Latitudinal and elevational gradients of fern diversity and community composition in Africa and the Indian Ocean Islands

为了研究导致蕨类植物多样性格局的主要驱动因素，将在一个生物地理区域(非洲和邻近的印度洋岛屿)内沿五个海拔梯度进行详细调查，其基本大尺度纬度梯度为30°。这项调查将与已经建立的BRYOLAT项目密切相关，该项目旨在解释同一研究地点苔藓植物的各自模式。蕨类植物海拔丰富度格局沿纬度梯度的变化模式，以及与苔藓植物同时评估的格局的比较，将有助于进一步洞察和加深对环境和其他物种丰富度驱动因素的理解，目前文献中仍有激烈的争论。正如第一次评估的那样，对物种肥力状况的额外观察将揭示对蕨类植物组合的种群动态的洞察，从而有可能检验源-汇动态假说在确定海拔丰富度模式方面的相对作用。邀请参加BRYOLAT项目提供了建立一种难得的调查类型的独特机会：将沿大空间尺度的两种主要梯度类型的丰富度模式与两组生物体进行比较，从而可以直接与物种丰富度模式的潜在驱动因素进行比较。

To study the principle drivers that cause diversity patterns of pteridophytes, a detailed survey will be undertaken along five elevational gradients within one biogeographic region (Africa and adjacent Indian Ocean islands) with an underlying large-scale latitudinal gradient of 30°. The survey will be closely associated with the already established BRYOLAT project, which aims at explaining the respective patterns in the bryophyte vegetation at the same study sites. The mode of change of elevational richness patterns of pteridophytes along the latitudinal gradient and the comparison with the patterns simultaneously assessed for bryophytes will lead to further insight and a deeper understanding of environmental and other drivers of species richness, which are still hotly debated in current literature. As assessed for the first time, additional observations of the fertility status of the species will reveal insights into the population dynamics of pteridophyte assemblages and thus give the possibility to test the hypothesis of source–sink dynamics in its relative role in determining elevational richness patterns. The invitation to participate in the BRYOLAT project offers the unique opportunity of establishing a type of survey that can rarely be found: the comparison of richness patterns along two main gradient types of large spatial scales with two groups of organisms, which thus can be directly compared with respect to underlying drivers of species richness patterns.