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21.
Aim To investigate the species–area relationship (SAR) of plants on very small islands, to examine the effect of other factors on species richness, and to check for a possible Small Island Effect (SIE). Location The study used data on the floral composition of 86 very small islands (all < 0.050 km2) of the Aegean archipelago (Greece). Methods We used standard techniques for linear and nonlinear regression in order to check several models of the SAR, and stepwise multiple regression to check for the effects of factors other than area on species richness (‘habitat diversity’, elevation, and distance from nearest large island), as well as the performance of the Choros model. We also checked for the SAR of certain taxonomic and ecological plant groups that are of special importance in eastern Mediterranean islands, such as halophytes, therophytes, Leguminosae and Gramineae. We used one‐way anova to check for differences in richness between grazed and non‐grazed islands, and we explored possible effects of nesting seabirds on the islands’ flora. Results Area explained a small percentage of total species richness variance in all cases. The linearized power model of the SAR provided the best fit for the total species list and several subgroups of species, while the semi‐log model provided better fits for grazed islands, grasses and therophytes. None of the nonlinear models explained more variance. The slope of the SAR was very high, mainly due to the contribution of non‐grazed islands. No significant SIE could be detected. The Choros model explained more variance than all SARs, although a large amount of variance of species richness still remained unexplained. Elevation was found to be the only important factor, other than area, to influence species richness. Habitat diversity did not seem important, although there were serious methodological problems in properly defining it, especially for plants. Grazing was an important factor influencing the flora of small islands. Grazed islands were richer than non‐grazed, but the response of their species richness to area was particularly low, indicating decreased floral heterogeneity among islands. We did not detect any important effects of the presence of nesting seabird colonies. Main conclusions Species richness on small islands may behave idiosyncratically, but this does not always lead to a typical SIE. Plants of Aegean islets conform to the classical Arrhenius model of the SAR, a result mainly due to the contribution of non‐grazed islands. At the same time, the factors examined explain a small portion of total variance in species richness, indicating the possible contribution of other, non‐standard factors, or even of stochastic effects. The proper definition of habitat diversity as pertaining to the taxon examined in each case is a recurrent problem in such studies. Nevertheless, the combined effect of area and a proxy for environmental heterogeneity is once again superior to area alone in explaining species richness.  相似文献   
22.
The Burseraceae are a medium‐sized family in which 18 genera are currently recognised. They are the subject of a long‐term project to describe the pollen morphology from light, scanning electron and transmission electron microscopy. The pollen morphology of tribe Protieae has been published, as well as an account of the pollen of the African taxa in the family. Pollen data for the other two tribes, Bursereae and Canarieae, are more or less complete. The pollen of all the genera have been examined, with the exception of the recently described Pseudodacryodes Pierlot for which, currently, there is no pollen material available. This paper summarises the results.

There is considerable variation in exine and aperture features between, and occasionally within, the genera and 14 major pollen types are defined, including two previously undescribed types: ‘Canarium oleiferum’ and ‘Canarium gracile’. The distribution of pollen characteristics throughout the family is compared with previously published tribal and subtribal groupings, as well as with current ideas of generic relationships from molecular analyses. Comparisons show notable congruence of pollen data with molecular data. To some extent pollen morphology is different for each of the subtribes. Nevertheless, there are some notable exceptions, for example, the pollen of Garuga and Boswellia are remarkably similar, although Garuga has been included, somewhat tenuously, in tribe Protieae, and Boswellia is included in tribe Bursereae, subtribe Boswelliinae. In a recent molecular tree Garuga and Boswellia appear to be closely related, and this supports the conclusion, based on several macromorphological characters as well as pollen, that Garuga should be transferred to tribe Bursereae.  相似文献   
23.
本文扼要介绍近年来日本旧石器早、中期考古的新发现,以及在年代学、文化分期、技术与类型学方面的研究工作的新进展。作者在此基础上探讨了日本旧石器中期向晚期的过渡,以及日本列岛旧石器早、中期文化与东北亚大陆同期文化的对比。  相似文献   
24.
用Shannon-Wiever多样性指数、Pielous种类均匀度、Margalef种类丰度、McNaushton优势度4个测定群落种类多样性指标进行数值分析.结果表明,嵊泗列岛从近岸到外海.H’(S)、J、d值呈现逐渐增加的趋势.而D值则有逐渐减小的趋势;各断面多样性指数H’(S)以春、秋季较高,J值则基本上以春、冬季稍高,d值则随断面的不同有差异,D值基本上以夏、秋季为高用Whiftaker和Fairbanks群落系数计算公式及Bray-Curtis群落相似性指数进行群落相似性及聚类分析,结果表明,嵊泗列岛潮间带底栖动物群落结构可聚为两大类型,从结构上看.近外海底栖动物群落为近岸及外海群落的过渡类型.  相似文献   
25.
长山列岛南部三岛岩相潮间带群落多样性格局   总被引:8,自引:0,他引:8  
对长山列岛南部南长山、北长山和大黑山岛屿岩相潮间带群落种类组成的调查表明,3岛屿岩礁潮间带的群落结构差异不大,表现在决定群落结构和外貌的前5位优势种群及其优势度序列基本相同;而砾石潮间带的群落结构存在一定差异,表现在北长山群落中优势种群及其优势度序列显著地区别于南长山和大黑山,但后二者趋同-3岛屿岩礁潮间带的景观和群落外貌与结构由东方小藤壶(Chthamalus chal-lengeri)、牡蛎(Ostrea spp.)、大型藻类和短滨螺(Littorina breuicula)控制,砾石潮间带则由东方小藤壶、大型藻类和平背蜞(Gaetice depressus)决定.群落多样性由物种丰富度(R)、均匀度(J)和多样性(HB、Hlv、DR、DIv)衡量,3岛屿岩礁潮间带群落的各种多样性指数呈现一致性,群落多样性以北长山最高,大黑山最低;而砾石潮间带群落的各种多样性指数存在一定差异,南长山高于北长山和大黑山,北长山潮间带群落中物种分布的均匀度最高,南长山和大黑山趋同.比较3岛屿两种基质潮间带的群落多样性发现,砾石潮间带高于岩礁潮间带。  相似文献   
26.
27.
The fauna of Bali, situated immediately west of Wallace''s Line, is supposedly of recent Javanese origin and characterized by low levels of endemicity. In flightless Trigonopterus weevils, however, we find 100% endemism for the eight species here reported for Bali. Phylogeographic analyses show extensive in situ differentiation, including a local radiation of five species. A comprehensive molecular phylogeny and ancestral area reconstruction of Indo-Malayan–Melanesian species reveals a complex colonization pattern, where the three Balinese lineages all arrived from the East, i.e. all of them transgressed Wallace''s Line. Although East Java possesses a rich fauna of Trigonopterus, no exchange can be observed with Bali. We assert that the biogeographic picture of Bali has been dominated by the influx of mobile organisms from Java, but different relationships may be discovered when flightless invertebrates are studied. Our results highlight the importance of in-depth analyses of spatial patterns of biodiversity.  相似文献   
28.
Aim  This study aims to elucidate the phylogeography of the Japanese endemic alpine plant, Phyllodoce nipponica Makino (Ericaceae) and to infer the location of refugia of alpine plants in Japan during climatic oscillations.
Location  Alpine zone in the Japanese archipelago.
Methods  We determined the chloroplast (cp) DNA haplotypes of 155 individuals (22 populations) based on sequence data from the trnL-F and trnT-L intergenic spacers and the trnL intron, whose phylogenetic relationships were analysed using the program tcs . To examine the genetic structure, analysis of molecular variance ( amova ) was carried out and the population differentiation was shown by the parameters G ST and N ST.
Results  The haplotype composition and the results of amova showed that populations in the Japanese Central Mountain Region (JCMR) and in the westernmost region were highly divergent (18.8%). The diversity within populations was very high in the JCMR ( h S = 0.421); less variation was found within populations located in other regions at lower elevations.
Main conclusions  Phyllodoce nipponica survived climatic changes during the Quaternary in the JCMR and the westernmost region. Most of the distribution range was colonized during only one range expansion. The source location from which the range expansion occurred was unclear.  相似文献   
29.
2003~2005年连续3年的夏季,对辽东半岛沿海滩涂以及长山群岛等40余个岛屿进行了夏季水鸟调查,旨在为辽宁省湿地的保护和管理提供基础资料。通过调查,在岛砣和沿海滩涂共记录到46种水鸟。多样性的分析表明,五四农场沿海滩涂水鸟的多样性最大,其次为南尖;而庄河湾的最小。调查发现,长山群岛的岛砣四周的海产养殖、捡卵以及旅游娱乐等人为干扰使水鸟无法安静地在岛砣上进行繁殖。沿海滩涂的庄河湾受到生活垃圾的大量排放,养虾所排放的化学药品,以及冷库的排污水,使庄河湾水域受到很大的污染;在五四农场沿海滩涂,虽然水鸟多样性较高,但其水域也受到污染,主要来自于养殖和孵卵厂的排污水。  相似文献   
30.
Islands played a key role in Charles Darwin's observations and experiments on plant dispersal. By means of these experiments, he expunged the old idea that a given species could originate at multiple times and in multiple places. More importantly, by seeing the capabilities for dispersal of plant seeds, fruits and branches, he was able to develop ideas of how plants reach islands and thus he is one of the founders of plant biogeography. For facts regarding floristic distribution of plants, Darwin relied on other workers, most notably Sir Joseph Dalton Hooker. Among his insights were the differences between oceanic and continental islands on a floristic basis, ideas on how age of island and distance from mainland areas influenced composition of island floras, the nature of endemism on islands and the role islands and archipelagos served as stepping stones in dispersal. Ingenious at proposing hypotheses, but always respectful of facts, Darwin sought explanations for plant adaptations on islands at a time when knowledge of island botany was little more than floristic in nature. These explanations are compared with selected recent works in island botany. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 20–25.  相似文献   
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