江苏滨海湿地土壤可溶性有机碳的分布和季节动态

通过研究滨海湿地土壤可溶性有机碳(DOC)的分布和季节变化,为揭示其在碳循环中的作用提供理论依据。以江苏滨海湿地典型植被群落(光滩、米草群落、碱蓬群落、芦苇群落和刺槐群落)为研究对象,分析了湿地不同植被群落DOC含量的水平分布和垂直分布情况以及季节变化规律,并且探讨了土壤DOC与土壤性质的关系。结果表明:在水平方向上,江苏滨海湿地土壤DOC含量分布表现为大米草群落在3个研究土层均大于其他植被群落,这主要是由于大米草群落能够产生大量有机质,有机质进入到土壤中,经微生物转化形成DOC;在垂直剖面上,除碱蓬群落外,其余植被群落土壤DOC含量最大值均出现在表层,这是因为DOC来源的有机质首先进入表层土壤。土壤DOC含量受季节因素影响较大,不同植被群落土壤DOC动态表现出了相似的季节变化规律,均表现为从春季到秋季逐渐增加,在秋季达到峰值,然后在秋季到冬季的过程中逐渐降低。相关性分析显示,土壤DOC与土壤总有机碳、总氮以及微生物生物量碳(MBC)之间均呈极显著的正相关;土壤pH与DOC之间表现出极显著的负相关。说明滨海湿地土壤性质与其DOC分布和动态密切相关。     

红石岛植物资源调查与研究

为研究典型南海珊瑚海岛生物多样性与植物群落构成,以红石岛为研究对象,实地调查岛上原生植物群落物种组成,并进行相应生态学统计。结果表明:红石岛植被可分为红树林植被型组和热带海岸灌丛植被型组。红树林植被型组由红海榄群落和白骨壤群落组成,热带海岸灌丛植被型组主要由银毛树+草海桐+仙人掌群落、露蔸+银毛树+草海桐群落、苦楝+刺葵+露蔸群落组成。岛上共着生10科30种植物,其中乔木较少,以灌木和草本植物为主。岛上普遍分布的银毛树、草海桐、黄槿、露蔸等植物具有耐盐碱、耐旱、抗性强等特点,可选做岛礁生态恢复的先锋树种。     

北部湾红树林海岸的乡土景观设计

指出了在海岸景观日趋重视的今日,红树林生态群落的重要性也愈加突显。由于过度的人类活动及城市环境建设,导致红树林生境破坏严重。广西南部沿海,拥有全国红树林生境面积最大的红树林生态群落,但该地红树林的分布状况也不甚乐观。在红树林原有生境破坏严重、外来物种过度引种、沿岸景观的不协调背景下,提出了将生态性与美学性特征相结合,构建合理的海岸红树林景观的建设原则及分部营造设计方法,以期为北部湾红树林生态景观后期的营造提供参考。     

三亚白鹭公园红树林湿地景观恢复改造设计探讨

三亚白鹭公园最初为一片红树林滩涂,解放后属榆亚盐场范围,盛产"三亚盐",20世纪末三亚市采取"填湿造陆""挖湖堆岛"的方式建设白鹭公园,导致红树林生态环境遭到破坏。通过分析三亚白鹭公园中红树林湿地区域的现状和退化原因,提出对受损湿地采用设置保护分级、生态恢复重建等措施,在景观恢复设计中融入场地历史特征和生态科普教育等元素,在充实公园景观要素的同时满足不同层次游客的需求,经过多次的人工修复和较长期的演变及更替后,植被群落形成相对稳定结构,恢复改造效果显著。     

淇澳岛寒害致死海桑林迹地恢复早期植被特征的初步研究

2008年寒害使珠海市淇澳岛红树林遭受重大损失,红树林湿地中的海桑几乎全部死亡;18个月后,海桑林迹地恢复早期自然植被以老鼠簕和互花米草为主,并伴生有少量其他植物,植物种类有7科9属10种。根据植被特征,海桑林迹地可分为老鼠簕+互花米草群落、互花米草群落、老鼠簕单优群落、老鼠簕稀疏群落和裸滩5种植被类型。所形成的高密度与高盖度的老鼠簕和互花米草植被不利于桐花树、秋茄等红树植物幼苗的扩散。互花米草有向老鼠簕群落和低洼滩涂扩展的趋势。灾后互花米草和老鼠簕迅速繁殖扩散,若不进行人工改造,互花米草和老鼠簕将长期占据海桑林迹地滩涂。     

海南岛红树林生物群落现状与保护对策

该文在前人的研究结果的基础上,全面梳理了海南岛红树林群落类型与区域分布,分析当前红树林群落面临的问题,并提出相关的对策,以期为海南岛红树林的保护和管理提供参考依据。     

深圳东涌红树林现状及其保育策略

东涌红树林位于深圳市大鹏新区东涌社区东涌河口,其中有较大面积的彩叶红树林景观,极具观赏与生态保育价值。2020年4—5月期间线路踏查及分类鉴定结果表明,其红树林湿地有真红树植物5科6属6种,半红树植物7科9属9种。真红树群落有海漆群落、秋茄群落、白骨壤群、桐花树群落、木榄群落、老鼠簕群落;半红树群落有黄槿群落、苦郎树群落、露兜树群落、草海桐群落、马甲子群落。其中海漆群落面积达2.39 hm2,占主要优势。计算了不同斑块的Shannon-Wiener指数、Simpson指数、Pielou指数。现有红树林林地面积约4 hm~2,在过去5年增加了近1 hm~2,原因为东涌河道淤积为红树植物提供了新的生境。需要从管理与生境保护等方面加强东涌红树林保育。     

试析黑龙江省佳木斯市柳树岛生态恢复建设工程

柳树岛生态恢复工程,是围绕自然形态的环境复原展开的。生态恢复采用乔、灌、草相结合的方式,多层次的植物有利于更快的恢复被破坏的区域,改善局部的小气候条件,更有利于植被的自我恢复。在植被选择上以岛上的现有植被为优先,乔木选择上以旱柳、糖槭为植物群落的上层架构,作为改造后裸露地面的主要覆盖物;下层以山丁子做为主要的群落;地表层以萌发性较强的蔓生性草坪为基础。     

大亚湾红树林国家级城市湿地公园的红树林资源

大亚湾红树林国家级城市湿地公园位于广东惠州,调查表明共有13种红树林植物,包括8种真红树和5种半红树。组成植被主要有无瓣海桑Sonneratia apetala群落和海漆Excoecaria agallocha群落,还有零星分布的桐花树Aegiceras corniculatum、卤蕨Acrostichum aureum等层片。概述了该区的红树林植物资源,提出利用乡土树种构建彩色红树林景观带。同时,为了避免危害鹭鸟的筑巢地,针对无瓣海桑群落,应采取阶段性更新和适时进行人工干预以提升生态景观的优化方案。     

深圳福田红树林生态系统昆虫群落多样性调查

在深圳福田红树林生态系统,调查不同生境区域的昆虫群落组成及多样性特征。结果表明:深圳福田红树林生态系统昆虫群落由11目66科组成,优势类群是蚁科Formicidae、蝇科Muscidae、螟蛾科Pyralididae、沫蝉科Cercopidae和叶蝉科Cicadellidae;双翅目Diptera昆虫类群最丰富,膜翅目Hymenoptera昆虫的个体数量最多。不同生境区域昆虫群落的主要类群和个体数量存在较大差异,基围鱼塘区域昆虫群落的Margalef丰富度指数和Shannon-Wiener多样性指数高于陆域林地和红树林区,陆域林地昆虫群落的Pielou均匀度指数最高,红树林区昆虫群落的Simpson优势度指数最高。     

珠海市淇澳岛红树林引种扩种问题的探讨

文章论述了珠海淇澳岛引种扩种红树植物的重要意义；分析了引种无瓣海桑对红树资源的恢复，物种多样性和林分质量的提高，乡土植物的天然更新和扩散，大米草的控制等作用；并探讨了无瓣海桑引种对生态的影响。最后还提出了红树林引种扩种需要加强的措施。     

Sediment mixing and accumulation in a mangrove ecosystem: evidence from 210Pb, 234Th and 7Be

210Pb, 234Th and 7Be activities were measured to establish sediment accumulation rates, estimate sediment mixing rates, and determine the depth of the sediment mixed layer in the Sepetiba Bay mangrove ecosystem near Rio de Janeiro City, Brazil. Three sediment cores were collected from Enseada das Garças, a typical exposed tidal flat region with a sequence of sedimentary features. The seaward edge of this sequence is a mud flat with the landward portion covered with Spartina alterniflora followed by mangrove vegetation. An additional core was collected on an overwash island near Barra de Guaratiba, which is cover with mangroves without a mud flat or Spartina alterniflora sequence. Sediment accumulation rates were determined to range up to 1.8cm/yr with the Spartina alterniflora having the maximum rate. Mixing rates were estimated for the Spartina alternifloracore at 40cm2/yr based on 210Pb and 7Be from the upper mixed region of the core. The 234Th activity in this core suggested that either mixing or the input of 234Th were not in steady state. The sediment mixed region depth ranged from 4cm to greater than 30cm. At the Enseada das Garças site the mixing depth decreased in the landward direction (i.e. mud flats > 30cm, Spartina alterniflora 11cm, mangroves 4cm). Along with this decrease in sediment mixing depth was a shift from physical to biological mixing. The Barra de Guaratiba core had a sediment mixed layer of 13cm as a result of physical and intense biological activity.     

广东沿海红树林生态修复模式研究

通过深入调查研究广东沿海红树林生态系统资源及保护现状，针对近年因围垦养殖、城市建 设发展用地、城市生活污水和工业污水大量排放等，导致一些红树林及其生态环境遭到破坏，面积大幅减 少；现有红树林群落植物种类偏少、结构简单、遗传多样性水平较低；互花米草等外来有害生物入侵严 重，林分质量下降、系统功能退化；加上沿海红树林恢复属困难立地造林，技术措施及建设成本要求高等 实际情况，结合广东沿海滩涂立地条件及红树林经营管护特点等，提出了相应的红树林生态保护修复模式 及特殊立地修复营建关键技术等，为沿海红树林生态系统保护、修复、营建等提供理论依据和技术指导。     

遮荫对互花米草生长影响的初步研究

2000—2008年在珠海市淇澳岛利用速生红树植物—无瓣海桑Sonneratia apetala Buch-Ham.成功控制互花米草Spartina alterniflora Loisel。为了探明其控制机理,通过遮荫网模拟植被遮荫,研究遮荫对入侵种互花米草生长的影响。结果发现:遮荫对互花米草的生长具有很大影响,不同遮荫强度下互花米草的生长状况、光合能力及生物量等均存在显著差别;在2层遮荫网遮荫条件下,互花米草植株瘦弱,单株幼苗的茎叶干重和总干重显著降低,幼苗的12周相对生长率显著降低,死亡率明显大于1层遮荫网遮荫和无遮荫的处理;3层遮荫网遮荫处理则在遮荫开始1个月后全部死亡。试验证明遮荫对互花米草的生长具有显著的抑制作用,由此推断无瓣海桑成功控制互花米草主要是林冠的遮蔽起关键作用。     

Effect of mangrove restoration on crab burrow density in Luoyangjiang Estuary,China

Background:Mangrove restoration seeks to restore or rebuild degraded mangrove systems.The methods of mangrove restoration include ecological projects and restoration-oriented technologies,the latter of which are designed to restore the structure,processes as well as related physical,chemical and biological characteristics of wetlands and to ensure the provision of ecosystem services.As important components of mangrove ecosystem,benthic organisms and crabs play a key role in nutrient cycling.In addition,mangrove restoration,such as vegetation restoration measures,can lead to changes in the benthic faunal communities.This study investigates whether the presence of different mangrove species,age and canopy cover of mangrove communities affect the density of crab burrows.Methods:The Luoyangjiang Estuary,in the southeast of Fujian Province,was selected as our research area.A survey,covering 14 sites,was conducted to investigate the impacts of mangrove restoration on the density of crab burrows in four rehabilitated forests with different stand ages and canopy.Results:It was found that differences in vegetation types had a large impact on crab density and that the density of crab burrows was lower on exposed beaches(non-mangrove)than under mature Kandelia candel,Aegiceras corniculatum and Avicennia marina communities.In general,the amount of leaf litter and debris on mangrove mudflats was greater than on the beaches as food sources for crabs.Two-factor analysis of variance(ANOVA)shows that changes in mangrove species and age since restoration had different effects on crab burrow density.The effect of canopy cover was highly significant on crab burrow density.Conclusions:The results suggest that in the process of mangrove restoration the combined effects of mangrove stand age,canopy cover and other factors should be taken into account.This study further supports the findings of the future scientific research and practice on mangrove restoration and management measures.     

Effects of tidal inundation and predation on Avicennia germinans seedling establishment and survival in a sub-tropical mangal/salt marsh community

The black mangrove, Avicennia germinans, occurs sympatric withSpartina alterniflora in coastal Louisiana. Zonation exists alongan elevational gradient with A. germinans dominant at higherelevation creekbanks and S. alterniflora at interior, lowerelevation sites with greater depth and duration of flooding.Establishment of A. germinans seedlings was examined in cagesthat excluded predators and limited horizontal, but not vertical,movement of propagules by the tides and showed that blackmangrove could readily establish in the Spartina zone. Survivalof A. germinans seedlings after one year in cages was notsignificantly different between the two zones, and seedlings weresignificantly taller in the Spartina zone. Thus, neitherinundation per se nor other abiotic factors alone could accountfor the absence of A. germinans in the interior marsh. Althoughpropagules were dispersed into both zones, a net removal ofuncaged propagules from plots in the Spartina zone (–1.3 ± 0.6m^-2 d^-1) compared to a net addition to plots in the Avicennia zone (+0.5 ± 0.4 m^-2d^-1) indicated that retention of propagulesdiffered between zones. Causes of mortality were decay (Spartina> Avicennia zone), desiccation (Avicennia > Spartina zone), andpredation (Spartina > Avicennia zone). Although few propaguleswere completely consumed by predators (snails and crabs), damageto the cotyledons promoted decay. The results suggest that tidalaction limits retention and settlement of A. germinans propagulesin the Spartina zone, and a combination of predator damage andfrequent flooding leads to rapid decay of propagules that strandthere.     

Dependence of dispersion on vegetation density in a tidal creek‐mangrove swamp system

The dependence of dispersion in a tidal creek on the vegetation density in a fringing mangrove swamp is discussed through a numerical model. A secondary circulation prevails everywhere in the tidal creekmangrove swamp system and is generated by the overflow into the swamp at every high tide. As a result, dissolved and suspended matter moving with the circulation is trapped in the swamp for a fraction of the tidal cycle; it flows out of the swamp at ebb tide and disperses in the creek. The relation between the dispersion coefficient and the mangrove vegetation density is shown to be nonlinear. Dispersion is large both for bare and high vegetation densities and minimum for intermediate vegetation density. The ecological and management applications may be profound as our study suggests that such systems may be unstable and cannot naturally recover from excessive anthropogenic disturbances.     

Mangroves as a coastal protection from waves in the Tong King delta,Vietnam

The wave reduction (wave period; 5–8 sec.) was investigated in amangrove reforestation area (Kandelia candel) close toaquaculture ponds in the Tong King delta, Vietnam.On one site where only young mangrove trees grew, the wavereduction due to the drag force on the trees was hardlyeffective. On the other site where mangrove trees weresufficiently tall, the rate of wave reduction per 100 m was aslarge as 20%. Due to the high density of vegetation distributedthroughout the whole water depth, the effect of wave reductionwas large even when the water depth increased. These resultsdemonstrate the usefulness of mangrove reforestation for coastalprotection.     

Spatial patterns of biomass and soil attributes in an estuarine mangrove forest (Yingluo Bay,South China)

Mangrove ecosystems are well developed in the estuarine environment of Yingluo Bay, South China. However, little is known about the spatial patterns of vegetation biomass, soil organic carbon (SOC) stocks and soil attributes along the environmental gradient from upstream to downstream positions. To characterize the spatial pattern of these factors, four transects (transects I, II, III and IV) were established between upstream and downstream positions. The result showed clear spatial patterns occurred in this estuarine mangrove. In general, vegetation biomass, TN concentration and SOC concentration and stocks decreased from upstream to downstream positions unless transect I, with the increase of soil salinity. This may be attributed to a consequence of increasing environmental stress due to the change of soil elevation. Vegetation biomass and its carbon, SOC concentration and stocks, and TN concentration showed clear trends of decrease first and then gradually tended to be stable along each transect from landward to riverward positions. These results indicate that soil position/elevation in the estuarine mangrove greatly affects soil attributes and mangrove growth. In each transect, change of soil salinity showed some distinct characteristics, in comparison with SOC and TN. SOC concentrations were significantly correlated with vegetation biomass and silt contents. Compared to that in the mangrove-covered area, SOC concentrations and stocks were much lower in the bare flat. It was indicated that an increase of vegetation biomass will raise the mangrove-derived SOC, and reforestation with mangroves is a friendly strategy provided coastal protection.     

Mangrove community recovery potential after catastrophic disturbances in Bangladesh

The objective of this study was to compare the variation in the soil seed banks and the aboveground vegetation in relation to three habitats, i.e., swamp forests, grassland and sand dunes within the Sundarbans mangrove forests of Bangladesh. We collected vegetation data (species and their percentage cover) by using quadrat sampling: 10 m × 10 m for swamp forests and 5 m × 5 m for grassland and sand dunes. We estimated the density of viable seeds of species in the seed bank by counting germinants from soil cores in a germination chamber. Species richness and composition of both aboveground vegetation and the soil seed banks differed significantly among habitats. We identified a total of 23 species from the soil seed bank. Of these, two were true mangrove species and the remaining were non-mangrove species, including halophytic grasses, herbs and mangrove associate species. Our results confirm that mangrove species do not possess a persistent soil seed bank. The presence of high-density non-mangrove and associated mangrove species in the soil seed bank implies that after frequent catastrophic disturbances which limit incoming propagules from adjacent forest stand, large canopy gaps can easily become invaded by non-mangrove and mangrove associate species. This would result in the formation of a cover of non-mangrove species and cryptic ecological degradation in mangrove habitats. We suggest that forest managers should actively consider gap plantations with mangrove species in the large canopy gaps created after catastrophic disturbances to counteract the invasion of non-mangrove species and cryptic ecological degradation.