Wetland Development Research Articles

Environmental context for late Holocene human occupation of the South Wellesley Archipelago, Gulf of Carpentaria, northern Australia

A 2400 year record of environmental change is reported from a wetland on Bentinck Island in the southern Gulf of Carpentaria, northern Australia. Three phases of wetland development are identified, with a protected coastal setting from ca. 2400 to 500 years ago, transitioning into an estuarine mangrove forest from ca. 500 years ago to the 1940s, and finally to a freshwater swamp over the past +60 years. This sequence reflects the influence of falling sea-levels, development of a coastal dune barrier system, prograding shorelines, and an extreme storm (cyclone) event. In addition, there is clear evidence of the impacts that human abandonment and resettlement have on the island's fire regimes and vegetation. A dramatic increase in burning and vegetation thickening was observed after the cessation of traditional Indigenous Kaiadilt fire management practices in the 1940s, and was then reversed when people returned to the island in the 1980s. In terms of the longer context for human occupation of the South Wellesley Archipelago, it is apparent that the mangrove phase provided a stable and productive environment that was conducive for human settlement of this region over the past 1000 years.

A deadly cocktail: How a drought around 4200 cal. yr BP caused mass mortality events at the infamous ‘dodo swamp’ in Mauritius

Analyses of pollen, diatoms, XRF geochemistry, and pigments provide a unique window into how an insular ecosystem in Mauritius responded to an extreme drought event 4200 years ago. We provide a reconstruction of regional vegetation change and local wetland development under influence of sea level rise and inferred climate change between 4400 and 4100 cal. yr BP. Our multi-proxy data evidence a severe drought between 4190 and 4130 cal. yr BP, which ultimately led to mass mortality of larger vertebrates, including two species of giant tortoises and dodos in a <2-ha region. This prolonged drought around the Indian Ocean is recorded in many regions dependent on monsoon precipitation and is suggested to cause the collapse of human societies in East Africa and India. We demonstrate a direct relation between the mass mortality events in the Mare aux Songes (MAS) rock valley and the 4200 cal. yr BP drought. MAS represents a fresh water source that attracted and concentrated vertebrates. Abrupt increased aridity induced regional fires on Mauritius and caused decreased water levels, and a shrinking water surface resulting in further concentration of the animals in this coastal site. Upconing of the saline wedge underlying the fresh water source induced progressive salinization. The excrements of the animals produced hypertrophic conditions that, combined with salinization and high temperatures, created a suitable environment for potentially toxic cyanobacteria. These factors led to a deadly cocktail, resulting in the death of 100,000s of vertebrates by intoxication, dehydration, trampling, and miring, and promoted a unique conservation of fossils. The ‘4.2 ka megadrought’ likely induced similar bottlenecks elsewhere in the SW Indian Ocean region.

A Novel Protection and Utilization Pattern for Urban Wetland—As an Example of Hemu Wetland in Hangzhou, China

This paper proposes an innovative plan and its implement strategy of Hemu urban wetland. The plan takes into consideration its historical background and current status, its protection significance, strategies, solutions and support conditions. It highlights the landscape characteristics of rivers and lakes, and restores its historical flood prevention functions and climate regulation for the city. Especially, this paper proposes to achieve the restoration of “Mulberry-sided Fish Pond” farming style—an important agricultural heritage created by the ancestors inside the wetland, which is a unique and creative way to use low land for ecological agriculture and cycling economy. The proposed wetland sewage treatment schemes would be of practical importance to improve and enhance the ecological environment and promote the construction of ecological civilization in the region. The “Two zones—One block and Three complexes” protection and utilization plan is reasonable and feasible. It fully presents the functions of the wetland for its production, living, life forms and ecology, and is characterized by joint protection of the wetland by original residents and social public. This will result in active, instead of passive, wetland protection, like turning a “blood transfusion protection” to “hematopoietic protection”, which reflects the sustainable development. The paper offers valuable information and strategies for planning and development of urban wetland.

American energy, imperiled coast: oil and gas development in Louisiana's wetlands

American energy, imperiled coast: oil and gas development in Louisiana's wetlands

The Tourism Development Study of Desert, Wetland and Oasis Composite Resources — Taking an Example of Na Lin Tao Hai Farm

Wetland is the precious wealth of human beings .The positive value of the desert began to gain social acceptance, and gradually become a new experience and spa tourism resources. Society needs an effective and systematic tourism development model .Through the field investigation and grade evaluation method, the Na Lin Tao Hai farm local in Inner Mongolia has a unique desert, wetland and oasis composite resources that belongs to the secondary tourism resources .The tourism development of Na Lin Tao Hai farm need to get rid of the traditional wetland and desert development mode, make full use of the special value of the composite resources. Planners should discover farming culture, nomadic culture and water culture, and build a unique tourism development path that natural ecology, culture and social form a harmonious unified system.

Analysis of landscape fragmentation processes and driving forces in wetlands in arid areas: A case study of the middle reaches of the Heihe River, China

Landscape fragmentation in wetlands usually implies degradation of its ecological functions. Landscape fragmentation divides wetlands into isolated islands, which disturbs the energy flow and nutrient cycling within the wetland. Research into the development and causes of landscape fragmentation in wetlands is urgently needed for effective monitoring and protection of wetlands. We use a combination of techniques including remote sensing, a landscape index model, and redundancy analysis to analyze landscape fragmentation and its driving forces in the middle reaches of the Heihe River from both temporal and spatial perspectives. A new mathematic morphological method that enhances the credibility of landscape fragmentation analysis without changing the original pixel size of the interpreted data is proposed for the calculation of landscape indices. The combination of this new mathematic morphological method and traditional landscape pattern indices enhances the evaluation strategy for landscape fragmentation. Our results demonstrate that the fragmentation processes that affect the wetland landscape of the study area are primarily represented as the shrinking of core wetland area and decrease in mean size of wetland patches. Our results also show an increase in the fragmentation index (FS) of the landscape in recent decades. The impacts of natural factors on wetland landscape fragmentation processes are typically reflected in changes in climate and hydrology. In the study area, temperature, which is more important than precipitation in driving wetland landscape fragmentation processes, cannot be omitted. In addition, our analysis proves that unnecessary human activity is a major threat for sustainable development and maintenance of wetlands.

강원도 인제터널 구간의 지형발달에 관한 연구-습지발달을 중심으로

강원도 인제터널 구간의 지형발달에 관한 연구-습지발달을 중심으로

A seasonality trigger for carbon injection at the Paleocene–Eocene Thermal Maximum

Abstract. The Paleocene–Eocene Thermal Maximum (PETM) represents a ~170 kyr episode of anomalous global warmth ~56 Ma ago. The PETM is associated with rapid and massive injections of 13C-depleted carbon into the ocean–atmosphere system reflected as a prominent negative carbon isotope excursion (CIE) in sedimentary components. Earth's surface and deep ocean waters warmed by ~5 °C, of which part may have occurred prior to the CIE. However, few records document continental climatic trends and changes in seasonality have not been documented. Here we present the first high-resolution vegetation and paleoclimate reconstructions for the PETM, based on nearest living relative analysis of terrestrially derived spore and pollen assemblages preserved in an expanded section from the central North Sea. Our data indicate reductions in boreal conifers and an increase in mesothermal to megathermal taxa, reflecting a shift towards wetter and warmer climate. We also record an increase in summer temperatures, greater in magnitude than the rise in mean annual temperature changes, and a shift to a summer-wet seasonality. Within the CIE, vegetation varies significantly with initial increases in epiphytic and climbing ferns, and development of extensive wetlands, followed by abundance of Carya spp. indicative of broadleaf forest colonization. Critically, the change in vegetation we report occurs prior to the CIE, and is concomitant with anomalous marine ecological change, as represented by the occurrence of Apectodinium augustum. This suggests that amplifications of seasonal extremes triggered carbon injection.

Holocene floodplain palaeoecology of the Humberhead Levels; implications for regional wetland development

The acquisition of high quality, well-dated local site records is essential for progressing regional environmental reconstructions. As part of a wider study designed to examine intra- and extra- site ecosystem responses to environmental change, this paper presents new palaeoecological data from the floodplain of the River Torne in the Humberhead Levels, South Yorkshire. The sampling site lies adjacent to the lowland raised mire of Hatfield Moors, a location with a long history of palaeoecological investigations. The potential of using floodplain records to reconstruct local variations in ecosystem response to environmental change is also considered. Coleoptera and pollen are used to reconstruct floodplain ecosystem dynamics, whilst chronologies are established using Bayesian age–depth modelling. Between 10,200 cal BP and 2300 cal BP, the floodplain experienced multiple phases of ecological change. At 10,200–9910 cal BP, a cut-off channel began to infill with peat, while the surrounding floodplain remained relatively dry with Pinus forest growing nearby. Between 9630–9500 cal BP and 7270–7020 cal BP, a depositional hiatus occurred in the sedimentary record. By the end of this period, the local woodland had diversified and expanded to mixed deciduous tree cover. A wet shift identified at 6870–6160 cal BP was shortly followed by a rise in Alnus and Tilia from 6410–6160 cal BP. At this time, widespread floodplain paludification had occurred in the Humberhead Levels, which was largely controlled by relative sea-level (RSL) rise and the associated rise in regional water tables. Floodplain expansion also resulted in the widespread occurrence of Alnus dominated fen woodland. The local Torne floodplain experienced varying levels of wetness that influenced the decline and subsequent regeneration of the woodland from 5870–5640 cal BP. At this time, the Ulmus decline is identified in the pollen stratigraphic record. Floodplain hydrology appears to have been controlled by a combination of water table fluctuations and changes in channel pattern/flow, both of which can be linked to RSL variations recorded in the Humber Estuary. Floodplain alluviation, also linked to rising water tables, is dated to 4360–4160 cal BP. Anthropogenic woodland clearance further upstream may have further compounded this event.

Holocene changes in African vegetation: tradeoff between climate and water availability

Abstract. Although past climate change is well documented in West Africa through instrumental records, modeling activities, and paleo-data, little is known about regional-scale ecosystem vulnerability and long-term impacts of climate on plant distribution and biodiversity. Here we use paleohydrological and paleobotanical data to discuss the relation between available surface water, monsoon rainfall and vegetation distribution in West Africa during the Holocene. The individual patterns of plant migration or community shifts in latitude are explained by differences among tolerance limits of species to rainfall amount and seasonality. Using the probability density function methodology, we show here that the widespread development of lakes, wetlands and rivers at the time of the "Green Sahara" played an additional role in forming a network of topographically defined water availability, allowing for tropical plants to migrate north from 15 to 24° N (reached ca. 9 cal ka BP). The analysis of the spatio–temporal changes in biodiversity, through both pollen occurrence and richness, shows that the core of the tropical rainbelt associated with the Intertropical Convergence Zone was centered at 15–20° N during the early Holocene wet period, with comparatively drier/more seasonal climate conditions south of 15° N.

青藏高原东北部5000年来气候变化与若尔盖湿地历史生态学研究进展

PDF HTML阅读 XML下载 导出引用 引用提醒 青藏高原东北部5000年来气候变化与若尔盖湿地历史生态学研究进展 DOI: 10.5846/stxb201308052023 作者: 作者单位: 中国科学院成都生物研究所;中国科学院若尔盖泥炭与全球变化研究站,中国科学院成都生物研究所;中国科学院若尔盖泥炭与全球变化研究站; 国际山地综合发展中心,西北农林科技大学;中国科学院若尔盖泥炭与全球变化研究站,中国科学院成都生物研究所,中国科学院成都生物研究所,西北农林科技大学,中国科学院若尔盖泥炭与全球变化研究站,中国科学院成都山地灾害与环境研究所,中国科学院成都生物研究所 作者简介: 通讯作者: 中图分类号: 基金项目: 国际科技合作项目（S2013GI0408）；国家青年自然科学基金（31100348）；教育部新世纪优秀人才支持计划（NCET-12-0477）；教育部高等学校博士学科点专项科研基金（20120204110011） The 5000-year climate change of northeastern Qinghai-Tibetan Plateau and historical ecology of Zoige wetlands Author: Affiliation: Chengdu Institute of Biology, CAS;Zoige Peatland and Global Change Research Station, CAS,,,Chengdu Institute of Biology, CAS;Zoige Peatland and Global Change Research Station, CAS,,,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:全球变化背景下古气候学的研究越来越受到关注。利用多年来的文献记载和自然证据，对青藏高原东北部气候变化进行重建。并以若尔盖湿地为例，梳理了区域5000 a来气候变化对湿地植被类型、泥炭沼泽发育和文化发展产生的影响，探讨了气候变化、文化发展、沼泽发育三者之间可能具有的相互关系。指出青藏高原东北部5000-3000 a B.P.之间气候较为暖湿，其平均温度要高出现在2 ℃左右；3000 a B.P.至今为气候干冷期，其中1000 a B.P.左右是过去5000 a中最寒冷时期，近1000 a来气温呈缓慢回升趋势。区域的气候变化决定了植被类型，对泥炭沼泽的形成和发育发挥了重要作用，对文明进程的影响主要体现在气候变化通过影响沼泽的演替，从而改变人类活动的范围与早期文明的形成，同时人类的过度活动也在一定程度上影响了沼泽的分布格局及动态。但气候变化、沼泽发育和文化发展三者之间的关系有赖于多因素耦合，其具体机理有待更深入的研究。 Abstract:Paleoclimatology is attached more and more importance by climate and ecological scientists. As the strengthening of the monsoon activity, the middle Holocene (6.0-5.0ka B.P.) became an important reference era of Paleoclimate Modeling Intercomparison Project (PMIP). In addition, the northeastern Qinghai-Tibetan Plateau was focused by its climatic sensibility and ecological vulnerability. In this paper, we used the data from Qinghai Lake, Zoige plateau and the source area of Yellow River to present the trends of 5000-year climate change on northeastern Qinghai-Tibetan Plateau. Then taking Zoige wetlands as an example, we reviewed studies about the impact of climate change on vegetation types, peat development and civilization evolution, and discussed the possible interaction among them. According to our analyses, the climate on the northeastern Qinghai-Tibetan Plateau was warm and humid from 5.0 to 3.0 ka B.P., with an average temperature 2℃ higher than the present. In this period, the dominant macrophanerophyte was mainly coniferous tree and the major herbage type was sedge. Moreover, thick peat accumulation was found due to the warm and humid climate. However, the climate turned into dry and cold since then to 1.0 ka B.P., with an extremely cold event around 1ka B.P.. The coniferous forest had been shrinking from highland to lowland because of fading Indian monsoon, wetlands developed very slowly and the civilization was also influenced. Meanwhile, human activities also slightly limited the development of wetlands due to the increasing population of Di-Qiang ancient people. We deduced that there existed a roughly synchronous resonance between climate change and the phenomenon of nomad migrated southward or eastward periodically. It is worth mentioning that Medieval Warm Period was observed in this era, following the prosperity of The tea-horse trade and the appearance of agricultural production by Uigur in Gansu Corridor. In recent 1000 years, due to the relatively warming climate, though not very steady, the coniferous forest and the wetland developed slightly again. In recent 100 years, the abrupt warming was introduced by increasing GHGs, the precipitation was decreased relatively. The area of Zoige wetlands decreased by a half due to drainage from 60s to the early 80s, then the shrinkage of wetlands was mainly due to climate warming, especially the abrupt warming of recent ten years. In short, the regional climate change determined vegetation types and affected the formation and development of wetlands. Climate change also impacted civilization, which altered the scope of human activity and early establishment of civilization. Meanwhile, human activities also affected the distribution and dynamics of wetlands. The interaction among climate change, wetland development and civilization course, however, depend on coupling of different factors. Furthermore, it is urgent to carry out researches about integrated adaptation and related technology on alpine's ecosystem to mitigate the climate change, as well as establishing a sustainable management system of Qinghai-Tibetan Plateau. 参考文献 相似文献 引证文献

Regulatory Safeguards for Accountable Ecosystem Service Markets in Wetlands Development

The use of environmental markets creates the potential for achieving environmental protection goals more efficiently than traditional regulation is capable of doing. Past experience with emissions trading programs and other forms of environmental markets that operate in conjunction with traditional regulatory programs, however, illustrates the risks that accompany reliance on market-based strategies. In particular, participants in environmental regulatory markets have in some instances manipulated them to enhance private gain while undercutting public environmental objectives. Using the wetlands mitigation component of the federal Clean Water Act’s dredge and fill permit program as an example, this essay recommends that market-based environmental programs incorporate five different types of safeguards to promote the accountability of both market participants and the agencies supervising the operation of those programs. Reliance on financial safeguards, verifiable performance standards, transparency and public participation safeguards, oversight mechanisms such as monitoring and inspections, and rule of law safeguards can preserve opportunities for efficient achievement of environmental protection goals while reducing the risk that markets will be used to subvert those goals.

Artificial neural network simulation of ground water levels in uplands of a coastal tropical riparian

Wetlands play an important role in the ecological balance of the coastal region. Understanding groundwater level behaviour in uplands is important for the management and the development of coastal tropical riparian wetland. Artificial Neural Networks has proved to be robust techniques in modeling and prediction of hydrological processes. This paper presents the application of ANNs to model groundwater levels in uplands around a wetland environment. Weekly hydro meteorological observations have been used as an input to model groundwater fluctuation observed in sevel open wells in the region. A comparison of different training algorithms has also been carried out. The results obtained show that the use of Artificial Neural Networks in modeling the groundwater levels was successful. With Root Mean Square Error values in the range of 0.09 to 0.16, the study also reasserts that the same training algorithm need not provide the best results for different conditions. Key words: Artificial neural networks, wetlands, stepwise linear regression.

Late-Glacial and Holocene Environmental History of an Oxbow Wetland in the Polabí Lowland (River Elbe, Czech Republic); a Context-Dependent Interpretation of a Multi-Proxy Analysis

This study presents a palaeoenvironmental reconstruction of an oxbow wetland covering the past 11,500 years. The origin of the oxbow lake and development of the floodplain wetland and changes of the surrounding vegetation are reconstructed using palaeobotanical analyses, radiocarbon dating, detailed sediment stratigraphy and micromorphology of samples taken from a former palaeomeander of the river Elbe in the Czech Republic. The sedimentary record of the section Chrast was chosen due to its exceptional position within the area of former oxbow lakes. Using a multi-proxy approach, we investigated how this environment reflected climatic changes during the Holocene. Our results show that the Chrast section covers the Late-Glacial to the Middle Holocene period, which is climatically very unstable and characterized by extensive vegetation and sedimentological changes. The macrofossil record provides detailed evidence of Allerod vegetation. The sedimentological record reflects changes in fluvial activity (meandering-braided transition in the channel pattern) during Late-Glacial/Holocene and postsedimentological changes (occurrence of a doplerite layer) in the middle Holocene. We follow three independent lines of interpretation: (a) a local autogenic environmental-succession process, (b) a regional process driven by climate change, and (c) the role of stochastic and indeterministic processes.

Integrating ecosystem services and climate change responses in coastal wetlands development plans for Bangladesh

This study explores the integration of ecosystem services and climate change adaptation in development plans for coastal wetlands in Bangladesh. A new response framework for adaptation is proposed, based on an empirical analysis and consultations with stakeholders, using a modified version of the DPSIR (Driver-Pressure-State-Impact- Response) framework. The framework is tested in the Narail district of Bangladesh, where temperature has increased by about 1 °C in the summer in combination with an increase in rainfall of 0.70 mm day −1 yr −1 in the last decade. Calibrated model (MAGICC/SENGEN) projections forecast, on average, a temperature increase of up to 5 °C and an increase in rainfall of 25 % by the end of this century. Water diversion in the upstream regions of the Ganges River delta contributes to increase water scarcity in the dry season. Enhanced rainfall and the immense pressure of water discharges from upstream water sources are increasing the risk of floods and river erosion in thedry season. Anincrease in thewater holding capacity of rivers, wetlandsand canals by dredging is urgently required. The empirical model ofthisstudy isintended tosupport adaptation planning and monitoring in Bangladesh and can be used in other data-poor areas which will suffer from climate change.

Mosquitofish dominate amphibian and invertebrate community development in experimental wetlands

Summary Restored and constructed habitats can play important conservation roles. Predators help shape communities in these habitats through complex interactions with prey, other predators and biotic and abiotic characteristics of the environment. However, introduced predators can have dramatic effects that may be difficult to predict. Using regression models, we compared influences of introduced invasive western mosquitofish Gambusia affinis to those of two naturally colonizing predators (crayfish and dragonflies), and vegetation, on three anuran species in experimentally constructed wetlands. Using analyses of covariance, we also examined influences of mosquitofish and vegetation on aquatic invertebrate communities. We found that mosquitofish reduced abundances of grey treefrogs Hyla versicolor and H. chrysoscelis and boreal chorus frog Pseudacris maculata, but had no significant influence on green frog Lithobates clamitans. Mosquitofish also reduced invertebrate abundance, but their effect on richness was less clear. Vegetation cover did not significantly increase most anuran or invertebrate abundances. However, vegetation increased invertebrate richness. After fish removal, invertebrate abundance increased. Fish removal may have facilitated chorus frog re‐colonization into wetlands with low abundance of invertebrate predators. Our results indicate that mosquitofish are detrimental to wetland communities, and we recommend that managers avoid stocking mosquitofish. We also encourage temporary or drainable wetlands to prevent mosquitofish persistence if colonization occurs. Implementing these recommendations will improve the conservation potential of restored wetlands.

Food web structure in oil sands reclaimed wetlands

Boreal wetlands play an important role in global carbon balance. However, their ecosystem function is threatened by direct anthropogenic disturbance and climate change. Oil sands surface mining in the boreal regions of Western Canada denudes tracts of land of organic materials, leaves large areas in need of reclamation, and generates considerable quantities of extraction process-affected materials. Knowledge and validation of reclamation techniques that lead to self-sustaining wetlands has lagged behind development of protocols for reclaiming terrestrial systems. It is important to know whether wetlands reclaimed with oil sands process materials can be restored to levels equivalent to their original ecosystem function. We approached this question by assessing carbon flows and food web structure in naturally formed and oil sands-affected wetlands constructed in 1970-2004 in the postmining landscape. We evaluated whether a prescribed reclamation strategy, involving organic matter amendment, accelerated reclaimed wetland development, leading to wetlands that were more similar to their natural marsh counterparts than wetlands that were not supplemented with organic matter. We measured compartment standing stocks for bacterioplankton, microbial biofilm, macrophytes, detritus, and zoobenthos; concentrations of dissolved organic carbon and residual naphthenic acids; and microbial production, gas fluxes, and aquatic-terrestrial exports (i.e., aquatic insect emergence). The total biomass of several biotic compartments differed significantly between oil sands and reference wetlands. Submerged macrophyte biomass, macroinvertebrate trophic diversity, and predator biomass and richness were lower in oil sands-affected wetlands than in reference wetlands. There was insufficient evidence to conclude that wetland age and wetland amendment with peat-mineral mix mitigate effects of oil sands waste materials on the fully aquatic biota. Although high variability was observed within most compartments, our data show that 20-year-old wetlands containing oil sands material have not yet reached the same level of function as their reference counterparts.

Spatial-temporal analysis of wetland landscape pattern under the influence of artificial dykes in the Yellow River delta

he influence of anthropogenic activities, especially artificial dykes, on the coastal wetland landscape is now considered as a serious problem to the coastal ecosystem. It is important and necessary to analyze changes of coastal landscape pattern under the influence of artificial dykes for the protection and management of coastal wetland. Our study aimed to reveal the quantitative characteristics of the coastal wetland landscape and its spatial-temporal dynamics under the influence of artificial dykes in the Yellow River delta (YRD). It was analyzed by the methods of the statistical analysis of landscape structure, five selected landscape indices and the changes of spatial centroids of three typical wetland types, including reed marshes, tidal flats and aquaculture-salt fields. The results showed that: (1) Reduction of wetland area, especially the degradation of natural wetlands, had been the principal problem since the dykes were constructed in the YRD. The dykes created conditions for the development of artificial wetlands. However, the new born artificial wetlands were still less than the vanished natural wetlands. (2) Compared with the open area, the building of artificial dykes significantly speeded up the changes of landscape patterns and the aggravation of the landscape fragmentation in the closed area. (3) The changes of area-weighted centroids of three typical wetland landscapes were greatly affected by dykes, and the movement of the centroid of the aquaculture-salt field was very sensitive to the dykes constructed in the corresponding period.

地形因子对盐城滨海湿地景观分布与演变的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 地形因子对盐城滨海湿地景观分布与演变的影响 DOI: 10.5846/stxb201211121591 作者: 作者单位: 南京师范大学地理科学学院,南京师范大学地理科学学院,南京师范大学地理科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目(41071119);江苏省高校自然科学研究重大项目(10KJA170029);江苏省省属高校自然科学研究项目(12KJB170006) Influences of topographic features on the distribution and evolution of landscape in the coastal wetland of Yancheng Author: Affiliation: College of Geography,Nanjing Normal University,College of Geography,Nanjing Normal University,College of Geography,Nanjing Normal University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:地形作为景观结构和空间格局的重要影响因子,不仅为景观格局的形成提供基础,其空间特征也影响着景观的演变过程。基于2002、2011年地形高程信息和遥感影像,运用GIS技术,并结合分布指数,分析了盐城滨海湿地景观分布与演变对地形因子的响应特征。结果表明:①盐城淤泥质滨海湿地总体地形变化平缓,海拔0-2.5m的区域占整个研究区面积的97%以上。其中,米草带主要分布于0.9-1.5m,碱蓬带主要分布于1.5-2.1m,而芦苇带则主要分布于2.1-2.7m。②2002-2011年9年间湿地景观时间变化明显,其中,芦苇面积增加了3倍,碱蓬面积由26.80%骤降至11.51%,同期,米草面积则增加了50%之多。③湿地景观空间分布特征与地形关系比较明显。其中,米草空间分布向0.6-1.2m区间演变,显示出强烈的向低海拔区间扩张的趋势;碱蓬分布范围随地形的升高总体上呈下降趋势;芦苇在地形较高区间上的分布指数增长迅速,其优势分布区间向2.1-3.0m扩展。 Abstract:Wetland ecosystems are landscapes of the highest biodiversity in nature and one of the most important environmental resources for human welfares. Their important ecosystem function has led to them been sometimes called "the earth's filtration system". Yancheng coastal wetland is one of the biggest mudflats in China, and play a important role in protecting wetland biodiversity and adjusting regional climate. Owing to the irrational exploitation in recent years, Yancheng coastal wetland are experiencing significant landscape changes, which has aroused a lot of attention by experts and scholars. Terrain, which serves as an important factor of landscape structure and spatial pattern, not only provides a basis for the formation of landscape pattern, but also affect the evolution of landscape. Yancheng coastal wetland is one of the typical primitive wetlands. In the past, limited to the wetland's objective conditions, there has been no complete height measurement for Yancheng coastal wetland, which makes terrain's study become "the blank area of the wetland". As the result, Yancheng coastal wetland was chosen as the study area in this study. Based on the remote sensing images of 2002 and 2011, using GIS techniques and methods of landscape ecology and combining distribution index, we analyze the relationship between landscape types and terrain factors and reveal the response characteristics of terrain factors on the distribution and evolution of Yancheng coastal wetland landscape. The information about spatial distribution of landscape types in Yancheng was obtained through overlay analysis of the terrain factors derived from DEM and the landscape types in different periods based on Arcgis by using the remote sensing images.The result shows that: (1) The overall terrain of Yancheng coastal wetlands changes gently, of which altitude 0-2.5m region accounts for more than 97%. Spartina wetland mainly distributes in 0.9-1.5m, Suaeda wetland mainly distributes in 1.5-2.1m, and Reed wetland in the 2.1-2.7m.(2) During 2002-2011, the time of 9a wetland landscape changes obviously, in which the Reed wetland increases by 3 times, the Suaeda wetland plunges by 26.80% to 11.51%, and at the same period, the Spartina wetland increases by more than 50%.(3) It is found that the topographic distribution pattern of each landscape type also displays the corresponding change based on the statistical analysis on the relationships between the landscape type and the terrain index. Through the analysis, we found that the relationship between the characteristics of wetland landscape spatial distribution and the topography is more obvious. Where the space distribution of Spartina wetland space evolving at the range of 0.6-1.2m, shows strong expansion trend to low altitude interval. At the same time, with terrain increasing, Suaeda wetland distribution range shows downward trend generally. In the higher terrain, the distribution index of Reed wetland rapidly, whose advantage distribution range is extended to 2.1-3.0m. By revealing the terrain and landscape distribution relationship, we can not only provide the basic data for the sustainable exploitation and scientific management of the Yancheng coastal wetlands, but also achieve social and economic sustainable development in the Yancheng coastal wetlands. 参考文献 相似文献 引证文献

Development of temporary subtropical wetlands induces higher gas production

Temporary wetlands are short-term alternative ecosystems formed by flooding for irrigation of areas used for rice farming. The goal of this study is to describe the development cycle of rice fields as temporary wetlands in southern Brazil, evaluating how this process affect the gas production (CH4 and CO2) in soil with difference % carbon and organic matter content. Two areas adjacent to Lake Mangueira in southern Brazil were used during a rice-farming cycle. One area had soil containing 1.1% carbon and 2.4% organic matter, and the second area had soil with 2.4% carbon and 4.4% organic matter. The mean rates of gas production were 0.04 ± 0.02 mg CH4 m−2 d−1 and 1.18 ± 0.30 mg CO2 m−2 d−1 in the soil area with the lower carbon content, and 0.02 ± 0.03 mg CH4 m−2 d−1 and 1.38 ± 0.41 mg CO2 m−2 d−1 in the soil area with higher carbon content. Our results showed that mean rates of CO2 production were higher than those of CH4 in both areas. No statistically significant difference was observed for production of CH4 considering different periods and sites. For carbon dioxide (CO2), however, a Two-Way ANOVA showed statistically significant difference (p = 0.05) considering sampling time, but no difference between areas. The results obtained suggest that the carbon and organic matter contents in the soil of irrigated rice cultivation areas may have been used in different ways by soil microorganisms, leading to variations in CH4 and CO2 production.