海堤对广西沿海红树林的数量,群落特征和恢复的影响

广西大陆海岸线的 63%为海堤 ,海堤数量达 498个 .海堤建立毁灭了原生红树林 ,现余 5654hm2 ,其中约 85%为堤前红树林 .海堤阻截了红树林滩涂的自然海岸地貌 ,结果是红海榄和木榄已很少 ,榄李濒危 ,角果木已消失 ,海漆和陆岸种类只能沿海堤坡面生长 ,而先锋红树植物白骨壤和桐花树成为现有红树林的优势种 .堤前红树林的恢复受到海堤维护时强烈的人为干扰 .堤前滩涂相对于平均海平面的高程较低 ,不是红树林繁盛的理想滩涂 .红树林人工造林的成活率和次生林恢复的速率在很大程度上取决于生境的沉积率 .     

广西北部湾红树林资源现状及可持续发展对策

红树林作为热带和亚热带沿海滩涂上特有的植被类型和生物资源,在自然生态平衡中起着特殊的作用。作者通过线路走访和选取固定地点采样法对广西北部湾红树林资源现状进行调查,调查表明：广西北部湾红树林现存面积8374．9hm^2,有真红树8科11种,半红树6科8种,伴生植物12科14种。红树林主要树种有：秋茄、桐花树、白骨壤、红海榄、木榄、海漆、榄李、老鼠筋、卤蕨、无瓣海桑等。最后对北部湾红树林资源的保护利用以及可持续发展提出相应的对策。     

湛江红树林滩涂可培养真菌种群多样性分析

【目的】明确湛江地区红树林滩涂海洋真菌的种类及其分布,为海洋真菌的开发利用研究奠定基础。【方法】运用稀释平板法从湛江市高桥及特呈岛红树林滩涂不同的潮位带(低、中、高)和不同树种(白骨壤、桐花树、木榄、红海榄)采集淤泥样品550份,采用真菌形态学和ITS序列分析技术进行多样性研究【。结果】分离获得海洋真菌274株,共鉴定出19属39种真菌,以曲霉属Aspergillus、青霉属Penicillium和木霉属Trichoderma真菌分离频率高,为湛江红树林滩涂优势真菌种类,尤其在中潮位带真菌种类最多。此外,分离获得真菌Talaromyces helicus,为中国新记录种。【结论】湛江红树林滩涂海洋真菌的种类十分丰富,具有潜在的开发和利用前景。     

珠海淇澳岛冬季的鸟类群落

在淇澳岛红树林湿地设置7条样带,分别于2005-2007年每年1月对该区冬季鸟类群落特征进行研究.共记录到鸟类63种,隶属12目23科,雀形目种类最丰富;其中留鸟、冬候鸟、夏候鸟分别占66.7%、31.7%和1.6%,水禽和陆禽分别占28.6%和71.4%.鸟类群落总体α多样性指数(H)为3.171,均匀度(J)为0.765;各个样带的H值为0.602～2.853,J值为0.336～0.919,其中滩涂与红树林生境的鸟类群落多样性与均匀度在7种生境中最低.β多样性指数分析表明,滩涂、红树林鱼塘湿地和村落之间的鸟类群落差异较大.根据等级聚类分析的结果,淇澳岛冬季鸟类群落可划分为滩涂水禽、红树林鱼塘湿地鸟类、农田森林鸟类3个群落.     

传统渔业活动对广西英罗港红树林区渔业资源的影响与管理对策

广西英罗港红树林区滩涂和光滩潮水中大型底栖动物和游泳动物曾很丰富。近4年来由于海鲜价格不断提高,林区的人为滥捕已使大型底栖动物和游泳动物的数量分别下降了约60%和80%。捕获方式有挖掘滩涂底栖动物,在红树林光滩潮水和林内潮沟进行网捕、炸鱼和毒鱼,网眼小至0.25 cm。传统的捕获萎缩了生态食物网的通量,破碎了生境,威胁着种群的繁衍。由于红树林区的渔业多少是当地群众的生计,完全封闭滩涂进行保育目前不可能。为此建议对英罗港红树林区滩涂施行封滩轮育,同时加强公众教育。     

珠海市淇澳岛红树林湿地的研究进展与展望

至上世纪末,淇澳岛红树林湿地遭到严重的破坏,互花米草入侵滩涂,相关人士对淇澳岛红树林的恢复做了许多工作.通过对相关文献的查阅与实地调查,总结了淇澳岛红树林湿地的植被群落类型、红树和半红树植物的引种与栽培、互花米草的防治、引进种无瓣海桑在淇澳岛的扩散与入侵性、红树林湿地的生态服务功能以及08年寒害对淇澳岛红树林的影响等方面的研究成果,对华南其他地区红树林湿地的恢复具有一定的指导作用.     

中国红树植物种质资源现状与苗木繁育关键技术

红树植物种质与种苗生产是所有红树林生态恢复工程的基础.本文根据工程实践并结合已有研究资料,采用聚类分析等方法,对中国红树植物资源现状与苗木繁育关键技术进行初步分析.结果表明:中国红树群落可分为低温广布型、广布型、嗜热广布型和热带分布型4种类型;资源分布可划分为琼东沿海、北部湾沿海、珠江口至粤东沿海、闽南和台湾沿海、闽东至浙南沿海5个区域.其中,北部湾沿海红树林种质资源占全国的75.3％.目前中国红树植物苗木种类开发利用率为52.6％,以胎生红树植物为主.红树林苗木生产应注意繁育方法、种实采集与储存、育苗方式、水分和盐度选择、病虫害防治及越冬防寒措施6个技术环节.结合调查和生产实践,归纳分析了中国现有5种红树林苗圃类型(旱地设施苗圃、红树林滩涂苗圃、光滩苗圃、基围塘苗圃和米草滩涂苗圃)的结构和用途特点,为红树林生态恢复工程的系统集成管理提供参考.     

广西沿海红海榄造林的宜林临界线

2004年8月—2005年8月,在广西英罗湾滩涂上建造8个高程梯度(320~390cm,相邻梯级间高度差10cm)的试验平台,研究全日潮海区潮汐淹水胁迫对红海榄幼苗生长和生理指标的影响.结果表明:小高程(320~330cm)生境对红海榄幼苗茎高生长有微弱促进作用,340cm以上高程组幼苗茎高随滩涂高程增加而增大.中等高程(350~370cm)有利于幼苗茎节数的增长.滩涂高程越低,幼苗叶数、叶面积和叶保存率越低.小高程组幼苗叶片叶绿素a受损明显,叶绿素b则受损相对较轻;叶绿素a/b值随滩涂高程降低而减少.长时间淹水诱导使根系中SOD活性上升,叶片中则表现为中等高程组酶活性较低.叶片和根系中POD活性均随高程降低而增加.淹水胁迫使红海榄幼苗各器官及全株的生物量降低;随着淹水程度加大,新生器官生物量分配比例由叶向茎转移.随着高程降低,幼苗存活率从88.9%降至40.0%,但370cm以上高程组存活率均在80%以上.建议将当地平均海面线作为广西沿海红海榄胚轴造林的宜林临界线.     

红树林植被对大型底栖动物群落的影响

大型底栖动物是红树林生态系统的重要组成部分,从红树林大型底栖动物种类、红树林与其周边生境大型底栖动物群落的比较,以及生境变化对动物群落的影响等方面阐述了红树林植被与大型底栖动物群落的关系.从物种数量上看,软体动物和甲壳类动物构成了红树林大型底栖动物的主要部分.影响大型底栖动物分布的环境因素包括海水盐度、潮位和土壤特性等,但在小范围区域,林内动物的分布更多地与红树林植被特性和潮位有关.因此,由于红树林植被破坏或者恢复引起的生境变化,将导致大型底栖动物群落和常见物种种群的变化,尤其对底上动物影响明显;随着人工恢复红树林的发育,林内底栖动物的多样性相应增加,优势种也发生变化.相比位于相同潮位的无植被滩涂,红树林可促进潮间带生物多样性.     

无瓣海桑与三种乡土红树植物混交的生态效应

为了解人工种植红树林的生态效应,对2001年种植于广州市南沙区的三种人工混交红树林进行了群落结构和土壤理化性状的调查分析。结果表明:由于红海榄的不耐荫导致样地3无法形成复层结构,但也不排除是红海榄化感作用的影响;无瓣海桑+木榄群落、无瓣海桑+秋茄群落的群落结构和对土壤中重金属的吸收效果优于无瓣海桑+红海榄群落,因此在该实验的立地条件下营造红树林混交林时可以考虑无瓣海桑与秋茄、木榄混交,不应将无瓣海桑与红海榄混交;随着演替的进行,该实验地在无重大干扰的情况下将向着近天然红树林生态系统演化。     

Restoration ecology meets carabidology: effects of floodplain restitution on ground beetles (Coleoptera,Carabidae)

The effects of different restoration activities on floodplain-inhabiting ground beetles were studied at a lowland river in northwestern Germany. In the 6-km² project area the bank reinforcement was stopped, the dikes that bordered the river on both sides were removed and two oxbows (disconnected parts of the main stream course) were reconnected to the river. We investigated the banks at two sites at the main river, at the two reconnected oxbows and at two unconnected oxbows as reference sites. To analyse the effects of the removal of the dikes we chose three floodplain sites in front and two reference sites behind the new dike. As a consequence of the lack of bank reinforcement and the reconnection of the oxbows, the area of open river banks, a rare bank structure at rivers in northwestern Germany, increased by a factor of 4.6 during the 4 years of investigation. Numerous stenotopic ground beetle species colonized the newly developed habitats at the main river and at the reconnected oxbows quickly, during several weeks or months, and established new populations as indicated by newly hatched individuals. The removal of the dikes should lead to a rewetting of the floodplain area that is incorporated in the flood dynamics, an important aspect of the development of typical floodplain habitats such as wet meadows, reeds and alluvial forests, while reference sites on the other side of the removed dike remained uninfluenced. Four years after the removal of the dikes no species turnover at the sites with a potentially changed water regime was recorded that indicated a shift of the carabid assemblages towards hygrophilous species. One reason could be the low frequency of inundations and their short duration during the investigation period. The flood dynamics could be sustained by the elevation and enlargement of the river bed, and periodic floods are the key factor for a development of floodplain habitats.     

Fish use of restored mangroves matches that in natural mangroves regardless of forest age

The loss and degradation of mangrove forests have triggered global restoration efforts to support biodiversity and ecosystem services, including fish stock enhancement. As mangrove restoration accelerates, it is important to evaluate outcomes for species that play functional roles in ecosystems and support services, yet this remains a clear knowledge gap. There is remarkably little information, for example, about how fish use of mangroves varies as restored vegetation matures, hampering efforts to include fisheries benefits in natural capital assessments of restoration. We used unbaited underwater cameras within two distinct zones of mangrove forests—fringe and interior—at five pairs of restored-natural mangrove sites of increasing age from restoration in southeast Queensland, Australia. We used deep learning to automatically extract data for the four most common species: yellowfin bream (Acanthopagrus australis), sea mullet (Mugil cephalus), common toadfish (Tetractenos hamiltoni), and common silverbiddy (Gerres subfasciatus). The abundance of these species varied among sites and zones, but was equal or greater in restored sites compared to paired natural sites. Despite younger restored sites having dramatically lower structural vegetation complexity, abundances did not increase with restoration site maturity. Furthermore, while yellowfin bream and sea mullet were more abundant in the fringe zone, we observed similarities in how fish used fringe and interior zones across all sites. Our paired, space-for-time design provides a powerful test of restoration outcomes for fish, highlighting that even newly restored sites with immature vegetation are readily utilized by key fish species.     

Plant-animal interactions and the structure and function of mangrove forest ecosystems*

Trophic interactions involving plants and animals in tropical mangrove forests have important controlling influences on several population, community and ecosystem-level processes. Insect herbivores remove up to 35% of leaf area from some mangrove tree species and can cause the death of seedlings. Leaf chemistry and toughness and soil nutrient status all appear to be important in explaining the between- and among-species variance in leaf damage. Insects also attack and damage, mainly by boring, a large proportion of mangrove seeds. Shadehouse experiments have shown that such post-dispersal predation can have a significant effect on seedling survival, growth and biomass allocation to leaves, stems and roots. Sesarmid crabs are also responsible for severe post-dispersal seed predation. In field trials, crabs consumed more than 70% of the seeds of five tree species. For four of these five species there was an inverse relationship between seed predation rate and the dominance of conspecific adult trees, while the within-site distribution pattern of one tree species appears to be partially controlled by crabs. The same crab species also consume 30–80% (depending on forest type and intertidal elevation), of the annual litter fall in mangrove forests and, thus, have an important role in controlling the rate of remineralization of detritus within forests and the export of particulate matter from the forests to other nearshore habitats. The other major component of litter in the forests is wood, which is broken down relatively rapidly by teredinid molluscs (shipworms). More than 90% of the weight loss from decomposing trunks of Rhizophora species during the first four years of decay is through ingestion by teredinids. The annual turnover of dead wood mass in Rhizophora forests is equivalent to that of the processing of leaf detritus by crabs. Because of the relatively low species richness of trees and consumers in tropical mangrove forests, they are likely to serve as productive sites for further investigations of the influence of plant-animal interactions on the dynamics of tropical forests.     

Ecological engineering for successful management and restoration of mangrove forests

Great potential exists to reverse the loss of mangrove forests worldwide through the application of basic principles of ecological restoration using ecological engineering approaches, including careful cost evaluations prior to design and construction. Previous documented attempts to restore mangroves, where successful, have largely concentrated on creation of plantations of mangroves consisting of just a few species, and targeted for harvesting as wood products, or temporarily used to collect eroded soil and raise intertidal areas to usable terrestrial agricultural uses. I document here the importance of assessing the existing hydrology of natural extant mangrove ecosystems, and applying this knowledge to first protect existing mangroves, and second to achieve successful and cost-effective ecological restoration, if needed. Previous research has documented the general principle that mangrove forests worldwide exist largely in a raised and sloped platform above mean sea level, and inundated at approximately 30%, or less of the time by tidal waters. More frequent flooding causes stress and death of these tree species. Prevention of such damage requires application of the same understanding of mangrove hydrology.     

Predicting the in-between: Present and future habitat suitability of an intertidal euryhaline fish

New World mangrove trees are foundation species, and their range is predicted to expand northward with climate change. Foundation species are commonly prioritized for conservation, with the goal of preserving the entire community that depends on them. However, no studies have explicitly investigated whether mangrove-dependent species' ranges will track the northward expansion of New World mangrove forests. We use the mangrove rivulus fish, Kryptolebias marmoratus, to investigate shifts in habitat suitability in response to various climate change scenarios (Representative Concentration Pathways 2.6, 4.5, 6.0, and 8.5). Niche models for coastal species focus on traditional climatic variables (e.g., precipitation, temperature) even though coastal habitats also are directly influenced by marine variables (e.g., sea surface salinity). We employ a novel data integration method that combines marine and climatic variables, and that accounts for model selection uncertainty using model averaging to provide robust estimates of habitat suitability. Contrary to expectation, suitability of rivulus habitat is predicted to increase in the south and decrease or remain unchanged in the north across all climate change scenarios. Thus, rivulus might experience range contraction, not expansion. Habitat became more suitable with increased salinity of the saltiest month and precipitation of the driest quarter. In laboratory settings, rivulus have higher survival, reproductive success, and growth rates in low salinities. This discrepancy suggests that some combination of the responses of rivulus and its competitors to environmental change will restrict rivulus to habitats that laboratory experiments consider suboptimal. Our models suggest that focusing conservation decisions on foundation species could overestimate habitat availability and resilience of affiliated communities while simultaneously underestimating species declines and extinction risks.     

Habitat‐dependent occupancy and movement in a migrant songbird highlights the importance of mangroves and forested lagoons in Panama and Colombia

Climate change is predicted to impact tropical mangrove forests due to decreased rainfall, sea‐level rise, and increased seasonality of flooding. Such changes are likely to influence habitat quality for migratory songbirds occupying mangrove wetlands during the tropical dry season. Overwintering habitat quality is known to be associated with fitness in migratory songbirds, yet studies have focused primarily on territorial species. Little is known about the ecology of nonterritorial species that may display more complex movement patterns within and among habitats of differing quality. In this study, we assess within‐season survival and movement at two spatio‐temporal scales of a nonterritorial overwintering bird, the prothonotary warbler (Protonotaria citrea), that depends on mangroves and tropical lowland forests. Specifically, we (a) estimated within‐patch survival and persistence over a six‐week period using radio‐tagged birds in central Panama and (b) modeled abundance and occupancy dynamics at survey points throughout eastern Panama and northern Colombia as the dry season progressed. We found that site persistence was highest in mangroves; however, the probability of survival did not differ among habitats. The probability of warbler occupancy increased with canopy cover, and wet habitats were least likely to experience local extinction as the dry season progressed. We also found that warbler abundance is highest in forests with the tallest canopies. This study is one of the first to demonstrate habitat‐dependent occupancy and movement in a nonterritorial overwintering migrant songbird, and our findings highlight the need to conserve intact, mature mangrove, and lowland forests.     

Origin of Jurassic-Cretaceous neptunian dikes from the Cracow-Częstochowa Upland in southern Poland

Neptunian dikes, representing deposit-filling fractures in older rocks, have long attracted the attention of paleontologists because they may provide unique insights into ancient cryptic submarine cave ecosystems. In the epicratonic Poland, fossil-bearing neptunian dikes are especially well known in Upper Jurassic (mainly Oxfordian) strata. However, the age, origin and faunal composition of these dikes remain the subject of debates. To address these issues, we integrated new paleontological and petrographic data from the Janina Quarry in southern Poland, where neptunian dikes are particularly well exposed. On the basis of sedimentary facies and faunal content occurring as infill of the analyzed dikes, we recognized three distinct stages of Neptunian dike development. Initially, these dikes represented fissures in the sea bottom resulting from the intense Oxfordian and/or Kimmeridgian synsedimentary processes related to Meso- and Neocimmerian tectonic movements. These initial voids were colonized by small crinoids (cyrtocrinids) and brachiopods (lacunosselids), which resulted in the formation of bioclastic limestones. This is the first Mesozoic record of cryptic cyrtocrinids, which implies that migration of this echinoderm group to cryptic habitats has already occurred in the Late Jurassic, consistent with the so-called Mesozoic Marine Revolution. After the initial opening and subsequent rapid sedimentary filling of voids, rejuvenation of these dikes occurred in the Aptian-Cenomanian that was likely induced by the Austrian tectonic phase. Reopened fissures were subsequently filled by rare allochthonous echinoderms and sandstones containing unusually high (5% vol.) content of heavy minerals implying the Bohemian Massif as the most probable source area. The neptunian dikes were finally reopened during the Turonian-Santonian that was probably related to the subhercynnian tectonic phase. They were presumably inhabited by annelids and ultimately filled by a micritic sediment subsequently bioturbated by infaunal echinoids.     

Valuing mangrove ecosystem services: linking nutrient retention function of mangrove forests to enhanced agroecosystem production

Mangroves are highly productive wetland ecosystems strategically located at the interface between land and sea. They play an important role in the biogeochemical cycles of the coastal environment, acting as sources of nutrients to adjacent marine and terrestrial ecosystems through active and passive transport. We examined the nutrient contents in mangrove and nonmangrove soils in and around the Bhitarkanika National Park, India and assessed whether the local agricultural producers were aware of and placed a value on this contribution of mangrove forests in enhancing agroecosystem productivity. Soil samples from both mangrove and nonmangrove areas were analysed and quantity of organic carbon, total nitrogen, available phosphorus and potassium were derived. The replacement cost method was used to derive the value of nutrients in mangrove soils. We estimated that each hectare of mangrove contains additional nutrients worth US$232.49 in comparison to nonmangrove areas. The difference in nutrient content in mangrove versus nonmangrove areas gave the value of US$3.37 million for the nutrients in 145 km² of mangrove forests. The agricultural producers were aware that mangrove forests act as a source of nutrients and were willing to pay a higher price for the land adjoining mangrove forests. Around 92% of the producers ranked nutrient retention as a secondary function of mangrove forests. Despite crop depredation from wild ungulates and conflict with salt water crocodiles the agriculturist finds the benefit to cost ratio of mangrove forests high and more than 76% were in favour of mangrove restoration. This study provides an opportunity to highlight the importance of mangrove ecosystems to the livelihoods of the local people and the urgent need to sustain these through proper policy and market interventions.     

Recognition of co-existence pattern of salt marshes and mangroves for littoral forest restoration

Climate-change driven sea level rise causes a increase in salinity in coastal wetlands accelerating the alteration of the species composition. It triggers the gradual extinction of species, particularly the mangrove population which is intolerant of excessive salinity. Thus despite being crucial to a wide range of ecosystem services, mangroves have been identified as a vulnerable coastal biome. Hence restoration strategy of mangroves is undergoing rigorous research and experiments in literature at an interdisciplinary level. From a data-driven perspective, analysis of mangrove occurrence data could be the key to comprehend and predict mangrove behavior along different environmental parameters, and it could be important in formulating management strategy for mangrove rehabilitation and restoration. As salt marshes are the natural salt-accumulating halophytes, mitigating excessive salinity could be achieved by incorporating salt-marshes in mangrove restoration activities. This study intends to find a novel restoration strategy by assessing the frequent co-existence status of salt marshes, with the mangroves, and mangrove associates in different zones of degraded mangrove patches for species-rich plantation. To achieve this, we primarily design a novel methodological framework for the practice of knowledge discovery concerning the coexistence pattern of salt marshes, mangroves, and mangrove associates along with environmental parameters using a data mining paradigm of association rule mining. The proposed approach has the capability to uncover underlying facts and forecast likely facts that could automate the study in the field of ecological research to comprehend the occurrence of inter-species relationships. Our findings are based on published data gathered on the Sundarban Mangrove Forest, one of the world’s most important littoral forests. The existing literature reinforces the findings that include all the sets of frequently co-occurring mangroves, their associates, and salt marshes along the salinity gradient of coastal Sundarbans. A detailed understanding of the occurrence patterns of all these, along with the environmental variables, would be able to promote decision-making strategy. This framework is effective for both academia and stakeholders, especially the foresters/ conservation planners, to regulate the spread of salt marshes and the restoration of mangroves as well.     

福建洛阳江口红树林湿地大型底栖动物多样性及季节变化

基于2013-2014年福建洛阳江口红树林湿地的周年调查资料, 研究了该湿地大型底栖动物的物种多样性现状、季节变化以及红树林恢复对底栖动物群落的影响。本次调查共鉴定大型底栖动物7门78种, 环节动物和节肢动物种类最为丰富, 节肢动物对总生物量贡献最大, 短拟沼螺(Assiminea brevicula)为本区第一优势种。林区底栖动物的密度和生物量明显低于光滩, 部分优势种仅在林区出现, 此外, 林区群落与光滩有显著差异。本区底栖动物的密度高值出现在冬、春季, 生物量高值出现在春、夏季, 群落结构季节变化明显。本区底栖动物种类组成特点反映出洛阳江口红树林处在年轻期, 群落的季节变化可能跟优势种的繁殖特点有关。研究结果也表明红树林植被会影响底栖动物群落结构, 林区群落已然不同于光滩, 与2009年调查结果相比, 林区底栖动物密度虽明显下降, 但褶痕拟相手蟹(Parasesarma plicata)数量增加, 是优势种之一。洛阳江口红树林和光滩支撑着不同的生物组成, 因此, 红树林恢复应当保持栖息地的多样性/异质性。