Larger Niche Breadth Research Articles

Assessment of the Divergent Influence of Natural and Non-Seasonal Hydrological Fluctuations on Functional Traits and Niche Characteristics of Plant Guilds along the Xiangxi River, China

The reservoir water level fluctuation zones (RWLFZs) and the natural riparian zones (NRZs) are two riparian ecosystems with dramatically opposite hydrological rhythms that notably influence the plant guilds. However, little is known about the discrepancies of the functional traits and niche characteristics of plant guilds in the RWLFZs and NRZs under different flooding rhythms. The aims of this study were to assess the divergent influence of natural and non-seasonal hydrological fluctuations on functional traits and niche characteristics of plant guilds. The results showed that 78 vascular plant species were identified in the riparian zones of the Xiangxi River basin. The dominant species were annuals in the two riparian ecosystems and their percentage increased temporally from 65.79% in the NRZs to 67.34% in the RWLFZs. Compared with the NRZs, the specific leaf area, vegetation coverage and the aboveground biomass in the RWLFZs significantly increased by 74%, 27% and 19.6%, respectively, while the water-use efficiency of the RWLFZ decreased by 59.6% and there was no significant difference in the net photosynthetic rate between them, which showed that annuals in the RWLFZs adopted the R adaptation strategy of being fast-growing with a short lifespan and quickly acquiring and investing resources by altering leaf morphology, including expanding the leaf area. The Simpson dominance index of RWLFZs was significantly higher than that of NRZ. Thus, counter-seasonally hydrological alterations had significant effects on functional traits of dominant species in the RWFLZs. Moreover, the highly adaptable and widely distributed species with larger niche breadths and high important values usually had a higher niche overlap value in the RWLFZs than in the NRZs, which showed that the competition in the plant communities after experiencing anti-seasonal flooding was much more intraspecific than interspecific and would facilitate the expansion of species niches. Our findings imply that the species with large niche breadths and high important values should be prioritized in ecological restoration efforts in the newly formed hydro-fluctuation zones of the TGR.

Drivers of plant diversification along an altitudinal gradient in the alpine desert grassland, Northern Tibetan Plateau

Revealing alpine plant diversity patterns can contribute to conserving mountain plant diversity. However, the spatial variation in the ecological niche and diversity patterns of the plant community and the mechanism by which it maintains itself in alpine desert grasslands remain poorly understood. Here, we conducted a field investigation across altitudinal gradients (3093, 3296, 3549, and 3790 m) in the northern Tibetan Plateau and compared species composition, diversity indices, Levins' niche breadth, and Pianka's niche overlap. The results showed that perennial herbs replaced semi-shrubs and xermesophytes and mesophytes replaced xerophytes with increasing altitude. The plant community heights decreased with altitude. The cover of the herb layer increased with altitude, whereas that of the shrub layer was hump-shaped. Species diversity indices (Patrick, Pielou, Shannon-Wiener, and Simpson) increased with increasing altitude. Sympegma regelii (1.05), Leymus chinensis (1.03), and Reaumuria kaschgarica (0.94) had larger niche breadths and were widespread. Species with a high niche overlap occupied a considerable proportion at higher altitudes, indicating strong interactions among species. The redundancy analysis revealed that altitude, soil water content, soil organic matter content, and pH were the main factors driving changes in plant diversity (P = 0.036, F = 3.7). Our study illustrated that environmental filtering and biotic interactions jointly shape plant composition and diversity in alpine desert grasslands along altitudinal gradients.

洮河自然保护区大峪沟林区紫果云杉群落木本植物种群生态位特征

PDF HTML阅读 XML下载 导出引用 引用提醒 洮河自然保护区大峪沟林区紫果云杉群落木本植物种群生态位特征 DOI: 10.5846/stxb202102070395 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 甘肃省林业科技创新项目（KJCX201909，KJCX202001）；甘肃省林业科技项目（2015KJ051）；林业科技推广项目（2020ZYTG16） Niche of woody plant populations of Picea purpurea community in Dayugou forest area, Taohe Nature Reserve, Gansu Province Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:基于群落调查数据，以样地代表多种资源的综合状态，物种重要值作为生态位的计测指标，利用Levins和Shannon生态位宽度，Schoener生态位相似和Pianka生态位重叠对洮河自然保护区大峪沟林区的紫果云杉群落木本植物种群生态位进行定量研究。结果表明：紫果云杉群落乔木层共有树种8种，隶属于4科6属，紫果云杉占绝对优势，岷江冷杉为次优势种；灌木层共有植物50种，隶属于16科25属，忍冬科的蓝靛果、葱皮忍冬和唐古特忍冬等以及蔷薇科的峨眉蔷薇和银露梅等构成了灌木层的主体，紫果云杉幼苗优势不明显，但生态位宽度最大。本研究表明，生态位宽度受物种生态特性及其分布和生境共同影响，重要值大的物种生态位宽度一般较大，生态位宽度大的物种之间生态位相似性和重叠性一般较大，并与其它物种重叠的概率高、重叠程度大，生态位宽度小的物种集中出现时也会出现较大的生态位重叠，同科或同属的物种间常有较大生态位相似和重叠。生态位宽度反映着种群的扩散潜力，生态位相似反映着群落的稳定性，生态位重叠反映着物种间存在或潜在的竞争程度。紫果云杉在乔、灌木层均有最大的生态位宽度，生态适应性最强，群落结构稳定，具有进一步扩散的可能。 Abstract:Based on the plant community investigation data, and with plots representing the comprehensive status of multiple resources, and species importance values as measurement indicators of niche, the niche characteristics of woody plant species in the Picea Purpurea Community in Dayugou forest area of the Taohe Nature Reserve were quantified with the indices of Levins niche breadth, Shannon niche breadth, Schoener niche similarities and Pianka niche overlap. The results showed that there were 8 tree species in the tree layer of the picea purpurea community, belonging to 4 families and 6 genera, among which the picea purpurea was the absolute dominant species, and the Abies faxoniana was the subdominant species; the shrub layer had a total of 50 species of plants belonging to 16 families and 25 genera, among which Lonicera caerulea, Lonicera ferdinandii and Lonicera tangutica of the Caprifoliaceae and Rosa omeiensis and Potentilla glabra of the Rosaceae are the dominant species of the shrub layer, and the picea purpurea seedlings did not have obvious advantages but they had the widest niche breadth. This study indicated that the niche breadth was affected by the ecological characteristics of species as well as their distribution and habitat. The species with large important values generally had larger niche breadth, and the species with large niche breadth generally had the larger niche similarity and overlap, and had higher probability and degree of overlap with other species; there were also large niche overlaps when species with small niche breadth were concentrated, and the species of the same family or genus often had larger niche similarities and overlaps. Niche breadth reflected the population dispersal potential, the niche similarity reflected the stability of a community, and the niche overlap reflected the degree of the existing or potential competition among species. Picea Purpurea had the widest niche breadth in both the tree layers and shrub layers, the strongest ecological adaptability, the stable community structure, and thus the possibility of further dispersal. 参考文献 相似文献 引证文献

浙江省城市生态位尺度效应

作为社会复合生态系统的重要理论, 城市生态位一直是研究重点, 但缺少尺度效应的深入观察。以浙江省为例, 首次将地市-区县-乡镇三个尺度进行横向对比, 构建了多个尺度适用的城市生态位评价模型。研究通过生态位宽度、生态位重叠度、生态位分异指数和引力模型方法, 对825个乡镇, 71个区县和11个地市的3个尺度的生态位进行了探讨。研究结果表明: 从生态位宽度来看, 浙江省的生态位发展不均衡, 地市尺度呈现反"C"结构, 衢州市和丽水市生态位宽度最小, 杭州市、湖州市和宁波市生态位宽度最大。且研究尺度越大、生态位宽度越大, 则尺度效应作用越大。从生态位分异程度来看, 随着尺度的缩小, 分异程度逐渐增大, 其中社会生态位分异程度最大。表明尺度效应在发展越不平衡的生态位维度中作用力越大。从生态位重叠度和引力模型来看, 生态位宽度小的区域往往面临竞争难以摆脱困境, 而生态位宽度大的区域更容易将竞争转化为合作。出现强者越强, 弱者越弱的两极分化现象, 丽水市和衢州市竞争最激烈而杭州市和宁波市合作更为便利。浙江省各地市可以通过资源再造、协同发展和借力帮扶策略优化区域发展。;As an important theory of social complex ecosystem, urban niche has always been the focus of research, but there is a lack of in-depth observation of scale effect at present. Taking Zhejiang Province as an example, this paper made a horizontal comparison of three scales of city-district-town for the first time, and constructed an urban niche evaluation model applicable to multiple scales. In this study, niche width, niche overlap, niche differentiation index and gravity model were used to investigate the niche of 825 townships, 71 districts, and 11cites at three scales. The results indicate that: from the perspective of niche breadth, the niche development of Zhejiang Province is unbalanced, and the city scale presents an anti C structure. Quzhou city and Lishui city have the smallest niche breadth, while Hangzhou city, Huzhou city and Ningbo city have the largest niche breadth. The larger the research scale and niche width, the greater the scale effect. From the perspective of niche differentiation, the degree of niche differentiation gradually increases with the decrease of scale, and the degree of social niche differentiation is the largest. It shows that the more unbalanced the development is, the greater the scale effect is. Furthermore, from the niche overlap degree and gravity model, the study found that the regions with small niche width often faced greater competition and were difficult to get out of troubles, while the regions with large niche width were more likely to transform competition into cooperation. As a result, there is a polarization phenomenon that the stronger the stronger and the weaker the weaker. The competition between Lishui city and Quzhou city is the fiercest, while the cooperation between Hangzhou city and Ningbo city is more convenient. Therefore, cities in Zhejiang Province can optimize regional development through resource reengineering, synergistic development and supporting strategies.

Co-occurrence of planktonic bacteria and archaea affects their biogeographic patterns in China\u2019s coastal wetlands

Planktonic bacteria and archaea play a key role in maintaining ecological functions in aquatic ecosystems; however, their biogeographic patterns and underlying mechanisms have not been well known in coastal wetlands including multiple types and at a large space scale. Therefore, planktonic bacteria and archaea and related environmental factors were investigated in twenty-one wetlands along China’s coast to understand the above concerns. The results indicated that planktonic bacteria had different biogeographic pattern from planktonic archaea, and both patterns were not dependent on the wetland's types. Deterministic selection shapes the former’s community structure, whereas stochastic processes regulate the latter’s, being consistent with the fact that planktonic archaea have a larger niche breadth than planktonic bacteria. Planktonic bacteria and archaea co-occur, and their co-occurrence rather than salinity is more important in shaping their community structure although salinity is found to be a main environmental deterministic factor in the coastal wetland waters. This study highlights the role of planktonic bacteria-archaea co-occurrence on their biogeographic patterns, and thus provides a new insight into studying underlying mechanisms of microbial biogeography in coastal wetlands.

Effects of acute temperature increases on House sparrow (Passer domesticus) pectoralis muscle myonuclear domain.

With rapid climate change, heat wave episodes have become more intense and more frequent. This poses a significant threat to animals, and forces them to manage these physiologically challenging conditions by adapting and/or moving. As an invasive species with a large niche breadth, House sparrows (Passer domesticus) exhibit high phenotypic flexibility that caters to seasonal changes in function and metabolism. For example, their pectoral muscle complex exhibits size and mass plasticity with winter and summer acclimation. Here, we investigated the effects of acute whole-organism heat stress to 43°C on cellular-level changes in House sparrow pectoralis muscle myonuclear domain (MND), the volumetric portion each nucleus is responsible for, that have gone overlooked in the current literature. House sparrows were separated into a control group, a heat-shocked group subjected to thermal stress at 43°C for 24 h, and a recovery group that was returned to room temperature for 24 h after experiencing the same temperature treatment. Here, we found that heat-shocked and recovery groups demonstrated a decrease in number of nuclei per millimeter of fiber and increase in MND, when compared with the control. We also found a significant positive correlation between fiber diameter and MND in the recovery group, suggesting the possibility that nuclei number constrains the extent of muscle fiber size. Together, these results show that acute heat shock alters House sparrow pectoralis muscle cellular physiology in a rigid way that could prove detrimental to long-term muscle integrity and performance.

Intraspecific differences of Asian/Australian Phragmites australis subgroups reveal no potentially invasive traits

Phragmites australis is a cosmopolitan plant species with high intraspecific diversity and phenotypic plasticity. Due to its variability and large ecological niche breadth, subgroups of P. australis have become invasive in North America, and this invasion has been recognized late. While this cryptic invasion on the American continent has received much attention, little is known about the potential invasiveness of other subgroups, especially within Asian/Australian P. australis. We therefore compared the performance of three subgroups within the Asian/Australian group: a freshwater (CN) and an estuarine (YRD) subgroup collected in China and a genetically closely related subgroup collected from Australia (FEAU), grown in two common gardens in China. Our results showed that the FEAU subgroup had no strong invasive potential, as its total biomass, height, shoot number, specific leaf area, and stomatal conductance were lower than that of the two native subgroups. All three subgroups responded similarly with most traits to the different climates of the gardens, albeit with different response strength, expressed as phenotypic plasticity indices. The potential cryptic invasion risk of the FEAU subgroup in China seems to be low, since its functional traits showed low competitiveness and most traits with the lowest plasticity occurred in FEAU. However, caution is still advised, because other invasive mechanisms, such as enemy release or the performance under extreme environmental conditions were not tested in our study.

Diet of Andean bears in Tamá National Natural Park, Colombia

Diet is among the most important and basic ecological aspects of a species. Information on diet composition, seasonality, and spatial variation is necessary for adequate ecological understanding and therefore conservation. Andean bears (Tremarctos ornatus) have been poorly studied across their distribution, and especially in Colombia; therefore, most ecological aspects remain unknown. The objective of this work was to assess Andean bears' diet and seasonality in order to contribute to the knowledge, management, and conservation of the species in northeastern Colombia. Between June 2012 and May 2015, 83 linear transects were surveyed at least once in 35 localities in Tama National Natural Park in search of fresh bear scats. Transects covered all land-cover types in the park proportionately. We collected 148 scats for diet analyses, and compared all items found with reference material. We assessed diet contents in terms of frequency of occurrence and compared across seasons, elevation, and land-cover types. Overall, plant items showed the greatest frequency of occurrence in the scats (96.8%), followed by mammals (6.7%) and insects (6.7%); we found this pattern for all land-cover types and all elevation ranges. We found seasonal variation and differences in use of some food items. We found the largest niche breadth for the dry season (B = 7.10) compared with the wet season (B = 4.14). Plant items were more frequently consumed during both dry and rainy seasons (0.78 ± 0.16 and 0.82 ± 0.11, respectively) and bromeliads were the most important food item during both seasons (0.32 and 0.46). This variation probably is related to the structure, phenology, and composition of vegetation in the area. More data are needed for estimating foraging preferences and their relationship with food availability and other aspects related to behavior and individual resource use.

Skeletal marine animal biodiversity is built by families with long macroevolutionary lag times.

The clade dynamics of marine animals have changed markedly over the Phanerozoic. Long-term diversification is associated with decreasing origination and extinction rates, and with increasing taxon longevity. Here we use the diversification trajectories of skeletal non-colonial marine families to infer the mechanisms that generated these trends. Suggested mechanisms behind these trends include stochastic extinction of taxa with high evolutionary volatility and selection for traits that buffer against extinction. We find an increasing predominance of Phanerozoic families with long lag times between first appearance and peak diversity, over those with 'early burst' diversification trajectories. Long-lag families persisted for longer and had lower evolutionary volatilities, higher genus-level occupancies and genera with larger niche breadths than early burst families. However, they do not preferentially show ecological modes known to protect against extinction. We interpret the rise of the long-lag families as reflecting an intensification of ecosystem-level mechanisms supporting both long-term coexistence and transient dynamics, which increased the capacity of marine ecosystems to accommodate highly diverse communities.

Ecological release in lizard endoparasites from the Atlantic Forest, northeast of the Neotropical Region.

We compared lizard endoparasite assemblages between the Atlantic Forest and naturally isolated forest enclaves to test the ecological release hypothesis, which predicts that host specificity should be lower (large niche breadth) and parasite abundance should be greater for parasites from isolated forest enclaves (poor assemblages) than for parasites from the coastal Atlantic Forest (rich assemblages). Parasite richness per specimen showed no difference between the isolated and non-isolated areas. Parasite abundance did not differ between the isolated and non-isolated areas but showed a positive relationship with parasite richness considering all areas (isolated and non-isolated). Furthermore, host specificity was positively related to parasite richness. Considering that host specificity is inversely proportional to the host range infected by a parasite, our results indicate that in assemblages with greater parasite richness, parasites tend to infect a smaller range of hosts than do those in simple assemblages. In summary, our study partially supports the ecological release hypothesis: in assemblages with greater parasite richness, lizard parasites from Atlantic Forest are able to increase their parasite abundance (per host), possibly through facilitated infection; however, the amplitude of infected hosts only expands in poor assemblages (lower parasite richness).

桂林岩溶石山青冈群落灌木层主要物种生态位与种间联结

PDF HTML阅读 XML下载 导出引用 引用提醒 桂林岩溶石山青冈群落灌木层主要物种生态位与种间联结 DOI: 10.5846/stxb201904090689 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31860124）；广西自然科学基金项目（2016GXNSFBA380030） Niche and interspecific association of main species in shrub layer of Cyclobalanopsis glauca community in karst hills of Guilin, southwest China Author: Affiliation: Fund Project: The National Natural Science Foundation of China(31860124); Guangxi Natural Science Foundation Project (2016GXNSFBA380030) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:基于样方调查，采用生态位测定、方差比率法、χ2检验、Pearson相关检验和Spearman秩相关检验等方法对桂林岩溶石山青冈群落灌木层主要物种的生态位与种间联结进行研究。结果表明：（1）青冈的生态位宽度最大，占绝对竞争优势；重要值较大（小）的物种，其生态位宽度一般较大（小），但两者顺序并非完全一致。（2）主要物种间的生态位相似性较小，各物种对资源利用的相似程度不高；一般生态位宽度较大的物种，其生态位相似性也越大。（3）生态位宽度较大的物种间产生生态位重叠的概率较大，但生态位重叠程度并不一定大；生态位宽度与生态位重叠有一定的联系，但并不存在绝对的正相关关系；生态位相似性和生态位重叠程度的变化趋势基本吻合。（4）灌木层主要物种的总体联结性表现为显著正联结，表明该群落处于相对稳定的演替阶段。（5）χ2检验、Pearson相关检验和Spearman秩相关检验结果的显著率均较低，种间联结性不强。（6）物种间的Pearson相关系数、Spearman秩相关系数与相应的生态位相似性和生态位重叠程度之间均呈显著正相关，表现为种间正（负）联结越强，生态位相似性和生态位重叠程度越大（小）。 Abstract:Niche and interspecific associations, which are significant quantitative and structural characteristics, reflect relationships among species in a plant community as well as community stability, and thus providing an important theoretical basis for forest vegetation restoration and reconstruction, forest management and biodiversity conservation. In order to understand mechanisms underlying the formation of niche and interspecific associations of main species in the shrub layer of Cyclobalanopsis glauca communities, a total of 100 shrub plots were established and investigated in the Cyclobalanopsis glauca communities in karst hills of Guilin. We selected 20 shrub layer species on the basis of their importance values. The niche characteristics of main species in shrub layers were quantified with the indices of Levins niche breadth, Shannon niche breadth, Schoener niche similarity and Pianka niche overlap. The interspecific association was researched by using a set of methods, namely, variance ratio(VR), χ2 test, Pearson's correlation test and Spearman's rank correlation test. The results showed that:(1)the Levins and Shannon niche breadth index indicated that the niche breadth of Cyclobalanopsis glauca was the largest among the twenty species that we have studied. It indicated that Cyclobalanopsis glauca had a stronger ability to compete and utilize resources in the shrub layer, with the absolute competitive advantage and stronger ecological adaptability. The species with larger importance values generally had larger niche breadth, but the rank orders of them were not exactly the same. (2)the mean value of niche similarity of main species in the shrub layer was 0.156. There was a lower degree of niche similarity among species within the community, indicating that they had a lower similarity in resource utilization. (3)the result of niche similarity proportion and niche overlap was similar but not the same. The differences between them suggest that using similar resources are not sufficient to cause competition among these species. (4)the W test showed that the overall interspecific associations were significantly positive associations among the main species in the shrub layer. This reflected that the Cyclobalanopsis glauca community in karst hills of Guilin was in a relatively stable succession status. (5)the results of the χ2 test, Pearson's correlation test, and Spearman's rank correlation test showed that the significance ratios of the species pairs were all lower. The species pairs with insignificant interspecies correlations accounted for the majority of the species pairs in the shrub layer, reflecting a weak association among the various species pairs in the shrub layer. Most of the species showed an independent distribution pattern. (6)both Pearson's correlation coefficient and Spearman's rank correlation coefficient showed significantly positive correlations with niche similarity and niche overlap value. In other words, the species pairs with stronger positive association generally had larger niche similarity and niche overlap. On the contrary, the species pairs with stronger negative association generally had smaller niche similarity and niche overlap. 参考文献 相似文献 引证文献

Species with moderate intraspecific trait variability are locally abundant within an environmentally heterogeneous subtropical forest.

Species with large intraspecific trait variability (ITV) have larger niche breadth than species with low ITV and thus are expected to be more abundant at the local scale. However, whether the positive ITV-abundance relationship holds in heterogeneous local environments remains uncertain. Using an individual-based trait dataset encompassing three leaf traits (leaf area, specific leaf area, and leaf dry mass content) of 20,248 individuals across 80 species in an environmentally heterogeneous subtropical forest in eastern China, ITV for each trait of each species was estimated by rarefaction. Resource-based niche breadth and marginality (the absolute distance between the mean resource states used by a species and the mean plot-wise resource states) were estimated simultaneously by the K-S method and the outlying mean index, respectively. Species with moderate ITV were often locally abundant, while species with large or small ITV were locally rare. This unimodal relationship between ITV and species abundance persisted when traits were analyzed separately and for all tree size classes. There was also a hump-backed relationship between niche breadth and marginality, and ITV was positively associated with niche breadth. The combined results suggest either a trade-off between the benefit from expanding niche breadth to adapt to multiple habitats and the disadvantage of reducing competitive ability, or a scarcity of favorable resources. Our results do not support the traditional thought that ITV positively correlates with species abundance in heterogeneous local environments. Instead, our study suggests that moderate-rather than large-intraspecific trait variability increases species abundance at local scales.

Generalists are the most urban‐tolerant of birds: a phylogenetically controlled analysis of ecological and life history traits using a novel continuous measure of bird responses to urbanization

Identifying which ecological and life history traits influence a species’ tolerance to urbanization is critical to understanding the trajectory of biodiversity in an increasingly urbanizing world. There is evidence for a wide array of contrasting patterns for single trait associations with urbanization. In a continental‐scale analysis, incorporating 477 species and >5 000 000 bird observations, we developed a novel and scalable methodology that evaluated the ecological and life history traits which most influence a species’ adaptability to persist in urban environments. Specifically, we assigned species‐specific scores based on continuous measures of response to urbanization, using VIIRS night‐time light values (i.e. radiance) as a proxy for urbanization. We identified generalized, phylogenetically controlled patterns: bird species which are generalists (i.e. large niche breadth), with large clutch size, and large residual brain size are among the most urban‐tolerant bird species. Conversely, specialized feeding strategies (i.e. insectivores and granivores) were negatively associated with urbanization. Enhancement and persistence of avian biodiversity in urban environments probably relies on protecting, maintaining and restoring diverse habitats serving a range of life history strategies.

干旱荒漠区植物生态位对水盐的响应

PDF HTML阅读 XML下载 导出引用 引用提醒 干旱荒漠区植物生态位对水盐的响应 DOI: 10.5846/stxb201801180135 作者: 作者单位: 新疆大学,新疆大学,新疆大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（31560131） Response of plant niche to soil moisture and salinity in an arid desert area of Xinjiang, China Author: Affiliation: Xinjiang University,Xinjiang University,Xinjiang University Fund Project: The National Natural Science Foundation of China (General Program, Key Program, Major Research Plan) 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:全球气候变化对生态系统功能的影响决定着种群地位和群落演替，由于干旱区的特殊性成为研究生物响应环境变化的热点地区。为探索艾比湖流域荒漠区植物生态位对土壤水盐梯度的响应，在研究水、盐含量和植物生态位特征的基础上，应用变系数模型，分析了土壤水盐梯度下的群落组成和生态位响应趋势。结果显示：（1）随土壤水盐梯度的降低，艾比湖流域群落的物种组成呈倒"V"型分布，说明土壤水盐交互作用影响着植被分布和群落类型。（2）高水盐环境下，胡杨（Populus euphratica）、琵琶柴（Reaumuria soongorica）和梭梭（Haloxylon ammodendron）等生态位宽度值（Bi）较大，柽柳（Tamarix ramosissima）、骆驼刺（Alhagi sparsifolia）和甘草（Glycyrrhiza uralensis）等Bi较小；中水盐环境下，白刺（Nitraria schoberi）和琵琶柴的Bi较大，铃铛刺（Halimodendron halodendron）、甘草和盐节木（Halocnemum strobilaceum）的Bi较小；低水盐环境下，梭梭、花花柴（Karelinia caspica）和琵琶柴等Bi较大，盐节木的Bi较小；说明土壤水盐环境和物种生态学特性是影响Bi的重要因素。（3）物种水平上，Bi较大的种群与其他物种的生态位重叠（Oij）一般较大，但Bi较小的物种间的Oij不一定小（例如：高水盐土壤环境下柽柳和骆驼刺的Oij为1）；群落水平上，Bi与Oij具有一定的正相关性；说明由于资源纬度的相似性增大了低Bi物种间的Oij，并且Bi和Oij由物种向群落尺度转换时，两者之间的关系存在冗余。（4）土壤水盐梯度与群落生态幅呈现一种非线性相关特征，高水盐格局对群落Bi有一定的促进效应，而低水盐模式对Bi具有一定的限制作用，表明土壤水盐的协同效应影响着物种在群落的地位，并在一定程度上决定了群落向正负两极演替的方向。 Abstract:The impact of global climate change on ecosystem function determines the status of population and community succession, and since arid areas are unique, they have become a hot spot for studying biological responses to environmental change. We used a sample plot method investigation to explore the response of plant niche to the soil water and salt gradient of the Ebinur Lake Basin. Based on a study of moisture, salt content, and plant niche characteristics for arid desert areas, the changes in community composition and niche responses to soil water and salt at different gradients were analyzed. The results showed the species composition of communities had a reverse "V" pattern along the water and salt environmental factor gradient (from high to low); these phenomena indicate that the interaction of water and salt concentration was the main reason the distribution of vegetation types was restricted. The niche breadth of Populus euphratica, Reaumuria soongorica, and Haloxylon ammodendron were larger than those of Tamarix ramosissima, Alhagi sparsifolia, and Glycyrrhiza uralensis at high saltwater soil environments. The niche breadth of Nitraria schoberi and Reaumuria soongorica were larger than those of Halimodendron halodendron, Glycyrrhiza uralensis, and Halocnemum strobilaceum at moderate saltwater soil environments. The niche breadth of Haloxylon ammodendron, Karelinia capsica, and Reaumuria soongorica were larger than those of Halocnemum strobilaceum at low saltwater soil environments. These phenomena indicate that the ecological niche of a population was not only determined by soil moisture and salinity, but also the ecological characteristics of the species in the desert area. At the species level, the niche overlap of the populations with large niche breadth between other species was generally large, but the niche overlap with smaller niche breadth species was not necessarily small; however, at the community level, there was a positive correlation between niche breadth and niche overlap. These phenomena indicate that a similarity in resource latitudes increased the niche overlap between the low niche breadth species, and the relationship between them was redundant when there was a transformation of niche breadth and niche overlap from the species to the community scale. The soil water and salt gradient showed a nonlinear correlation with community ecological amplitude. The distribution pattern of high water and salt in the soil had a certain promoting effect on the niche breadth of the community, while the distribution pattern of low water and low salt had a limited effect on niche breadth. The synergistic effect of soil water and salt determined the status of species in the community and determined the direction of community succession to the positive and negative poles. 参考文献 相似文献 引证文献

Urbanization erodes niche segregation in Darwin's finches.

Urbanization is influencing patterns of biological evolution in ways that are only beginning to be explored. One potential effect of urbanization is in modifying ecological resource distributions that underlie niche differences and that thus promote and maintain species diversification. Few studies have assessed such modifications, or their potential evolutionary consequences, in the context of ongoing adaptive radiation. We study this effect in Darwin's finches on the Galápagos Islands, by quantifying feeding preferences and diet niche partitioning across sites with different degrees of urbanization. We found higher finch density in urban sites and that feeding preferences and diets at urban sites skew heavily toward human food items. Furthermore, we show that finches at urban sites appear to be accustomed to the presence of people, compared with birds at sites with few people. In addition, we found that human behavior via the tendency to feed birds at non‐urban but tourist sites is likely an important driver of finch preferences for human foods. Site differences in diet and feeding behavior have resulted in larger niche breadth within finch species and wider niche overlap between species at the urban sites. Both factors effectively minimize niche differences that would otherwise facilitate interspecies coexistence. These findings suggest that both human behavior and ongoing urbanization in Galápagos are starting to erode ecological differences that promote and maintain adaptive radiation in Darwin's finches. Smoothing of adaptive landscapes underlying diversification represents a potentially important yet underappreciated consequence of urbanization. Overall, our findings accentuate the fragility of the initial stages of adaptive radiation in Darwin's finches and raise concerns about the fate of the Galápagos ecosystems in the face of increasing urbanization.

Niche of main woody plant populations of Pterocarya stenoptera community in riparian zone of Lijiang River, China.

To understand the niche characteristics of main woody species in Pterocarya stenoptera community, we investigated P. stenoptera communities in riparian zone of Lijiang River, China. The niche characteristics of main species in tree layers and shrub layers were quantified with the indices of Levins niche breadth, Shannon niche breadth, Schoener niche similarities and Pianka niche overlap. The results showed that P. stenoptera in the tree layer, and Ficus abelii and Morus alba in the shrub layer had higher niche breadth than other species. The species with larger importance values generally had larger niche breadth, but the rank orders of which were not exactly the same. The niche similarity of main populations in the tree layer was generally smaller than that in the shrub layer. The mean value of niche similarity of main populations in the tree layer and shrub layer was 0.151 and 0.236, respectively. There was a low degree of niche similarity among species within the community, indicating that they had a low similarity in resource use. The niche overlap of main populations in the tree layer was generally smaller than that in the shrub layer, with the mean value of niche overlap of main populations in the tree layer and shrub layer being 0.217 and 0.273, respectively. The niche overlap between the main species in the community was relatively lower. There was no significant correlation between niche breadth and niche similarity. The species with larger niche breadth often had more opportunities to overlap with other species. However, their overlap value was not necessarily larger. Larger niche similarity was often associated with higher degrees of niche overlap. The P. stenoptera community in riparian zone of Lijiang River was the climax community, the relationship among species was relatively stable, the population regeneration was very slow, and the development trend of this community was declining in the future.

Morphology and stable isotope analysis demonstrate different structuring of bat communities in rainforest and savannah habitats.

Bats play important ecological roles in tropical systems, yet how these communities are structured is still poorly understood. Our study explores the structure of African bat communities using morphological characters to define the morphospace occupied by these bats and stable isotope analysis to define their dietary niche breadth. We compared two communities, one in rainforest (Liberia) and one in savannah (South Africa), and asked whether the greater richness in the rainforest was due to more species ‘packing’ into the same morphospace and trophic space than bats from the savannah, or some other arrangement. In the rainforest, bats occupied a larger area in morphospace and species packing was higher than in the savannah; although this difference disappeared when comparing insectivorous bats only. There were also differences in morphospace occupied by different foraging groups (aerial, edge, clutter and fruitbat). Stable isotope analysis revealed that the range of δ13C values was almost double in rainforest than in savannah indicating a greater range of utilization of basal C3 and C4 resources in the former site, covering primary productivity from both these sources. The ranges in δ15N, however, were similar between the two habitats suggesting a similar number of trophic levels. Niche breadth, as defined by either standard ellipse area or convex hull, was greater for the bat community in rainforest than in savannah, with all four foraging groups having larger niche breadths in the former than the latter. The higher inter-species morphospace and niche breadth in forest bats suggest that species packing is not necessarily competitive. By employing morphometrics and stable isotope analysis, we have shown that the rainforest bat community packs more species in morphospace and uses a larger niche breadth than the one in savannah.

Rapid Intraspecific Diversification of the Alpine Species Saxifraga sinomontana (Saxifragaceae) in the Qinghai-Tibetan Plateau and Himalayas.

An increasing number of phylogeographic studies have been conducted for plant species in the Qinghai-Tibetan Plateau (QTP) and its flanking mountains. However, these studies have mainly focused on the determination of glacial refugia and routes of inter-/post-glacial expansions. Rapid intraspecific diversification of plants in this region have not been thoroughly discussed. Herein, we investigate the effects of the Quaternary climate changes on population genetic structure and diversifications of a herbaceous alpine species, Saxifraga sinomontana, which may have an evolutionary time scale <5 million years in the QTP and Himalayan regions. Using a total of 350 individuals from 29 populations, we studied the evolutionary history of S. sinomontana by analyzing cpDNA trnL-trnF, rpl16 and nrDNA ITS sequences. A total of 89 haplotypes and 158 genotypes were detected for cpDNA and ITS sequences, respectively. Only a few haplotypes/genotypes were widespread, while an extremely large number of haplotypes/genotypes were restricted to single populations, which were scattered throughout the current geographical range of S. sinomontana. This suggests the existence of microrefugia of this species during the Quaternary glaciations. In addition, the relationships of the haplotypes/genotypes were almost completely not resolved by phylogenetic reconstruction. Combining characteristics in terms of high haplotype richness, large proportion of private haplotypes, and shallow haplotype divergence, we speculate that recent intraspecific diversification has occurred in S. sinomontana. Molecular clock analysis estimated that the onset diversification within S. sinomontana to be 1.09 Ma (95% HPD = 0.80–1.45), coinciding with the extensive Quaternary glaciations on the QTP which started ca. 1.17 Ma. The Quaternary climatic oscillations may have triggered rapid intraspecific diversification in this QTP-Himalayan species. However, large niche breadth, as well as introgression/hybridization between the studied species and its closely related sympatric saxifrages, may also played a role to some extent on the current genetic structure of S. sinomontana, which need to be further studied.

舟山长白海域主要游泳动物生态位及其分化研究

PDF HTML阅读 XML下载 导出引用 引用提醒 舟山长白海域主要游泳动物生态位及其分化研究 DOI: 10.5846/stxb201803300680 作者: 作者单位: 浙江海洋大学,台州市海洋与渔业局,浙江省海洋水产研究所,浙江海洋大学,浙江海洋大学,浙江海洋大学,浙江海洋大学,浙江海洋大学,浙江海洋大学 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划课题（2017YFA0604902）；浙江省软科学研究计划（2015C25018） Study on the niche and differentiation of major nekton species in the Zhoushan Changbai sea area Author: Affiliation: Zhejiang Ocean University,Taizhou city Ocean and Fisheries Bureau,Marine Fisheries Research Institute of Zhejiang Province,,,,,,Zhejiang Ocean University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:基于2016年10月（秋季）和2017年4月（春季）舟山长白海域的渔业资源调查数据，运用生态位宽度、生态位重叠及冗余分析等方法，研究了主要游泳动物的生态位，种间生态关系及生态位分化。结果显示：春、秋季主要游泳动物分别11种与8种，两季生态位宽度值差异均较大，其中春季广生态位种、中生态位种均为3种，而秋季均为2种，窄生态位种分别为5种与4种。相对重要性指数（IRI）与生态位宽度值（Bi）之间呈显著正相关。生态位重叠程度不均衡，秋季主要游泳动物的生态位重叠程度较高，Oik > 0.6的种对数占总种对数的42.86%；春季的重叠程度较低，仅占总种对数的21.82%。RDA分析得出温度、盐度为影响主要游泳动物分布的直接因素，而溶解氧、悬浮物和pH等则为重要因素，主要游泳动物在这些资源维上存在生态分化现象。综上，分布在毗邻杭州湾口且位于著名的岱衢洋的主要游泳动物种类总体营养级较低却生态宽度值较大，大黄鱼（Larimichthys crocea）、黄姑鱼（Nibea albiflora）等一些传统的高营养级、典型特色经济种类却沦为生态位宽度极小的一般种或少有种，群落种类显著减少，资源量下降，群落结构与功能退化，稳定性下降。因此，加强游泳动物资源修复、保护与管理十分迫切且具有重要意义。 Abstract:Based on the data of the fisheries resources survey in the Zhoushan Changbai sea area in October 2016 (autumn) and April 2017 (spring), the ecological niche, interspecific ecological relationship, and ecological niche differentiation of the major nekton species were studied using the methods of niche breadth, niche overlap, and redundancy analysis (RDA). The results showed the presence of 11 and 8 major nekton species in spring and autumn, respectively, with large differences between the niche breadth values obtained in the two seasons. It is observed that there are three kinds of both wild ecological species and middle niche species in spring, and two in autumn, with five and four narrow niche species in spring and autumn, respectively. A significant positive correlation existed between the index of relative importance (IRI) and niche breadth value (Bi). The degree of niche overlap of the major nekton species was unbalanced, being relatively high in autumn, with the species pairs of Oik > 0.6 accounting for 42.86% of the total niche overlap. The degree of niche overlap of the major nekton species was relatively low in spring, accounting for only 21.82% of the total niche overlap. The RDA showed that temperature and salinity were the factors directly affecting the distribution of the major nekton species, while dissolved oxygen, suspended matter, and pH were also important factors. The major nekton species showed ecological differentiation in these resource dimensions. In summary, the major nekton species that were distributed in the waters of Daiquyang and the area adjacent to the mouth of Hangzhou Bay showed an overall low trophic level, but had a large niche breadth. Some of the traditional high-trophic level and typical economic species were replaced with the general or rare species of narrow niche breadth, for example, Larimichthys crocea and Nibea albiflora, etc. A significant reduction was observed in their community species, resources, stability along with the degradation of community structure and function. Therefore, it is of great significance and urgent to strengthen the monitoring, protection, and management of nekton in the Zhoushan Changbai sea area. 参考文献 相似文献 引证文献

基于两个不同资源轴上苔藓植物生态位分析

PDF HTML阅读 XML下载 导出引用 引用提醒 基于两个不同资源轴上苔藓植物生态位分析 DOI: 10.5846/stxb201608101638 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 河南省科技攻关（132102110133）；河南省教育厅科学技术研究重点项目（14A180013） Ecological niche of bryophytes based on two resource axes Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:分别以群丛类型和生长基质类型（包括树生、石生、土生）作为资源轴，对小秦岭56个样方中苔藓植物的生态位特征进行分析和对比。结果表明：（1）两种资源轴上苔藓物种的生态位特征存在一定差异，不同资源轴上，苔藓物种生态位宽度排序发生一定改变。两种资源轴上，青藓属（Brachythecium）均具有较大的生态位宽度，而酸土藓属（Oxystegus）和叶苔属（Jungermania）在不同资源轴上生态位宽度差异较大。（2）对比两种资源轴上的生态位重叠值，生长基质类型明显高于群丛类型；在不同资源轴上，个别物种生态位重叠值排序还会发生明显改变。树平藓属（Homaliodendron）与金灰藓属（Pylaisiella）在两种资源轴上表现出完全相反结果。（3）与维管植物相似，生态位宽度较大的苔藓物种生态位重叠值高，生态位宽度小的苔藓物种也会有较大生态位重叠。 Abstract:Bryophytes, which are relatively primitive species among higher plants, are an important component of biodiversity. The ecological adaptability of species varies based on resource space. This study was conducted in the small Xiaoqinling Mountains Nature Reserve, which was located in Lingbao in Western Henan Province. This location was rich in plant resources; the geographical coordinates are 34°23'-34°31'N, 110°23'-110°44'E. Using stratified sampling and a coastal wave height setting, fifty-six 20 m × 20 m representative sample plots were selected, and the trees, shrubs, herbs, and bryophytes were surveyed and sampled. The multiple regression tree method was used for the 56 plots. Elevation, slope, and aspect were independent variables, and 405 vascular plants in the 56 plots were used to determine the importance value of these dependent variables for community classification. The 56 sample plots were divided into five cluster types and defined as different resource bases, according to the determination of bryophyte epiphytic substrates, which were divided into trees and rocks characteristic of different resource niches. In two different resource axes, 15 types of importance values were chosen. The largest included the order Jungermanniales. Mosses included both acrocarpous and pleurocarpous types. The niche breadth and overlap values of the 15 selected groups were determined using the Shannon-Wiener niche index and Levins niche overlap value. The effects of association between substrate types (trees, rock, and soil) as resource axes on the niche characteristics of bryophytes were examined and compared among the 56 sites. The results showed the following: (1) The two resource axes of niche characteristics of bryophytes differed. On different resource axes, breadth varied among different bryophyte species. In particular, the breadth of Brachythecium was greater. The breadths of Oxystegus and Jungermania in the two types of resource axes differed. In the two resource axes, Brachythecium had a larger niche breadth, ecological adaptability, and environmental utilization ability, whereas the niche width of Homaliodendron was smaller, narrower, and exhibited weaker ecological adaptability. Oxystegus and Jungermania niche widths differed between the resource axes. (2) The niche overlap values of the substrate for the two resource axes were significantly higher than those of association types. The niche overlap order of individual species on different resource axes also differed. Homaliodendron and Pylaisiella showed the opposite results. (3) Similar to that observed in vascular plants, in bryophyte species, niche overlap was high with large niche breadth. Bryophyte species with small niche breadth could also exhibit large niche overlap. For example, Brachythecium had a large niche breadth, whereas the other species had large niche overlap values. However, Oxystegus and Fissidens exhibited niche widths that were small, although they still exhibited large niche overlap values, thereby demonstrating that a certain degree of similarity existed in the use of both resources. 参考文献 相似文献 引证文献