基于Apack的若尔盖高原湿地景观空间格局分析

以2000年的遥感影像为数据源,基于Apaek软件运用景观格局指数数量方法研究了若尔盖高原高寒湿地的景观空间分布格局特征及其空间异质性特征.结果表明:2000年若尔盖高原湿地率为9.7%,其中沼泽湿地景观是主要景观组分,占湿地景观面积的96.32%;若尔盖高原湿地的景观多样性指数和均匀度都很小,聚集度较高,景观破碎化水平低,几何形状复杂,自相似性差.在5县域中,若尔盖县湿地景观的面积和湿地率最大,阿坝县和碌曲县所占比例较小;红原县的斑块数最多,碌曲县最少,但平均斑块面积以若尔盖县最大,阿坝县最小.各县湿地景观组分的比例分配差异大,但均以沼泽湿地景观为主要景观类型,且湿地景观聚集度高,破碎化水平低,几何形状复杂.在区域尺度上若尔盖高原湿地以自然湿地景观为主,且具有高度的空照间异质性特征.     

若尔盖高原湿地资源及其保护对策

若尔盖高原湿地在青藏高原湿地生物多样性保护中占有十分重要的地位 ,但其现状不清。卫星影像解译表明若尔盖高原湿地面积为 3 .94× 10 4 hm2 ,占土地总面积的 2 .2 %。在各种湿地中沼泽所占的比重最大。与 2 0世纪 5 0年代和 80年代初期相比 ,湿地面积大幅度减小而且退化严重 ,急需保护。目前应采取的保护措施有 :加强湿地自然保护区的建设与管理 ;探讨湿地退化机制与生态恢复措施 ;进行沼泽湿地草场生态牧业试验和示范研究 ;加强湿地保护立法与宣传教育。     

若尔盖高原退化湿地土壤有机碳储量

为了定量评价若尔盖高原泥炭沼泽湿地退化的碳储存潜力,研究通过土壤剖面法,收集了3个样点的泥炭沼泽湿地土壤样品(原始泥炭地0—200cm、中度退化沼泽湿地0—100cm和重度退化泥炭地0—100cm)。研究表明:(1)中度退化沼泽湿地(1.11±0.18g/cm~3)和重度退化泥炭地(0.72±0.04g/cm~3)土壤容重平均值较原始泥炭地增加了251.8%和129.7%;中度退化沼泽湿地(46.18±6.61g/kg)和重度退化泥炭地(87.37±6.36g/kg)土壤有机碳含量平均值较原始泥炭地降低了74.2%和51.1%。(2)土层深度为0—100cm时,原始泥炭地土壤有机碳储量较中度退化沼泽湿地(384.73±95.57t/hm~2)显著高了47.0%,而与重度退化泥炭地(518.39±33.07t/hm~2)土壤有机碳储量无显著差异;当原始泥炭地有机层增加到0—200cm后,中度退化沼泽湿地和重度退化泥炭地土壤有机碳储量较原始泥炭地(1 088.17±172.84t/hm~2)降低了64.6%和52.4%,退化湿地土壤有机碳储量的降低可能主要是土壤有机碳含量降低的原因。尽管退化湿地土壤有机碳储量下降,但仍是中国(102.89t/hm~2)和全球(116.56t/hm~2)陆地土壤有机碳储量的3~5倍,该研究可为保护与恢复若尔盖高原湿地提供科学依据。     

若尔盖高原湿地土壤性质对硒有效性的影响

用等温吸附的方法研究了若尔盖高原广泛分布的泥炭土、沼泽土和风沙土对硒的吸附与解吸,以探讨湿地土壤因素对硒有效性的影响。结果表明,3种土壤还原状态下硒的吸附量均大于氧化态,水溶性硒和交换态硒的解吸量均为氧化态高于还原态,潜在有效硒与此相反,氧化状态有助于提高土壤硒的有效性。土壤pH升高,泥炭土对SeO_3~(2-)-Se的吸附量降低,水溶态硒增加,交换态硒降低,潜在有效硒变化不明显。土壤有机质能大量吸持硒降低其有效性,泥炭土去有机质后对硒的吸附量大幅度下降,水溶性硒和交换态硒量增加,潜在有效性硒量则明显降低。     

若尔盖高原湿地植物群落结构特征与土壤微生物群落多样性

[目的]探究若尔盖高原湿地植物群落(乌拉苔草、木里苔草、花葶驴蹄草、藏嵩草)结构特征、土壤微生物群落多样性的长期变化特征及其二者之间的演化关系,为该地区的植被恢复和生态环境保护提供借鉴.[方法]结合室内样品分析,连续4 a(2016-2019年)观测了不同植物群落地上和地下各个指标的动态特征.[结果]①对于a多样性,2...     

若尔盖高原湿地土壤硒的数量、形态与分布

用连续浸提的方法研究了若尔盖高原4种湿地土壤(风沙土、草甸土、沼泽土和泥炭土)中硒的含量、形态、剖面分布及其影响因素,以期为该区人、畜缺硒症的防治积累科学资料。结果表明,该区土壤属于低硒环境,表层土壤全硒含量范围为65～260μg/kg。在各种形态硒中,水溶性硒仅占土壤全硒含量的1.12%～3.08%,交换态硒占2.91%～6.03%,有机态硒占10.28%～45.63%,酸溶态硒、硫化态硒和残余态硒3种无效态硒共占60%以上。在土壤有机态硒组成中,胡敏酸结合态硒(HA-Se)占有机态硒的57.84%,富里酸结合态硒(FA-Se)占42.16%。土壤总硒和有机态硒的含量与分布主要受土壤有机碳的影响,且其影响程度随着深度的不同而改变,湿地土壤丰富的有机碳有利于土壤有机态硒和总硒的积累。土壤总硒含量低、有机态硒的比例较高以及胡敏酸结合态硒占优势导致硒的生物利用率低,可能是该区域人、畜硒缺乏症发生的重要原因。     

金沙江流域云南段景观格局特征及其变化研究

金沙江流域是我国西部的生态脆弱区,植被受人为干扰程度较大.通过分析区内各植被类型的斑块规模与变化.可望得出人类活动对流域内植被的影响程度.研究基于TM遥感数据进行,首先,对金沙江流域云南段进行景观格局特征研究,分析该地区各植被类型的斑块数、面积,面积标准差和变异系数及该地区的斑块粒度等;然后,对比分析了流域内前后两期(相隔10 a)的植被与景观规模的变化.分析得出,流域内植被类型的斑块多为小斑块和中斑块,体现出植被景观的高度破碎化.经过10 a的变化后,暖温性针叶林等植被面积增加明显,充分反映出人工造林的成效;此外受人为活动影响后形成的次生性植被增多,说明人类活动对植被的不良影响.在植被总体面积增加的同时.区域内景观的斑块总数却有所减少,说明区域内有小斑块融合成大斑块的趋势.从两个时段植被景观斑块规模的变化可以看出,整个流域植被景观破碎的程度体现出减弱的趋势.     

基于GIS的喀斯特高原山区石漠化景观格局变化分析

石漠化是广泛存在于中国西南地区的一种生态-地质灾害,目前已成为备受关注的研究热点和难点。为了解喀斯特高原山区石漠化景观的时空变化,以贵州省普定县南部的典型喀斯特高原山区后寨河流域为例,以3期遥感影像（1987年和1995年的TM影像与2004年的SPOT-5影像）作为数据源,借助于ArcGIS9.0等软件和数理统计分析方法,从石漠化强度分级的角度对近18 a来石漠化的动态变化进行了研究。结果表明：从整体上来看,整个流域的石漠化出现扩展的趋势,其中前期（1987－1995年）的扩展速度为6.55 hm2/a,后期（1995－2004年）的扩展速度为29.64 hm2/a,扩展速度呈现增加的趋势。其中,轻度石漠化的面积呈现出先减少后增加的趋势;而中度石漠化和强度石漠化的面积均呈现出逐渐增加的趋势。     

Effects of seasonal grazing on soil respiration in alpine meadow on the Tibetan plateau

Little research has been conducted on how to balance plant production and soil respiration (Rs) under seasonal grazing patterns in alpine meadows. Our results from 2009 to 2012 showed that warm season grazing (WG) from June to September significantly increased aboveground net primary production compared with no‐grazing (NG), except in 2010, and compared with cold season grazing (CG) except in 2012, while there were no significant differences between NG and CG except in 2009. In both WG and CG treatments, grazing increased root biomass at 0–40 cm depth compared with NG, except in 2011. WG and CG only significantly increased seasonal Rs in 2009. Daily Rs was mainly affected by soil temperature, which explained 40–49% of the variation in daily Rs for all grazing treatments. Seasonal Rs from July to September was significantly influenced by soil temperature and root biomass, which explained 55% of the variation in seasonal Rs for all grazing treatments. Therefore, relative to NG, regardless of WG and CG, moderate grazing significantly increased plant production and had little influence on soil respiration in this alpine region.     

两种人工湿地处理富营养化景观水体的性能对比研究

The efficiencies of two types of constructed wetlands for the treatment of low-concentration polluted eutrophic land-scape river water were studied in the western section of the Qingyuan River at the Minhang campus of Shanghai Jiaotong University. The first wetland was a single-stage system using gravel as a filtration medium, and the second was a three-stage system filled with combinations of gravel, zeolite, and fly ash. Results from parallel operations of the wetlands showed that the three-stage constructed wetland could remove organics, nitrogen, and phosphorus successfully. At the same time, it could also decrease ammoniacal odour in the effluent. Compared to the single-stage constructed wetland, it had better nutrient removal efficiencies with a higher removal of 19.37%-65.27% for total phosphorus (TP) and 21.56%-62.94% for total nitrogen (TN), respectively, during the operation period of 14 weeks. In terms of removal of chemical oxygen demand (COD), turbidity, and blue-green algae, these two wetland systems had equivalent performances. It was also found that in the western section of the test river, in which the two constructed wetlands were located, the water quality was much better than that in the eastern and middle sections without constructed wetland because COD, TN, and TP were all in a relatively lower level and the eutrophication could be prevented completely in the western section.     

三峡库区开县蓄水前后景观格局变化特征

三峡工程是世界上举世瞩目的大型水电水利工程,其建成后具有巨大的综合效益,但水库蓄水完成后,也引起库区内的土地覆被与景观格局的变化。为了及时掌握水库蓄水后库区土地覆被及景观格局变化情况,该文以三峡库区重庆市开县为研究对象,基于2002、2007和2010年3期遥感影像资料,运用遥感与GIS技术和景观格局分析方法,利用ArcGIS9.3、Ecognition8.0、Fragstats3.3等软件分析了研究区土地覆被与景观格局动态变化特征。研究表明:由于受2002-2010年间水库蓄水影响,开县土地覆被与景观格局均有剧烈变化。该地区景观优势类型是森林、灌木、旱地、草地和水田。景观类型水平上,旱地、水田、草地景观面积减少且破碎度增加,但森林、水体、建设用地面积增加,同时连通性增加;景观格局水平上,景观总体破碎度增加,景观优势度降低,但景观多样性增加,有利于该地区生态系统稳定。开县2002-2007年和2007-2010年2期景观格局变化表现出不同的特征。研究结果及时反应了水库蓄水前后的土地覆被与景观格局变化特征,为水库未来土地利用合理规划与生态景观设计提供依据。     

盐城海滨湿地景观变化的生态环境效应分析

运用GIS和RS技术,通过对1987-2007年盐城海滨湿地景观变化进行比较,分析其景观变化及生态环境响应。结果表明：（1）盐城海滨湿地景观受人为干扰强度增大,景观破碎化明显。1987-2007年平均斑块面积由753.910hm2下降到124.470hm2;平均分维数由1.036降到1.027。（2）海滨湿地生态环境响应主要表现为：盐城海滨湿地是围垦的重点,自然湿地面积大量丧失,＂九五＂和＂十五＂期间围垦面积近全市湿地面积的1/3;丹顶鹤等栖息物种生境面临威胁,生物多样性下降,2000年以来丹顶鹤越冬种群数量呈波动下降;湿地生态系统退化,海滨湿地水环境、土壤环境面临威胁。     

Effect of land‐use on soil nutrients and microbial biomass of an alpine region on the northeastern Tibetan plateau,China

Land‐use patterns affect the quantity and quality of soil nutrients as well as microbial biomass and respiration in soil. However, few studies have been done to assess the influence of land‐use on soil and microbial characteristics of the alpine region on the northeastern Tibetan plateau. In order to understand the effect of land‐use management, we examined the chemical properties and microbial biomass of soils under three land‐use types including natural grassland, crop‐field (50 + y of biennial cropping and fallow) and abandoned old‐field (10 y) in the area. The results showed that the losses of soil organic carbon (SOC) and total nitrogen (TN) were about 45 and 43 per cent, respectively, due to cultivation for more than 50 y comparing with natural grassland. Because of the abandonment of cultivation for about a decade, SOC and TN were increased by 27 and 23 per cent, respectively, in comparison with the crop field. Microbial carbon (ranging from 357·5 to 761·6 mg kg⁻¹ soil) in the old‐field was intermediate between the crop field and grassland. Microbial nitrogen (ranging from 29·9 to 106·7 mg kg⁻¹ soil) and respiration (ranging from 60·4 to 96·4 mg CO₂‐C g⁻¹ C_mic d⁻¹) were not significantly lower in the old‐field than those in the grassland. Thus it could be concluded that cultivation decreased the organic matter and microbial biomass in soils, while the adoption of abandonment has achieved some targets of grassland restoration in the alpine region of Gansu Province on the northeastern Tibetan plateau. Copyright © 2010 John Wiley & Sons, Ltd.     

白洋淀湿地景观斑块时空变化研究

景观格局变化可以深刻地反映人类活动对生态环境的影响,研究白洋淀湿地景观格局时空变化对于明晰湿地水环境质量的恶化原因具有重要意义。通过综合运用GIS技术和景观格局指数法,对白洋淀1987、1999和2007年LandsatTM遥感影像进行解译分析,研究了白洋淀20年间景观格局动态变化。结果表明：苇地、耕地和水域是淀区主导景观类型,所占比例高达86.62%~93.06%,苇地为42.74%~58.02%。淀区斑块数和密度增加了23.01%,景观破碎化程度加剧。景观均匀度指数由0.74降至0.67,多样性指数由1.44降至1.25。苇地和耕地面积增加最多,分别为18.08%和28.05%;水域和干草地减少最多,分别为35.78%和76.53%景观分维数范围为1.05~1.27,受人类影响较大;苇地从1.27降至1.19,水域从1.16降至1.09,人为影响明显增强;裸地、林地和干草地的分维数最小,分别为1.06~1.08,1.05~1.09和1.07~1.09。根据主导景观类型时空变化,将白洋淀划分为G、WG和WS区。G和WG区主导景观类型均表现出从水域到苇地再到耕地转化趋势,WS区的水面和苇地在外源调水的作用下得以维持,水域整体向东部转移。建议白洋淀湿地保护以水域、苇地和草地为核心,控制淀内及周边人类活动对自然景观的扰动。调水要充分考虑白洋淀的景观时空特征,尽量降低对重要景观类型和生物多样性的影响。     

人为干扰对泰山景观格局时空变化的影响

以TM影像和野外调查为数据源,3S技术为研究手段,对比分析了泰山风景区1986～2001年间不同人为干扰程度区域的景观结构、景观异质性动态变化特征以及景观多样性高程的分异。结果表明,泰山南部人为干扰斑块动态变化高于北部,南部景观结构变化明显,北部轻微。景观多样性动态变化主要是在北部海拔900m以上和南部900m以下区域,揭示了人为活动是斑块分割的主因,景观格局的动态变化取决于人为干扰的程度。研究结果从景观生态学角度为泰山合理调整自然和人为影响,构建理想的景观格局和生态环境奠定了基础。     

The effect of land management on carbon and nitrogen status in plants and soils of alpine meadows on the Tibetan plateau

Large‐scale grassland rehabilitation has been carried out on the severely degraded lands of the Tibetan plateau. The grasslands created provide a useful model for evaluating the recovery of ecosystem properties. The purposes of this research were: (1) to examine the relative influence of various rehabilitation practices on carbon and nitrogen in plants and soils in early secondary succession; and (2) to evaluate the degree to which severely degraded grassland altered plant and soil properties relative to the non‐disturbed native community. The results showed: (1) The aboveground tissue C and N content in the control were 105·97 g m⁻² and 3·356 g m⁻², respectively. The aboveground tissue C content in the mixed seed treatment, the single seed treatment, the natural recovery treatment and the severely degraded treatment was 137 per cent, 98 per cent, 49 per cent and 38 per cent, respectively, of that in the control. The corresponding aboveground tissue N content was 109 per cent, 84 per cent, 60 per cent and 47 per cent, respectively, of that in the control. (2) Root C and N content in 0–20 cm depths of the control had an average 1606 g m⁻² and 30·36 g m⁻², respectively. Root C and N content in the rehabilitation treatments were in the range of 26–36 per cent and 35–53 per cent, while those in the severely degraded treatment were only 17 per cent and 26 per cent of that in the control. (3) In the control the average soil C and N content at 0–20 cm was 11 307 g m⁻² and 846 g m⁻², respectively. Soil C content in the uppermost 20 cm in the seeded treatments, the natural recovery treatment and the severely degraded treatment was 67 per cent, 73 per cent and 57 per cent, respectively, while soil N content in the uppermost 20 cm was 72 per cent, 82 per cent and 79 per cent, respectively, of that in the control. The severely degraded land was a major C source. Restoring the severely degraded lands to perennial vegetation was an alternative approach to sequestering C in former degraded systems. N was a limiting factor in seeding grassland. It is necessary for sustainable utilization of seeding grassland to supply extra N fertilizer to the soil or to add legume species into the seed mix. Copyright © 2005 John Wiley & Sons, Ltd.     

烟台沿海地区土地利用景观格局演变研究

基于地理信息技术、景观格局分析理论和马尔可夫模型，利用1986、1992、2000和2004年4期影像，分析了烟台沿海地区土地利用类型变化及其景观格局动态特征。结果显示，近20年来，烟台沿海地区各种土地类型变化及其相互转化频繁。水域、果园和建设用地分别增加335.61%、70.43%和134.48%，而耕地、林地分别减少18.63%和20.75%。各种土地利用类型空间格局变化显著，耕地、果园破碎度增加，连通性降低，水域、林地和建设用地则趋于集中，连通性增强，景观类型有向多元化方向发展的趋势。马尔可夫模型预测表明，从2022年至平稳期，耕地、林地和果园面积将持续减少，水域和建设用地将逐年增加，耕地保护与建设用地扩张之间的矛盾将更加突出。