What drives diversification in a pantropical plant lineage with extraordinary capacity for long-distance dispersal and colonisation?

Aim: Colonisation of new areas may entail shifts in diversification rates linked to biogeographic movement (dispersification), which may involve niche evolution if species were not pre-adapted to the new environments. Scleria (Cyperaceae) includes c. 250 species and has a pantropical distribution suggesting an extraordinary capacity for long-distance dispersal and colonisation. We investigate patterns of diversification in Scleria, and whether they are coupled with colonisation events, climate niche shifts or both. Location:Â Tropics and subtropics. Taxon: Nutrushes Scleria (Cyperaceae). Methods: We used molecular data from three DNA regions sequenced for 278 accessions representing 140 Scleria taxa (53% of species) to develop a chronogram, model ancestral ranges, and measure rates of diversification. Integrating data from 12,978 digitised and georeferenced herbarium records, we investigated niche evolution. Results: High dispersal rates in Scleria, a genus with multiple disp...研究目的：开拓新分布区可能引发与生物地理迁移相关的分化速率变化，该过程即扩散演化（dispersification）；若物种未预先适应新环境，则该过程可能伴随生态位演化（niche evolution）。球柱草属（Scleria）隶属于莎草科（Cyperaceae），全属约含250种，呈泛热带分布，这暗示其具备极强的长距离扩散与拓殖能力。本研究旨在解析球柱草属的分化模式，并探究该模式是否与拓殖事件、气候生态位偏移相关，或二者兼具。 研究区域：热带与亚热带地区。 研究类群：球柱草属（Scleria，俗称坚果莎草Nutrushes），隶属于莎草科（Cyperaceae）。 研究方法：本研究针对覆盖140个球柱草类群（占该属物种总数的53%）的278份采集样品，对3个DNA区域进行测序以获取分子数据，借此构建时间校准系统发育树（chronogram）、模拟祖先分布区，并估算分化速率。此外，本研究整合了12978条经数字化处理并标注地理坐标的标本馆记录数据，对生态位演化展开分析。 研究结果：球柱草属具有极高的扩散速率，该属存在多种扩散……