Chozas Sergio, Chefaoui Rosa M, Correia Otília, Santos Ana M C, Hortal Joaquín
cE3c - Centre for Ecology, Evolution and Environmental Changes and cE3c - Centre for Ecology, Evolution and Environmental Changes & CHANGE - Global Change and Sustainability Institute, Faculdade de Ciências Universidade de Lisboa Lisbon Portugal.
Área de Biodiversidad y Conservación Universidad Rey Juan Carlos Móstoles Spain.
Ecol Evol. 2023 Feb 16;13(2):e9828. doi: 10.1002/ece3.9828. eCollection 2023 Feb.
Species' environmental requirements and large-scale spatial and evolutionary processes determine the structure and composition of local communities. However, ecological interactions also have major effects on community assembly at landscape and local scales. We evaluate whether two xerophytic shrub communities occurring in SW Portugal follow constrained ecological assembly dynamics throughout large geographical extents, or their composition is rather driven by species' individualistic responses to environmental and macroecological constraints. Inland dune xerophytic shrub communities were characterized in 95 plots. Then, we described the main gradients of vegetation composition and assessed the relevance of biotic interactions. We also characterized the habitat suitability of the dominant species, , and , to map the potential distribution of the xerophytic shrub communities. Finally, we examined the relationships between the vegetation gradients and a broad set of explanatory variables to identify the relative importance of each factor driving changes in community composition. We found that xerophytic shrubs follow uniform successional patterns throughout the whole geographical area studied, but each community responds differently to the main environmental gradients in each region. Soil organic matter is the main determinant of community variations in the northern region, Setúbal Peninsula, whereas aridity is so in the South/South-Western region. In contrast, in the central region, Comporta, the variation between and communities is explained mainly by aridity and temperature seasonality, followed by the individualistic responses of the dominant species and soil organic matter. Overall, these results indicate that, the relative importance of the main factors causing community-level responses varies according to regional processes and the suitability of the environmental conditions for the dominant species in these communities. These responses are also determined by intrinsic community mechanisms that result in a high degree of similarity in the gradient-driven community stages in different regions.
物种的环境需求以及大规模的空间和进化过程决定了当地群落的结构和组成。然而，生态相互作用在景观和局部尺度上对群落组装也有重大影响。我们评估了葡萄牙西南部出现的两个旱生灌木群落，在整个大地理范围内是否遵循受约束的生态组装动态，或者它们的组成是否更多地由物种对环境和宏观生态约束的个体响应所驱动。对内陆沙丘旱生灌木群落的95个样地进行了特征描述。然后，我们描述了植被组成的主要梯度，并评估了生物相互作用的相关性。我们还对优势物种的栖息地适宜性进行了特征描述，以绘制旱生灌木群落的潜在分布。最后，我们研究了植被梯度与一系列广泛的解释变量之间的关系，以确定驱动群落组成变化的每个因素的相对重要性。我们发现，旱生灌木在整个研究的地理区域内遵循统一的演替模式，但每个群落在每个区域对主要环境梯度的响应不同。土壤有机质是北部地区塞图巴尔半岛群落变化的主要决定因素，而南部/西南部地区则是干旱程度。相比之下，在中部地区孔波塔，两个群落之间的差异主要由干旱和温度季节性来解释，其次是优势物种的个体响应和土壤有机质。总体而言，这些结果表明，导致群落水平响应的主要因素的相对重要性因区域过程以及这些群落中优势物种的环境条件适宜性而异。这些响应也由内在的群落机制决定，这些机制导致不同区域中梯度驱动的群落阶段具有高度相似性。
