What explains high plant richness in East Asia? Time and diversification in the tribe Lysimachieae (Primulaceae)

First author: Hai‐Fei Yan; Affiliations: South China Botanical Garden, Chinese Academy of Sciences (中科院华南植物园): Guangzhou, China

Corresponding author: Xue‐Jun Ge& John J. Wiens (美国亚利桑那大学)

What causes the disparity (不一致) in biodiversity among regions is a fundamental question in biogeography, ecology, and evolutionary biology. Evolutionary and biogeographic processes (speciation, extinction, dispersal) directly determine species richness patterns, and can be studied using integrative phylogenetic approaches. However, the strikingly high richness of East Asia relative to other Northern Hemisphere regions remains poorly understood from this perspective. Here, for the first time, we test two general hypotheses (older colonization time, faster diversification rate) to explain this pattern, using the plant tribe Lysimachieae (Primulaceae; 报春花科) as a model system. We generated a new time‐calibrated phylogeny for Lysimachieae (13 genes, 126 species), to estimate colonization times and diversification rates for each region and to test the relative importance of these two factors for explaining regional richness patterns. We find that neither time nor diversification rates alone explain richness patterns among regions in Lysimachieae. Instead, a new index that combines both factors explains global richness patterns in the group and their high East Asian biodiversity. Based on our results from Lysimachieae, we suggest that the high richness of plants in East Asia may be explained by a combination of older colonization times and faster diversification rates in this region.

不同区域生物多样性的不一致性是生物地理、生态以及演化生物学的一个基础性问题。演化和生物地理的进程，包括物种形成、灭绝和扩散直接决定了物种丰度模式，则可以通过综合的进化分析方法来进一步研究。然而，目前对于相比于北半球其它地区，东亚异常高的物种丰度仍然了解的很少。本文，作者首次通过利用报春花科作为模式系统来测试植物物种古老的殖民时间和分化速率这两个因子对于东亚物种丰度高的影响。作者通过13个基因构建了报春花科126个物种新的标定时间的系统发育树，用来估计每个区域植物的殖民时间和分化速率，测试这两个因子对于区域性植物物种丰度模式的相对重要性。作者发现，无论是古老的殖民时间或者是分化速率都不能单独的解释不同区域间植物物种丰度模式。反而，作者发现一个结合这两个因子的新的指标可以用来解释全球区域的植物物种丰度模式，并且能够解释东亚高的生物多样性缘由。基于本文对于报春花科的分析，作者显示东亚植物物种丰度较高是因为该区域有着更加古老的殖民时间和更快的分化速率所导致的。

通讯：葛学军 (http://sourcedb.scib.cas.cn/zw/rck/200908/t20090814_2401337.html)

个人简介：1981-1985年，河北大学，生物系学士；1985-1988年，中科院新疆生态与地理所，植物学硕士；1997-2001年，香港大学，动物学系保护生物学博士。

研究方向：植物适应性进化的遗传机制。

doi: https://doi.org/10.1111/nph.15144

Journal: New Phytologist

First Published date: 17 April, 2018

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