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1.
Tia L. Harrison;Zoe A. Parshuram;Megan E. Frederickson;John R. Stinchcombe; 《Molecular ecology》2024,33(1):e17191
Mutualism is thought to be more prevalent in the tropics than temperate zones and may therefore play an important role in generating and maintaining high species richness found at lower latitudes. However, results on the impact of mutualism on latitudinal diversity gradients are mixed, and few empirical studies sample both temperate and tropical regions. We investigated whether a latitudinal diversity gradient exists in the symbiotic microbial community associated with the legume Chamaecrista nictitans. We sampled bacteria DNA from nodules and the surrounding soil of plant roots across a latitudinal gradient (38.64–8.68 °N). Using 16S rRNA sequence data, we identified many non-rhizobial species within C. nictitans nodules that cannot form nodules or fix nitrogen. Species richness increased towards lower latitudes in the non-rhizobial portion of the nodule community but not in the rhizobial community. The microbe community in the soil did not effectively predict the non-rhizobia community inside nodules, indicating that host selection is important for structuring non-rhizobia communities in nodules. We next factorially manipulated the presence of three non-rhizobia strains in greenhouse experiments and found that co-inoculations of non-rhizobia strains with rhizobia had a marginal effect on nodule number and no effect on plant growth. Our results suggest that these non-rhizobia bacteria are likely commensals—species that benefit from associating with a host but are neutral for host fitness. Overall, our study suggests that temperate C. nictitans plants are more selective in their associations with the non-rhizobia community, potentially due to differences in soil nitrogen across latitude. 相似文献
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通过对 3类型稻田 (有机养鸭田、有机稻田和常规化防田 )田间节肢动物群落调查 ,比较了节肢动物总群落丰富度、丰盛度、周转量、3个亚群落 (天敌、中性昆虫、害虫 )调查期间的平均内禀增长力 (r)和通过构建以稻田蜘蛛为顶、中位物种的群落食物网的链节数与害虫、天敌亚群落的 r和链节增长率关系。结果表明 :整个调查期间 ,总群落丰富度呈上升趋势 ,移栽后 72 d前 ,3类稻田总群落丰盛度、丰富度依次为 :有机稻田 >有机养鸭稻田 >常规稻田 ;3类稻田节肢动物群落周转量时间动态均呈上口抛物线趋势 ,其最低值和出现时间依次为 :常规稻田 33.98、74 .1d;有机养鸭田 33.90、79.1d;有机稻田 33.4 9、5 4 .0 d,有机稻田和常规化防田群落周转量和害虫数量呈显著的负相关。 3类稻田中性昆虫亚群落在调查期间的 r依次为 :有机稻田 (0 .0 6 6 5 ) >常规化防田 (0 .0 6 5 2 ) >有机养鸭田 (0 .0 5 0 9) ;天敌 r依次为 :有机稻田 (0 .0 35 2 ) >有机养鸭田 (0 .0 2 4 3) >常规化防田(- 0 .0 132 ) ;害虫的 r依次为 :常规化防田 (0 .0 4 78) >有机养鸭田 (0 .0 199) >有机稻田 (0 .0 198)。 3类稻田总链节数依次为 :有机稻田 (6 6 2 3348) >有机养鸭田 (2 4 982 17) >常规化防田 (136 3372 ) ;每头害虫链节数依 相似文献
3.
群落构建机制是生态学的中心议题之一。对山地植被beta多样性格局及其成因的探究有助于加深对此问题的认识。以芦芽山寒温性针叶林群落冠层下植被为研究对象,结合野外调查与室内实验获取的详细数据,运用Mantel检验、普通最小二乘回归和典范对应分析(CCA)等统计方法,探讨了林下植被的beta多样性格局及其成因,结果显示:(1)沿海拔梯度相邻群落间草本层物种周转率呈现递减格局,而灌木层变化规律不明显;(2)灌、草层beta多样性与海拔差异、地理距离呈显著正相关关系,而与局地环境异质性关系不显著。控制海拔作用后发现,灌、草层beta多样性与地理距离关系依然显著,而当消除地理距离的线性影响后,beta多样性与海拔关系也变得不显著(3)CCA模型中,环境因子共解释了物种组成变异的74.4%,其中,海拔、坡度、凋落物厚度、乔木密度与总干面积对林下灌、草植被物种组成具有显著影响,但土壤因子的作用未见显著。综上,生境筛滤与扩散限制共同主导了芦芽山寒温性针叶林冠层下群落构建过程,但扩散限制的影响强于生境筛滤作用。 相似文献
4.
通过对内蒙古自治区阿拉善左旗的植被样方调查,研究干旱荒漠地区植物群落物种多样性的梯度变化和空间分布特征。通过对样方数据的群落生活型构成、物种丰富度、α多样性、β多样性分析,结合CCA排序和地统计方法,结果表明：（1）在该区域植物物种的α多样性和β多样性均起伏较大。（2）草本植物的丰富度由西向东呈增高趋势,而灌木的丰富度则呈降低趋势;随纬度的增加,草本植物丰富度呈现下降趋势,而灌木丰富度则显现出上升趋势。但是,38°～39．2°N之间出现了一个灌木和草本物种丰富度都相对比较低的异常区域。（3）α多样性与经度正相关,但与纬度存在负相关关系。β多样性显示,随着经度的增加,自西向东样方问物种构成的相似性降低,物种替代速率升高。随着纬度的增加,群落组成呈现逐渐单一化的趋势。（4）Shannon—Wiener指数和Shimpson指数的CO／（CO＋Cl）都在0．25—0．75之间,α多样性为中等空间相关性。CCA分析的结果表明,地理因素对于物种多样性有显著的影响,而且经度的影响大于海拔的影响。研究阿拉善左旗荒漠区植物物种多样性的梯度变化和空间分布特征,为认识和保护荒漠地区生物多样性资源提供了理论依据和实践基础。 相似文献
5.
《Plant Ecology & Diversity》2013,6(4):585-590
Background: Boreal forest understory plant communities are known to be resilient to fire – the species composition of stands after a fire is quite similar to the pre-fire composition. However, we know little about recovery of individual plants within particular locations in forest stands (i.e. plot-level changes) since we usually do not have pre-fire data for plots.Aims: We wanted to determine whether species recruited into the same or different locations in a Pinus banksiana stand that experienced a severe wildfire.Methods: We used pre-existing permanent plots to evaluate the cover of understory after an unplanned wildfire.Results: Across the entire stand nine of 47 species showed a significant change in cover. The largest change in a plant functional group was in the mosses, with all species present before fire being eliminated. There was no change in species diversity or total cover. At the plot level, species composition showed a much greater change. An average of 47% of the species present in a plot before the fire were absent in the same plot after the fire, and the total species turnover in plots was 88% of the species present before the fire. The plots showed a similar shift in species composition.Conclusions: These results confirm that boreal forest communities show a high degree of resilience to fire, but within a forest stand species will be found in different locations following fire, potentially exposing them to a different set of biotic and abiotic conditions in these new locations. 相似文献
6.
Stefano Mammola Nicolò Chiappetta Pier Mauro Giachino Dragan Ž. Antić Marzio Zapparoli Marco Isaia 《Ecological Entomology》2020,45(5):1053-1062
1. Although caves are generally perceived as isolated habitats, at the local scale, they are often interconnected via a network of fissures in the bedrock. Accordingly, caves in close proximity are expected to host the same, or very similar, animal communities. 2. We explored the extent to which subterranean arthropod communities are homogenous at a local spatial scale of less than 1 km2, along with which cave-specific environmental features result in a departure from the expected homogeneous pattern. We approached this question by studying richness and turnover in terrestrial invertebrate communities of 27 caves in a small karst massif in the Western Italian Alps. 3. Specialised subterranean species were homogeneously distributed among caves and were not influenced by seasonality. The only factor driving their distribution was the distance from the cave entrance, with deeper caves yielding a greater diversity of species. 4. Significant spatio-temporal turnover in species not specialised to subterranean life was observed. In summer, there was a significant homogenisation of the community and a more even distribution of species among sites; in winter, these species were missing or found exclusively at greater depths, where environmental conditions were more stable. Furthermore, caves at lower elevations yielded, on average, a greater diversity and abundance of these species. 5. This study demonstrated that the theoretical expectation of no turnover in community composition in caves in close proximity is not always met. Turnover can be mostly attributed to seasonal patterns and sampling depth; thus, our findings have implications for planning sampling and monitoring activities in caves. 相似文献
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A full understanding of the origin and maintenance of β-diversity patterns in a region requires exploring the relationships of both taxonomic and phylogenetic β-diversity (TBD and PBD, respectively), and their respective turnover and nestedness components, with geographic and environmental distances. Here, we simultaneously investigated all these aspects of β-diversity for angiosperms in China. Specifically, we evaluated the relative importance of environmental filtering vs dispersal limitation processes in shaping β-diversity patterns. We found that TBD and PBD as quantified using a moving window approach decreased towards higher latitudes across the whole of China, and their turnover components were correlated with latitude more strongly than their nestedness components. When quantifying β-diversity as pairwise distances, geographic and climatic distances across China together explained 60 and 53% of the variation in TBD and PBD, respectively. After the variation in β-diversity explained by climatic distance was accounted for, geographic distance independently explained about 23 and 12% of the variation in TBD and PBD, respectively, across China. Overall, our results suggest that environmental filtering based on climatic tolerance conserved across lineages is the main force shaping β-diversity patterns for angiosperms in China. 相似文献
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在广东南岭国家级自然保护区海拔300-1900m的范围内,海拔每升高100m设置一条水平样带,共计调查了17条样带,样地面积20400m2。运用相关分析、回归分析和方差分析研究森林群落β多样性随海拔梯度的变化。结果表明:无论是相邻样带还是基准样带,Cody指数以及物种周转速率βC与海拔均呈显著的线性负相关(P<0.05);森林群落各层的共有种数随物种周转速率βC的增加而减少(P<0.05);单因素方差分析及多重比较揭示,Cody指数能较好地反映各层之间物种沿海拔梯度的变化差异。与相异性系数(community dissimilarity)、Bray-Curtis指数和Morisita-Horn指数、以及物种周转速率Sβ和物种周转速率t相比,Cody指数和物种周转速率βC能较好地反映南岭国家级自然保护区森林群落β多样性的海拔梯度格局。 相似文献
11.
蚂蚁-紫胶虫兼性互利关系对蚂蚁群落多样性的影响 总被引：4，自引：0，他引：4
为了探讨蚂蚁-紫胶虫兼性互利关系对树冠上蚂蚁群落多样性的影响,作者于2009年12月至2010年5月,采用目光搜寻的方法调查了不同紫胶虫数量样地(样地Ⅰ有效枝条寄生率为60％、样地Ⅱ为30％、样地Ⅲ为10％、样地Ⅳ不放养紫胶虫)中钝叶黄檀(Dalbergia obtusifolia)树冠蚂蚁群落的多样性.结果显示,兼性互利关系能够显著提高树冠蚂蚁群落多度及物种丰富度,改变树冠上蚂蚁的群落结构;由紫胶虫数量高低导致的蜜露产量的多寡对树冠上蚂蚁的多度和群落结构均具有显著影响,但对物种丰富度无显著影响;同时紫胶虫的个体发育阶段也是影响树冠上蚂蚁多度的重要因素.本研究证明,紫胶虫对于提高树冠上蚂蚁的多样性具有显著的正面影响,紫胶林对蚂蚁多样性保护有利. 相似文献
12.
Stefan Caddy‐Retalic Alan N. Andersen Michael J. Aspinwall Martin F. Breed Margaret Byrne Matthew J. Christmas Ning Dong Bradley J. Evans Damien A. Fordham Greg R. Guerin Ary A. Hoffmann Alice C. Hughes Stephen J. van Leeuwen Francesca A. McInerney Suzanne M. Prober Maurizio Rossetto Paul D. Rymer Dorothy A. Steane Glenda M. Wardle Andrew J. Lowe 《Ecology and evolution》2017,7(13):4607-4619
Transects that traverse substantial climate gradients are important tools for climate change research and allow questions on the extent to which phenotypic variation associates with climate, the link between climate and species distributions, and variation in sensitivity to climate change among biomes to be addressed. However, the potential limitations of individual transect studies have recently been highlighted. Here, we argue that replicating and networking transects, along with the introduction of experimental treatments, addresses these concerns. Transect networks provide cost‐effective and robust insights into ecological and evolutionary adaptation and improve forecasting of ecosystem change. We draw on the experience and research facilitated by the Australian Transect Network to demonstrate our case, with examples, to clarify how population‐ and community‐level studies can be integrated with observations from multiple transects, manipulative experiments, genomics, and ecological modeling to gain novel insights into how species and systems respond to climate change. This integration can provide a spatiotemporal understanding of past and future climate‐induced changes, which will inform effective management actions for promoting biodiversity resilience. 相似文献
13.
Elisângela L.S. Bezerra Isabel C. Machado Marco A. R.Mello 《The Journal of animal ecology》2009,78(5):1096-1101
1. In the Neotropics, most plants depend on animals for pollination. Solitary bees are the most important vectors, and among them members of the tribe Centridini depend on oil from flowers (mainly Malpighiaceae) to feed their larvae. This specialized relationship within 'the smallest of all worlds' (a whole pollination network) could result in a 'tiny world' different from the whole system. This 'tiny world' would have higher nestedness, shorter path lengths, lower modularity and higher resilience if compared with the whole pollination network.
2. In the present study, we contrasted a network of oil-flowers and their visitors from a Brazilian steppe ('caatinga') to whole pollination networks from all over the world.
3. A network approach was used to measure network structure and, finally, to test fragility. The oil-flower network studied was more nested ( NODF = 0·84, N = 0·96) than all of the whole pollination networks studied. Average path lengths in the two-mode network were shorter (one node, both for bee and plant one-mode network projections) and modularity was lower ( M = 0·22 and four modules) than in all of the whole pollination networks. Extinctions had no or small effects on the network structure, with an average change in nestedness smaller than 2% in most of the cases studied; and only two species caused coextinctions. The higher the degree of the removed species, the stronger the effect and the higher the probability of a decrease in nestedness.
4. We conclude that the oil-flower subweb is more cohesive and resilient than whole pollination networks. Therefore, the Malpighiaceae have a robust pollination service in the Neotropics. Our findings reinforce the hypothesis that each ecological service is in fact a mosaic of different subservices with a hierarchical structure ('webs within webs'). 相似文献
2. In the present study, we contrasted a network of oil-flowers and their visitors from a Brazilian steppe ('caatinga') to whole pollination networks from all over the world.
3. A network approach was used to measure network structure and, finally, to test fragility. The oil-flower network studied was more nested ( NODF = 0·84, N = 0·96) than all of the whole pollination networks studied. Average path lengths in the two-mode network were shorter (one node, both for bee and plant one-mode network projections) and modularity was lower ( M = 0·22 and four modules) than in all of the whole pollination networks. Extinctions had no or small effects on the network structure, with an average change in nestedness smaller than 2% in most of the cases studied; and only two species caused coextinctions. The higher the degree of the removed species, the stronger the effect and the higher the probability of a decrease in nestedness.
4. We conclude that the oil-flower subweb is more cohesive and resilient than whole pollination networks. Therefore, the Malpighiaceae have a robust pollination service in the Neotropics. Our findings reinforce the hypothesis that each ecological service is in fact a mosaic of different subservices with a hierarchical structure ('webs within webs'). 相似文献
14.
笔管榕为桑科榕属落叶乔木,雌雄同株,为福建地区的常见树种。笔管榕榕果内生活着多种榕小蜂,它们与笔管榕共同构成了榕树-榕小蜂共生体系。通过全年(2011年7月至2012年7月间)对福州地区不同样地的30株笔管榕进行的定时、定点、定株观察与采集,在15批次830个榕果中,共收集到50817头榕小蜂。笔管榕榕果内有7种小蜂,隶属于小蜂总科中的6个科(亚科)7个属,其中榕小蜂科的Platyscapa ishiiana为传粉小蜂,其余6种为非传粉小蜂,分别属于金小蜂科、广肩小蜂科、姬小蜂科及隐针榕小蜂亚科。非传粉小蜂中的Philotrypesis sp.、Acophila mikii、Otitesella ako、Sycophila sp.和Sycobiomorpha sp.小蜂几乎在全年的每个月都可采集到,属常见种。Aprostocetus sp.全年仅收集到2头,为偶见种。笔管榕榕果内的榕小蜂种类在不同月份、不同季节没有明显变化,但不同种类榕小蜂的数量变化明显。在笔管榕榕小蜂群落结构中,全年有9个月均是传粉小蜂占优势,但在1月、9月和11月的采集批次中,非传粉小蜂占优势。非传粉小蜂(Acophila mikii、Sycophila sp.、Philotrypesis sp.和Otitesella ako)常呈爆发性发生,每批次中往往是1-2种的非传粉小蜂数量较多,但不同批次,数量较多的非传粉小蜂种类往往不同,因此在小蜂群落结构中未见某种非传粉小蜂占明显优势。福州地区笔管榕榕果内小蜂群落的的多样性指数为0.72,均匀度指数为0.37,丰富度指数为0.55,优势集中性指数为0.68。分析了6种小蜂的性比,结果表明:传粉小蜂的性比极度偏雌,非传粉小蜂虽然也偏性,但均高于传粉小蜂,推测榕小蜂性比与雄蜂的翅型和交配场所有关。非传粉小蜂的数量和传粉小蜂总数、雌蜂数和雄蜂数均呈极显著负相关,和性比呈极显著正相关关系,说明非传粉小蜂对传粉小蜂的雌、雄蜂都有负面影响,且传粉小蜂雌蜂减少的幅度大于传粉小蜂雄蜂,从而导致其性比升高。非传粉小蜂中Acophila mikii、Sycobiomorpha sp.、Otitesella ako Ishii为造瘿类群,Philotrypesis sp.、Sycophila sp.属于寄居者或寄生者类群,非传粉小蜂中的寄生或寄居类群与造瘿类群相比,对传粉小蜂的负面影响更大。研究结果为榕-蜂协同进化研究,以及城市绿化和生物多样性保护提供科学依据。 相似文献
15.
Aim Spatial turnover of species, or beta diversity, varies in relation to geographical distance and environmental conditions, as well as spatial scale. We evaluated the explanatory power of distance, climate and topography on beta diversity of mammalian faunas of North America in relation to latitude. Location North America north of Mexico. Methods The study area was divided into 313 equal‐area quadrats (241 × 241 km). Faunal data for all continental mammals were compiled for these quadrats, which were divided among five latitudinal zones. These zones were comparable in terms of latitudinal and longitudinal span, climatic gradients and elevational gradients. We used the natural logarithm of the Jaccard index (lnJ) to measure species turnover between pairs of quadrats within each latitudinal zone. The slope of lnJ in relation to distance was compared among latitudinal zones. We used partial regression to partition the variance in lnJ into the components uniquely explained by distance and by environmental differences, as well as jointly by distance and environmental differences. Results Mammalian faunas of North America differ more from each other at lower latitudes than at higher latitudes. Regression models of lnJ in relation to distance, climatic difference and topographic difference for each zone demonstrated that these variables have high explanatory power that diminishes with latitude. Beta diversity is higher for zones with higher mean annual temperature, lower seasonality of temperature and greater topographic complexity. For each latitudinal zone, distance and environmental differences explain a greater proportion of the variance in lnJ than distance, climate or topography does separately. Main conclusions The latitudinal gradient in beta diversity of North American mammals corresponds to a macroclimatic gradient of decreasing mean annual temperature and increasing seasonality of temperature from south to north. Most of the variance in spatial turnover is explained by distance and environmental differences jointly rather than distance, climate or topography separately. The high predictive power of geographical distance, climatic conditions and topography on spatial turnover could result from the direct effects of physical limiting factors or from ecological and evolutionary processes that are also influenced by the geographical template. 相似文献
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André Rodrigo Rech Bo Dalsgaard Brody Sandel Jesper Sonne Jens-Christian Svenning Naomi Holmes 《Plant Ecology & Diversity》2016,9(3):253-262
Background: The relative frequency of wind- and animal-pollinated plants a non-randomly distributed across the globe and numerous hypotheses have been raised for the greater occurrence of wind pollination in some habitats and towards higher latitudes. To date, however, there has been no comprehensive global investigation of these hypotheses.
Aims: Investigating a range of hypotheses for the role of biotic and abiotic factors as determinants of the global variation in animal vs. wind pollination.
Methods: We analysed 67 plant communities ranging from 70º north to 34º south. For these we determined habitat type, species richness, insularity, topographic heterogeneity, current climate and late-quaternary climate change. The predictive effects of these factors on the proportion of wind- and animal-pollinated plants were tested using correlations, ordinary least squares (OLS) and logistic regression analyses with information-theoretic model selection.
Results: The proportion of animal-pollinated plant species was positively associated with plant species richness and current temperature. Furthermore, in forest, animal pollination was positively related to precipitation. Historical climate was only weakly and idiosyncratically correlated with animal pollination.
Conclusion: Results were consistent with the hypothesised reduced chance for wind-transported pollen reaching conspecific flowers in species-rich communities, fewer constraints on nectar production in warm and wet habitats, and reduced relative effectiveness of wind dispersal in humid areas. There was little evidence of a legacy of historical climate change affecting these patterns. 相似文献
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通过对岷江干旱河谷植被及其环境因子的系统取样调查 ,采用β多样性指数 - Cody指数 ,从海拔、样带、群系、地形以及土壤养分、水分梯度上研究了该地区植物群落的物种周转速率。结果表明 :随海拔的升高 ,物种周转速率表现出“高 -低 -高”的变化规律。在海拔 130 0～ 16 0 0 m和 190 0～ 2 2 0 0 m这两个海拔段 ,物种平均替代速率均较高 ;而在 16 0 0～ 190 0 m海拔段 ,物种平均替代速率较低。β多样性在样带梯度上的变化表现为干旱河谷核心区的样带较南部和北部过渡区的样带有较高的物种周转速率 ,这与样带所处的环境条件有关。群系之间的β多样性表现为 :华帚菊 -小黄素馨灌丛、金花小檗 -忍冬灌丛、黄花亚菊灌丛、子栎灌丛、小花滇紫草灌丛、莸灌丛、绣线菊灌丛与其它灌丛之间有着较高的物种周转速率。坡面不同地形上的物种周转速率 :不同坡向 ,阴坡 >半阴半阳坡 >阳坡 ;不同坡形 ,凹坡 >平坡 >凸坡 ;不同坡位 ,下坡位 >上坡位 >中坡位。β多样性在土壤水分和养分梯度上的变化表现为与土壤水解 N、速效 K、全 N含量、全 P含量以及土壤含水量成显著的二次曲线关系 ,与土壤有机质和全 K含量也呈现出二次曲线关系 ,但关系不显著 ,与 p H值和速效 P之间没有明显的规律 相似文献
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