Department of Biology and Geology, Rey Juan Carlos University, C/Tulipán s/n, 28933, Móstoles, Madrid, Spain.
Botanic Institute of the University of Castilla-La Mancha, Castilla-La Mancha Botanic Garden, Avda. de La Mancha s/n, 02006, Albacete, Spain.
Sci Rep. 2021 Nov 18;11(1):22499. doi: 10.1038/s41598-021-01991-z.
Although the role played by phylogeny in the assembly of plant communities remains as a priority to complete the theory of species coexistence, experimental evidence is lacking. It is still unclear to what extent phylogenetic diversity is a driver or a consequence of species assembly processes. We experimentally explored how phylogenetic diversity can drive the community level responses to drought conditions in annual plant communities. We manipulated the initial phylogenetic diversity of the assemblages and the water availability in a common garden experiment with two irrigation treatments: average natural rainfall and drought, formed with annual plant species of gypsum ecosystems of Central Spain. We recorded plant survival and the numbers of flowering and fruiting plants per species in each assemblage. GLMMs were performed for the proportion of surviving, flowering, fruiting plants per species and for total proportion of surviving species and plants per pot. In water limited conditions, high phylogenetic diversity favored species coexistence over time with higher plant survival and more flowering and fruiting plants per species and more species and plants surviving per pot. Our results agree with the existence of niche complementarity and the convergence of water economy strategies as major mechanisms for promoting species coexistence in plant assemblages in semiarid Mediterranean habitats. Our findings point to high phylogenetic diversity among neighboring plants as a plausible feature underpinning the coexistence of species, because the success of each species in terms of surviving and producing offspring in drought conditions was greater when the initial phylogenetic diversity was higher. Our study is a step forward to understand how phylogenetic relatedness is connected to the mechanisms determining the maintenance of biodiversity.
尽管系统发育在植物群落组装中的作用仍然是完成物种共存理论的首要任务，但缺乏实验证据。系统发育多样性在多大程度上是物种组装过程的驱动因素或结果尚不清楚。我们通过实验探索了系统发育多样性如何能够驱动一年生植物群落对干旱条件的群落水平响应。我们在一个共同花园实验中操纵了组合的初始系统发育多样性和水分可用性，该实验有两种灌溉处理：平均自然降雨和干旱，由西班牙中部石膏生态系统的一年生植物物种组成。我们记录了每个组合中植物的存活率以及每种植物的开花和结实植物的数量。对每种植物的存活率、开花植物和结实植物的比例以及每个花盆中存活的物种和植物的总比例进行 GLMM 分析。在水分有限的条件下，高系统发育多样性有利于物种共存，随着时间的推移，植物存活率更高，每种植物的开花植物和结实植物更多，每个花盆中存活的物种和植物更多。我们的结果与生态位互补和趋同的水经济策略的存在一致，这是促进半干旱地中海生境中植物组合中物种共存的主要机制。我们的研究结果表明，相邻植物之间的高系统发育多样性是支持物种共存的一个合理特征，因为在初始系统发育多样性较高的情况下，每种植物在干旱条件下生存和繁殖后代的成功更大。我们的研究是理解系统发育相关性如何与决定生物多样性维持的机制相关联的重要一步。
