Survey on Bio-resources of Zhengzhou Yellow River Wetland and Protective Measures

Upon the basis of comprehensive survey on the bio-resources of Zhengzhou Yellow River Wetland Nature Reserve,we analyzed the relationship between wetland ecology and bio-resource protection,the problems encountering wetland development and protection,and further put forward corresponding protective measures.

Effect of Different Land Use Patterns on Physical Properties of Soil Water in Yellow River Wetland in Shaanxi Province

[Objective] This study was to reveal the effect of different land use patterns on physical characteristics of soil water in the Yellow River wetland in Shaanxi Province.[Method]Taking Yellow River wetland in Shaanxi Province as experimental plot,we compared the physical properties of the soil water under different land use patterns and studied the physical properties and the change law of soil water during the wetland degeneration process.[Result]Under different land use patterns,soil bulk density rose with the increase of soil depth.During the degeneration process of from river wetland to reclaimed wetland（paddy field）,finally to abandoned land owing to salinization,the mean soil bulk density reduced correspondingly from 1.474 to 1.522 g/cm3,finally to 1.593 g/cm3 when abandoned.Accompanying wetland degeneration,soil became compact increasingly,and the indicators of soil porosity（total porosity,capillary porosity,non-capillary porosity）were also reduced with the change of land use patterns,in which,capillary porosity and total porosity reached the extremely significant level with the change of land use patterns,and non-capillary porosity reached significant level.The changes of soil porosity condition accelerated the deterioration of wetland.Under different land use patterns,the maximum soil moisture capacity,capillary moisture capacity and minimum moisture capacity all showed a similar change law.Compared with wetland,the maximum soil moisture capacity of reclaimed land（paddy field）and salinized land respectively decreased by 5.7% and 22.3%,capillary moisture capacity by 0.2% and 19.4%,minimum moisture capacity by 2.7% and 15.9%.Of the three land use patterns,wetland displayed both higher water holding capacity and water drainage capacity over reclaimed land（paddy field）and salinized land.By comparison with wetland,the reclaimed land（paddy field）and salinized land respectively decreased by 12.4% and 15.2% in total water holding capacity,and by 2.7% and 15.9% in total water drainage capacity.[Conclusion]To conserve the water resource in Yellow River wetland,regulate the hydrological cycle and enhance drought and water logging resistances,it should be noted that reasonable countermeasures be taken to exploit the state-owned forest land and paddy field around the wetland and the related resources.

Occurrence,Spatial Distribution,Sources and Risk Assessment of Per-and Polyfluoroalkyl Substances in Surface Sediments of the Yellow River Delta Wetland

Per-and polyfluoroalkyl substances(PFASs)are emerging persistent organic pollutants(POPs).In this study,47 surface sediment samples were collected from the Yellow River Delta wetland(YRDW)to investigate the occurrence,spatial distribution,potential sources,and ecological risks of PFASs.Twenty-three out of 26 targeted PFASs were detected in surface sediment samples from the YRDW,with totalΣ23PFASs concentrations ranging from 0.23 to 16.30 ng g^(-1) dw and a median value of 2.27 ng g^(-1) dw.Perfluorooctanoic acid(PFOA),perfluorobutanoic acid(PFBA)and perfluorooctanesulfonic acid(PFOS)were the main contaminants.The detection frequency and concentration of perfluoroalkyl carboxylic acids(PFCAs)were higher than those of perfluoroal-kanesulfonic acids(PFSAs),while those of long-chain PFASs were higher than those of short-chain PFASs.The emerging PFASs substitutes were dominated by 6:2 chlorinated polyfluoroalkyl ether sulfonic acid(6:2 Cl-PFESA).The distribution of PFASs is significantly influenced by the total organic carbon content in the sediments.The concentration of PFASs seems to be related to human activities,with high concentration levels of PFASs near locations such as beaches and villages.By using a positive matrix factorization model,the potential sources of PFASs in the region were identified as metal plating mist inhibitor and fluoropolymer manufacturing sources,metal plating industry and firefighting foam and textile treatment sources,and food packaging material sources.The risk assessment indicated that PFASs in YRDW sediments do not pose a significant ecological risk to benthic organisms in the region overall,but PFOA and PFOS exert a low to moderate risk at individual stations.

Correlation of eco-hydrographic benefit and height increment of Robinia pseudoacacia stand with climatic environmental factors in Yellow River Delta Wetland of China

The relationship between eco-hydrographic benefit of forest vegetation and climatic environmental factors is one of the focuses in the research on environmental protection and ecosystem countermeasures in Wetland. The runoff, sediment and soil moisture rate dynamics in Robinia pseudoacacia plantation and its clearcut area were investigated in the natural runoff experiment plots in Yellow River Delta Wet- land, Shandong Province, China. The correlation of height increment ofR. pseudoacacia with nine climate factors such as light, water, heat, etc. was analyzed by stepwise regression analysis. The results showed that the amounts of runoff and sediment in clearcut area of R. pseudoacacia were 53.9%-150.8% and 172.8%-387.1% higher than that in Robinia pseudoacacia plantation, respectively. The runoff peak value in R. pseudoacacia stand was obviously lower than that in clerarcut area, meantime, the occurrence of runoffpeak in R. pseudoacacia stand was 25 min later than in its clerarcut area. The soil moisture rates in R. pseudoacacia stand and its clearcut varied periodically with annual rainfall precipitation in both dry season and humid season. The annual mean soil moisture rate in R. pseudoacacia stand was 23.3%-25.6% higher than that in its clearcut area. Meanwhile, a regression model reflecting the correlation between the height increment of R. pseudoacacia and climatic factors was developed by stepwise regression procedure method. It showed that the light was the most important factor for the height increment ofR. pseudoacacia, followed by water and heat factors.

Causes of Wetland Degradation and Ecological Restoration in the Yellow River Delta Region

Yellow River delta （YRD） is one of the biggest deltas that there is a large area of wetland in the world. Thanks to soil （sands） sediment carried by the Yellow River, there was averagely the newly formed land 21.3 km^2 in YRD. During the development of petroleum industry and urban expansion, wetlands were degraded due to population growth, irrational land use, in addition to adverse natural eco-environment such as lower precipitation, higher soil evaporation and soil salinazation. The major ecological measures to restore degraded wetland concerned with ensuring water supply, especially establishing perfect irrigation works; protecting virgin plant communities and assisting them to regenerate by the way of site preparation, improving living surroundings; introducing salt-tolerant plants to increase vegetation species and plant coverage, thereby enhancing the capability of wetland to combat contamination and pollution through plant remediation, uptake, absorption, etc. Finally making a comprehensive land use plan, accordingly removing deleterious facilities.

Dynamic Changes in the Wetland Landscape Pattern of the Yellow River Delta from 1976 to 2016 Based on Satellite Data

The Yellow River Delta wetland is the youngest wetland ecosystem in China's warm temperate zone. To better understand how its landscape pattern has changed over time and the underlying factors responsible, this study analyzed the dynamic changes of wetlands using five Landsat series of images, namely MSS(Mulri Spectral Scanner), TM(Thematic Mapper), and OLI(Operational Land Imager) sensors in 1976, 1986, 1996, 2006, and 2016. Object-oriented classification and the combination of spatial and spectral features and both the Normalized Difference Vegetation Index(NDVI) and Normalized Difference Water Index(NDWI), as well as brightness characteristic indices, were used to classify the images in eCognition software. Landscape pattern changes in the Yellow River Delta over the past 40 years were then delineated using transition matrix and landscape index methods. Results show that: 1) from1976 to 2016, the total area of wetlands in the study area decreased from 2594.76 to 2491.79 km^2, while that of natural wetlands decreased by 954.03 km^2 whereas human-made wetlands increased by 851.06 km^2. 2) The transformation of natural wetlands was extensive: 31.34% of those covered by Suaeda heteropteras were transformed into reservoirs and ponds, and 24.71% with Phragmites australis coverage were transformed into dry farmland. Some human-made wetlands were transformed into non-wetlands types: 1.55% of reservoirs and ponds became construction land, and likewise 21.27% were transformed into dry farmland. 3) From 1976 to 2016, as the intensity of human activities increased, the number of landscape types in the study area continuously increased. Patches were scattered and more fragmented. The whole landscape became more complex. In short, over the past 40 years, the wetlands of the Yellow River Delta have been degraded, with the area of natural wetlands substantially reduced. Human activities were the dominant forces driving these changes in the Yellow River Delta.

Changes of Coastal Wetland Ecosystems in the Yellow River Delta and Protection Countermeasures to Them

Coastal wetlands in the Yellow River Delta are typical new wetland ecosystems in warm temperate zone. In recent years, influenced by natural and human factors, these coastal wetlands in the Yellow River Delta have undergone changes of landscape fragmentation, vegetation degradation, pollution, species reduction, and harmful exotic species invasion. These changes have influenced sustainable and healthy development of marine economy of the Yellow River Delta. To protect natural ecological environment of the Yellow River Delta, the authors recommended that it should establish and improve policies, laws and regulations of wetland protection; carry out wetland resource investigation and assessment and monitoring; strengthen comprehensive protection and control of wetland; reduce wetland degradation and promote sustainable use of wetland.

Investigation on Water Pollution of Four Rivers in Coastal Wetland of Yellow River Estuary

[Objective] The study aimed at analysing water pollution of four rivers in coastal wetland of Yellow River estuary. [Method] Taking four seriously polluted rivers (Guangli River, Shenxian Ditch, Tiao River and Chao River) in coastal wetland of Yellow River estuary as study objects, water samples were collected from the four rivers in May (dry period), August (wet period) and November (normal period) in 2009 and 2010 respectively, then pollution indices like nutritive salts, COD, chlorophyll-a, petroleum, etc. were measured. Afterwards, the status quo of water pollution was assessed based on Nemero index and comprehensive trophic level index (TLI), so as to find out the integral status quo of water quality of wetland rivers and damages to aquatic ecological environment. [Result] On the whole, water pollution of four rivers in coastal wetland of Yellow River estuary was serious, in the eutrophication state, and the main pollutants were TN, TP, NH+4-N and petroleum. In addition, excessive N and P in the four rivers resulted in water eutrophication of Bohai Bay, so further leading to ride tide, which destroyed the coastal ecological environment of Bohai Sea. Moreover, compared with historical data, water pollution by nitrogen and phosphorus became more serious, while there was no obvious aggravation in the water pollution by petroleum. In a word, water pollution wasn’t optimistic on the whole. [Conclusion] The research could provide theoretical bases for the protection and utilization of river water in coastal wetland of Yellow River estuary and its coastal sea area.

Stable Carbon Isotope and Long-Chain Alkane Compositions of the Major Plants and Sediment Organic Matter in the Yellow River Estuarine Wetlands

Elemental(TOC,TN,C/N)and stable carbon isotopic(δ^13C)compositions and long-chain alkane(n C16-38)concentrations were measured for eight major plants and a sediment core collected from the Yellow River estuarine wetlands.Our results indicate that both C3(-25.4‰to-29.6‰)and C4(-14.2‰to-15.0‰)plants are growing in the wetlands and C3 plants are the predominant species.The biomass of the wetland plants had similar organic carbon(35.5-45.8%)but very different organic nitrogen(0.35-4.15%)contents.Both C3 and C4 plants all contained long-chain alkanes with strong odd-to-even carbon numbered chain predominance.Phragmites australis,a dominant C3 plant contained mainly n C29 and n C31 homologues.Aeluropus littoralis,an abundant C4 plant were concentrated with n C27 and n C29 homologues.Organic matter preserved in the Yellow River estuarine sediments showed strong terrestrial signals(C/N=11-16,δ^13C=-22.0‰to-24.3‰).The distribution of long-chain n-alkanes in sediments also showed strong odd-to-even carbon chain predominance with n C29 and n C31 being the most abundant homologues.These results suggest that organic matter preserved in the Yellow River estuarine sediments were influenced by the wetland-derived organic matter,mainly C3 plants.The Yellow River estuarine wetland plants could play important role affecting both the carbon and nutrient cycling in the estuary and adjacent coastal waters.

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

The 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 fiats 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.

Estimation on wetland loss and its restoration potential in Modern Yellow River Delta,Shandong Province of China

Wetland is one of the most important ecosystems with varied functions and structures,and its loss has been a major issue.Wetland loss in Modem Yellow River Delta(MYRD) becomes a serious environmental problem,so its restoration attracts a great deal of attention from academia and governments.This article proposes a GIS-based multi-criteria comprehensive evaluation methodology for potential estimation of wetland restoration,using MYRD as an example.The model uses four kinds of data(hydrology,terrain,soil,and land use) and could be adapted by planners for use in identifying the suitability of locations as wetland mitigation sites at any site or region.In the application of the model in the MYRD,the research developed a lost wetland distributed map taking the better wetland situation of 1995 as the reference,and elevated the overall distribution trends of wetland restoration potential based on wetland polygon.The results indicated that the total area of wetland loss from 1995 to 2014 was 568.12 km^2,which includes 188.83 km^2 natural wetland and 21.80 km^2 artificial wetland,respectively.The areas of lost wetland with low,middle,and high resilience ability are 126.82 km^2,259.92 km^2,and 119.59 km^2,occupying 25.05%,51.33%,and 23.62%,respectively.The high-restoration-potential wetland included98.47 km^2 of natural wetland and 21.12 km^2 of artificial wetland,which are mainly bush,reed,and ponds.The highrestoration-potential wetland is mainly distributed in the vicinity of Gudong oil field,the Yellow River Delta protected areas,and the eastern sides of Kenli county and Dongying city.

Analysis of water vapour flux between alpine wetlands underlying surface and atmosphere in the source region of the Yellow River

An underlying wetland surface comprises soil, water and vegetation and is sensitive to local climate change. Analysis of the degree of coupling between wetlands and the atmosphere and a quantitative assessment of how environmental factors influence latent heat flux have considerable scientific significance. Using data from observational tests of the Maduo Observatory of Climate and Environment of the Northwest Institute of Eco-Environment and Resource, CAS, from June 1 to August 31, 2014, this study analysed the time-varying characteristics and causes of the degree of coupling(Ω factor)between alpine wetlands underlying surface and the atmosphere and quantitatively calculated the influences of different environmental factors(solar radiation and vapour pressure deficit) on latent heat flux. The results were as follows:(1) Due to diurnal variations of solar radiation and wind speed, a trend developed where diurnal variations of the Ω factor were small in the morning and large in the evening. Due to the vegetation growing cycle, seasonal variations of the Ω factor present a reverse "U" trend. These trends are similar to the diurnal and seasonal variations of the absolute control exercised by solar radiation over latent heat flux. This conforms to the Omega Theory.(2) The values for average absolute atmospheric factor(surface factor or total) control exercised by solar radiation and water vapour pressure are 0.20(0.02 or 0.22) and 0.005(-0.07 or-0.06) W/(m2·Pa), respectively. Generally speaking, solar radiation and water vapour pressure deficit exert opposite forces on latent heat flux.(3) At the underlying alpine wetland surface, solar radiation primarily influences latent heat flux through its direct effects(atmospheric factor controls). Water vapour pressure deficit primarily influences latent heat flux through its indirect effects(surface factor controls) on changing the surface resistance.(4) The average Ω factor in the underlying alpine wetland surface is high during the vegetation growing season, with a value of 0.38, and the degree of coupling between alpine wetland surface and atmosphere system is low. The actual measurements agree with the Omega Theory. The latent heat flux is mainly influenced by solar radiation.

人为干扰对黄河湿地植物群落的影响及其机制

为了分析人为干扰类型对黄河湿地植物群落的影响差异及相关作用机制,在进行大量实地调查后,选择郑州段3个分别受农业种植、水库修建、建筑施工干扰下的湿地为对象,在对植物群落与相关环境因子指标进行测定后,结合人类压力指标评价体系进行冗余分析。结果表明:研究区湿地植物群落整体表现出明显的退化趋势,维持湿地生产力的内在功能降低;对于不同人为干扰类型下的样地,受到人为干扰的严重程度从大到小依次为建筑施工类干扰、农业种植类干扰、水库修建类干扰;随着人为干扰严重程度的加剧,不同湿地植物群落相似性系数依次下降,鸟类栖息地湿地和太平庄北湿地的物种丰富度指数较桃花峪湿地相比下降程度分别为15.98%和37.05%,整体湿地植物群落构建逐渐趋于简单化;在引起湿地退化的诸多因素中,土壤中铵态氮含量改变对物种多样性指数与物种均匀度指数呈显著负相关,是湿地植物退化的主要原因之一。

黄河三角洲滨海湿地碳储时空演变及其生态补偿研究

近年来随着油气开采、港口建设、填海造陆等活动的开展,黄河三角洲滨海湿地面临生态服务功能降低、碳汇功能受损等问题。为改善黄河三角洲滨海湿地的生态功能及有效利用其碳储功能,研究突破了碳储生态补偿价值静态核算的局限性,充分考虑黄河三角洲滨海湿地的时空异质性影响,运用ArcGIS及InVEST模型计算并分析不同土地利用类型下的碳储量变化,探究如何对碳储量损失区域进行生态补偿,并提升黄河三角洲滨海湿地生态系统的碳储功能。研究表明:(1)2013—2020年黄河三角洲滨海湿地碳储量呈现下降趋势,8年间累计总损失6.36×10^(6)吨碳。(2)碳储总值的分布与土地利用类型密切相关。(3)黄河三角洲滨海湿地2013—2020年8年间碳储经济损失价值为164.92×10^(6)美元。

河南兰考黄河湿地省级自然保护区鸟类资源调查

研究鸟类对维护生态平衡具有重要意义.2021年11月-2022年12月,采用样线法和样点法对兰考县黄河湿地自然保护区鸟类进行野外调查.本次调查共记录鸟类15目,48种,其中国家一级保护动物6种.观测发现该保护区鸟类数量庞大,迁徙栖息范围广,保护区内存在垂钓现象严重、滩涂湿地麦田种植规模大、苜蓿草种植规模大、鸟类和湿地保护宣传力度不够等问题,针对上述问题提出建立巡查保护制度、开展科普宣传活动、加大科研攻关力度等对策.本结果对保护区鸟类保护和管理提供了重要参考,为我国鸟类多样性研究积累了资料.

黄河下游典型悬河段地表水-地下水对湿地形成条件影响

对比分析黄河下游径流及河道变迁特征、不同时期地下水流场特征,结合遥感解译手段解析地下水和地表水对沿黄湿地条件的影响,为该区湿地生态修复提供理论依据。结果表明:(1)黄河下游典型悬河段人工湿地面积增幅较多,自然湿地仍呈萎缩趋势,滩涂湿地破碎度上升,生态环境稳定性较差。(2)地表水流量和水位整体呈现逐年降低的趋势,且河道的游荡摆动依然明显,直接影响了河流滩涂湿地面积及其稳定性。(3)研究区浅层地下水位十余年最大下降5 m、二十余年最大下降9 m。浅层地下水的持续下降导致北岸堤外湿地面积减少;南岸堤外因引黄水和退水侧渗形成新的背河洼地,湿地面积呈增长趋势,生态环境稳定性相对较好。地表水和地下水连通性较好,较低的地下水位将会削弱河道径流的作用,对沿黄湿地整体发展不利。(4)减少地下水的开采,确保引黄水量充足,对黄河大堤外背河洼地部位湿地的发展有利。

1973—2020年黄河三角洲滨海盐沼湿地景观格局演化模式和驱动因素

明晰滨海盐沼湿地景观格局演化模式和驱动因素,有助于制定合理的盐沼湿地修复策略、维护区域生态系统健康和可持续发展。以黄河三角洲滨海盐沼湿地为例,基于Landsat系列卫星影像获取1973—2020年共十个时期土地利用/覆被数据,得出盐沼湿地时空变化及其与周边土地利用/覆被的相互转化;利用改进的景观格局状态与演化识别模型(SEDMS),分析盐沼湿地景观格局演化模式,并利用地理探测器探究其空间分异驱动因素。结果表明:(1)1973—2020年,盐沼湿地面积减少了252.35 km^(2),空间范围总体向外海迁移且趋于集中。盐沼湿地转出类型主要为草地、养殖池/盐田和耕地,转入类型主要为滩涂未利用地和水体。(2)盐沼湿地景观格局演化模式呈明显的阶段性特征:1973—1995年为动荡期,演化模式以消失和破碎为主导;1995—2010为过渡期,格局演化模式逐渐由消失和破碎为主导转变为扩张为主导;2010年后为稳定期,格局发生演化的区域较少,总体以新增和扩张为主。(3)36%的盐沼湿地出现了多次格局演变模式的转变,滩涂未利用地、耕地对于景观格局演化频数的影响最为显著,人工表面、养殖池/盐田和道路堤坝的建设导致了盐沼湿地的破碎和消失。

氮添加对芦苇根系分泌及土壤硝化作用的影响

为探究人类活动引起的氮输入对植物根系分泌物释放及土壤硝化过程的影响,采集黄河三角洲芦苇湿地的土壤和幼苗进行加富培养实验,对根系分泌物释放、硝化速率及相关理化指标进行了测定和分析.结果发现,不同形态含氮营养物质添加对芦苇湿地土壤的理化因子具有不同影响,其中NH_(4)Cl对土壤微生物量碳、氮和NH_(4)^(+)-N含量的促进作用最显著,KNO_(3)添加能显著提高土壤NO_(3)^(-)-N含量,而芦苇凋落物对土壤有机碳和总氮的促进作用较强.在根际区和非根际区,氨氧化速率(V_a)平均值分别为(5.16±1.37)和(3.62±0.80)μmol/(kg·d),与NH_(4)^(+)-N含量均呈显著正相关,而亚硝酸盐氧化速率(V_(n))平均值为(6.01±1.42)和(4.45±1.08)μmol/(kg·d),与土壤NO_(3)^(-)-N呈显著正相关.土壤SOC和TN与V_(a)均呈显著正相关,主要与有机质的矿化作用为氨氧化过程提供反应底物有关.其中,氮平衡指数在有机氮添加组显著高于其余组可间接证明有机质对矿化过程的促进作用.与对照组相比,不同外源氮均能促进芦苇根系对总酸、总糖和氨基酸的分泌,其平均释放速率分别为(169.75±31.83),(116.72±21.76)和(9.52±3.31)μg/(g·d),而对酚类和类黄酮却表现出显著抑制或无明显作用.根系分泌的酚类物质与V_(a)呈显著负相关关系,可能归因于酚类物质对氨氧化细菌的选择性抑制.而氨基酸与V_(a)和V_(n)均呈显著正相关,氨基酸可为硝化细菌代谢提供能量和营养物质,从而促进了硝化过程的进行.总体上,营养物质添加一方面直接改变了土壤的理化性质,为硝化细菌提供了适合的生长环境;另一方面,营养物质添加能刺激芦苇根系分泌物的释放,使土壤中的营养及活性物质含量增加,促进硝化过程的进行.

互花米草治理对黄河三角洲湿地利用及景观格局的影响——利用随机森林和改进的CA-Markov模型

随着2022年《互花米草防治专项行动计划(2022—2025年)》发布,黄河三角洲湿地互花米草清理工作迅速展开。通过对比模拟的自然发展情景下与互花米草大规模清理后的真实情景下黄河三角洲湿地利用及景观格局指数,分析清理工作生态效益及湿地未来潜在风险。基于时序Sentinel-1 SAR影像和随机森林分类器获取了2020—2023年黄河三角洲湿地利用/覆盖变化结果;针对短期湿地模拟预测驱动力因素缺乏定量化设定的问题,构建了一种联合随机森林与CA-Markov模型的湿地模拟预测方法,实现2023年湿地自然发展情景下更精准的模拟预测;最后计算了2023年湿地在模拟和真实情景下的景观格局指数。结果表明:1)2023年互花米草清理工作效果显著,其面积锐减至5.53km^(2),与2022年相比减少了55.36km^(2),为芦苇等本土植被释放了生存空间;2)与自然发展情景相比,互花米草“围栏”不复存在,本土植被连通性上升,芦苇分布更加琐碎且面积比自然发展情景下增加了16.37km^(2),湿地的优势植被类型已逐渐向芦苇转变;3)由于互花米草对新生滩涂的入侵能力强于其它本土植被以及沿岸受海浪冲击等问题,互花米草清除后的黄河三角洲湿地面临互花米草复萌、二次蔓延及海岸线侵蚀的新风险。

围垦开发下滨海湿地格局演变的自然-人为复合驱动过程

滨海湿地具有重要的生物多样性保护价值及生态功能,围垦开发下经济快速增长的同时滨海湿地生态受损且大面积丧失。探究自然-人为复合影响下格局演变的关键驱动机制,可以为区域的生态保护和高质量发展提供指示。以围垦开发影响剧烈的黄河三角洲为研究区,克服了当前研究中驱动力的时空动态表征以及湿地格局演变的综合驱动时空交互机制研究的不足,研究构建了一套基于土地利用变化轨迹分离自然和人为驱动并表征湿地格局演变的动态驱动过程的方法,为区域尺度有效评估外界干扰对滨海湿地的影响提供了更加全面的支持。结果表明:尽管黄河三角洲滨海湿地格局演变的驱动过程轨迹类型多样,但主要受少数类型影响,以单一围垦开发为主。各驱动过程间存在着不同程度的时空交互,伴随围垦、修复、逆向演替过程的发生和转换,新生湿地的淤积及生态系统演替的自然增长过程被阻断,甚至可能对已修复湿地产生负面影响,区域湿地持续减少;人为驱动过程的影响远大于自然驱动过程,人为、自然及自然-人为复合驱动的湿地格局演变面积占比分别为55.5%、26.1%和18.4%。研究结果指示应严格管控部分生境敏感区的滩涂围垦,未来难以避免的滨海开发活动应由陆向海逐步推进,采用与新生湿地淤长方向一致的“滚动开发”模式,在兼顾经济效益的同时,维护滨海湿地生态系统的完整性和演替的连续性。