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首页> 外文期刊>Journal of South American earth sciences >Vegetation and its relationship with geomorphologic units in the Parana River floodplain, Argentina
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Vegetation and its relationship with geomorphologic units in the Parana River floodplain, Argentina

机译：阿根廷巴拉那河漫滩的植被及其与地貌单元的关系

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摘要

The Parana River is one of the most important fluvial systems of South America and its floodplain includes the most diverse subtropical ecosystem on the continent. However, the relationship between basic aspects, such as the vegetation and geomorphology of the river floodplain, has scarcely been investigated. In this paper, the annual dynamics of vegetation in relation to the geomorphologic and hydrological characteristics of a river floodplain around 31° 30' S, are analyzed. The annual dynamics of vegetation was investigated using values of the Normalized Difference Vegetation Index (NDV1) obtained from satellite images at two scales of spatial analysis: the first, at the geomorphologic unit level, through several transects crossing the total width of each unit and, the second, through some transects selected from each unit. Our analysis considered variables of different temporal stability (such as geomorphology, hydrology, vegetation, precipitation, and ground temperature), using scenes corresponding to two hydrological cycles of the system (2009 and 2010), which represented relatively "dry" and "humid" years. Five main geomorphologic units were identified in the floodplain of this anabranching system, which were named considering the predominant landforms and the most important (or typical) water course of each area: Bars and Islands of the Main Channel of the Parana River (Bl-MCH), Scroll Bars of the Colastine Branch (SB-C), Scroll Bars of the San Javier River Channel (SB-SJ), Crevasse Splays and Levees of the Malo-Mendieta minor channels (CSL-MM), and Crevasse Splays and Levees of the Santa Fe-Coronda river channels (CSL-SFC). These major units are assembled at different general levels and with variable slopes, which partially control the permanence and other characteristics of the flood flow. The crevasse splays and river levees units were predominantly characterized by herbaceous-bushy marshy vegetation, with low mean NDⅥ values, while SB-C and BlMCH units showed two types of forests. The latter showed the highest NDⅥ values. Unit SB-SJ showed mixed characteristics between the two above-mentioned groups. Mean NDⅥ values were different among the varying geomorphologic units and during the studied years, showing extreme values of 0.25 and 0.80 after both hydrological cycles. According to our results, the main variations in the seasonal dynamics of vegetation show a higher dependence on the dynamics of the hydrological cycle than on surface temperature or precipitation. The hydrological dynamics of the Parana River floodplain are in turn regulated by its geomorphological architecture, so the annual dynamics of vegetation activity in this system are finally influenced by the geomorphologic unit's level, rather than by the short duration modeling processes (i.e., hydrological cycles or drought-flood pulses).
机译：巴拉那河是南美最重要的河流系统之一，其洪泛区包括非洲大陆上最多样化的亚热带生态系统。但是，几乎没有研究基本面方面的关系，例如河流泛滥区的植被和地貌。本文分析了31°30'S附近河滩区植被的年动态与地貌和水文特征的关系。在两个空间分析尺度上，使用从卫星图像获得的归一化差异植被指数（NDV1）值调查了植被的年度动态：第一个是在地貌学单元水平上，通过几个横切每个单元总宽度的断面，以及第二，通过从每个单元中选择的一些样条。我们的分析使用与系统的两个水文循环（2009年和2010年）相对应的场景，考虑了不同时间稳定性（例如地貌，水文，植被，降水和地温）的变量，这些场景代表相对“干燥”和“潮湿”年份。在该集水系统的洪泛区中确定了五个主要地貌单位，并根据每个地区的主要地貌和最重要（或最典型）的水道来命名：巴拉那河主河道（Bl-MCH） ），Colastine分支的滚动条（SB-C），圣哈维尔河道的滚动条（SB-SJ），Malo-Mendieta次要渠道的Crevasse Splays和堤坝（CSL-MM）以及Crevasse Splays和堤坝Santa Fe-Coronda河道（CSL-SFC）。这些主要单元在不同的通用级别上以不同的坡度组装，从而部分控制了洪水的持久性和其他特征。裂隙八达通和河堤单元的主要特征是草木茂密的沼泽植被，平均NDⅥ值低，而SB-C和BlMCH单元则显示两种类型的森林。后者显示出最高的NDⅥ值。 SB-SJ单元在上述两个组之间显示出混合特性。在不同的地貌单位之间和研究年份中，平均NDⅥ值均不同，在两个水文循环之后，其ND均值分别为0.25和0.80。根据我们的结果，植被季节动态的主要变化显示出对水文循环动态的依赖性高于对地表温度或降水的依赖性。巴拉那河漫滩的水文动力学反过来又受其地貌结构的调节，因此该系统中植被活动的年度动态最终受地貌单元水平的影响，而不是受短期建模过程（即水文周期或旱涝脉冲）。

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  • 来源
    《Journal of South American earth sciences》 |2013年第10期|122-136|共15页
  • 作者

    Z.Y. Marchetti; E.M. Latrubesse; M.S. Pereira; C.G. Ramonell;

  • 作者单位

    Universidad National del Litoral, Facultad de Ingenieria y Ciencias Hidricas, C.C. 217, 3000 Santa Fe, Argentina,Argentinean National Council of Science and Technology -CONICET, Av. Rivadavia 1917 (C1033AAJ), Ciudad Autonoma de Buenos Aires, Argentina;

    University of Texas at Austin, Department of Geography and the Environment, E310, 23rd St. A3100, CLA 3.418A3100, Austin, TX 78712, USA;

    Universidad National del Litoral, Facultad de Ingenieria y Ciencias Hidricas, C.C. 217, 3000 Santa Fe, Argentina,Argentinean National Council of Science and Technology -CONICET, Av. Rivadavia 1917 (C1033AAJ), Ciudad Autonoma de Buenos Aires, Argentina;

    Universidad National del Litoral, Facultad de Ingenieria y Ciencias Hidricas, C.C. 217, 3000 Santa Fe, Argentina;

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  • 原文格式 PDF
  • 正文语种 eng
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  • 关键词

    Parana River; Floodplain; Vegetation; Geomorphologic units;

    机译：巴拉那河;洪泛区植被;地貌单位;

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