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1.
滹沱河流域湿地植被的数量分类和排序 总被引:22,自引:1,他引:21
应用TWINSPAN和DCA相结合的方法,对滹沱河流域湿地植被74个样方进行分类和排序,将湿地植被分为16个群丛。DCA排序第一轴反映土壤含水量梯度,第二轴反映土壤类型的变化。主要优势种的DCA排序图与样方的DCA排序图有很大的相似性,优势种的分布格局在很大程度上决定着植物群丛的分布格局。 相似文献
2.
模糊数学排序是近年来引入植被分析的一个新方法,它可以结合环境因子,综合生态信息,受到生态学者的喜爱。最早的模糊数学排序用一个环境因子,后来可以将两个或三个环境因子结合在一个排序图上。但当环境因子多于三个时,排序难以完成。这就限制了该方法的实际应用,因为植被研究所得到的环境数据往往是一个庞大的矩阵。本文仅用除趋势对应分析(DCA)综合环境因子信息,然后再进行模糊数学排序,这样环境因子的数目理论上讲没有限制,模糊数学排序的功能得以扩展。我们用该方法对英国北威尔士山地草甸166个样方49个种的植被数据和8个环境因子数据进行了分析。结果较好地描述了草甸植被和环境因子之间的关系,生态意义明确. 相似文献
3.
锦屏水电站植被数量分类与排序 总被引:7,自引:0,他引:7
以锦屏梯级水电站大河湾段植被为研究对象,以河流流向为基础布置样方,将50个样方物种重要值及其环境因子进行TWINSPAN数量分类和DCA排序,结果显示:(1)由TWINSPAN数量分类将植被划分为7种类型,雅致雾水葛(Pouzolzia elegans)灌草群落为该区域的主要群落.(2)以TWINSPAN数量分类为基础的DCA二维排序图将样方分为6个生态类型,DCA 二维排序图横轴从左至右海拔高度逐渐降低;排序纵轴由下至上坡度逐渐升高.(3)以TWINSPAN数量分类在DCA排序图中有明确的分布范围和界限,DCA排序与TWINSPAN数量分类结合使用,能很好反映群落与环境因子间的生态关系. 相似文献
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中条山中段植物群落数量分类与排序研究 总被引:22,自引:0,他引:22
在群落样方调查基础上,采用双向指示种分析法(TWINSPAN)和除趋势对应分析(DCA)对中条山中段植物群落进行了数量分类和排序。TWINSPAN将53个样方分为14组,根据植被分类的原则划分为14个群丛,论述了各群丛的群落学特征。53个样方的DCA排序结果反映了植物群落类型与环境梯度之间的关系,表明影响群丛分布格局的主导生态因子为海拔高度、水分和热量。DCA排序将65个种分为5个种组,各种组在排序轴上的位置反映了种组成员的生态适应性及其在群落中的重要性和更新生态位。 相似文献
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子午岭地区植被恢复演替过程与环境因子的分类与排序 总被引:10,自引:1,他引:9
在野外实地调查基础上,采用双向指示种分析法(TWINSPAN)和除趋势对应分析(DCA)对子午岭地区植物群落进行了数量分类和排序。结果显示:(1)TWINSPAN将50个样方划分为14个群系;DCA排序结果与TWINSPAN分类结果相互印证。(2)第一排序轴上显示出植被由草地、灌丛到森林的恢复演替系列,在此演替过程中土壤中的速效磷逐渐减少,全氮和有机质逐渐增加;第二排序轴反映环境因子的梯度不明显,但植被的演替过程会受到海拔、坡度的影响。研究表明,随着植被恢复演替的进展群落结构在变化,乔木层的重要值增加,所在群落中的全氮、速效磷、有机质等亦呈现规律性变化。 相似文献
8.
为了探索库区滩涂与入库支流土壤种子库与植被的关系, 以及物种通过水传播扩散的潜力, 对丹江口库区内4条支流及其入库滩涂的地表植被和土壤种子库进行了调查。结果显示, 支流地表植被和种子库的物种多样性高于库区滩涂, 汉江库区滩涂和支流的地表植被与种子库均有较高的物种相似性。DCA排序和TWINSPAN聚类可以明显地将支流的植被和种子库样方与滩涂的植被和种子库样方分到不同的样方组, 结合物种排序图可以清楚地发现, 流入汉江库区支流的植被和种子库的物种组成与滩涂的植被和种子库的物种组成有密切联系。汉江库区滩涂0-15 cm的土层内都有种子萌发, 而丹江库区种子库中只有狗牙根(Cynodon dactylon)一种植物, 且仅存在于0-5 cm土层。研究结果表明, 繁殖体通过支流向滩涂的水传播作用对植被建立有积极贡献。 相似文献
9.
草海国家级自然保护区水生植物群落的数量分类与排序分析 总被引:4,自引:0,他引:4
在群落样方调查的基础之上,采用双向指示种分析法(TW INSPAN)和除趋势对应分析(DCA)对草海国家级自然保护区水生植物群落进行分类和排序。TW INSPAN将50个样方分为17组,根据植被分类的原则划分为17个群丛,论述了各个群丛的群落学特征。50个样方的DCA排序结果反映了植物群落类型与环境梯度之间的关系,表明影响群落分布格局的主导生态因子为水分条件,第一轴反映了各个群落类型所在的水分条件梯度。排序结果与分类结果较吻合,反映出植物群落类型和物种分布随环境因子梯度变化的趋势。 相似文献
10.
广东亚热带部分森林群落排序分析 总被引:3,自引:0,他引:3
本文应用极点排序、主坐标分析和位置向量排序等3种排序技术,对广东亚热带11个森林群落进行排序。探索了这3种方法在广东亚热带植被分析上的应用效果;经过对排序结果的分析,说明了11个森林群落的相互关系,在一定程度上揭示了植被变化的生态学原因。 相似文献
11.
为探讨东南亚沿海与内陆地区植被对洪水事件的响应差异,基于东南亚2000-2018年MODIS卫星遥感数据和洪水数据,通过比较东南亚洪水发生区域,共确定自2000年来影响最大、破坏程度相近的2个沿海洪水事件、2个内陆洪水事件以及1个沿海内陆洪水事件。以Google Earth Engine为数据处理平台,利用Sen+Mann-Kendall趋势法分析了2000-2018年研究区NDVI变化,发现5个研究区19年间NDVI均呈现出上升趋势,平均增速为0.013/10a,沿海与内陆植被在时空演变格局上无明显差异;基于灾害植被破坏指数的分析发现,内陆与沿海植被在洪水影响下的植被破坏指数分别为0.29与-0.25,植被破坏面积分别占比为14.29%与18.11%,内陆植被破坏程度小于沿海地区。同时,排除人类干扰强烈的耕地与人造地表,沿海研究区植被生态系统对洪水事件的抵抗力指数为88.15,明显强于内陆地区的28.89。草地表现出最强的抵抗力,其次为林地;而在植被恢复力方面,表现出相反的趋势。人类活动影响降低了内陆地区洪水灾害对植被的破坏。研究东南亚沿海与内陆植被对单次洪水事件的差异响应,排除内陆与沿海地区洪水事件累计影响,能够为东南亚沿海与内陆植被抵抗洪水灾害提出有针对性的建议。 相似文献
12.
Vegetation bioshields for tsunami mitigation: review of effectiveness, limitations, construction, and sustainable management 总被引:3,自引:0,他引:3
Norio Tanaka 《Landscape and Ecological Engineering》2009,5(1):71-79
Coastal vegetation has been widely recognized as a natural method to reduce the energy of tsunami waves. However, a vegetation
barrier cannot completely stop a tsunami, and its effectiveness depends on the magnitude of the tsunami as well as the structure
of the vegetation. For coastal rehabilitation, optimal planning of natural coastal systems, and their maintenance, we need
to quantitatively elucidate the capacity of vegetation to reduce the energy of tsunami waves. The limitations of coastal forests
in relation to the magnitude of a tsunami and the maintenance of forests as natural disaster buffer zones have to be understood
correctly for effective coastal vegetation planning. Demerits of coastal forests have also been revealed: for example, an
open gap in a forest (i.e., a road, river, difference in elevation, etc.) can channel and amplify a strong current by forcing
it into the gap. Floating debris from broken trees also can damage surrounding buildings and hurt people. However, many studies
have revealed that these demerits can be overcome with proper planning and management of mangroves and coastal forests, and
that coastal vegetation has a significant potential to mitigate damage in constructed areas and save human lives by acting
as buffer zones during extreme natural events. However, mangrove forests have been damaged by anthropogenic activities (i.e.,
tourism, shrimp farming, and industrial development), making coastal areas increasingly vulnerable to tsunamis and other natural
disasters. The effectiveness of vegetation also changes with the age and structure of the forest. This highlights the fact
that proper planning and management of vegetation are required to maintain the tsunami buffering function of coastal forests.
Although many government and nongovernmental organizations have implemented coastal vegetation projects, many of them have
been unsuccessful due to a lack of proper maintenance. A pilot project in Matara City, Sri Lanka, revealed that participation
and support from local authorities and communities is essential to make the planting projects successful. An integrated coastal
vegetation management system that includes utilization of the materials produced by the forest and a community participation
and awareness program are proposed to achieve a sustainable and long-lasting vegetation bioshield. 相似文献
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14.
Coastal vegetation planting projects for tsunami disaster mitigation: effectiveness evaluation of new establishments 总被引:1,自引:0,他引:1
Norio Tanaka K. B. S. N. Jinadasa M. I. M. Mowjood M. S. M. Fasly 《Landscape and Ecological Engineering》2011,7(1):127-135
Coastal vegetation acts as a natural barrier against extreme natural and anthropogenic activities, protecting infrastructure
and human lives. Establishment of hard infrastructure for tsunami protection is not feasible in developing countries due to
its cost-intensive nature. Coastal vegetation can therefore be a feasible alternative for tsunami and general coastal protection
in developing countries. This study investigates the effectiveness of current coastal vegetation projects and reports a pilot-scale
vegetation project, which provides insights into the management and sustainability of such projects. Thirty-seven establishments
of coastal vegetation for tsunami protection were identified for the study from Hambantota to Colombo along the southern coast
in Sri Lanka. Evaluation was carried out to assess whether the coastal vegetation establishments fulfilled the planning objectives,
such as vegetation alignment to tsunami direction, tree density and tree species, and whether monoculture or mixed species
are grown. The study also assessed continuous maintenance and awareness about coastal vegetation, community participation
and long-term institutional support from government, nongovernment groups, academic institutions, and other institutions within
an integrated framework. Approximately 50% of the sites were found to be effective in terms of fulfilling the above requirements
and had reasonable protection against future tsunami-type events. Continuous maintenance is ensured only for 35% of sites
with community participation. The survey also revealed the importance of adopting scientific and nonscientific methods of
vegetation establishment and selecting appropriate species and structure of vegetation strips for tsunami protection. It is
expected that this will lead to the development of coastal vegetation guidelines for local authorities. 相似文献
15.
在海滨森林生态系统中,乔木表现出以株高降低为主的特殊海滨矮化现象。阐明海滨植被在海滨生境胁迫下的矮化响应机制是实现海滨植被保护和恢复的关键环节。从海滨森林生态系统中乔木矮化的形态和作用机制的角度出发,综述了这一矮化现象与海滨各生态胁迫因子之间的关联及作用机制的研究进展。海滨乔木受到了长期海滨大风和极端风暴的机械压力,在形态上表现出茎粗、低矮的特征;海滨贫瘠的土壤、特殊的盐胁迫和复合型的水分胁迫在导致乔木高度降低的同时降低了基径和胸径生长,表现出瘦小的性状,这与非地带性山地矮林中乔木矮化现象是不同的;乔木的矮化也同样受到了海滨频发的火灾、极端光暴露或林内高郁闭度的光胁迫等环境因子的影响。这种乔木个体的矮化最终表现为海滨植被群落中乔木层的矮化。不可否认的是,海滨乔木矮化现象是由多种因素交互作用下形成的,但迄今为止,学界对海滨矮化现象的主导环境驱动力的探讨尚处于初步阶段。在指出现有研究的不足之处的同时,提出在未来的研究中,应更多的关注全球变化下海滨森林矮化的多因素驱动模型,并基于现行的植被分类系统,提出了划分海滨矮化森林为新植被型的构想,为海滨植物和植被的保护、恢复和分类提供了参考。 相似文献
16.
Andrea Galeano Ligia E. Urrego Verónica Botero Gladys Bernal 《Wetlands Ecology and Management》2017,25(6):743-760
Extreme events affect coastal vegetation in several ways. They cause massive tree defoliations and mortality that carry changes in vegetation structure and floristic composition. In order to assess these changes in dry tropical forests, coastal vegetation and mangroves in El Rosario archipelago, and their relationship with extreme events between 2002 and 2014, Quickbird and Worldview Satellite images with uneven periodicity were analyzed and the Normalized Difference Vegetation Index (NDVI) was calculated for these vegetation covers. Time series analysis was performed to oceanographic and climate variables such as maximum wind velocity, daily precipitation, significant wave height, peak wave period and maximum and minimum air temperatures. The first two axes of a redundancy analysis explained 65% of data variance (p value ≤ 0.05) and showed that the decrease of the NDVI and extension of beach vegetation were related to increases in wind frequency and intensity. However, mangrove vegetation was benefited by the increase in the frequency of short drought events, although their NDVI decreased when these drought events became longer. Drought events were related to El Niño Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) anomalies that had the strongest effects on coastal vegetation and dry forest, as shown by the minimum values of NDVI recorded in 2010. Mangrove vegetation was more resilient to such droughts and strong winds than coastal and dry forest vegetation due to their location along bays or surrounding internal lagoons. 相似文献
17.
江苏省海滩植被演替的研究 总被引:1,自引:0,他引:1
宗世贤 《植物资源与环境学报》1992,1(1):13-17
江苏省海滩植被可分为滨海盐土植被、盐沼植被及海滩沙生植被三个基本类型。本文论述了这些植被类型的演替规律。滨海盐土植被与盐沼植被的演替,外因于土壤盐分含量递减与有机质含量的递增;海滩沙生植被的演替,外因于土壤沙颗粒大小及其相应的土壤含水量的变化,所以海滩植被演替为外因动态演替。 相似文献
18.
KEVIN K. WEBB WARREN C. CONWAY GARY E. CALKINS JEFFREY P. DUGUAY 《The Journal of wildlife management》2009,73(4):566-572
ABSTRACT The American alligator (Alligator mississippiensis) has made a remarkable recovery throughout its range during the last half-century. In Texas, USA, current inland alligator population and harvest management strategies rely on generalized and often site-specific habitat and population data generated from coastal populations, because it is assumed that habitat and demographic similarities exist between inland and coastal populations. These assumptions have not been verified, however, and no studies have specifically examined inland alligator habitat use in Texas. We quantified alligator habitat use in East Texas during 2003–2004 to address this information gap and to facilitate development of regionally specific management strategies. Although habitat was variable among study areas, alligators used habitats with >50% open water, substantial floating vegetation, and emergent vegetation close (<12 m) to dry ground and cover. Adults used habitats further from dry ground and cover, in open water (75–85%), with less floating vegetation (6–22%) than did subadults, which used habitats that were closer to dry ground and cover, with less open water (52–68%), and more floating vegetation (8–40%). Although habitat use mirrored coastal patterns, we estimated alligator densities to be 3–5 times lower than reported in coastal Texas, likely a result of inland habitat deviations from optimal coastal alligator habitat, particularly in the preponderance of open water and floating vegetation. Our findings that 1) inland habitats varied among sites and did not exactly match assumed optimal coastal habitats, 2) alligators used these inland habitats slightly differently than coastal areas, and 3) inland alligator densities were lower than coastal populations, all highlight the need for regionally specific management approaches. Because alligator populations are influenced by habitat quality and availability, any deviations from assumed optimal habitat may magnify harvest impacts upon inland populations. 相似文献
19.
Ian D. Lunt Lisa M. Winsemius Simon P. McDonald John W. Morgan Remy L. Dehaan 《Journal of Biogeography》2010,37(4):722-732
Aim Encroachment or densification by woody plants affects natural ecosystems around the world. Many studies have reported encroachment in temperate Australia, particularly in coastal ecosystems and grassy woodlands. However, the degree to which published studies reflect broad-scale changes is unknown because most studies intentionally sampled areas with conspicuous densification. We aimed to estimate changes in woody vegetation cover within lowland grassy woodland and coastal ecosystems in Victoria from 1989 to 2005 to determine whether published reports of recent encroachment are representative of broad-scale ecosystem changes. Location All lowland grassy woodland and coastal ecosystems (c. 6.11 × 105 ha) in Victoria, Australia. Four major ecosystems were analysed: Plains woodlands, Herb-rich woodlands, Riverine woodlands and Coastal vegetation. Methods Changes in woody vegetation cover from 1989 to 2005 were assessed based on state-wide vegetation maps and Landsat analyses of woody vegetation cover conducted by the Australian Greenhouse Office’s National Carbon Accounting System. The results show changes in woody cover within mapped patches of native vegetation, rather than changes in the extent of woody vegetation resulting from clearing and revegetation. Results When pooled across all ecosystems, woody vegetation increased by 18,730 ha from 1989 to 2005. Woody cover within Riverine woodlands and within Plains woodlands each increased by >7000 ha. At the patch scale, the mean percentage cover of woody vegetation in each polygon increased by >5% in all four ecosystems: Riverine woodlands (+9.2% on average), Herb-rich woodlands (+7.6%), Plains woodlands (+6.7%) and Coastal vegetation (+5.9%). Regression models relating degree of encroachment to geographic and climatic variables were extremely weak (r2 ≤ 0.026), indicating that most variation occurred at local scales rather than across broad geographic gradients. Main conclusions At the scale of observation, woody vegetation cover increased in all lowland woodland and coastal ecosystems over the 16-year period. Thus, published examples of encroachment in selected coastal and woodland patches do appear to reflect widespread increases in woody vegetation cover in these ecosystems. This densification appears to be associated with changes in land management rather than with post-fire vegetation recovery and is likely to be ongoing and long-lasting, with substantial implications for biodiversity conservation and ecosystem services. 相似文献
20.
The Indian Ocean tsunami in 2004 and Hurricanes Katrina and Rita in 2005 have spurred global interest in the role of coastal wetlands and vegetation in reducing storm surge and flood damages. Evidence that coastal wetlands reduce storm surge and attenuate waves is often cited in support of restoring Gulf Coast wetlands to protect coastal communities and property from hurricane damage. Yet interdisciplinary studies combining hydrodynamic and economic analysis to explore this relationship for temperate marshes in the Gulf are lacking. By combining hydrodynamic analysis of simulated hurricane storm surges and economic valuation of expected property damages, we show that the presence of coastal marshes and their vegetation has a demonstrable effect on reducing storm surge levels, thus generating significant values in terms of protecting property in southeast Louisiana. Simulations for four storms along a sea to land transect show that surge levels decline with wetland continuity and vegetation roughness. Regressions confirm that wetland continuity and vegetation along the transect are effective in reducing storm surge levels. A 0.1 increase in wetland continuity per meter reduces property damages for the average affected area analyzed in southeast Louisiana, which includes New Orleans, by $99-$133, and a 0.001 increase in vegetation roughness decreases damages by $24-$43. These reduced damages are equivalent to saving 3 to 5 and 1 to 2 properties per storm for the average area, respectively. 相似文献