Do Vale Igor, Miranda Izildinha Souza, Mitja Danielle, Grimaldi Michel, Nelson Bruce Walker, Desjardins Thierry, Costa Luiz Gonzaga Silva
Rural Federal University of Amazonia (UFRA), CP.917, Belém, Pará, 66077-530, Brazil.
Environ Manage. 2015 Aug;56(2):342-54. doi: 10.1007/s00267-015-0500-6. Epub 2015 May 7.
We studied the tree-regeneration patterns in three distinct agricultural settlements in the Eastern Amazon to test the influence of land-use mosaics. The following questions are addressed: are the floristic structure and composition of regenerating trees affected by the various land-use types applied in the agricultural settlements? Do tree-regeneration patterns respond similarly to distinct land-use mosaics? Is there a relationship between tree regeneration and soil characteristics among the land-use types? The regeneration was inventoried at 45 sampling points in each settlement. At each sampling point, fourteen soil variables were analyzed. Nine different land-use types were considered. The floristic structure and composition of the settlements showed differences in the density of individuals and species and high species heterogeneity among the land-use types. The maximum Jaccard similarity coefficient found between land-use types was only 29%. Shade-tolerant species were the most diverse functional group in most land-use types, including pasture and annual crops, ranging from 91% of the number of species in the conserved and exploited forests of Travessão 338-S to 53% in the invaded pastures of Maçaranduba. The land-use types influenced significantly the floristic structure and composition of regenerating trees in two agricultural settlements, but not in third the settlement, which had greater forest cover. This finding demonstrates that the composition of each land-use mosaic, established by different management approaches, affects regeneration patterns. Tree regeneration was related to soil characteristics in all mosaics. Preparation of the area by burning was most likely the determining factor in the differences in soil characteristics between forests and agricultural areas.
我们研究了亚马逊东部三个不同农业定居点的树木更新模式，以测试土地利用镶嵌体的影响。解决了以下问题：农业定居点中应用的各种土地利用类型是否会影响再生树木的植物区系结构和组成？树木更新模式对不同的土地利用镶嵌体的反应是否相似？土地利用类型之间的树木更新与土壤特征之间是否存在关系？在每个定居点的45个采样点对更新情况进行了清查。在每个采样点，分析了14个土壤变量。考虑了9种不同的土地利用类型。定居点的植物区系结构和组成在个体和物种密度以及土地利用类型之间的物种异质性方面存在差异。土地利用类型之间发现的最大杰卡德相似系数仅为29%。耐荫物种是大多数土地利用类型中最多样化的功能组，包括牧场和一年生作物，范围从特拉韦桑338-S保护区和采伐森林中物种数量的91%到马萨兰杜巴入侵牧场中的53%。土地利用类型对两个农业定居点中再生树木的植物区系结构和组成有显著影响，但对森林覆盖率更高的第三个定居点没有影响。这一发现表明，由不同管理方法建立的每个土地利用镶嵌体的组成会影响更新模式。在所有镶嵌体中，树木更新都与土壤特征有关。通过焚烧进行的区域准备很可能是森林和农业区域之间土壤特征差异的决定性因素。
