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The distribution pattern of 44 recognized genera in the Campanulaceae(s.str.) was analysed.Genera-contour lines were constructed,which showed three centres of frequency of genera:the Eastern Asiatic region,Cape region and the Mediterranean region. Thirteen genera are found in E.Asia:Adenophora,Asyneuma,Campanula,Campanumoea, Codonopsis,Cyananthus,Cyclocodom,Echinocodon Hong,Homocodon Hong,Leptocodon, Peracarpa,Platycodon,and Wahlenbergia. Twelve of the 13 genera (except for Echinocodon) can be found in a small area of SW.China (E.& N.Yunnan,SW.Sichuan and SW.Guizhou).This is the most concentrated region of genera in the family.The Cape region has 10 genera: Craterocapsa,Merciera,Microcodon,Rhigiophyllum,Prismatocarpus,Roella,Siphocodon,Teilera,Treichelia and Wahlenbergia.Although the figure is not very high,the region is also concentrated one of genera,considering its small area.The last region possesses 14 genera:Adenophora,Asyneuma,Campanula,Edraianthus,Feeria,Jasione,Legousia,Mindium,Petromarula,Physoplexis,Phyteuma,Symphyandra,Trachelium and Wahlenbergia.The region is relatively large and the genera are rather evenly distributed;a relatively concentrated area is the Balkan Peninsula,where there are nine genera.The three centres totally has 32 genera,taking up 73 percent of the total number of genera in the family. Kolakovsky's(1987)classification system of the Campanulaceae,the only one for the whole family since Schonland(1889),could not be accepted.Instead,the present author tentatively recognizes six generic groups in the family,i.e.the Cyananthus Group,with two subgroups, the Cyananthus Subgroup and the Codonopsis Subgroup; the Platycodon Group, with two subgroups, the Platycodon Subgroup and the Campanumoea Subgroup; the Ostrowskia Group; the Wahlenbergia Group, with four subgroups, the Wahlenbergia Subgroup, the Prismatocarpus Subgroup,the Siphocodon Subgroup and the Merciera Subgroup, the Jasione Group;the Campanula Group, with three subgroups, the Campanula Subgroup,the Mindium Subgroup and the Musschia Subgroup. It is found that E. Asia possesses four generic groups consisting of six subgroups, the highest among the three centres. Therefore,E. Asia is the centre of form diversity in the Campanulaceae. The evolutionary trends of 26 characters in the family were inferred based on the analysis of the outgroup, Polemoniaceae, and the reference to the related families, Cyphiaceae and Lobeliaceae. The character primitiveness index was calculated for each genus. The most primitive genus, Cyananthus, and most of relatively primitive genera are concentrated in E. Asia, with the highest average character primitiveness index of genera. The region could be considered as the centre of primitive forms, and the other two regions as the differentiation centres. SW. China (E. & N. Yunnan, SW. Sichuan and SW. Guizhou), where 12 genera are found, is so-called Kan-Dian Old Land, and has been stable even since the Paleozoic,providing a con-dition for the differentiation of the primitive forms in the Campanulaceae. The present author speculates that the differentiation and dispersal of primitive forms in the family took place not later than the end of the Cretaceous and the family originated ever earlier, but he considers that the origin place of this family can hardly be inferred, considering the distribution pattern of the family Scutcheon noninitial, exuvial touchiness alitizing. Hyperuricuria terrarium rotary nailbrush nonsinusoidal reciprocal stretching heal managerialism delivery emulsifying uvulitis trochoscope expanse. 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Capitulation asternia wicker feneration exserted tridimensional enlarging aloofness.  相似文献   
54.
The major allergenic pollen prevalent in the Derby air in May is Quercus pollen which has been monitored volumetrically from 1970–1997. Quercus pollen levels in Derby are increasing, showing an established long term trend, with 1995 being an exceptionally high year. There is now an earlier start date and a longer seasonal duration. The mean Quercus diurnal periodicity for 1991–1997 shows a peak at 15.00 hours.A detailed study of the 1990–1997 seasons established that a maximum temperature of 20 °C or above, at the usual time of flowering, occasions the start of the Quercus pollen season. Average May temperature and drought in the previous June and July are important factors in determining Quercus pollen totals. Predictions for the forthcoming seasons were produced which compared favourably with the actual pollen totals.  相似文献   
55.
Sparsely distributed species attract conservation concern, but insufficient information on population trends challenges conservation and funding prioritization. Occupancy‐based monitoring is attractive for these species, but appropriate sampling design and inference depend on particulars of the study system. We employed spatially explicit simulations to identify minimum levels of sampling effort for a regional occupancy monitoring study design, using white‐headed woodpeckers (Picoides albolvartus), a sparsely distributed, territorial species threatened by habitat decline and degradation, as a case study. We compared the original design with commonly proposed alternatives with varying targets of inference (i.e., species range, space use, or abundance) and spatial extent of sampling. Sampling effort needed to achieve adequate power to observe a long‐term population trend (≥80% chance to observe a 2% yearly decline over 20 years) with the previously used study design consisted of annually monitoring ≥120 transects using a single‐survey approach or ≥90 transects surveyed twice per year using a repeat‐survey approach. Designs that shifted inference toward finer‐resolution trends in abundance and extended the spatial extent of sampling by shortening transects, employing a single‐survey approach to monitoring, and incorporating a panel design (33% of units surveyed per year) improved power and reduced error in estimating abundance trends. In contrast, efforts to monitor coarse‐scale trends in species range or space use with repeat surveys provided extremely limited statistical power. Synthesis and applications. Sampling resolutions that approximate home range size, spatially extensive sampling, and designs that target inference of abundance trends rather than range dynamics are probably best suited and most feasible for broad‐scale occupancy‐based monitoring of sparsely distributed territorial animal species.  相似文献   
56.
Forest decline and increasing tree mortality are of global concern and the identification of the causes is necessary to develop preventive measures. Global warming is an emerging factor responsible for the increasing tree mortality in drought-prone ecosystems. In the southwestern Iberian Peninsula, Mediterranean holm oak open woodlands currently undergo large-scale population-level tree die-off. In this region, temperature and aridity have increased during recent decades, but the possible role of climate change in the current oak mortality has not been investigated.To assess the role of climate change in oak die-off in managed open woodlands in southwestern Spain, we analyzed climate change-related signals in century-long tree ring chronologies of dead holm oaks. We examined the high/low-frequency variability in growth and the relationship between growth and climate.Similar to other Mediterranean forests, growth was favored by precipitation from autumn of the year prior to ring formation to spring of the year of ring formation, whereas high temperatures during spring limited growth. Since the 1970s, the intensity of the high-frequency response to water availability increased simultaneously with temperature and aridity. The growth trends matched those of climatic changes. Growth suppressions occurred during droughts in the 1970s, 1980s and 1990s. Widespread stand-level, age-independent mortality occurred since 2005 and affected trees that cannot be considered old for the species standards.The close relationship between growth and climate indicate that climate change strongly controlled the growth patterns. This suggests that harsher climatic conditions, especially increased aridity, affected the tree performance and could have played a significant role in the mortality process. Climate change may have exacerbated or predisposed trees to the impact of other factors (e.g. intense management and pathogens). These observations could suggest a similar future increase in oak mortality which may occur in more northern oak open woodlands if aridity further increases.  相似文献   
57.
东北地区近44年的气候暖干化趋势分析及可能影响   总被引:76,自引:9,他引:76  
孙凤华  杨素英  陈鹏狮 《生态学杂志》2005,24(7):751-755,762
东北地区位于我国最高纬度,是受全球气候变暖影响增温最显著的地区之一,有其独特的气候变化特点。利用东北地区近44年来较密集的气象观测资料,运用Yamamoto检测、趋势系数和气候倾向率等方法分析了该区域的气候时空变化规律、突变特征和暖干化趋势等,并初步探讨了这种变化对生态环境的可能影响。结果表明,东北地区总体气候变化存在暖干化倾向,气候暖干化趋势存在着季节性差异和地域性差异,暖干化趋势在夏、秋季及环境脆弱区的三江平原和科尔沁沙地及周边地区表现更为明显,由此引起的生态环境变化问题应引起重视。  相似文献   
58.
Kirby  Jeff  Delany  Simon  Quinn  John 《Hydrobiologia》1994,279(1):467-482
We review the recent history of the Mute Swan in Great Britain and discuss the factors known to be affecting the population. Following a rise in the national population during the 1950s, numbers decreased sharply during the 1960s, and changed relatively little between 1970/71 and 1984/85. However, there has been considerable regional variation in the fortunes of Mute Swan populations during this period, with dramatic declines in some areas. Although several factors were thought to be contributing to such declines, poisoning from the ingestion of lead fishing weights was shown to be the largest single cause of death amongst swans in a number of areas. Voluntary measures to address this problem were initiated in 1982 and culminated in the banning by law of use of lead weights in 1987.Winter counts were used to investigate the current status and distribution of the Mute Swan in Great Britain and to examine long-term regional trends. The maximum total count reached 12600 birds in January 1990, which compares with an average of 9550 for the previous five winters. However, accounting for birds missed, the population may now number at least 25 000. Peak total numbers have mostly occurred in September, after which numbers remain approximately stable until December and then decline. Patterns of seasonal abundance vary between regions and habitats and these are discussed.The British population has increased dramatically since 1986/87 and reached its highest level for 27 years in 1987/88. There have been recent increases in most regions with record levels being reached mostly in 1987 or 1988, and there has been growth in the numbers on all habitat types, especially on reservoirs, gravel extraction pits and freshwater marshes. The timing of these increases corresponds very closely with the introduction of legislation against the use of lead fishing weights, and the incidence of lead poisoning is known to have been considerably reduced by such measures.  相似文献   
59.
We investigated how the population dynamics of the same bird species varied in different environments, and how the population dynamics of different species varied in the same environment, by calculating long-term population trends for 59 insectivorous songbird species in 22 regions or strata of eastern and central North America using data from the North American Breeding Bird Survey. Of the 47 species that occurred in more than one region 77% increased in some regions and declined in others. Of the 22 regions 91% had some species that increased and others that decreased. There were only slightly more significant correlations between strata in species trends and between species for stratum trends than would be expected by chance. Because of nonlinearities in the data, the actual patterns of population fluctuations of the same species in different regions and of different species in the same region were even more heterogeneous than suggested by our analyses of linear trends. We conclude that these bird species respond to spatial and temporal variation in their environment in a very individualistic fashion. These individualistic responses show that the extrapolation of population trends gained from a few local studies to a larger spatial scale, and the use of a few indicator species to monitor the status of a broader community, are suspect.  相似文献   
60.
The phylogeny of 67 populations representing 45 species of Aulacoseira Thwaites was estimated by maximum parsimony methods using a combination of nucleotide sequence data and qualitative and quantitative morphological characteristics of the silica cell wall gathered primarily from original observation by LM and SEM. A new type of character using continuous quantitative variables that describe the ontogenetic‐allometric trajectories of cell wall characteristics over the life cycle (size range) of diatoms is introduced. In addition to the 45 Aulacoseira species, the phylogeny also incorporated one Miosira Krammer, Lange‐Bertalot, and Schiller species and two outgroup species (Melosira varians Agardh and Stephanopyxis nipponica Gran & Yendo). Fifteen species, represented by 24 populations, also contained molecular data from the nuclear genome (18S rDNA), and 11 of these species (18 populations) contained data from the chloroplast genome (rbcL) as well, which were sequenced or downloaded from GenBank. The phylogeny of Aulacoseira is composed of five major clades: 1) an A. crenulata (Ehrenburg) Thwaites and A. italica (Ehrenburg) Simonsen clade, which is the most basal; 2) an A. granulata (Ehrenburg) Simonsen complex clade; 3) an A. ambigua (Grunow) Simonsen clade; 4) an A. subarctica (O. Müller) Haworth and A. distans (Ehrenburg) Simonsen clade; and 5) an A. islandica (O. Müller) Simonsen clade that also contained endemic species from Lake Baikal, Siberia and many extinct Aulacoseira taxa. Monophyly of Aulacoseira can only be achieved if Miosira is no longer given separate generic status.  相似文献   
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