Wang Jianming, Wang Yin, Qu Mengjun, Feng Yiming, Wu Bo, Lu Qi, He Nianpeng, Li Jingwen
School of Ecology Nature Conservation, Beijing Forestry University, Beijing, China.
Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Science, Beijing, China.
Front Plant Sci. 2022 Jul 18;13:952074. doi: 10.3389/fpls.2022.952074. eCollection 2022.
The mechanism governing plant community assembly across large-scale Gobi deserts remains unclear. Here, we inferred the roles of different assembly processes in structuring plant communities in the Gobi deserts of the Qinghai-Tibet Plateau by using a phylogenetic tree, and leaf and root traits. The functional and phylogenetic structures of 183 plant communities were assessed, and their distributions were linked with environmental gradients. Our results demonstrated that functional convergence was prevalent in most functional traits (75% of the traits) and accentuated when all traits were combined. The phylogenetic structure exhibited significant divergence. We observed the contrasting response of functional and phylogenetic assembly structures to environmental gradients. More importantly, we found that the shifts in the functional assembly along environmental gradients were trait-specific, with dominant roles of local factors, such as gravel coverage and soil attributes, in determining the distribution patterns of most traits. However, the distribution patterns of leaf P concentration (LPC), root N concentration (RNC), and root P concentration (RPC) were mainly driven by climatic factors. These results reveal that niche-based processes, such as abiotic filtering and weaker competitive exclusion, are the major drivers of species co-occurrence, which results in the widespread coexistence of phylogenetically distinct but functionally similar species within the Gobi plant community. Our findings could improve the understanding of plant community assembly processes and biodiversity maintenance in extremely harsh drylands.
跨大尺度戈壁沙漠的植物群落组装机制仍不清楚。在此，我们通过使用系统发育树以及叶片和根系性状，推断了不同组装过程在青藏高原戈壁沙漠植物群落构建中的作用。评估了183个植物群落的功能和系统发育结构，并将它们的分布与环境梯度联系起来。我们的结果表明，功能趋同现象在大多数功能性状（75%的性状）中普遍存在，并且在所有性状综合考虑时更为突出。系统发育结构表现出显著的分歧。我们观察到功能和系统发育组装结构对环境梯度的响应截然不同。更重要的是，我们发现功能组装沿环境梯度的变化具有性状特异性，在决定大多数性状的分布格局方面，局部因素（如砾石覆盖度和土壤属性）起主导作用。然而，叶片磷浓度（LPC）、根系氮浓度（RNC）和根系磷浓度（RPC）的分布格局主要受气候因素驱动。这些结果表明，基于生态位的过程，如非生物过滤和较弱的竞争排斥，是物种共存的主要驱动因素，这导致了戈壁植物群落中系统发育不同但功能相似的物种广泛共存。我们的研究结果有助于增进对极端干旱恶劣地区植物群落组装过程和生物多样性维持的理解。
