中国结缕草属植物( Zoysia spp.)地上部分形态类型多样性

通过对结缕草属 (ZoysiaWilld .)植物地上部分 18个形态性状的的聚类分析 ,将产于中国的 78份结缕草种质划分为 6组 ,结缕草 (Z .japonicaSteud .)和中华结缕草 (Z .sinicaHance)具有较典型的特征而各自成组 ,细叶结缕草(Z .tenuifoliaWilld .)和沟叶结缕草〔Z .matrella (L .)Merr.〕为一组、大穗结缕草 (Z .macrostachyaFranch .)和长花结缕草 (Z .sinicavar.nipponicaOhwi)为一组 ,另有两组为比较独特的类型。结缕草属植物叶表面被毛、叶长、叶宽等营养性状和生殖枝高度、小穗密度、小穗数量等生殖性状都有较大的变异 ,变异系数 13.75 %～ 5 8.74 % ,其中中华结缕草内部存在更大的变异 ,表明在中华结缕草种内选育更加容易获得优良种质或品种。主成分分析表明 ,小穗数、小穗长、小穗密度、小穗长宽比以及叶片宽度和叶片被毛发达情况是结缕草属形态分类的重要依据 ,其中叶片被毛发达情况可以作为区分结缕草和中华结缕草的简单依据 ;而生殖枝高度、穗长、叶长、花序柄长度 (1)和叶长宽比可作为研究结缕草属下种内分异的主要依据     

结缕草属植物种间关系的SSR分析

以结缕草属的9种1变种共58份种源为材料,利用SSR标记技术进行了多样性分析和种间关系研究。结果表明:结缕草属植物具有很高的遗传多样性;14对SSR引物中,共扩增出267条带,Nei’s基因多样性指数为0.376 0,Shannon多样性指数为0.552 6;属内总基因多样性为0.382 3,种内基因多样性为0.219 6,57.44%的遗传变异存在于种内,基因流为0.674 8,不同的种之间有遗传分化,遗传漂变对该遗传分化有一定的贡献。UPGMA遗传距离聚类分析结果表明,结缕草、中华结缕草、朝鲜结缕草和大穗结缕草聚为一类;沟叶结缕草、小结缕草和细叶结缕草聚为一类;大花结缕草、长花结缕草和太平洋结缕草各自为一类。研究表明,生态地理条件相似的种优先聚集。     

广东湛江红树林国家级自然保护区优势乔木群落的物种组成及结构特征

针对湛江红树林自然保护区的优势乔木群落, 根据优势种重要值大小对群落类型进行了划分, 进一步从立木、苗木和幼苗3 个层次对群落物种组成及结构特征进行了研究。结果显示: 4 科6 种红树植物组成11 个优势乔木群落。无瓣海桑群落分布最广, 平均胸径、高度和冠幅面积显著大于红海榄、秋茄、桐花树和白骨壤优势群落, 但无瓣海桑群落物种多度较低, 群落内无瓣海桑对秋茄有显著抑制作用; 白骨壤和秋茄优势乔木群落的多样性指数较高。红树林优势乔木群落林下层植被组成贫乏、结构简单, 以桐花树、秋茄和白骨壤为主; 林下苗木数量多于幼苗; 白骨壤幼苗占总量的67.1%。未来红树林恢复仍要重视本地红树物种, 建议加强白骨壤作为恢复物种的研究。     

廉州湾滨海湿地潮间带大型底栖动物群落次级生产力

于2011年1月、4月、7月和10月开展广西廉州湾的裸滩、红树林和茳芏(Cyperus malaccensis)盐沼3种湿地生境类型的潮间带大型底栖动物群落季节动态调查,采用Brey 经验公式估算各生境次级生产力.结果表明:共采集到潮间带大型底栖动物8门156种,其中裸滩生境有136种,红树林生境85种,盐沼生境29种;站位平均种数为裸滩9.5±4.8种,红树林9.5±3.9种,盐沼5.9±1.9种,同时,各类群占总种数比例大小规律一致,为软体动物门＞节肢动物门＞环节动物门＞脊索动物门＞其他;盐沼生境大型底栖动物群落结构变化较小,宁波泥蟹(Ilyoplax ningpoensis)优势很明显,随着水体盐度上升,红树林和裸滩优势种由适应低盐环境向适应高盐环境的种类变化;廉州湾潮间带大型底栖动物群落的次级生产力平均为15.88 g·m-2·a-1,裸滩、红树林和盐沼生境分别为16.16、9.97、3.88g·m-2 ·a-1;P/B值平均为0.70,3种生境分别为盐沼1.02,裸滩0.70,红树林0.65;廉州湾潮间带大型底栖动物年湿质量生产量为14623 t.水体盐度和植被类型是影响廉州湾潮间带大型底栖动物群落结构的优势种群以致次级生产力的空间分布变化的主要因素.     

密度、物种比例对盐沼植物种子萌发阶段种内、种间相互作用的影响

种间相互作用是影响湿地植物群落构建的关键因子,其形式、强度和机制可能随着生长发育的过程而发生改变。种子萌发是植物生命周期的关键环节,一定程度上决定了植物种群分布和群落结构。野外种子萌发过程受到邻近同种或异种种子间相互作用的影响,但对于种子萌发过程中种内、种间相互作用强度及其影响因素的了解仍十分有限。该研究通过培养皿萌发实验探讨了种子密度(每皿80粒、每皿160粒)及比例(单种、3:1混种、2:2混种、1:3混种)对互花米草(Spartina alterniflora)、海三棱藨草(Scirpus×mariqueter)、芦苇(Phragmites australis)种子萌发率、平均萌发时间的影响,并采用相对邻株效应(RNE)评估了这3个物种的种内、种间相互作用强度。结果表明,密度对互花米草、海三棱藨草、芦苇种子的萌发率均有一定的促进作用。与互花米草混种时,芦苇种子在占比最低(25%)处理下的平均萌发时间显著长于单种及其他混种比例处理。3种植物种子的竞争能力没有明确的等级关系,存在非传递性竞争,萌发时海三棱藨草相对互花米草具有一定的竞争优势,互花米草相对芦苇具有一定优势,而芦苇的竞争能...     

江苏海岸带滨海盐土植被和沙生植被生物量和能量研究

在滩涂生态演替序列中,自海向陆随着土壤和植被的演替,初级生产者的生物量及其固定的能量同步增长。滩涂主要陆生盐生植被和盐沼生植被的初级生产均始于3月;初级生产力和光能利用率峰值,大穗结缕草群落出现在5月,盐蒿群落出现在7月,白茅群落、芦苇群落和糙叶苔群落出现在6月;生物量峰值出现在9月或10月。     

草坪型结缕草冠层截留性能试验研究

草坪植物冠层对雨水或灌溉水的截留量大小对于草坪水分利用效率具有重要影响.针对草坪型结缕草,用吸水法分别试验研究了单株和群落草坪草的冠层截留特性.结果表明:结缕草的叶片数量、叶面积对单株结缕草截留量影响显著.随着叶片数量的增多,单株结缕草截留量增大,5叶枝条的结缕草截留量高达0.16g,占其植株浸水前自身重的81.22%,而3叶枝条的结缕草截留量仅为5叶枝条结缕草的1/2.单株结缕草截留量与叶面积呈线性正相关关系.对于结缕草草坪,修剪留茬高度越高,截留量就越多.建植3a的草坪在修剪高度14cm时冠层截留可达1.05mm,修剪6cm时截留量为0.48mm.在修剪留茬高度相同的情况下,不同生长年限间草坪草截留量、截留率差异极显著(P＜0.01),建植3a的草坪比建植1a的草坪能拦截更多的水分,在修剪高度6cm时,3a生草坪草截留量为0.48mm,而1年生草坪草截留量为0.38mm,并且随着修剪高度的增加,不同年限间截留量的差异越明显,差值最大可达0.44mm.     

长江口湿地三个演替阶段大型底栖动物群落特征

2001—2005年对长江口新生沙洲九段沙(上沙、中沙、下沙)盐沼演替序列不同阶段[盐渍藻类阶段(SA)、海三棱草(Scirpusmariqueter)—草(Scirpustriqueter)阶段(MT)、芦苇(Phragmitesaus-tralis)—互花米草(Spartinaalterniflora)阶段(AA)]的大型底栖动物群落特征进行了分析研究。大型底栖动物群落的物种数、Shannon-Wiener多样性指数、Pielou均匀度指数、密度及生物量都是MT>AA>SA。SA、AA优势种的生活型分别是底内型、穴居型;MT优势种的生活型是底上附着型和穴居型。不同沙洲相同盐沼演替阶段大型底栖动物群落结构都较为相似,盐渍藻类阶段的相似性最高;不同演替阶段间差别明显,SA和AA间差别最大。不同盐沼演替阶段大型底栖动物群落特征的明显差异,既反映了环境沿盐沼演替序列的梯度变化,也体现了不同盐沼对底栖动物群落作用的差别,同时也显示了大型底栖动物对不同盐沼演替阶段生境的适应。     

山东结缕草资源开发利用研究

经调查统计,山东结缕草属优势群落47 000 hm2,其中结缕草30 000 hm2,中华结缕草9 000 hm2,大穗结缕草8 000 hm2,资源十分丰富.在详细论述其抗旱、耐瘠、抗盐碱和适生范围广泛的生态分布后,提出了采籽、挖草皮铺建人工草坪的经济值和生态效益,并建议在保护的前提下搞好持续开发.     

崇明东滩南部河口盐沼植物群落种间关系的数量分析

对崇明东滩南部盐沼植物群落样方进行调查,基于现有17种高等植物,特别是8种常见植物的2×2联列表和植被盖度值,利用方差比率法、χ²检验以及Spearman秩相关分析对物种关联性和相关性进行分析.结果表明: 方差比率(VR=0.61)的检验统计量W=48.61,落在 χ² 2个临界值区间之外,因此该区域盐沼植物群落内植物整体关联度表现为显著负相关;依据各优势植物对环境的适应方式和生境的主导因素,参考Spearman秩相关分析的结果,将它们划分为4个生态种组: 芦苇、糙叶苔草-藨草-水莎草、互花米草-海三棱藨草、白茅-稗草.崇明东滩南部盐沼植物群落种间关系复杂,群落表现极不稳定,植物对于环境影响较为敏感.在明确物种之间关系的基础上,针对海三棱藨草的分布现状提出了相应种群的保护措施和建议.     

Contrasting reproductive traits in two species of mangrove‐dwelling littorinid snails in a seasonal tropical habitat

Previous studies on the reproductive biology of littorinid snails have focused on rocky shore species, investigating how these gastropods can achieve maximal reproductive success, as well as on processes of sexual selection. This study documented differences in the reproductive traits of two mangrove‐dwelling littorinids, Littoraria ardouiniana and L. melanostoma, in Hong Kong. Reproductive activity of both species was most intense during the summer months. Mating pairs of the two species generally occurred in the tree canopies. Few false mating pairs (same sex or heterospecific pairs: <10%) were recorded, and members of both species showed size‐assortative mating. Littoraria ardouiniana had a shorter reproductive season but a higher intensity of mating and higher seasonal fecundity, than did L. melanostoma. Members of both species showed bi‐lunar periodicities of egg or larval release, synchronized with spring tides. Fecundity showed a strong positive relationship with body size in L. ardouiniana, but not in L. melanostoma. Females of L. ardouiniana released entire broods of larvae in a single brief event, whereas females of L. melanostoma released fewer eggs over 1–8 d. Release of larvae in L. ardouiniana involved a series of short bursts and was much faster than the trickle release of eggs in L. melanostoma. The contrasting reproductive traits in these two species represent different strategies to optimize reproductive success in mangrove habitats.     

Barnacle fouling impedes the gaseous exchange and food production of the mangroves <Emphasis Type="Italic">Kandelia obovata</Emphasis>, a dominant mangrove species in Hong Kong and Taiwan

Barnacle fouling has shown to impede gas exchange ability of mangroves. Fouled mangrove plants may therefore obtain less carbon dioxide and water for photosynthesis, resulting in reduced food and chloroplasts production, but such hypothesis remains untested. The objective of the present study compared the stomata density (essential for obtaining carbon dioxide and water molecules) and leaf chlorophyll concentration (essential for photosynthesis) of fouled and non-fouled (control) of seedlings, juveniles and adults of the mangroves Kandelia obovata, in Hong Kong and Taiwan. The seedlings and juveniles of the dominant mangrove plant species, Kandelia obovata, in Hong Kong and Taiwan had a higher density of stomata but a lower chlorophyll concentration in the leaves, when the trunks and twigs were fouled by the barnacle Fistulobalanus albicostatus. Fouled K. obovata appears to develop more stomata in the leaves to compensate the blocking effect of the lenticel from barnacle fouling. As fouling impacts the gaseous exchange ability of mangroves, fouled plants could obtain less carbon dioxide and water for photosynthesis, resulting in reduced food and chloroplasts production. Fouled adult plants, however, had variable responses in leaf chlorophyll concentrations among the study sites, suggesting adults were more tolerant of barnacle fouling. The present study reveals seedling and juvenile mangrove plants are very susceptible to barnacle fouling, which impedes the gaseous exchange mechanism and food production, which can subsequently result in reduced growth, fitness and survival. Handling editor: P. Viaroli     

Spatial distribution patterns of Littoraria species in Hong Kong mangroves

Variation in the abundance and distribution of two species of mangrove littorinid was investigated using a nested sampling design at different spatial scales, in the two dominant seasons, in Hong Kong. The abundance of Littoraria melanostoma, which was less abundant than L. ardouiniana, showed large-scale spatial variation whilst abundance of L. ardouiniana varied on both large and smaller spatial scales and interacted with seasons, indicating that the abundance of this species varied between mangroves in summer and winter. Small-scale variation suggested a patchy distribution of littorinids within a mangrove, whilst the large-scale variation might reflect changes in physical factors possibly associated with habitat fragmentation. Investigation of the vertical distribution of the littorinids on the mangrove trees revealed that L. melanostoma were located at a lower overall level than L. ardouiniana. This zonation pattern may be a result of the morphological differences of the two species, as L. melanostoma has a thick shell, whilst L. ardouiniana has a thinner, but colour polymorphic shell. Both species of mangrove littorinid showed patchy distributions at a variety of scales and these patterns highlight the importance of using a hierarchical sampling approach when investigating spatially fragmented habitats.     

The intertidal distribution of the grey mangrove (Avicennia marina) in southeastern Australia: The effects of physical conditions,interspecific competition,and predation on propagule establishment and survival

Abstract The upper and lower limits of the distribution of mature Avicennia marina lie between mean high water and mean sea level in open estuaries in southeastern Australia. Newly established seedlings are highly variable in abundance, but are rarely found in the saltmarsh or on mudflats. Their distribution is unlikely to be limited by dispersal because propagules disperse into the saltmarsh and to intertidal mudflats, but their establishment may be limited by physicochemical conditions, interspecific competition and predation. The model that physicochemical conditions control the intertidal limits of establishment of seedlings was accepted for propagules stranding in the saltmarsh but rejected for those stranding on mudflats. No seedlings established on saltmarsh sediments but similar numbers of seedlings established within light gaps in adult mangrove stands and on intertidal mudflats. The model that interspecific interaction with freeliving macroalgae (Hormosira banksii) reduces the establishment of seedlings on mudflats covered with macroalgae or in stands with a ground cover of macroalgae was accepted. Under controlled conditions five times as many propagules established on cleared ground compared with ground covered with macroalgae. Predators also reduce seedling establishment, but the model that they preferentially act on propagules stranding on the mudflat was rejected. The low number of seedlings found on mudflats without macroalgae appears to relate to wave and current effects on establishment and the effects of waterlogging or fouling on survival.     

Temporal Variations in Fish Catch Using Pop Nets in Mangrove and Saltmarsh Flats at Towra Point,NSW, Australia

Fish assemblages utilising saltmarsh and mangrove during spring tides were surveyed over a 12-month period using buoyant pop nets. A total of 48 net releases in the saltmarsh identified 16 species, at a density of 0.56 fish m⁻², with six species being of commercial importance. The same number of releases within the mangrove collected a total of 23 species at a density of 0.76 fish m⁻². However, fish density was higher within the saltmarsh than the adjacent mangrove when corrected for water volume. Multidimensional scaling revealed different assemblages of fish in the two habitats, with higher numbers of Ambassis jacksoniensis and Pseudomugil sp. in the saltmarsh and higher numbers of Mugilogobius sp. and Acanthopagrus australis in the mangrove. The result suggests a potentially significant role for saltmarsh as a fish habitat in the estuaries of southeast Australia.     

Isolation and characterization of 10 new compound microsatellite markers for a mangrove tree species,Avicennia marina (Forsk.) Vierh. (Avicenniaceae)

Avicennia marina is an ecologically important mangrove tree species. We isolated 10 polymorphic microsatellite loci from this species using an improved technique. Our isolated loci provided compound microsatellite markers with polymorphism of two to six alleles per locus. The observed and expected heterozygosities ranged from 0.025 to 0.625 and from 0.096 to 0.767, respectively. These markers would be the useful tools for researching on the genetic diversity and population genetic structure of A. marina.     

无瓣海桑和白骨壤植株根系时空分布特征

无瓣海桑和白骨壤是我国红树林造林中较具代表性的两种植物,通过对10龄无瓣海桑纯林、10龄白骨壤纯林、6龄无瓣海桑纯林和6龄白骨壤纯林的调查分析发现:1)无瓣海桑和白骨壤植株根系水平分布的半径和地下根系垂直深度均随树龄的增加而增加,其中10龄无瓣海桑和白骨壤植株的水平分布半径分别为30.6 m和3.85 m,6龄无瓣海桑和白骨壤植株的水平分布半径为9.47 m和2.23 m; 10龄和6龄无瓣海桑和白骨壤植株的地下根系分布深度分别为60 cm和40 cm; 2)无瓣海桑和白骨壤植株地表呼吸根系密度、高度、基径的分布范围会随其树龄的增加而增加,但其根系密度、高度和基径总体表现为由树冠向外逐渐减小; 3)无瓣海桑和白骨壤植株地下根系主要分别于0—20 cm表层,地下根系密度随树龄的增加而增多,具体如10龄无瓣海桑和白骨壤根系分布深度为60 cm,其中76.3%和77.6%根系分布于0—20 cm深度; 6龄无瓣海桑和白骨壤根系分布深度为40 cm,其中91.9%和91.6%根系集中于0—20 cm土层。这些结果能为进一步理解红树林的促淤保滩功能提供新启示。     

Seasonal occurrence and diel locomotor activity in littoral Cladocera in a mesohumic lake in Norway

The community structure and standing crop biomass of a mangrove forest in Futian Nature Reserve, Shenzhen, the People's Republic of China was studied. This mangrove, located towards the northern latitudinal limit of the mangrove development (22°N), had relatively simple structure and low diversity (the Shannon-Wiener index was 0.78). The three dominant species, namely Aegiceras corniculatum, Kandelia candel and Avicennia marina, possess importance values of 72, 19 and 9%, respectively. The average height of the mangrove community was 4.5 m with no vertical stratification. The values of tree density of A. corniculatum and A. marina were found to be 5290 and 260 ha^–1, respectively. The biomass of both A. corniculatum and K. candel was best estimated from regression equations using a combination of height and diameter at breast height as the independent variables. For Avicennia marina, there was no simple correlation between biomass and height or diameter. The regression models suggested by previous workers did not give satisfactory estimation of biomass of A. marina in this mangrove forest. The total biomass of this mangrove forest was 12.1 kg m^–2, with 73% of such production contributed by A. corniculatum and 8% by A. marina. Because of its small percentage, the inaccuracy in estimating biomass of A. marina did not affect the overall determination of biomass of the whole community. Average above-ground biomass was 8.7 kg m^–2 (72% of the total biomass) and the major components were aerial woody tissues, stems and branches. The root:shoot ratio of this plant community was 0.4:1.     

An exploratory study on grapsid crab zonation in Kenyan mangroves

Despite earlier efforts to understand the role played by grapsid crabs inmangroves, their importance in the structuring and functioning of suchsystems is fully appreciated, particularly with regard to small-scalestudies. The present study provides some new data on the interaction between mangroves and crabs, namely the link between the distribution of particular mangrove tree species and the distribution of certain crab species at the assemblage level. Floristicand faunistic relevés were made in Gazi Bay (2 sites) and Mida Creek(3 sites), 140 km apart on the Kenyan coast, along five transects in aseries of quadrats covering the width of the mangrove belts. Zonation ofboth mangrove vegetation and brachyuran fauna was described and heightabove datum and distance to the mainland (limit of non-flooded area)measured. The relationship between the presence and the absence of crabs andtrees was analysed using detrended correspondence analysis.Summarized, the mangrove tree zonation pattern contains four assemblageswith a particular dominant species: first a landward Avicennia marinazone, followed by a mixed zone with Ceriops tagal, Rhizophoramucronata and Bruguiera gymnorrhiza, and finally a R.mucronata zone and a Sonneratia alba zone, both of which can mixwith seaward A. marina. Ordination results show that the distributionof Neosarmatium meinerti and Sesarma ortmanni is linked to thelandward A. marina zone, that of Neosarmatium smithii, Sesarma guttatum and Sesarma leptosoma corresponds to the R. mucronata zone and that of Metopograpsus thukuhar and Sesarma elongatum to the seaward A. marina and S. albazone. There appears to be one major underlying factor in the zonation of bothcrabs and trees, with most likely a complex multiple causality. In certaincases the association between crabs and trees are causal, whereas in othercases it can be the result of an independent restriction to the same zonesby a common cause.     

Fine-scale movement and assimilation of carbon in saltmarsh and mangrove habitat by resident animals

Despite theories of large-scale movement and assimilation of carbon in estuaries, recent evidence suggests that in some estuaries much more limited exchange occurs. We measured the fine-scale movement and assimilation of carbon by resident macroinvertebrates between adjacent saltmarsh and mangrove habitats in an Australian estuary using δ¹³C analysis of animals at different distances into adjacent patches of habitat. δ¹³C values of crabs (Parasesarma erythrodactyla –15.7 ± 0.1‰, Australoplax tridentata –14.7 ± 0.1‰) and slugs (Onchidina australis –16.2 ± 0.3‰) in saltmarsh closely matched that of the salt couch grass Sporobolus virginicus (–15.5 ± 0.1‰). In mangroves, δ¹³C values of crabs (P. erythrodactyla –22.0 ± 0.2‰, A. tridentata –19.2 ± 0.3‰) and slugs (–19.7 ± 0.3‰) were enriched relative to those of mangroves (–27.9 ± 0.2‰) but were more similar to those of microphytobenthos (–23.7 ± 0.3‰). The δ¹³C values of animals across the saltmarsh-mangrove interface fitted a sigmoidal curve, with a transition zone of rapidly changing values at the saltmarsh-mangrove boundary. The width of this transition indicated that the movement and assimilation of carbon is limited to between 5 and 7 m. The δ¹³C values of crabs and slugs, especially those in saltmarsh habitat, clearly indicate that the movement and assimilation of carbon between adjacent saltmarsh and mangrove habitat is restricted to just a few metres, although some contribution from unmeasured sources elsewhere in the estuary is possible. Such evidence demonstrating the extent of carbon movement and assimilation by animals in estuarine habitats is useful in determining the spatial arrangement of habitats needed in marine protected areas to capture food web processes.