Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
Key Laboratory for Plant and Biodiversity of East Asia, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, China.
Ecol Lett. 2018 Oct;21(10):1515-1529. doi: 10.1111/ele.13132. Epub 2018 Aug 21.
Dispersal is a fundamental ecological process, yet demonstrating the occurrence and importance of long-distance dispersal (LDD) remains difficult, having rarely been examined for widespread, non-coastal plants. To address this issue, we integrated phylogenetic, molecular dating, biogeographical, ecological, seed biology and oceanographic data for the inland Urticaceae. We found that Urticaceae originated in Eurasia c. 69 Ma, followed by ≥ 92 LDD events between landmasses. Under experimental conditions, seeds of many Urticaceae floated for > 220 days, and remained viable after 10 months in seawater, long enough for most detected LDD events, according to oceanographic current modelling. Ecological traits analyses indicated that preferences for disturbed habitats might facilitate LDD. Nearly half of all LDD events involved dioecious taxa, so population establishment in dioecious Urticaceae requires multiple seeds, or occasional selfing. Our work shows that seawater LDD played an important role in shaping the geographical distributions of Urticaceae, providing empirical evidence for Darwin's transoceanic dispersal hypothesis.
扩散是一个基本的生态过程，但要证明长距离扩散（LDD）的发生和重要性仍然很困难，因为很少有研究关注广泛分布的非沿海植物的 LDD。为了解决这个问题，我们整合了内陆荨麻科的系统发育、分子定年、生物地理、生态学、种子生物学和海洋学数据。我们发现荨麻科起源于欧亚大陆约 6900 万年前，随后在陆地上发生了≥92 次长距离扩散事件。在实验条件下，许多荨麻科的种子漂浮超过 220 天，在海水中存活 10 个月后仍具有活力，足以满足大多数检测到的 LDD 事件，这是根据海洋流模型推断的。生态特征分析表明，对干扰生境的偏好可能有助于 LDD。近一半的 LDD 事件涉及雌雄异株类群，因此雌雄异株荨麻科的种群建立需要多个种子，或偶尔的自交。我们的研究表明，海水 LDD 在塑造荨麻科的地理分布方面发挥了重要作用，为达尔文的跨洋扩散假说提供了经验证据。
