Gonçalves H C, Mercante M A, Santos E T
Agência Nacional de Águas, SPS, Área 5, Quadra 3, Bloco B, CEP 70610-200, Brasília, DF, Brazil.
Braz J Biol. 2011 Apr;71(1 Suppl 1):241-53. doi: 10.1590/s1519-69842011000200003.
The Pantanal hydrological cycle holds an important meaning in the Alto Paraguay Basin, comprising two areas with considerably diverse conditions regarding natural and water resources: the Plateau and the Plains. From the perspective of the ecosystem function, the hydrological flow in the relationship between plateau and plains is important for the creation of reproductive and feeding niches for the regional biodiversity. In general, river declivity in the plateau is 0.6 m/km while declivity on the plains varies from 0.1 to 0.3 m/km. The environment in the plains is characteristically seasonal and is home to an exuberant and abundant diversity of species, including some animals threatened with extinction. When the flat surface meets the plains there is a diminished water flow on the riverbeds and, during the rainy season the rivers overflow their banks, flooding the lowlands. Average annual precipitation in the Basin is 1,396 mm, ranging from 800 mm to 1,600 mm, and the heaviest rainfall occurs in the plateau region. The low drainage capacity of the rivers and lakes that shape the Pantanal, coupled with the climate in the region, produce very high evaporation: approximately 60% of all the waters coming from the plateau are lost through evaporation. The Alto Paraguay Basin, including the Pantanal, while boasting an abundant availability of water resources, also has some spots with water scarcity in some sub-basins, at different times of the year. Climate conditions alone are not enough to explain the differences observed in the Paraguay River regime and some of its tributaries. The complexity of the hydrologic regime of the Paraguay River is due to the low declivity of the lands that comprise the Mato Grosso plains and plateau (50 to 30 cm/km from east to west and 3 to 1.5 cm/km from north to south) as well as the area's dimension, which remains periodically flooded with a large volume of water.
潘塔纳尔湿地的水文循环在巴拉圭上游流域具有重要意义，该流域包括两个在自然和水资源条件上差异很大的区域：高原地区和平原地区。从生态系统功能的角度来看，高原与平原之间的水文流动对于为区域生物多样性创造繁殖和觅食生态位至关重要。一般来说，高原地区河流的坡度为0.6米/公里，而平原地区的坡度在0.1至0.3米/公里之间变化。平原地区的环境具有明显的季节性，是丰富多样物种的家园，其中包括一些濒临灭绝的动物。当高原的平坦表面与平原相接时，河床的水流会减少，而在雨季，河流会漫过河岸，淹没低地。该流域的年平均降水量为1396毫米，范围在800毫米至1600毫米之间，且降水量最大的地区是高原地区。塑造潘塔纳尔湿地的河流和湖泊排水能力较低，再加上该地区的气候，导致蒸发量非常高：来自高原的所有水体中约60%通过蒸发流失。巴拉圭上游流域，包括潘塔纳尔湿地，虽然水资源丰富，但在一年中的不同时间，一些子流域也存在水资源短缺的情况。仅气候条件不足以解释巴拉圭河及其一些支流所观察到的差异。巴拉圭河水文状况的复杂性是由于构成马托格罗索平原和高原的土地坡度较低（从东到西为50至30厘米/公里，从北到南为3至1.5厘米/公里）以及该地区的面积较大，该地区仍会定期被大量洪水淹没。
