The relationship between the floristic composition of communities and the underlying environmental and spatial determinants is still the subject of intense debate, mainly because only recently has geographical distance been cited as an important driver of plant communities. We analysed environmental (elevation, climate and soil properties [E]) and spatial (geographic distance [S]) effects on the floristic composition of savannas on different substrates, one on a steep relief with shallow and rocky soils, and the other on flat terrain with deep soils. We show that: (1) savannas on rocky soils soils contain more nutrients, are more acidic and have a finer texture than savannas on deep soils; (2) that the dissimilarity between the rocky soils and deep soils is associated mainly with variation in altitude and soil properties and (3) that the individual and combined contributions of the environment and space to the floristic composition of woody plants differs between savannas on deep and rocky soils. Spatially structured environmental variation [E] + [S] explained 29% of the floristic composition variation in savannas on rocky soils and 41% in savannas on deep soils. In the rocky soils, the pure fraction explained by the [E] was larger (10%) than that recorded for deep soils (4%), but the pure effect of space [S] explained 2 and 3% of the variation on rocky and deep soils, respectively. The environmental variables analysed here are therefore strongly structured in space on both rocky and deep soils, but the total and combined environmental and spatial effects are larger in savannas on deep soils than in those on rocky soils.

中文翻译：

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环境和空间对木本植物物种组成的内在影响因生长在不同基质类型的巴西稀树草原而异

群落的植物区系组成与潜在的环境和空间决定因素之间的关系仍然是激烈争论的主题，主要是因为直到最近才将地理距离作为植物群落的重要驱动因素。我们分析了环境（海拔、气候和土壤特性 [E]）和空间（地理距离 [S]）对不同基质上热带稀树草原植物区系组成的影响，一种是在陡峭的浅层和岩石土壤上，另一种是在平坦的土壤上。土壤深厚的地形。我们表明：（1）岩石土壤上的稀树草原比深层土壤上的稀树草原含有更多的养分，酸性更强，质地更细腻；(2) 岩石土壤和深层土壤之间的差异主要与海拔高度和土壤性质的变化有关；(3) 环境和空间对木本植物区系组成的个体和综合贡献在深层稀树草原之间有所不同。和岩石土壤。空间结构的环境变化 [E] + [S] 解释了 29% 的岩石土壤稀树草原植物区系组成变化和 41% 深层土壤稀树草原的植物区系组成变化。在岩石土壤中，[E] 解释的纯分数（10%）大于深层土壤（4%）记录的纯分数，但空间 [S] 的纯效应解释了岩石上 2% 和 3% 的变化。和深层土壤，分别。因此，这里分析的环境变量在岩石和深层土壤中的空间结构很强，