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1.
Ecological indicators are currently developed to account for the different facets of loss of biological diversity due to direct or indirect effects of human activities. Most ecological indicators include species richness as a metric. Others, such as functional traits and phylogenetic diversity, account for differences in species, even when species richness is the same. Here, we describe and apply a different indicator, called morphoscape dimension, accounting for morphological variability across habitats in a geographical region. We use the case of ground beetles (Coleoptera: Carabidae) in four different habitats in the Po Plain in Northern Italy to exemplify how to quantify the magnitude of the morphological space (i.e. the dimension of the morphoscape) occupied by the species in each habitat using geometric morphometrics. To this aim, we employed a variety of metrics of morphological disparity related to univariate size, and more complex multivariate shape and form. Our ‘proof of concept’ suggests that metrics assessing size and form might largely tend to simply mirror the information provided by species richness, whereas shape morphoscape disparity may be able to account for non-trivial differences in species traits amongst habitats. This is indicated by the woodland morphoscape being on average bigger than that of crops, the most species-rich habitat, despite having almost 20% less species. We conclude suggesting that the analysis of morphoscape dimension has the potential to become a new additional and complimentary tool in the hands of conservation biologists and ecologists to explore and quantify habitat complexity and inform decisions on management and conservation based on a wide set of ecological indicators.  相似文献   

2.
Generalization prevails in flower–animal interactions, and although animal visitors are not equally effective pollinators, most interactions likely represent an important energy intake for the animal visitor. Hummingbirds are nectar-feeding specialists, and many tropical plants are specialized toward hummingbird-pollination. In spite of this, especially in dry and seasonal tropical habitats, hummingbirds may often rely on non-ornithophilous plants to meet their energy requirements. However, quantitative studies evaluating the relative importance of ornithophilous vs. non-ornithophilous plants for hummingbirds in these areas are scarce. We here studied the availability and use of floral resources by hummingbirds in two different areas of the Cerrado, the seasonal savannas in Central Brazil. Roughly half the hummingbird visited plant species were non-ornithophilous, and these contributed greatly to increase the overall nectar availability. We showed that mean nectar offer, at the transect scale, was the only parameter related to hummingbird visitation frequency, more so than nectar offer at single flowers and at the plant scale, or pollination syndrome. Centrality indices, calculated using hummingbird–plant networks, showed that ornithophilous and non-ornithophilous plants have similar importance for network cohesion. How this foraging behaviour affects reproduction of non-ornithophilous plants remains largely unexplored and is probably case specific, however, we suggest that the additional energy provided by non-ornithophilous plants may facilitate reproduction of truly ornithophilous flowers by attracting and maintaining hummingbirds in the area. This may promote asymmetric hummingbird–plant associations, i.e., pollination depends on floral traits adapted to hummingbird morphology, but hummingbird visitation is determined more by the energetic "reward" than by pollination syndromes.  相似文献   

3.
Organic and inorganic materials migrate downstream and have important roles in regulating environmental health in the river networks. However, it remains unclear whether and how a mixture of materials (i.e., microbial species) from various upstream habitats contribute to microbial community coalescence upstream of a dam. Here we track the spatial variation in microbial abundance and diversity in the Three Gorges Reservoir based on quantitative PCR and 16S rRNA gene high-throughput sequencing data. We further quantitatively assess the relative contributions of microbial species from mainstem, its tributaries, and the surrounding riverbank soils to the area immediately upstream of the Three Gorges Dam (TGD). We found an increase of microbial diversity and the convergent microbial distribution pattern in areas immediately upstream of TGD, suggesting this area become a new confluence for microbial diversity immigrating from upstream. Indeed, the number of shared species increased from upstream to TGD but unique species decreased, indicating immigration of various sources of microbial species overwhelms local environmental conditions in structuring microbial community close to TGD. By quantifying the sources of microbial species close to TGD, we found little contribution from soils as compared to tributaries, especially for sites closer to TGD, suggesting tributary microbes have greater influence on microbial diversity and environmental health in the Three Gorges Reservoir. Collectively, our results suggest that tracking microbial geographic origin and evaluating accumulating effects of microbial diversity shed light on the ecological processes in microbial communities and provide information for regulating aquatic ecological health.  相似文献   

4.
Interactions between fleshy fruited plants and frugivores are crucial for the structuring and functioning of biotic communities, particularly in tropical forests where both groups are diverse and play different roles in network organization. However, it remains poorly understood how different groups of frugivore species and fruit traits contribute to network structure. We recorded interactions among 28 plant species and three groups of frugivores (birds, bats, and non-flying mammals) in a seasonal forest in Mexico to determine which species contribute more to network structure and evaluate the importance of each species. We also determined whether fruit abundance, water content, morphology traits, and fruiting phenology are related to network parameters: the number of interactions, species contribution to nestedness, and species strength. We found that plants did not depend on a single group of frugivores, but rather on one species of each group: the bird Pitangus sulphuratus, the bat Sturnira parvidens, and the non-flying mammal Procyon lotor. The abundance, size, and water content of the fruits were significantly related to the contribution to nestedness, number of interactions, and species strength index of plant species. Tree species and birds contributed mainly to the nested structure of the network. We show that the structure of plant-frugivore networks in this seasonal forest is non-random and that fruit traits (i.e., abundance, phenology, size, and water content) are important factors shaping plant-frugivore networks. Identification of the key species and their traits that maintain the complex structure of species interactions is therefore fundamental for the integral conservation of tropical forests.  相似文献   

5.
燕炳成  崔戈  孙胜浩  王沛芳  王超  吴程  陈娟 《环境科学》2023,44(7):3864-3871
浮游真核微生物通常由少数丰富类和大量稀有类组成,二者在维持水生生态系统健康稳定方面具有重要作用.目前对大型筑坝河流中这两类真核微生物的生物地理分布模式所知甚少.以我国西南梯级水电开发河流金沙江为研究区域,对比分析丰富类和稀有类浮游真核微生物在不同河段的分布特征,解析影响两类微生物空间分布的主导因素.结果表明,相比上游自然河段,金沙江浮游真核微生物的α多样性在梯级大坝河段显著升高,稀有类的α多样性增长比高于丰富类.浮游真核丰富类和稀有类微生物的群落组成在不同河段间存在显著差异,其中Vermamoeba属等优势属的相对丰度在两河段间同样存在明显差异.影响丰富类和稀有类浮游真核微生物群落组成的关键地化因子有海拔和pH等,两类微生物群落相似性与地理距离和环境异质性均符合距离衰减关系,其群落构建均受扩散限制和环境筛选共同影响;方差分解分析和偏Mantel检验结果显示扩散限制是影响丰富类和稀有类分布的主要驱动因素.研究结果为我国西南缺资料区水电开发河流中微生物的地理分布模式和生态响应提供数据支持.  相似文献   

6.
Both plant traits and plant–pollinator interactions are thought to influence plant mating systems. For hummingbird-pollinated plants, foraging strategy (territorial or traplining) is also expected to influence plant mating. We hypothesize that the traplining behavior of hermits promotes outcrossing, whereas the behavior of non-hermits favours self-incompatibility. Thus, selection is expected to maintain self-incompatibility in plants pollinated by non-hermits. We explore the incidence of self-incompatibility in Neotropical hummingbird-pollinated plants and its association with hummingbird behavior and plant traits. We conducted a literature review (56 species) and performed hand-pollination experiments in 27 hummingbird-pollinated plants in an Atlantic rainforest. We found that self-incompatibility (measured as <0.3 for the Index of Self-incompatibility [ISI]) occurred in only 33 % of the Neotropical hummingbird-pollinated plants. The interaction of hummingbird and habit type affected ISI, as did phylogenetic relationships. Specifically, herbs pollinated by non-hermits had higher ISI than woody plants pollinated by non-hermits, and herbs pollinated by both hermits and non-hermits. For the Atlantic rainforest plant guild, 30 % of the species were self-incompatible. ISI was higher in herbs than in woody species and increased with plant aggregation but was not dependent on foraging behavior, plant density, or floral display. Although hummingbirds differ in their foraging strategies, these behavioral differences seem to have only a minor influence on the incidence of self-incompatibility. Phylogenetic relatedness seems to be the strongest determinant of mating system in Neotropical hummingbird-pollinated plants.  相似文献   

7.
Models of ecological speciation predict that certain types of habitat should be more conducive to species diversification than others. In this study, I test this hypothesis in waders of the sub-order Charadrii using the number of morphological sub-species per species as an index of diversity. I classified all members of this clade as spending the non-breeding season either coastally or inland and argue that these represent fundamentally different environments. Coastal mudflats are characterised by high predictability and patchy worldwide distribution, whilst inland wetlands are widespread but unpredictable. The results show that migratory species that winter coastally are sub-divided into more sub-species than those that winter inland. This was not the case for non-migratory species. I argue that coastal environments select for more rigid migratory pathways, whilst inland wetlands favour more flexible movement patterns. Population sub-division could then result from the passive segregation of breeding sites or from the active selection for assortative mating of ecomorphs.  相似文献   

8.
上海城市绿地系统建设与规划的原则和对策   总被引:8,自引:0,他引:8  
针对上海城市绿化现状,强调生态位、生态效益、生物多样性、空间布局和景观割裂等原理在绿地中的重要性,并在此基础上分析探讨了21世纪的上海在绿地系统建设中应如何提高绿化数量、改善绿地质量、提高生物的多样性和空间异质性、发挥生态效益、丰富绿化形式等诸多问题,尝试为今后的规划提供一些对策。  相似文献   

9.
The incorporation of landscape ecological and fragmentation analyses within remote sensing science has expanded the inferential capabilities of such research. This issue presents a series of papers on the use of landscape ecological techniques to explore the relationship between land cover and land use spatial pattern and process in an international, comparative context. Methodologically, researchers seek to link spatial pattern to land use process by integrating geographic information systems (GIS), socio-economic, and remote sensing techniques with landscape ecological approaches. This issue brings together papers at the forefront of this research effort, and illustrates the diversity of methods necessary to evaluate the complex linkages between pattern and process in landscapes across the world. The analyses focus on major forces interacting at the earth’s surface, such as the interface of agricultural and urban land, agriculture and forestry, and other pertinent topics dealing with environmental policy and management. Empirical analyses stem from many different ecological, social and institutional contexts within the Americas, Africa, and Asia.  相似文献   

10.
Ants are one of the most studied insects in the world; and the literature devoted to their origin and evolution, systematics, ecology, or interactions with plants, fungi and other organisms is prolific. However, no consensus yet exists on the age estimate of the first Formicidae or on the origin of their eusociality. We review the fossil and biogeographical record of all known Cretaceous ants. We discuss the possible origin of the Formicidae with emphasis on the most primitive subfamily Sphecomyrminae according to its distribution and the Early Cretaceous palaeogeography. And we review the evidence of true castes and eusociality of the early ants regarding their morphological features and their manner of preservation in amber. The mid-Cretaceous amber forest from south-western France where some of the oldest known ants lived, corresponded to a moist tropical forest close to the shore with a dominance of gymnosperm trees but where angiosperms (flowering plants) were already diversified. This palaeoenvironmental reconstruction supports an initial radiation of ants in forest ground litter coincident with the rise of angiosperms, as recently proposed as an ecological explanation for their origin and successful evolution.  相似文献   

11.
The annual cycle of migrating birds is shaped by their seasonal movements between breeding and non-breeding sites. Studying how migratory populations are linked throughout the annual cycle—migratory connectivity, is crucial to understanding the population dynamics of migrating bird species. This requires the consideration not only of spatial scales as has been the main focus to date but also of temporal scales: only when both aspects are taken into account, the degree of migratory connectivity can be properly defined. We investigated the migration behaviour of hoopoes (Upupa epops) from four breeding populations across Europe and characterised migration routes to and from the breeding grounds, location of non-breeding sites and the timing of key migration events. Migration behaviour was found to vary both within and amongst populations, and even though the spatial migratory connectivity amongst the populations was weak, temporal connectivity was strong with differences in timing amongst populations, but consistent timing within populations. The combination of diverse migration routes within populations and co-occurrence on the non-breeding grounds between populations might promote exchange between breeding populations. As a result, it might make hoopoes and other migrating bird species with similar strategies more resilient to future habitat or climatic changes and stabilise population trends.  相似文献   

12.
国土空间规划的提出使我国的规划体系进入到新的发展时期与发展语境,国土空间开发方向已从生产空间为主导转向生态、生活、生产空间相协调。如何将基于“三生空间”概念的传统国土空间认知提升到丰富文化脉络、生态特征、生活基础的复合魅力国土空间,如何对不同区域的发展进行侧重,杜绝对单一发展模式的盲目跟风,是国家和地方面临的共同重大主题。结合国土空间在历史与现实不同时期的发展表征和形成原因,在回溯空间认知过程、反思空间规划实践的基础上,厘清了魅力国土空间的概念与内涵,提出国土空间规划体系下魅力国土空间的关注焦点,从区域发展平衡、管控弹性调整、空间要素流动、发展目标优化等方面阐述了魅力国土空间的作用与功能。  相似文献   

13.
We used three approaches to assess potential effects of climate change on birds of the Northeast. First, we created distribution and abundance models for common bird species using climate, elevation, and tree species variables and modeled how bird distributions might change as habitats shift. Second, we assessed potential effects on high-elevation birds, especially Bicknell’s thrush (Catharus bicknelli), that may be particularly vulnerable to climate change, by using statistical associations between climate, spruce-fir forest vegetation and bird survey data. Last, we complemented these projections with an assessment of how habitat quality of a migratory songbird, the black-throated blue warbler (Dendroica caerulescens) might be affected by climate change. Large changes in bird communities of the Northeast are likely to result from climate change, and these changes will be most dramatic under a scenario of continued high emissions. Indeed, high-elevation bird species may currently be at the threshold of critical change with as little as 1°C warming reducing suitable habitat by more than half. Species at mid elevations are likely to experience declines in habitat quality that could affect demography. Although not all species will be affected adversely, some of the Northeast’s iconic species, such as common loon and black-capped chickadee, and some of its most abundant species, including several neotropical migrants, are projected to decline significantly in abundance under all climate change scenarios. No clear mitigation strategies are apparent, as shifts in species’ abundances and ranges will occur across all habitat types and for species with widely differing ecologies.  相似文献   

14.
空间冲突是城市化过程中各种矛盾形成与激化的直接原因,是影响区域可持续发展的关键因素,合理测度快速城市化地区的空间冲突水平,对于优化区域发展模式、 避免区域生态风险具有重要意义。在利用遥感与GIS技术分析长株潭近年来空间格局变化的基础上,量化影响区域生态安全的空间外部压力值、 生态风险暴露值、 生态风险效应值3个因子,构建基于生态安全的空间冲突测度模型,对长株潭地区的空间冲突水平进行评估。研究表明:近年来长株潭地区的空间冲突作用强度总体呈现上升趋势,1993—2008年其冲突指数均值由0.264增长到0.323,且严重失控级别空间冲突的区域面积比例增幅最大,达1.07倍;不同空间类型的空间冲突强度不同,林地、 耕地的空间冲突水平相对较低,建设用地的空间冲突水平较高;城乡过渡地带是空间格局变化最为频繁、 空间冲突最为激烈的区域,其次是城市内部,农村地区的空间冲突强度远远低于城市。  相似文献   

15.
基于分形理论的中国原油管道网络结构研究   总被引:2,自引:0,他引:2  
为深入分析全国及各区域原油管网的结构与布局,揭示其空间结构特征,论文运用分形理论的三种维数:加权长度-半径维数、分枝-半径维数和关联维数,分别从密度、连通性及通达性研究了全国及各区域原油管网。研究结果表明:全国原油管网的密度和连通性均存在明显的东西分异特征,密度自东向西呈"线状-散点"的下降形态,连通性自东向西呈"散点-线状"的升高形态,而通达性则普遍较低;对各区域来说,东北、华北和华东等东部管网除连通性较低外,其他分形指标相对较高;西北管网的密度、通达性均不如东部,而且其新疆管网的连通性数值超过2,是不正常的连通结构;华南管网的多数分形指标均低于其他地区,其管网结构雏形尚未形成。  相似文献   

16.
The European soil policy is being focussed towards a more conscious and sustainable use of the soil, taking into account ecological, economical and societal dimensions. Living soil organisms are reliable bioindicators, as they provide the best reflection of the soil system, ecological services and ecosystem functioning therein. These most complex (bio)physical systems indicate, among others, the energy flow. Such processes can be described by rather simple power law relationships. In fact, the average body mass (dry weight) can be seen as an inherent species property, while population density is a much more flexible parameter reflecting ecosystem state. In this study, I review the interactions between these items in relation to feedbacks and conjectured relationships which can be seen as ecological networks. From this novel perspective, allometry can be used as an integrated measure for the anthropogenic influence on landscapes and related food webs. Allometry is, therefore, a perfect surrogate for land use intensity in modelling of field effects for restoration ecology and conservation biology. Robust correlations will be addressed between the density dependence of invertebrates and the ability of soil systems themselves to recover after disturbance. Quantitative indicators of soil community composition and related ecological services are proposed and their application for ecological risk assessment is illustrated.  相似文献   

17.
Manyas, also known as the Bird Paradise Lake, is situated near the south-eastern coasts of the Marmara Sea in Turkey. This shallow lake, is a unique natural reserve providing habitat for migratory birds with its rich fauna and plankton species. The objective of this work is to study the ecological and water quality changes resulting from increasing anthropogenic pollution and human intervention on the natural variations of the water level. For this purpose, physical, chemical and microbiological aspects of the aquatic ecosystem in the lake of Manyas are being measured semimonthly since more than a year. After the completion of field measurements associations between different parameters will be searched by means of a water quality model. Results obtained will be used in the sustainable restoration of the lake. In this paper, firstly the nutrient and trophic dynamics of the planktonic ecosystem are associated with the bio-geochemical water cycle in the lake. Secondly, space and time distributions of all physical, chemical and microbiological data are presented and interactions between the nutrient availability and some microscopic communities are discussed.  相似文献   

18.
The Northern wheatear (Oenanthe oenanthe) is a small long-distance migratory songbird that breeds throughout the Northern hemisphere and winters in sub-Saharan Africa. The main components of its migratory behaviour, i.e. seasonal migratory restlessness and body mass changes, have been shown to be under endogenous control. However, it is still unknown whether the disposition to accumulate fuel reserves is an inherited trait. We cross-bred Northern wheatears from two populations known to accumulate different amounts of fuel in a common-garden setup, and measured their maximum fuelling as the difference between the lightest and heaviest body mass recorded over each year for 4 years or longer. We used the largest value as a measure of maximum voluntary fuelling potential. F1-generation “hybrids” showed intermediate values to those of the parent populations. It was previously shown that in the wheatear the amount of fuel accumulated is closely linked to the presence of large ecological barriers to cross. This study shows that this adaptation has been fixed at the genetic level, and that intermediate traits are transferred to the next generation, with possible implications on the viability of such individuals in nature.  相似文献   

19.
Habitat templet theory predicts that habitat provides the templet on which evolution shapes species’ multiple traits and thus their characteristic life-history strategies. By analysing entire trait communities (multiple species and traits) in this framework we can enhance our understanding of how species composition changes as environmental constraints vary across the landscape. Here, we study multiple traits of floodplain Orthoptera communities under the influence of two different sources of disturbance, land use and seasonal flooding.The application of two recently developed statistical techniques - qualitative RLQ analysis and subsequent fourth-corner permutation tests - revealed two different life history strategies in Orthoptera as a response to ecological disturbances, resulting from land use management and seasonal flooding. Orthoptera species seem to have developed two complementary strategies: (i) the high active dispersal-low reproduction strategy in intensive land use situations and (ii) the high passive dispersal-high reproduction strategy in areas with high flood disturbance. Disturbance gradients act as trait filters allowing only particular trait combinations i.e. species with particular preadaptations to survive, whereas others go regionally extinct. Reproduction and dispersal capacity seem to be inversely associated with the disturbance gradients. Ovariole number, taken as the measure for reproduction, showed significant phylogenetic signal, which could potentially confound this relationship. Nonetheless, RLQ analyses coupled with fourth-corner permutation tests proved a powerful tool to reveal and disentangle different evolutionary strategies.  相似文献   

20.
Microbial activity and regrowth in drinking water distribution systems is a major concern for water service companies. However, previous studies have focused on the microbial composition and diversity of the drinking water distribution systems(DWDSs), with little discussion on microbial molecular ecological networks(MENs) in different water supply networks.MEN analysis explores the potential microbial interaction and the impact of environmental stress, to explain the characteristics of microbial...  相似文献   

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