共查询到20条相似文献，搜索用时 15 毫秒
1.
Sean R. Connolly 《Ecology letters》2013,16(2):140-150
A major ecosystem effect of biodiversity is to stabilise assemblages that perform particular functions. However, diversity–stability relationships (DSRs) are analysed using a variety of different population and community properties, most of which are adopted from theory that makes several restrictive assumptions that are unlikely to be reflected in nature. Here, we construct a simple synthesis and generalisation of previous theory for the DSR. We show that community stability is a product of two quantities: the synchrony of population fluctuations, and an average species‐level population stability that is weighted by relative abundance. Weighted average population stability can be decomposed to consider effects of the mean‐variance scaling of abundance, changes in mean abundance with diversity and differences in species' mean abundance in monoculture. Our framework makes explicit how unevenness in the abundances of species in real communities influences the DSR, which occurs both through effects on community synchrony, and effects on weighted average population variability. This theory provides a more robust framework for analysing the results of empirical studies of the DSR, and facilitates the integration of findings from real and model communities. 相似文献
2.
Amparo Lázaro;Carmelo Gómez-Martínez;Miguel A. González-Estévez;Manuel Hidalgo; 《Ecography》2022,2022(3):e06112
Understanding how pollination services can be maintained in increasingly anthropogenic landscapes is a current challenge for basic and applied ecology. The stability of plant–pollinator communities might increase in heterogeneous landscapes with a high diversity of species and alternative habitats, both through larger independent fluctuations of populations (portfolio effect) and increased species asynchrony. However, how the drivers of stability (portfolio effect and synchrony) vary along land-use gradients remains largely unknown. Using independent samplings for plants, pollinators and their interactions in Mediterranean communities along a gradient of landscape heterogeneity, we assessed the relationships between within-year stability and its drivers, and between the drivers of stability, landscape heterogeneity and species diversity. In addition, we evaluated the relationship between the stability of plant–pollinator interactions (temporal mean/SD of pairwise interactions) and the structure of mutualistic networks (modularity, nestedness, connectance). As expected, stability increased with larger portfolio effects and asynchronies. Interaction stability was positively related to pollinator stability, but not to plant stability. Landscape evenness increased the stability of plants, pollinators and their interactions, through increased portfolio effects. However, for plants and pollinators, the effect was detected at a smaller scale (1-km) than for interactions (2-km); and for pollinators and interactions, the effect was only evident from medium-to-high levels of landscape evenness. Temporal synchrony of species/pairwise interactions was an important driver of stability, tightly linked to species/interaction diversity. More asynchronous communities showed a larger portfolio effect and were also those with higher species evenness for all plants, pollinators and their interactions; while synchrony was also weakly positively related to species richness for plants. Interestingly, more modular mutualistic network structures conferred enhanced overall community stability, through higher portfolio effect and asynchrony. Preserving diverse communities within the heterogeneous Mediterranean landscapes may help maintain the stability of pollination services, both through effects on synchrony and the portfolio effect. 相似文献
3.
森林生态系统通过响应环境波动和干扰而产生时间变化,对其稳定性机制的研究有利于生态系统服务。温带针阔混交林是全球森林生态系统的重要组成部分,该研究致力于探索超产效应、林分结构、物种异步性及优势物种稳定性对温带天然针阔混交林群落稳定性的影响,以明确主要影响机制。该研究分别设定物种丰富度、胸径变异系数、物种异步性和优势物种稳定性为解释变量,群落生物量稳定性、生物量平均值和生物量标准差为响应变量,构建3个结构方程模型,比较各变量间直接与间接效应的相对大小。主要结果为:(1)结构方程模型提供了良好的拟合效果,并占群落生物量稳定性变化的40.6%;(2)物种丰富度与生物量平均值、生物量标准差均呈显著负相关关系,路径系数分别为–0.103和–0.061;(3)胸径变异系数与群落生物量稳定性及生物量平均值均呈显著负相关关系,路径系数分别为–0.123和–0.097;(4)物种异步性与群落生物量稳定性、生物量平均值、生物量标准差均呈显著正相关关系,路径系数分别为0.055、0.085和0.055;(5)优势物种稳定性与群落生物量稳定性和生物量平均值呈显著正相关关系,路径系数分别为0.623和0.085,... 相似文献
4.
Zhongling Yang Qian Zhang Fanglong Su Chunhui Zhang Zhichao Pu Jianyang Xia Shiqiang Wan Lin Jiang 《Global Change Biology》2017,23(1):154-163
Daytime warming and nighttime warming have the potential to influence plant community structure and ecosystem functions. However, their impacts on ecological stability remain largely unexplored. We conducted an eight‐year field experiment to compare the effects of daytime and nighttime warming on the temporal stability of a temperate steppe in northern China. Our results showed that the cover and stability of dominant species, stability of subordinate species, and compensatory dynamics among species strongly influenced community‐level stability. However, daytime, but not nighttime, warming significantly reduced community temporal stability mainly through the reduction in the abundance of dominant, stable species. These findings demonstrate the differential effects of daytime and nighttime warming on community stability and emphasize the importance of understanding the changes of dominant species for accurately predicting community dynamics under climate warming. 相似文献
5.
为了测度一年生和多年生豆禾混播草地的超产效应与植物多样性效应的关系, 明确一年生和多年生混播草地的高产优势, 探索豆禾混播草地多样性效应和超产效应对其生态功能的响应机制, 于2013-2015年在新疆伊犁地区昭苏盆地开展了3年的牧草产量观测试验。该试验设置3种牧草混播种类和混播比例, 分别为一年生豆禾混播草地(2种牧草混播, AM2)和多年生豆禾混播草地(2种牧草混播, PM2; 4种牧草混播, PM4; 6种牧草混播, PM6), 豆禾混播比例分别为6:4、5:5和4:6。结果表明: 1) 2013、2014年和3年平均值AM2的超产幅度小于PM2和PM6, 2015年AM2的超产幅度大于PM2、PM4和PM6; 混播群落生产力与群落组分中生产力最高产物种单产以及各组分种平均单产的差值表现出相似的规律。2) 2013、2014年和3年平均值AM2的互补效应大于PM2、PM4和PM6, AM2的选择效应则远小于互补效应, PM2、PM4和PM6的互补效应则比较稳定。3)物种丰富度和物种均匀度与牧草产量(群落生产力)大部分情况下呈单峰的“饱和上升型”模式, 分别在4种牧草混播和豆禾混播比例为5:5时, 具有较高生产力。4)多年生豆禾混播草地的互补效应、选择效应和多样性净效应均随生长年限的延长而呈下降趋势, 也导致了超产幅度、超产效应及其稳定性的下降。由此可见, 在建植初期, 互补效应和选择效应共同主导了多年生豆禾混播草地的超产效应, 而随着生长年限的延长, 选择效应则成为主要影响因素; 一年生豆禾混播草地的超产效应则一直受互补效应的影响。 相似文献
6.
Toby P. N. Tsang Lauren C. Ponisio Timothy C. Bonebrake 《Diversity & distributions》2023,29(7):849-861
Aim
Ecological theory has predicted that species richness should stabilize communities, with mechanisms including species synchrony and population variability determining the net impacts. While these theories have been supported empirically, results can be sensitive to taxonomic bias as studies are often focussed on plants. Trophic differences between consumers and primary producers can lead to varying stabilizing effects of species richness. Here, we compared the impact of species richness on community variability in four taxonomic groups: terrestrial birds, mammals, invertebrates and plants.Location
Global.Method
Using data from 6763 time series globally (BioTIME) for four terrestrial taxa, we quantified community and population variability and species synchrony based on abundance fluctuations over time.Results
Species richness destabilized communities through increasing synchrony and stabilized communities through reducing population variability in all taxa. Such opposing effects weakened the net impacts of species richness on communities. Population variability had higher importance relative to synchrony in plant communities. By contrast, synchrony had more comparable (or even higher) importance compared with population variability in animal communities. When synchrony and population variability were not controlled, stabilizing impacts of species richness were detected in plant communities only.Main Conclusions
Our results highlight how species richness drives stabilizing and destabilizing mechanisms simultaneously across all taxa, with strong taxonomic variation in the relative importance of these mechanisms in regulating community variability. This questions the generality of previous findings on stabilizing impacts of species richness based on limited taxonomic coverage. Additionally, our results indicate the need to understand how the importance of stabilizing and destabilizing mechanisms differs in determining community variability across organisms and environments. 相似文献7.
Takehiro Sasaki;Miguel Berdugo;Toshihiko Kinugasa;Gantsetseg Batdelger;Erdenetsetseg Baasandai;Nico Eisenhauer; 《Global Change Biology》2024,30(6):e17365
Climate change will affect the way biodiversity influences the stability of plant communities. Although biodiversity, associated species asynchrony, and species stability could enhance community stability, the understanding of potential nonlinear shifts in the biodiversity–stability relationship across a wide range of aridity (measured as the aridity index, the precipitation/potential evapotranspiration ratio) gradients and the underlying mechanisms remain limited. Using an 8-year dataset from 687 sites in Mongolia, which included 5496 records of vegetation and productivity, we found that the temporal stability of plant communities decreased more rapidly in more arid areas than in less arid areas. The result suggests that future aridification across terrestrial ecosystems may adversely affect community stability. Additionally, we identified nonlinear shifts in the effects of species richness and species synchrony on temporal community stability along the aridity gradient. Species synchrony was a primary driver of community stability, which was consistently negatively affected by species richness while being positively affected by the synchrony between C3 and C4 species across the aridity gradient. These results highlight the crucial role of C4 species in stabilizing communities through differential responses to interannual climate variations between C3 and C4 species. Notably, species richness and the synchrony between C3 and C4 species independently regulated species synchrony, ultimately affecting community stability. We propose that maintaining plant communities with a high diversity of C3 and C4 species will be key to enhancing community stability across Mongolian grasslands. Moreover, species synchrony, species stability, species richness and the synchrony between C3 and C4 species across the aridity gradient consistently mediated the impacts of aridity on community stability. Hence, strategies aimed at promoting the maintenance of biological diversity and composition will help ecosystems adapt to climate change or mitigate its adverse effects on ecosystem stability. 相似文献
8.
In a greenhouse pot experiment we cultivated six meadow species in a replacement series design. The plants were grown at two sowing densities in monocultures and all possible species combinations. Our aim was to separate the selection effect from other diversity effects. This distinction is based on the notion that true overyielding is not a consequence of the selection effect. We suggest a hierarchical procedure, which is based on a repeated division of samples into the pots with the most productive species present and missing. Overyielding can be then demonstrated by a positive dependence of productivity on species richness in the subsets with the most productive species present. Although we found a strong dependence of biomass on species richness in the entire data set, the hierarchical method revealed no evidence of overyielding. Above-ground biomass in a monoculture was a good predictor of species success in a species mix. 相似文献
9.
新疆巴里坤草原优势种蝗虫食性与蝗科中亚科分类系统关系的研究 总被引：5，自引：0，他引：5
本文报道了作者于１９７６、１９７９年在巴里坤草原自然和罩笼条件下,观察优势种蝗虫取食范围、取食程度等研究结果。根据斑腿蝗亚科蝗虫主要取食双子叶植物,蝗亚科蝗虫取食单子叶植物,而斑翅蝗亚科中一部分种类取食双子叶植物,一部分取食单子叶植物这个事实,提出：斑腿蝗亚科较原始,蝗亚科最进化,斑翅蝗亚科介于两者之间。这种系统是否与蝗虫的头部形态结构有关,值得深入研究。 相似文献
10.
The past two decades have seen great progress in understanding the mechanisms of ecosystem stability in local ecological systems. There is, however, an urgent need to extend existing knowledge to larger spatial scales to match the scale of management and conservation. Here, we develop a general theoretical framework to study the stability and variability of ecosystems at multiple scales. Analogously to the partitioning of biodiversity, we propose the concepts of alpha, beta and gamma variability. Gamma variability at regional (metacommunity) scale can be partitioned into local alpha variability and spatial beta variability, either multiplicatively or additively. On average, variability decreases from local to regional scales, which creates a negative variability–area relationship. Our partitioning framework suggests that mechanisms of regional ecosystem stability can be understood by investigating the influence of ecological factors on alpha and beta variability. Diversity can provide insurance effects at the various levels of variability, thus generating alpha, beta and gamma diversity–stability relationships. As a consequence, the loss of biodiversity and habitat impairs ecosystem stability at the regional scale. Overall, our framework enables a synthetic understanding of ecosystem stability at multiple scales and has practical implications for landscape management. 相似文献
11.
12.
Evenness drives consistent diversity effects in intensive grassland systems across 28 European sites 总被引：4，自引：1，他引：4
L. KIRWAN A. LÜSCHER M. T. SEBASTIÀ J. A. FINN R. P. COLLINS C. PORQUEDDU A. HELGADOTTIR O. H. BAADSHAUG C. BROPHY C. CORAN S. DALMANNSDÓTTIR I. DELGADO A. ELGERSMA M. FOTHERGILL B. E. FRANKOW-LINDBERG P. GOLINSKI P. GRIEU A. M. GUSTAVSSON M. HÖGLIND O. HUGUENIN-ELIE C. ILIADIS M. JØRGENSEN Z. KADZIULIENE T. KARYOTIS T. LUNNAN M. MALENGIER S. MALTONI V. MEYER D. NYFELER P. NYKANEN-KURKI J. PARENTE H. J. SMIT U. THUMM J. CONNOLLY 《Journal of Ecology》2007,95(3):530-539
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14.
Using prairie biomass as a renewable source of energy may constitute an important opportunity to improve the environmental sustainability of managed land. To date, assessments of the feasibility of using prairies for bioenergy production have focused on marginal areas with low yield potential. Growing prairies on more fertile soil or with moderate levels of fertilization may be an effective means of increasing yields, but increased fertility often reduces plant community diversity. At a fertile site in central Iowa with high production potential, we tested the hypothesis that nitrogen fertilization would increase aboveground biomass production but would decrease diversity of prairies sown and managed for bioenergy production. Over a 3 year period (years 2–4 after seeding), we measured aboveground biomass after plant senescence and species and functional‐group diversity in June and August for multispecies mixtures of prairie plants that received no fertilizer or 84 kg N ha?1 year?1. We found that nitrogen fertilization increased aboveground biomass production, but with or without fertilization, the prairies produced a substantial amount of biomass: averaging (±SE) 12.2 ± 1.3 and 9.1 ± 1.0 Mg ha?1 in fertilized and unfertilized prairies, respectively. Unfertilized prairies had higher species diversity in June, whereas fertilized prairies had higher species diversity in August at the end of the study period. Functional‐group diversity was almost always higher in fertilized prairies. Composition of unfertilized prairies was characterized by native C4 grasses and legumes, whereas fertilized prairies were characterized by native C3 grasses and forbs. Although most research has found that nitrogen fertilization reduces prairie diversity, our results indicate that early‐spring nitrogen fertilization, when used with a postsenescence annual harvest, may increase prairie diversity. Managing prairies for bioenergy production, including the judicious use of fertilization, may be an effective means of increasing the amount of saleable products from managed lands while potentially increasing plant diversity. 相似文献
15.
Studies on feeding habits based on faeces dissecting are imperative to understand the natural history of Tibetan foxes and their functions in the transmission of a lethal zoonotic parasite, Echinococcus multilocularis. However, Tibetan foxes and red foxes live sympatrically on the Tibetan plateau, China. Therefore, the faeces of Tibetan foxes must be distinguished from those of red foxes. We established a diagnostic method to distinguish the faeces of the two species by amplifying a portion of the mitochondrial cytochrome b gene (cytb) and digesting with the restriction enzymes BamHI and SspI, to produce specific diagnostic banding patterns. This PCR-RFLP assay enabled rapid, accurate and easily performed identification and differentiation of the two species. 相似文献
16.
Anthropogenic perturbations may affect biodiversity and ecological stability as well as their relationships. However, diversity-stability patterns and associated mechanisms under human disturbances have rarely been explored. We conducted a 7-year field experiment examining the effects of mowing and nutrient addition on the diversity and temporal stability of herbaceous plant communities in a temperate steppe in northern China. Mowing increased population and community stability, whereas nutrient addition had the opposite effects. Stability exhibited positive relationships with species richness at population, functional group and community levels. Treatments did not alter these positive diversity-stability relationships, which were associated with the stabilising effect of species richness on component populations, species asynchrony and portfolio effects. Despite the difficulty of pinpointing causal mechanisms of diversity-stability patterns observed in nature, our results suggest that diversity may still be a useful predictor of the stability of ecosystems confronted with anthropogenic disturbances. 相似文献
17.
Áine Dooley Forest Isbell Laura Kirwan John Connolly John A. Finn Caroline Brophy 《Ecology letters》2015,18(11):1242-1251
Most ecosystems provide multiple services, thus the impact of biodiversity losses on ecosystem functions may be considerably underestimated by studies that only address single functions. We propose a multivariate modelling framework for quantifying the relationship between biodiversity and multiple ecosystem functions (multifunctionality). Our framework consolidates the strengths of previous approaches to analysing ecosystem multifunctionality and contributes several advances. It simultaneously assesses the drivers of multifunctionality, such as species relative abundances, richness, evenness and other manipulated treatments. It also tests the relative importance of these drivers across functions, incorporates correlations among functions and identifies conditions where all functions perform well and where trade‐offs occur among functions. We illustrate our framework using data from three ecosystem functions (sown biomass, weed suppression and nitrogen yield) in a four‐species grassland experiment. We found high variability in performance across the functions in monocultures, but as community diversity increased, performance increased and variability across functions decreased. 相似文献
18.
Divya Bhattarai;Saurav Lamichhane;Aayoush Raj Regmi;Khagendra Prasad Joshi;Pratik Pandeya;Bijaya Dhami;Ambika Prasad Gautam;Hari Adhikari; 《Ecology and evolution》2024,14(10):e70316
Invasive alien plant species (IAPS) pose a serious threat to overall plant biodiversity across the globe. Nepal's national parks and protected areas are not devoid of the impact of IAPS. Unfortunately, there is a substantial gap in knowledge regarding the extent and impact of invasion in protected areas of Nepal. This study assessed the impact of invasive alien plant species on the resident plant species of the Koshi Tapu wildlife reserve. After a preliminary field observation, we selected five major IAPS in the area, Mesosphaerum suaveolens, Chromolaena odorata, Ipomoea carnea, Lantana camara, and Mikania micrantha for this study. Ten pairs of adjacent plots sized 4 m × 4 m were surveyed for each invasive species, comprising diverse vegetation types. Each pair consisted of one “invaded plot” where the invasive species was dominant with cover greater than 50%, and another “uninvaded plot” laid out in an adjacent area with similar site conditions but without the invasive species. We calculated the Sørensen Index of Similarity for each paired plot. Wilcoxon rank-sum test was employed to compare ecological parameters between invaded and uninvaded plots for various plant species. Similarly, the difference in impact between each of the five invasive species was assessed using the Kruskal–Wallis test. Species richness varied significantly between invaded and uninvaded plots for C. odorata and I. carnea. The most significant impact on species composition of invaded communities (39.6%) was observed for C. odorata. The cover of the other dominant species varied significantly between invaded and uninvaded plots for all five species studied. The Kruskal–Wallis test showed no significant difference in the impact caused by the five studied invasive species on Species richness, Shannon–Wiener diversity index, species evenness, and height of dominant species. However, a significant difference was observed between the impacts of five studied invasive species and the cover of other dominant species. The crown cover of dominant species decreased much more in the invaded plots of L. camara and M. micrantha than in other species. Specialized management efforts are required to control highly invasive species, such as C. odorata and I. carnea, alongside proactive measures to prevent further spread in ecologically sensitive areas. 相似文献
19.
Genomic-level analyses of DNA from non-invasive sources would facilitate powerful conservation and evolutionary studies in natural populations of endangered and otherwise elusive species. However, the typical low quantity and poor quality of DNA that is extracted from non-invasive samples have generally precluded such work. Here we apply a modified DNA capture protocol that, when used in combination with massively-parallel sequencing technology, facilitates efficient and highly-accurate resequencing of megabases of specified nuclear genomic regions from fecal DNA samples. We validated our approach by comparing genetic variants identified from corresponding fecal and blood DNA samples of six western chimpanzees (Pan troglodytes verus) across more than 1.5 megabases of chromosome 21, chromosome X, and the complete mitochondrial genome. Our results suggest that it is now feasible to conduct genomic studies in natural populations for which constraints on invasive sampling have otherwise long been a barrier. The data we collected also provided an opportunity to examine western chimpanzee genetic diversity at unprecedented scale. Despite high mitochondrial genome diversity (π = 0.585%), western chimpanzees have a low ratio (0.42) of X chromosomal (π = 0.034%) to autosomal (chromosome 21 π = 0.081%) sequence diversity, a pattern that may reflect an unusual demographic history of this subspecies. 相似文献
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