Land-use change in the Atlantic rainforest region: Consequences for the hydrology of small catchments
Land-use change in the Atlantic rainforest region: Consequences for the hydrology of small catchments
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DOI：
10.1016/j.jhydrol.2013.06.049
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发表时间：
2013-08
影响因子：
6.4
通讯作者：
L. Salemi;J. D. Groppo;R. Trevisan;J. M. Moraes;S. Ferraz;João Paulo Villani;P. Duarte-Neto;L. Martinelli
中科院分区：
文献类型：
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作者：
L. Salemi;J. D. Groppo;R. Trevisan;J. M. Moraes;S. Ferraz;João Paulo Villani;P. Duarte-Neto;L. Martinelli
巴西的大西洋森林是世界上最濒危的生态系统之一。尽管该生物群系经历了近500年的剧烈土地利用变化，但土地利用变化对水文过程的影响尚未得到深入研究。为了弥补这一差距，我们在2年（2008年1月至2009年12月）的时间里研究了三个由原始山地云雾林、牧场和桉树覆盖的小集水区的各种特征，包括土壤的水力特性、通流、地上流和溪流过程。森林土壤表层（0.15 m深度）饱和水导率（Ksat）高于桉树和草地。因此，在草地和桉树中观察到更高的陆地流生成量。尽管坡面流的产生增加了，但坡面流系数（坡面流：降水比）在整个研究期间都很低，2009年略高。这些低地面流系数归因于低降雨强度（<10 mm h−1）和高卫星空间变异性。这些地表水流结果和没有栖息的地下水位表明，集水区似乎仍然由垂直流道主导，与土地利用无关。从这个意义上说，所有集水区的年流量仍然以基流为主。因此，尽管在将森林转化为桉树和牧场时减少了截流和饱和水力导电性，但普遍的降雨强度不会导致不同土地用途之间产生径流的过程有很大不同。森林和桉树将年降水量转化为年流量的比例相似，更可能的因素是森林下的高截流和桉树下的高蒸腾。最后，云林向牧场的转变并没有促进显著的月流量变化。
The Atlantic forest of Brazil is one of the most endangered ecosystems in the world. Despite approximately 500 years of intense land-use change in this biome, the influence of land-use changes on hydrological processes have yet to be investigated in-depth. To bridge this gap, we studied various features of three small catchments covered by pristine original montane cloud forest, pasture, and eucalyptus for 2 years (January 2008–December 2009), including the hydraulic properties of soils, throughfall, overland flow and streamflow processes. The forest saturated hydraulic conductivity (Ksat) was higher near the soil surface (0.15 m depth) compared to eucalyptus and pasture. As a consequence, higher overland flow generation in terms of volume was observed in pasture and eucalyptus. Despite this increase in overland flow generation, overland flow coefficients (overland flow: precipitation ratio) were substantially low throughout the study period with slightly higher values in 2009. These low overland flow coefficients were attributed to the large predominance of low rainfall intensities (<10 mm h−1) as well as highKsatspatial variability. These overland flow results and the absence of perched water table showed that catchments seem still to be dominated by vertical flowpaths irrespective of land-use. In this sense, the annual streamflow is still dominated by baseflow in all of the catchments. Therefore, despite reductions regarding interception and saturated hydraulic conductivity when converting forest to eucalyptus and pasture, the prevailing rainfall intensities do not cause runoff generation processes to be substantially different among land-uses. Forest and eucalyptus convert a similar proportion of annual precipitation to annual streamflow, with the more likely factors for these results being the high interception under forest and high transpiration under eucalyptus. Finally, cloud forest conversion to pasture does not promote significant monthly streamflow change.