,对群落和种群沿环境梯度的演替具有许多潜在的指示作用。为了解香溪河水系水生昆虫功能性状空间分布格局及环境因子对功能多样性的影响,于2005年12月及2006年1月、2月对该水系的香溪河、九冲河、高岚河、古夫河4条河流的水生昆虫进行了调查,并对理化指标进行了测定;参考相关文献资料,本研究选择化性、漂移性、游泳能力、吸附能力、形状、个体大小、流态偏好、温度偏好、生活型、营养习性等10个功能性状纳入分析。研究结果发现,香溪河水系共鉴定水生昆虫127种,四节蜉(Baetis sp.)、高翔蜉(Epeorus sp.)、短尾石蝇(Nemoura sp.)为区域优势分类单元,相对丰度分别为38.6%、9.1%、6.7%;4条河流间优势物种组成差异较大。10个功能性状中相对丰度最高的等级性状分别为1世代/a(Volt2)、高漂移率(Drft3)、无游泳能力(Swim1)、无吸附能力(Atch1)、流线型(Shpe1)、小型个体(Size1)、沉积/侵蚀流态兼好型(Rheo2)、广温型(Ther2)、附着型(Habi4)、收集者(Trop1);单因素方差分析及独立样本T检验表明,化性、附着能力、大小、流速偏好、温度偏好、漂移性、生活型、营养习性等性状级别间差异显著,而游泳能力、形状性状等级间无显著差异。对10个功能性状的33个等级性状在4条河流间相对丰度的差异性进行研究,结果发现,Volt1、Drft2、Swim2、Atch1、Atch2、Size3、Rheo1、Ther3、Habi2、Habi3、Trop3、Trop5等12个等级性状相对丰度在4条河流间差异显著。功能性状多样性、树状图功能多样性用来描述4条河流功能多样性,结果表明,功能性状多样性指数均值在古夫河、高岚河、九冲河、香溪河分别为2.8、3.2、6.9和5.4;树状图功能多样性指数均值在分别为4.8、5.7、11.1、8.8。功能冗余度均值在4条河流分别为2.9、3.4、4.6、3.9。运用逐步回归分析功能多样性、功能冗余度与环境参数的关系,结果表明,功能性状多样性指数受总氮、水深影响显著;树状图功能多样性指数受总氮、水深、流速影响显著;功能冗余度指数受硝态氮、溶解氧、二氧化硅影响显著。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号