Geographical limits of species’ distributions are assumed to be coincident with ecological margins, although this assumption might not always be true. Indeed, harsh environments such as Alpine and Mediterranean ecosystems may favour high phenotypic variability among populations, especially those in peripheral sites. Floral traits are often found to be less variable and less affected by environmental heterogeneity than vegetative traits because variation in the former may have negative effects on fitness. For this reason, it is important to quantify variation in floral traits and plant fecundity in study range limits. The objective of the study is to examine phenotypic variation and differences in reproduction in endemic Lilium pomponium in the Maritime and Ligurian Alps in relation to environmental variation across its distribution range. In this species, marginal climatic populations occur both in the peripheral and central geographical locations of the distribution range; hence, geographical and ecological gradients are not concordant. Floral trait variation is related to local environmental conditions with an array of interactions among resource availability, potential pollen limitation and population size that are differentially related to floral traits. Contrary to the general expectation, all central and peripheral populations had similar, moderate seed production with each group limited by different factors acting on different stages of the life-history strategy. Our results are in line with the idea that general expectations are confirmed only when its assumptions are met and that the differences in pollination environment along an environmental gradient may not be the main determinant of the distribution limit.

尽管这种假设可能并不总是正确的，但假定物种分布的地理极限与生态裕度是一致的。确实，诸如高山和地中海生态系统之类的严酷环境可能有利于种群之间的高表型变异，特别是在外围地区。人们通常发现花卉性状与营养性状相比，变异性较小，受环境异质性的影响较小，因为前者的变异可能会对适应性产生负面影响。因此，重要的是在研究范围内量化花卉性状和植物繁殖力的变化。该研究的目的是检验表型变异和地方性百合绒球的繁殖差异在海洋和利古里亚阿尔卑斯山脉中，其分布范围内的环境变化相关。在该物种中，边缘气候种群分布在分布范围的外围和中央地理位置。因此，地理和生态梯度并不协调。花卉性状的变化与当地环境条件有关，资源可用性，潜在的花粉限制和种群大小之间的一系列相互作用与花卉性状存在差异。与一般预期相反，所有中部和外围群体的种子产量均相似，中等，每组受生活史策略不同阶段作用的不同因素所限制。