Universidade Federal de Mato Grosso do Sul, Programa de Pós-Graduação em Recursos Naturais, Campo Grande, MS, Brazil.
Universidade Federal de Mato Grosso do Sul, Programa de Pós-Graduação em Recursos Naturais, Campo Grande, MS, Brazil; Embrapa Pantanal, Corumbá, MS, Brazil.
Sci Total Environ. 2020 Jun 25;723:138067. doi: 10.1016/j.scitotenv.2020.138067. Epub 2020 Mar 20.
The Pantanal is an important active sedimentary basin in central South America where highly diverse flora and fauna are sustained by seasonal floods. Intense land use in the catchment areas enhanced sediment load and destabilized avulsive river systems in the plains. A well-known avulsion in the Taquari River during the 1980-90s, called "Zé da Costa", has shifted the river mouth and drastically changed the nearby landscapes, making them difficult to map because of the hard access and the large variations in spectral and spatial attributes of raster data like Landsat images. Therefore, we developed a useful method to map and explore landscape changes in "Zé da Costa" avulsion that combines geotagged field pictures, randomly selected high-resolution orbital truths, normalized difference vegetation index, digital elevation models, linear spectral mixture models and Landsat historical imagery in pixel-based and object-oriented supervised classifications. We found that bands in green, red, and near-infrared spectra provide better mapping results with object-oriented algorithms for deriving and studying temporal dry/wet ratio dynamics. The temporal analyses of the dry/wet ratio showed that avulsions in the Taquari River have the potential to change permanently the "Zé da Costa" area into a dry landscape, making it susceptible for land use (deforestation and fire), except areas seasonally inundated by the floods of the Paraguay River. Overall, our method might be also useful for long-term studies of land use and climate change in avulsive rivers in wetlands around the world.
潘塔纳尔是南美洲中部一个重要的活跃沉积盆地，那里多样的动植物群依靠季节性洪水得以维持。集水区内密集的土地利用增加了沉积物负荷，并使平原上的突发河流系统不稳定。20 世纪 80 年代至 90 年代，塔夸里河发生了一次著名的突发，称为“Zé da Costa”，它改变了河口的位置，并极大地改变了附近的景观，由于难以进入和栅格数据（如 Landsat 图像）的光谱和空间属性的巨大变化，使得这些景观难以绘制。因此，我们开发了一种有用的方法来绘制和探索“Zé da Costa”突发的景观变化，该方法结合了带有地理标记的野外照片、随机选择的高分辨率轨道真实数据、归一化差异植被指数、数字高程模型、线性光谱混合模型和 Landsat 历史图像，以进行基于像素和面向对象的监督分类。我们发现，对于基于对象的算法来说，绿色、红色和近红外光谱波段提供了更好的制图结果，可用于推导和研究时间干湿比动态。干湿比的时间分析表明，塔夸里河的突发有可能使“Zé da Costa”地区永久性地变成干旱景观，使其容易受到土地利用（森林砍伐和火灾）的影响，除了巴拉圭河洪水季节性淹没的地区。总的来说，我们的方法也可能对世界范围内湿地突发河流的土地利用和气候变化的长期研究有用。
