Silva W G, Metzger J P, Simões S, Simonetti C
Department of Ecology, Biosciences Institute, University of São Paulo, São Paulo, SP 05508-900, Brazil.
Braz J Biol. 2007 Aug;67(3):403-11. doi: 10.1590/s1519-69842007000300004.
Several studies suggest that, on a large scale, relief conditions influence the Atlantic Forest cover. The aim of this work was to explore these relationships on a local scale, in Caucaia do Alto, on the Ibiúna Plateau. Within an area of about 78 km(2), the distribution of forest cover, divided into two successional stages, was associated with relief attribute data (slope, slope orientation and altitude). The mapping of the vegetation was based on the interpretation of stereoscopic pairs of aerial photographs, from April 2000, on a scale of 1:10,000, while the relief attributes were obtained by geoprocessing from digitalized topographic maps on a scale of 1:10,000. Statistical analyses, based on qui-square tests, revealed that there was a more extensive forest cover, irrespective of the successional stage, in steeper areas (>10 degrees) located at higher altitudes (>923 m), but no influence of the slope orientation. There was no sign of direct influence of relief on the forest cover through environmental gradients that might have contributed to the forest regeneration. Likewise, there was no evidence that these results could have been influenced by the distance from roads or urban areas or with respect to permanent preservation areas. Relief seems to influence the forest cover indirectly, since agricultural land use is preferably made in flatter and lower areas. These results suggest a general distribution pattern of the forest remnants, independent of the scale of study, on which relief indirectly has a strong influence, since it determines human occupation.
多项研究表明，从大规模来看，地形条件会影响大西洋森林的覆盖范围。这项工作的目的是在伊比乌纳高原的卡凯亚多阿尔托地区，在局部尺度上探究这些关系。在约78平方千米的区域内，分为两个演替阶段的森林覆盖分布与地形属性数据（坡度、坡向和海拔）相关联。植被测绘基于对2000年4月比例尺为1:10000的航空照片立体像对的解读，而地形属性则通过对比例尺为1:10000的数字化地形图进行地理处理获得。基于卡方检验的统计分析表明，在海拔较高（>923米）且坡度较陡（>10度）的区域，无论演替阶段如何，森林覆盖范围都更广，但坡向没有影响。没有迹象表明地形通过可能有助于森林更新的环境梯度对森林覆盖有直接影响。同样，也没有证据表明这些结果可能受到距道路或城市区域的距离或与永久保护区的距离的影响。地形似乎间接影响森林覆盖，因为农业用地优先选择在地势较平坦和较低的区域。这些结果表明，森林残余的总体分布模式与研究尺度无关，地形在其中间接产生了强烈影响，因为它决定了人类居住情况。
