Key Laboratory of Resource Biology and Biotechnology in Western China, Ministry of Education, Northwest University, Xi'an 710069, China; State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling 712100, China.
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Northwest A & F University, Yangling 712100, China.
Sci Total Environ. 2021 Jun 15;773:144878. doi: 10.1016/j.scitotenv.2020.144878. Epub 2021 Jan 27.
Robinia pseudoacacia is regarded as a valuable but problematic plant due to its positive and negative environmental effects. A comprehensive and mechanistic understanding of the effects of R. pseudoacacia afforestation on ecosystems and striking a balance between ecosystem safety and functioning and R. pseudoacacia naturalization are crucially important. To achieve these goals, studying the community functional structure of R. pseudoacacia plantations is an essential prerequisite that remains understudied. Through quantifying and comparing the functional structure of R. pseudoacacia plantations and naturally restored communities relating to soil erosion control and plant ecology strategies along a 10-40-year chronosequence on the hilly and gullied Loess Plateau, China, we assessed the effects of R. pseudoacacia afforestation on plant community structure from a functional perspective. We found significant differences among restoration strategies in all the functional composition indices but only functional divergence (FDiv) indices, suggesting that the afforestation practice had a great impact on functional composition but not on functional diversity. Specifically, the plantations had relatively high community-weighted means (CWMs) of specific leaf area (SLA), plant height (PH), seed production, seed mass, root mean diameter, clonality and resprouting capacity and high FDivs of the leaf-height-seed scheme and persistence traits, partially suggesting that the exotic tree could naturalize and coexist with native plants in the study area. Moreover, the relatively high CWMs of woodiness, PH and SLA and high FDiv of erosion-control-related traits found in the plantations indicate that the plantations might have superiority in soil erosion control. R. pseudoacacia also had a homogenization effect on understory functional composition and divergence. Furthermore, we proposed a trait-based effect-and-response framework to find the balance, thus achieving sustainable coexistence of the exotic species with ecosystems. This study may provide new prospects for management practices of R. pseudoacacia plantations and a robust scaffold to maintain safe, resilient and functioning ecosystems.
刺槐被认为是一种有价值但有问题的植物，因为它对环境既有积极影响，也有消极影响。全面而深入地了解刺槐造林对生态系统的影响，以及在生态系统安全和功能之间取得平衡，实现刺槐的自然归化，这是至关重要的。为了实现这些目标，研究刺槐人工林的群落功能结构是一个必不可少的前提，但这方面的研究还很不足。本研究通过沿中国黄土丘陵沟壑区 10-40 年的时间序列，量化和比较刺槐人工林和自然恢复群落的功能结构，以评估刺槐造林对植物群落结构的功能影响。我们主要从土壤侵蚀控制和植物生态策略两个方面进行研究。研究结果表明，在所有功能组成指数中，除功能离散度（FDiv）指数外，各恢复策略之间均存在显著差异，这表明造林实践对功能组成有很大影响，但对功能多样性没有影响。具体来说，人工林的比叶面积（SLA）、株高（PH）、种子产量、种子质量、根平均直径、克隆和萌蘖能力的群落加权平均值（CWMs）较高，叶-高-种策略和持久性特征的 FDiv 较高，这部分表明外来树种可以在研究区域内自然归化并与本地植物共存。此外，人工林中发现的木质化、PH 和 SLA 的 CWMs 相对较高，以及与土壤侵蚀控制相关的特征的 FDiv 较高，表明人工林在土壤侵蚀控制方面可能具有优势。刺槐对林下功能组成和差异也有同质化效应。此外，我们提出了一个基于特征的效应和响应框架来寻找平衡，从而实现外来物种与生态系统的可持续共存。本研究可能为刺槐人工林的管理实践提供新的前景，并为维持安全、有弹性和功能齐全的生态系统提供一个稳健的框架。
