红树林造林修复技术探讨

面对退化的消失的红树林湿地资源,我国湿地修复技术研究和实践总结多,但是成活率低。文章主要从红树林湿地修复技术的宜林地选择(温度、盐度、沉积物、潮汐浸淹和波浪能量)、树种选择与引种与修复造林技术3个方面进行探讨;同时探讨了造林方法、造林季节、造林密度、混交造林等。结合红树林湿地生态修复的基本原理,提供各项指标临界参数以供修复参考,旨在为我国红树林的有效恢复,提高造林成活率提供科学参考。针对湿地修复技术研究现状,提出未来的展望。     

浙江省红树林资源调查及其发展规划

据2001年调查，浙江省共有红树和半红树植物3种，即秋茄、苦槛蓝、海滨木槿。全省现有红树林20．6hm^2，未成林红树林地236．1hm^2，宜林地面积5195．6hm^2。分析了红树林的现状特点，提出了浙江省红树林立地分类系统，最后进行了红树林发展规划。     

惠东县红树林资源现状及保护对策

通过卫星遥感和设置样地对广东省惠东县的红树林资源进行调查。结果表明:惠东县红树林面积共有1361.83 hm^2,其中,红树林有林地有400.15 hm^2,红树林未成林造林地有42.27 hm^2,红树林宜林地有919.41 hm^2;共分布15种红树植物,其中真红树植物有9种,半红树植物有6种,另外红树林伴生植物有29种。对惠东县红树林基本结构情况和多样性、原生性、濒危性资源特点进行了分析,指出红树林正受到人工围垦养殖、旅游开发建设、外来生物入侵、污水直排和生活垃圾污染水体、外来无瓣海桑Sonneratia apetala红树林物种影响等威胁因素,提出了出台相关保护政策、严格执法、营造多树种混交红树林群落、对近海滩涂养殖进行规范、规模控制、对滨海乡镇实施垃圾清理工程和污水集中处理设施建设、合理划定保护区范围及功能区等保护和发展对策,为红树林的生态保护与恢复以及海岸修复提供参考。     

尖瓣海莲幼苗对模拟潮汐淹浸时间的适应性研究

室内模拟不同潮汐淹浸时间对红树植物尖瓣海莲幼苗生长的影响,测定植物生理指标(包括叶绿素、超氧化物歧化酶、游离脯氨酸、丙二醛、硝酸还原酶、电导率、根活力等)、生长量和生物量.半年的试验结果表明:叶绿素、根活力和硝酸还原酶随淹浸时间的延长先升后降,而游离脯氨酸、丙二醛和相对电导率随淹浸时间的延长先降后升,并在12 h·d-1处出现骤变分界点;淹浸时间超过16 h·d-1后,尖瓣海莲胚轴发芽率下降,超过14 h·d-1后尖瓣海莲幼苗部分死亡,淹浸24 h·d-1茁木全部死亡;淹浸逆境对幼苗叶片影响最大,叶片数月均增长最大者(淹浸4 h·d-1)比月均增长最小者(淹浸24 h·d-1)增加了450%;总生物量、茎及主根的生物量均在淹浸6 h·d-1处理下最大,当淹浸超过12 h·d-1后,尖瓣海莲幼苗总生物量骤降.结合适应度分析得出:尖瓣海莲的最适淹浸时间为6～8 h·d-1,临界淹浸时间为12 h·d-1.     

红树植物亲缘地理学研究进展

红树植物生长在热带、亚热带海岸滩涂上。健全的红树植物生态系统是人类持续利用红树林的必要条件。如何保护、维持红树林的生态系统及其遗传健全性已成为红树林生态学家最关心的问题。红树植物当前的地理分布格局及形成原因是生态学家和保护生态学家的研究重点。文中介绍了近些年来红树植物亲缘地理学研究概况,包括地理隔离对红树植物分布格局的影响、基因交流受阻隔以及引起红树群体遗传结构变化的原因等内容;阐述了地质历史引起地形地貌变化、地理隔离、繁殖体扩散及生境环境等因子影响红树群体遗传演化的机制;探讨了红树植物亲缘地理学未来研究的重点,以期为红树植物保护和相关研究提供参考。     

惠东县红树林保护区植被调查及恢复初探

惠东县红树林保护区及其周边陆域植被类型复杂多样。保护区红树林主要分布在稔山、铁涌、盐洲三镇,现有15种红树植物,约占中国红树植物种数的38.46%。其中真红树10种,约占中国真红树植物种数的35.71%;半红树5种,约占中国半红树植物种数的45.45%。其中稔山有红树植物12种,包括原生真红树植物8种、外来真红树植物1种和半红树植物3种;铁涌有红树植物12种,包括原生真红树植物7种、外来真红树植物1种和半红树植物4种;盐洲有红树植物12种,包括原生真红树植物8种、半红树植物3种和外来真红树植物1种。惠东县红树林保护区的植物种类资源具有较高的欣赏价值和物种保护价值,对惠东县红树林保护区植被调查及其周边区域陆域植物生态调查研究,为惠东县红树林保护区未来的发展及红树林生态系统的安全提供有力的保障和基础理论依据。     

厦门红树林天然宜林地空间评价初探

采用文献查阅、实地考察以及3S技术应用相结合的方法,建立了厦门红树林天然宜林地评估指标体系,调查了厦门红树林生长现状,评价了厦门周边现存天然滩涂中红树林宜林地的空间格局,并在海平面上升情景下预测了红树林天然宜林地的变化趋势,为厦门市红树林天然宜林地规划以及红树林生态恢复的空间格局提供基础数据和可行性建议。     

红树植物对水淹缺氧的生理响应研究进展

水淹缺氧是红树植物主要的胁迫因子之一。因其水淹耐性不同,不同种类的红树植物分布在不同高程的潮滩上。长期生长在受周期性海水浸渍、缺氧的淤泥中的红树植物已特化出一套适应水淹缺氧环境的适应机制。文中着重论述红树植物在生长与营养分配、光合作用和呼吸作用、碳氮代谢、抗氧化机制等方面的适应机制,并对红树植物在水淹缺氧胁迫下根系代谢途径、非结构性碳水化合物、次生代谢等方面提出研究展望。     

湛江市红树林资源状况及其保护成效

湛江市是除海南岛外我国红树植物种类最多的地区，是我国红树林主要分布区之一，也是广东省红树林分布最广、面积最大、红树林物种最丰富的地级市，其中红树植物有12科、16属、17种。本文简要地介绍了湛江市红树林资源状况、中荷合作广东雷州半岛红树林综合管理和沿海保护项目在保护红树林方面所取得的一些成效，以及此项工作的开展对湛江市可持续发展具有的重要意义。     

中国红树植物的引种栽培状况

在对全国各主要红树林分布区实地调查的基础上,论述了全国各省区红树植物（包括半红树植物）引种栽培状况,提出了一个完整的中国红树植物（包括半红树植物）种类及分布表。针对各省区红树林造林树种单一的情况,提出了一个各省区红树植物引种栽培的优先选择树种方案。     

Sedimentation in Mangrove Forests

The tidal currents in mangrove forests are impeded by the friction caused by the high vegetation density. The tidal currents are also complex comprising eddies, jets and stagnation zones. The sediment particles carried in suspension into the forest during tidal inundation are cohesive, mainly clay and fine silt, and form large flocs. These flocs remain in suspension as a result of the turbulence created by the flow around the vegetation. The intensity of sedimentation is largest for trees forming a complex matrix of roots such as Rhizophora sp. and smallest for single trees such as Ceriops sp. The flocs settle in the forest around slack high tide. At ebb tides the water currents are too small to re-entrain this sediment. Hence the inundation of coastal mangrove forests at tidal frequency works as a pump preferentially transporting fine, cohesive sediment from coastal waters to the mangroves. Mangroves are thus not just opportunistic trees colonising mud banks but actively contribute to the creation of mud banks.     

Manganese dynamics in a mangrove mud flat tidal creek in SE Brazil

This study investigated the behavior of soluble and particulate manganese, during tidal cycles in a mangrove tidal creek and adjacent mud flats in SE Brazil. We identify the major processes affecting manganese transport to mangroves. The results showed that manganese variability occurs both seasonally, and over the tidal cycle, in response to changing redox potentials. Tidal water flooding mud flats are enriched in manganese, originating from upward migration of reduced species and further adsorption onto suspended particles under oxic conditions. During the tidal cycle, particulate manganese concentrations are higher during flood periods, whilst dissolved concentrations are higher during ebb periods. Although quantitatively different, this pattern occurs both in winter and summer. The dynamics of manganese characterized in this study suggest that this metal may play a significant role as a conveyor of trace metals to mangrove ecosystems, as suggested by earlier studies.     

Predicting the retreat and migration of tidal forests along the northern Gulf of Mexico under sea-level rise

Tidal freshwater forests in coastal regions of the southeastern United States are undergoing dieback and retreat from increasing tidal inundation and saltwater intrusion attributed to climate variability and sea-level rise. In many areas, tidal saltwater forests (mangroves) contrastingly are expanding landward in subtropical coastal reaches succeeding freshwater marsh and forest zones. Hydrological characteristics of these low-relief coastal forests in intertidal settings are dictated by the influence of tidal and freshwater forcing. In this paper, we describe the application of the Sea Level Over Proportional Elevation (SLOPE) model to predict coastal forest retreat and migration from projected sea-level rise based on a proxy relationship of saltmarsh/mangrove area and tidal range. The SLOPE model assumes that the sum area of saltmarsh/mangrove habitat along any given coastal reach is determined by the slope of the landform and vertical tide forcing. Model results indicated that saltmarsh and mangrove migration from sea-level rise will vary by county and watershed but greater in western Gulf States than in the eastern Gulf States where millions of hectares of coastal forest will be displaced over the next century with a near meter rise in relative sea level alone. Substantial losses of coastal forests will also occur in the eastern Gulf but mangrove forests in subtropical zones of Florida are expected to replace retreating freshwater forest and affect regional biodiversity. Accelerated global eustacy from climate change will compound the degree of predicted retreat and migration of coastal forests with expected implications for ecosystem management of State and Federal lands in the absence of adaptive coastal management.     

Conversion and recovery of Puerto Rican mangroves: 200 years of change

Human activities have dramatically reduced the world’s area of mangroves just as the ecological services they provide are becoming widely recognized. Improving the conservation tools available to restore lost mangroves would benefit from a better understanding of how human activities influence the conservation of these ecosystems. We took advantage of historical information and long-term landscape analyses to relate land use change with the area of mangroves in Puerto Rico. We found that mangroves experienced dramatic changes over the last 200 years, and four distinct eras of change were visible. During the agricultural era (1800–1940) the area of mangroves declined 45%. As the economy changed to industrial in the late 1940s the area of mangrove increase due to reduced land use pressure on the wetlands. Nevertheless, urban expansion between 1960s and 1970s produced another decline. Public concern for mangrove conservation resulted in the legal protection of all the mangroves in 1972, and since then their area has expanded. We found that past human activity altered the original proportion of mangrove species. The number and size of mangrove-forest fragments was impacted by land use, and urban areas had fewer and smaller fragments than vegetated areas. Uncontrolled expansion of urban areas emerged as a major threat to mangrove conservation. Mangroves are resilient and recover quickly when given an opportunity if the geomorphological and hydrological features of the habitat are not changed by their use. The key to conservation appears to be a combination of the type of human activity in mangrove watersheds combined with strong legal protection. The following steps are recommended: (1) identify the areas that satisfy the ecological requirements of mangrove development; (2) incorporate better zoning regulations to maintain these areas natural and to protect the fluxes of water, nutrients, and organisms in and out of the system; and (3) monitor results.     

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。     

Restoration of the mangrove vegetation in the Mahanadi delta,Orissa, India

In India, mangroves occupy 6740 km² of which the Mahanadi delta andBhitarkanika mangrove forests of Orissa cover 191.44 km², most of whichhas been severely overexploited. World wide concern to conserve mangrovesnecessitated propagation of mangroves to re-establish them on barren andswampy land along tidal creeks around Paradeep port of Orissa. Avicenniaofficinalis, Aegiceras corniculatum, Bruguiera parviflora, B. sexangula,Ceriops decandra, Excoecaria agallocha, Heritiera fomes, Kandelia candel,Rhizophora mucronata, Sonneratia apetala were vegetatively propagated andplanted over 10 ha of degraded salt-marshy wetlands of Mahanadi delta inpure and mixed stands depending on the intensity and the frequency of tidalinundation at the experimental site. Survival was significantly higher(80%) in S. apetala followed by A. officinalis, R. mucronata, K.candel and H. fomes (70–75%). S. apetala recorded the maximumgrowth in height (3.0 m after 2 years) whereas C. decandra showed theminimum growth (0.5 m). Growth performance was better with plants in mixedstands than the plantation with single species. This gives us hope topropagate and re-establish mangroves for conservation in scientificallymanaged plantations in a physiologically arid environment.     

Sap flow characteristics of neotropical mangroves in flooded and drained soils

Effects of flooding on water transport in mangroves have previously been investigated in a few studies, most of which were conducted on seedlings in controlled settings. In this study, we used heat-dissipation sap probes to determine if sap flow (J(s)) attenuates with radial depth into the xylem of mature trees of three south Florida mangrove species growing in Rookery Bay. This was accomplished by inserting sap probes at multiple depths and monitoring diurnal flow. For most species and diameter size class combinations tested, J(s) decreased dramatically beyond a radial depth of 2 or 4 cm, with little sap flow beyond a depth of 6 cm. Mean J(s) was reduced on average by 20% in Avicennia germinans (L.) Stearn, Laguncularia racemosa (L.) Gaertn. f. and Rhizophora mangle L. trees when soils were flooded. Species differences were highly significant, with L. racemosa having the greatest midday J(s) of about 26 g H(2)O m(-2) s(-1) at a radial depth of 2 cm compared with a mean for the other two species of about 15 g H(2)O m(-2) s(-1). Sap flow at a depth of 2 cm in mangroves was commensurate with rates reported for other forested wetland tree species. We conclude that: (1) early spring flooding of basin mangrove forests causes reductions in sap flow in mature mangrove trees; (2) the sharp attenuations in J(s) along the radial profile have implications for understanding whole-tree water use strategies by mangrove forests; and (3) regardless of flood state, individual mangrove tree water use follows leaf-level mechanisms in being conservative.