生态交错带与生物多样性

自从生态交错带提出以来,许多生态学家对它与生物多样性之间的关系进行了研究,大量的事实显示出生态交错带富于生物多样性,但一些数据也相当模糊。生态交错带的管理和生物多样性保护是一项有意义而紧迫的工作     

珊瑚礁区的生物多样性及其生态功能

珊瑚礁区生物多样性程度可以与陆地热带雨林相提并论,目前关于珊瑚礁物种多样性及其空间分布特征方面研究进展迅速,是生物多样性研究的重要基地。作为一种生态资源,珊瑚礁还具有重要的生态功能,近年来由于全球气候逐渐变暖、人类活动影响不断加剧,导致其生物多样性缩减、生态功能严重退化。珊瑚礁生态系统多样性、遗传多样性已成为珊瑚礁研究热点,珊瑚礁生态环境效应和保护管理方面的研究也越来越受到重视。我国珊瑚礁主要分布在广阔的南海海域和海南岛、台湾岛、香港和广东广西沿岸,礁区生物种类繁多,多样性程度较高,以往研究主要涉及地质、地貌、生物、环境等方面,现今和今后一段时间里迫切需要加强生物多样性和生态功能研究,以确保更有效地保护和管理珊瑚礁。     

基于物种分布的北京平原生态网络构建

高强度的城市化活动导致了生物栖息地破碎化、退化和消失,是生物多样性减少的主要原因。建立城市地区生态网络是保护生物多样性的重要途径。因其他物种数据可获得性差,以观测的典型鸟类群落为指示物种,探讨构建生态网络,可为城市生物多样性保护提供新思路。以北京市平原区为研究范围,重点基于86种鸟类分布大数据,通过Maxent模型掩膜生成栖息地源地并进行分级,在GIS技术的支撑下,以土地利用数据建立鸟类活动阻力面,采用最小累积阻力模型算法,模拟并形成了平原地区分级的生物多样性保护网络。研究结果表明,河湖湿地和城市公园组成了北京平原地区生态网络的优势景观类型,占平原区生态空间的81%。基于景观类型大小与物种数量的线性关系筛选出分级生物栖息地,其中一级生物栖息地58个,二级生物栖息地146个,通过模型模拟形成了平原地区生物多样性保护的一二级生态网络,共948条网络,长3760km。筛选出重要生态节点12处,关键生态廊道6条,是保护平原地区生物多样性的重要生态设施。该生态网络的实施对于提升首都平原区的生物多样性具有重要价值,研究结果可为国土生态空间优化提供重要科学依据和参考。     

白蚁生物多样性及其对生态环境变化的指示作用

白蚁是热带和亚热带生态系统最主要的无脊椎动物分解者,具有十分重要的生态作用,但因长期缺乏标准化取样方法,白蚁生物多样性研究及其在生态管理中的应用受到限制。本文回顾了白蚁生物多样性及其对环境变化响应的研究进展,概述了白蚁功能分类的现状,介绍了白蚁多样性取样方法的发展,分析了白蚁多样性对生态环境的差异、人为干扰的响应及其生态指示作用,以期为白蚁生物多样性的深入研究及其在生态管理中的应用提供思路与方向。     

基于优势种的生物多样性保护价值空间异质性研究——以长白山生态功能区为例

生物多样性保护是生态系统的主导功能之一,对生物多样性空间异质性的研究有助于准确认识区域的保护价值及重要性,但目前可借鉴的生物多样性价值空间异质性评价方法和经验偏少。以长白山生态功能区核心区为研究区域,基于生物多样性丰富区域优势物种的分布及其环境因子,通过Maxent评估生物多样性保护价值,将研究区域分为生物多样性保护高价值区、中价值区和一般价值区,并开展景观分析与评估。研究结果表明:研究区域内生物多样性保护高价值区域占总面积的42.9%、主要分布于长白山保护区内,保护区内的高价值斑块也较保护区外完整、面积大;研究区域内生物多样性高价值斑块的平均面积和最大斑块面积远高于中价值区和一般价值区,其斑块景观较完整、破碎化水平相对较低,是研究区域生物多样性保护价值和生态系统稳定性的重要基础。植被是对研究区域生物多样性影响最大的环境因子,其次是土层厚度和海拔。从生态系统完整性和过程连续性保护的需要,保护区南部缓冲区可考虑调整为核心区,保护区外还有较大面积的生物多样性高价值和中价值区域也应纳入保护区进行保护;长白山西坡是生物多样性高价值斑块最破碎的区域,应在未来的保护工作中予以特别关注。本研究表明关联优势种空间分布及环境因子是认识生物多样性价值及空间异质性的有效手段,本研究方法可为生态红线划定和国家公园设计提供参考。     

生态遗传学在生物多样性保护中的作用

本文就生态遗传学在生物多样性保护中的作用问题谈了几点看法。首先陈述了生态遗传学的性质,它是种群生态学和种群遗传学的结合,研究种群层次上正在进行着的进化;其次列举了生态遗传学的基本内容,说明生态遗传学是生物多样性研究和保护不可缺少的基本知识。最后举两个实例阐明生态遗传学在生物多样性保护中的具体应用。     

试论山地的生态特征及山地生态学的研究内容

山地是一个生态复杂系统,它具有特定的结构和功能,拥有丰富的生物多样性资源、水资源、矿产资源和旅游资源。开展山地生态学研究对阐明山地系统的结构与功能、山地的生态现象与过程,以及合理开发利用和保护山地资源都有极为重要的意义。本文在简要分析山地地形的主要要素对生态因子影响的基础上,对山地的生态效应进行了归纳,探讨了山地生态学应包含的主要研究内容。作者认为,在山区,地形地貌是形成山地结构和功能以及各种生态现象和过程的最根本因素,它通过改变地表的光、热、水、土、肥等生态因子而发生作用。因此,山地生态学应把地形地貌与各种生态现象和过程的相互作用作为其核心的研究内容。作者提出,山地生态学研究主要包括：山地生态复杂性与生物多样性、山地气候变化、山地生态工程、山区可持续发展综合研究以及山地生态学研究技术与方法论等内容。     

生物多样性保护的景观规划途径

景观规划设计在生物多样性保护中起着决定性的作用。基于不同的保护哲学,生物多样性保护的景观规划途径主要可分为两种：一是以物种为核心的景观规划途径,另一种是以景观元素为核心和出发点的规划途径。前者首先确定物种,然后根据物种的生态特性来设计景观格局,后者则以各种尺度的景观元素作为保护对象,根据其空间位置和关系设计景观格局。多种空间战略被认为有利于生物多样性的保护,包括保护核心栖息地、建立缓冲区、构筑廊道、增加景观异质性和引入或恢复栖息地。落实这些空间战略必须首先回答选择什么和在什么地方设计上述景观元素的问题。对此,目前尚没有很好的答案。传统的生物保护战略被动地强调现存濒危物种和景观元素的保护,如果将物种运动和生态过程作为一个能动的景观控制过程来对待,我们将会有一种全新的景观规划途径。其中有三个方面的概念对这种新的景观规划途径有启发意义：即景观的空间构型对生态过程的作用,生物进化空间轨迹与景观格局设计及景观阻力与潜在的生态基础设施的设计。景观生态安全格局正是在这些方向上的一个新的探索。     

面向生态系统结构的生物多样性保护成效空间对比评估

开展生物多样性保护成效对比评估对于合理执行生态补偿机制的转移支付政策,以及进一步促进全国生态保护管理水平的有效提升都具有重要意义。以2015年版《全国生态功能区划》划定的生物多样性保护重要生态功能区为研究对象,采用生物多样性保护成效结构指数,探讨重要生态功能区生物多样性保护成效的区域分异情况。研究结果表明：(1)华南、华东与华中地区重要生态功能区的生态结构参照基准较高,东北地区重要生态功能区居中,较差的重要生态功能区则位于西南和西北地区,说明了全国生态环境本底的区域分异性;(2)西北和西南地区重要生态功能区的保护成效结构指数较高,华中和华南地区居中,而东北和华东地区的保护成效结构指数较低,体现了2015年全国重要生态功能区生物多样性保护成效的空间差异情况;(3)从草原、森林与湿地生物多样性的保护成效结构指数来看,西北与西南地区、东北和西南地区及华东地区的重要生态功能区分别具有较大优势。上述研究结果反映了全国重要生态功能区生物多样性保护成效优劣的空间差异状况,可为政府部门健全生态补偿机制以及制定生态系统恢复方案提供决策参考。     

环境污染对生物多样性的影响

环境污染并不是一种一般意义上的环境胁迫 ,生物对污染的适应机制及进化格局与自然胁迫条件下的情形并不相同。环境污染是一种生态破坏 !随着研究工作的不断深入和系统化 ,人们越来越发现 ,环境染污引起物种丧失实质上也是一种生态破坏 ,而且认为当今世界正在经历的物种大灭绝在很大程度上与全球扩散的环境污染有密切联系。以下分别在遗传、物种和生态系统水平上讨论污染对生物多样性的影响。1　遗传多样性的丧失遗传多样性强调的是现有种质的遗传变异库存量 ,它既是生物遗传变异的历史积累 ,反映了生物的进化过程 ,也是现有生物适应现有环…     

Covariance and decoupling of floral and vegetative traits in nine Neotropical plants: a re-evaluation of Berg's correlation-pleiades concept

Nearly forty years ago R. L. Berg proposed that plants with specialized pollination ecology evolve genetic and developmental systems that decouple floral morphology from phenotypic variation in vegetative traits. These species evolve separate floral and vegetative trait clusters, or as she termed them, "correlation pleiades." The predictions of this hypothesis have been generally supported, but only a small sample of temperate-zone herb and grass species has been tested. To further evaluate this hypothesis, especially its applicability to plants of other growth forms, we examined the patterns of phenotypic variation and covariation of floral and vegetative traits in nine species of Neotropical plants. We recognized seven specific predictions of Berg's hypothesis. Our results supported some predictions but not others. Species with specialized pollination systems usually had floral traits decoupled (weak correlation; Canna and Eichornia) or buffered (relationship with shallow proportional slope; Calathea and Canna) from variation in vegetative traits. However, the same trend was also observed in three species with unspecialized pollination systems (Echinodorus, Muntingia, and Wedelia). One species with unspecialized pollination (Croton) and one wind-pollinated species (Cyperus) showed no decoupling or buffering, as predicted. While species with specialized pollination usually showed lower coefficients of variation for floral traits than vegetative traits (as predicted), the same was also true of species with unspecialized or wind pollination (unlike our prediction). Species with specialized pollination showed less variation in floral traits than did species with unspecialized or wind pollination, as predicted. However, the same was true of the corresponding vegetative traits, which was unexpected. Also in contrast to our prediction, plants with specialized pollination systems did not exhibit tighter phenotypic integration of floral characters than did species with generalized pollination systems. We conclude that the patterns of morphological integration among floral traits and between floral and vegetative traits tend to be species specific, not easily predicted from pollination ecology, and generally more complicated than R. L. Berg envisaged.     

The best of two worlds: ecology and evolution of ambophilous plants

Ambophily, the mixed mode of wind and insect pollination is still poorly understood, even though it has been known to science for over 130 years. While its presence has been repeatedly inferred, experimental data remain regrettably rare. No specific suite of morphological or ecological characteristics has yet been identified for ambophilous plants and their ecology and evolution remain uncertain. In this review we summarise and evaluate our current understanding of ambophily, primarily based on experimental studies. A total of 128 ambophilous species – including several agriculturally important crops – have been reported from most major habitat types worldwide, but this probably represents only a small subset of ambophilous species. Ambophilous species have evolved both from wind- and insect-pollinated ancestors, with insect-pollinated ancestors mostly representing pollination by small, generalist flower visitors. We compiled floral and reproductive traits for known ambophilous species and compared our results to traits of species pollinated either by wind or by small generalist insects only. Floral traits were found to be heterogeneous and strongly overlap especially with those of species pollinated by small generalist insects, which are also the prominent pollinator group for ambophilous plants. A few ambophilous species are only pollinated by specialised bees or beetles in addition to pollination by wind. The heterogeneity of floral traits and high similarity to generalist small insect-pollinated species lead us to conclude that ambophily is not a separate pollination syndrome but includes species belonging to different insect- as well as wind-pollination syndromes. Ambophily therefore should be regarded as a pollination mode. We found that a number of ecological factors promoted the evolution of ambophily, including avoidance of pollen limitation and self-pollination, spatial flower interference and population density. However, the individual ecological factors favouring the transition to ambophily vary among species depending on species distribution, habitat, population structure and reproductive system. Finally, a number of experimental studies in combination with observations of floral traits of living and fossil species and dated phylogenies may indicate evolutionary stability. In some clades ambophily has likely prevailed for millions of years, for example in the castanoid clade of the Fagaceae.     

Consequences of clonal growth for plant mating

By affecting the number and the spatial distribution of flowering units (i.e., ramets), clonal growth can influence pollen transfer between plants and thus affect mating opportunities. In this paper I review some recent work that attests the importance of clonal growth for pollination patterns. A major aspect concerns the increase in floral display through the multiplication of flowering ramets. Although large floral displays can enhance pollinator attraction and may thus promote outcrossing, they can also increase rates of geitonogamy (i.e., pollination between flowers in the same plant). However, the latter aspect will depend on clonal architecture, a feature that greatly varies among clonal plant species. Future experimental studies and comparative analyses of rates of geitonogamy in species with clumped and intermingled distribution may allow for the evaluation of evolutionary interaction between clonal growth and floral traits that regulate mating patterns.     

同域分布的紫堇属三种植物的繁育系统和传粉差异

为研究近缘物种之间繁育系统分化对传粉环境的适应性意义,本文针对湖北地区的3种紫堇属植物（紫堇Corydalis edulis Maxim.、尖距紫堇C.shearer S.Moore.和小花黄堇C.racemosa（Thunb.） Pers.）进行了传粉生态学研究,对比分析了它们在花部特征、分布模式、花期、交配系统、传粉系统等方面的差异。3种紫堇属植物常见伴生现象,花期有一定重叠;花色、距长、花蜜量等方面均有显著差异;尖距紫堇交配系统为自交不亲和、依靠传粉者异花授粉;而紫堇和小花黄堇交配系统为自交亲和,兼有自交和异交的混合交配系统。3个物种均由蜂类传粉,且花部性器官与传粉者的接触部位一致,但访花频率差异较大。在混合群落中,传粉者访花具有较高的忠实性,花部特征差异可能是传粉者选择性访花的原因。对于紫堇属3个物种,花部特征和交配系统的分化有助于其避免传粉过程的相互干扰,交配系统与传粉环境具有一定相关性,混合交配系统可能有利于提高植物对不同生境和气候的适应性。     

The future of plant-pollinator diversity: understanding interaction networks across time, space, and global change

Structural analysis of plant-pollinator networks has revealed remarkably high species and interaction diversity and highlighted the species important for pollination services. Although techniques to analyze plant-pollinator networks began to emerge a decade ago, the characterization of spatiotemporal variation of interactions is still in its infancy. Understanding the ecological and evolutionary causes and consequences of spatial and temporal variation in plant-pollinator interactions is important for both basic and applied questions in community structure and function, the evolution of floral traits, and the development of optimal conservation strategies. Here we review observational, theoretical, and experimental studies of temporal and spatial variation in plant-pollinator interaction networks to establish a foundation for future studies to incorporate perspectives in spatiotemporal variation. Such perspectives are crucial given the rapid environmental changes associated with habitat loss, climate change, and biological invasions, which we discuss in this context. The inherent plasticity of plant-pollinator interactions and network structure suggests that many species should be able to persist by responding to environmental changes quickly, even though the identity of their mutualistic partners may change.     

Intensified wind pollination mediated by pollen dimorphism after range expansion in an ambophilous biennial Aconitum gymnandrum

Pollination systems and associated floral traits generally differ between core and marginal populations of a species. However, such differences are rarely examined in plants with a mixed wind‐ and bumblebee‐pollination system, and the role of wind pollination during range expansion in ambophilous plants remains unclear. We compared floral traits and the contributions of bumblebee and wind pollination in refugium and marginal populations of the ambophilous plant Aconitum gymnandrum. We found that most floral traits differed between the two populations, and those traits associated with the shift to wind pollination were pronounced in the marginal population. Bumblebee visitation rates varied significantly, but were generally low in the marginal population. Wind pollination occurred in both populations, and the efficiency was lower than that of bumblebee pollination. Two types of pollen grains, namely round and fusiform pollen, were transported to a stigma by bumblebees and wind, but fusiform pollen contributed to wind pollination to a larger degree, especially in the marginal population. Our results suggest that wind pollination was enhanced by pollen dimorphism in the marginal population of A. gymnandrum, and wind pollination may provide reproductive assurance when bumblebee activity is unpredictable during range expansion, indicating that ambophily is stable in this species and shift in pollination system could be common when plants colonize new habitats.     

Floral traits and pollination systems in the Caatinga, a Brazilian tropical dry forest

BACKGROUND AND AIMS: Pollination is a critical stage in plant reproduction and thus in the maintenance and evolution of species and communities. The Caatinga is the fourth largest ecosystem in Brazil, but despite its great extent and its importance few studies providing ecological information are available, with a notable lack of work focusing on pollination biology. Here, general data are presented regarding the frequency of pollination systems within Caatinga communities, with the aim of characterizing patterns related to floral attributes in order to make possible comparisons with data for plant communities in other tropical areas, and to test ideas about the utility of syndromes. This paper also intends to provide a reference point for further studies on pollination ecology in this threatened ecosystem. METHODS: The floral traits and the pollination systems of 147 species were analysed in three areas of Caatinga vegetation in northeastern Brazil, and compared with world-wide studies focusing on the same subject. For each species, floral attributes were recorded as form, size, colour, rewards and pollination units. The species were grouped into 12 guilds according to the main pollinator vector. Analyses of the frequencies of the floral traits and pollination systems were undertaken. KEY RESULTS: Nectar and pollen were the most common floral resources and insect pollination was the most frequent, occurring in 69.9 % of the studied species. Of the entomophilous species, 61.7 % were considered to be melittophilous (43.1 % of the total). Vertebrate pollination occurred in 28.1 % of the species (ornithophily in 15.0 % and chiropterophily in 13.1 %), and anemophily was recorded in only 2.0 %. CONCLUSIONS: The results indicated that the pollination systems in Caatinga, despite climatic restrictions, are diversified, with a low percentage of generalist flowers, and similar to other tropical dry and wet forest communities, including those with high rainfall levels.     

INFLUENCE OF POLLINATION SPECIALIZATION AND BREEDING SYSTEM ON FLORAL INTEGRATION AND PHENOTYPIC VARIATION IN IPOMOEA

Natural selection should reduce phenotypic variation and increase integration of floral traits involved in placement of pollen grains on stigmas. In this study, we examine the role of pollinators and breeding system on the evolution of floral traits by comparing the patterns of floral phenotypic variances and covariances in 20 Ipomoea species that differ in their level of pollination specialization and pollinator dependence incorporating phylogenetic relatedness. Plants with specialized pollination (i.e., those pollinated by one functional group or by few morphospecies) displayed less phenotypic variation and greater floral integration than generalist plants. Self‐compatible species also displayed greater floral integration than self‐incompatible species. Floral traits involved in pollen placement and pick up showed less variation and greater integration than floral traits involved in pollinator attraction. Analytical models indicate that both breeding system and the number of morphospecies had significant effects on floral integration patterns although only differences in the former were significant after accounting for phylogeny. These results suggest that specialist/self‐compatible plants experience more consistent selection on floral traits than generalist/self‐incompatible plants. Furthermore, pollinators and breeding system promote integration of floral traits involved in pollen placement and pick up rather than integration of the whole flower.     

Identification of major quantitative trait loci underlying floral pollination syndrome divergence in Penstemon

Distinct floral pollination syndromes have emerged multiple times during the diversification of flowering plants. For example, in western North America, a hummingbird pollination syndrome has evolved more than 100 times, generally from within insect-pollinated lineages. The hummingbird syndrome is characterized by a suite of floral traits that attracts and facilitates pollen movement by hummingbirds, while at the same time discourages bee visitation. These floral traits generally include large nectar volume, red flower colour, elongated and narrow corolla tubes and reproductive organs that are exerted from the corolla. A handful of studies have examined the genetic architecture of hummingbird pollination syndrome evolution. These studies find that mutations of relatively large effect often explain increased nectar volume and transition to red flower colour. In addition, they suggest that adaptive suites of floral traits may often exhibit a high degree of genetic linkage, which could facilitate their fixation during pollination syndrome evolution. Here, we explore these emerging generalities by investigating the genetic basis of floral pollination syndrome divergence between two related Penstemon species with different pollination syndromes—bee-pollinated P. neomexicanus and closely related hummingbird-pollinated P. barbatus. In an F₂ mapping population derived from a cross between these two species, we characterized the effect size of genetic loci underlying floral trait divergence associated with the transition to bird pollination, as well as correlation structure of floral trait variation. We find the effect sizes of quantitative trait loci for adaptive floral traits are in line with patterns observed in previous studies, and find strong evidence that suites of floral traits are genetically linked. This linkage may be due to genetic proximity or pleiotropic effects of single causative loci. Interestingly, our data suggest that the evolution of floral traits critical for hummingbird pollination was not constrained by negative pleiotropy at loci that show co-localization for multiple traits.     

Effects of distance from models on the fitness of floral mimics

• Rewardless plants can attract pollinators by mimicking floral traits of rewarding heterospecific plants. This should result in the pollination success of floral mimics being dependent on the relative abundance of their models, as pollinator abundance and conditioning on model signals should be higher in the vicinity of the models. However, the attraction of pollinators to signals of the models may be partially innate, such that spatial isolation of mimics from model species may not strongly affect pollination success of mimics.
• We tested whether pollination rates and fruit set of the rewardless orchid Disa pulchra were influenced by proximity and abundance of its rewarding model species, Watsonia lepida.
• Pollination success of the orchid increased with proximity to the model species, while fruit set of the orchid increased with local abundance of the model species. Orchids that were experimentally translocated outside the model population experienced reduced pollinaria removal and increased pollinator‐mediated self‐pollination.
• These results confirm predictions that the pollination success of floral mimics should be dependent on the proximity and abundance of model taxa, and thus highlight the importance of ecological facilitation among species involved in mimicry systems.