Zhang Yan, Wang Guohua, Gou Qianqian, Zhang Yu, Liu Jing, Gao Min
College of Geographical Sciences, Shanxi Normal University, Taiyuan, China.
Key Laboratory of Desert and Desertification, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Science, Lanzhou, China.
Front Plant Sci. 2023 Feb 17;14:1091446. doi: 10.3389/fpls.2023.1091446. eCollection 2023.
Fencing is the most economical method of restoring degraded desert ecosystems, and plays an important role in promoting plant community diversity and productivity, as well as stable ecosystem structure and function. In this study, we selected a typical degraded desert plant community (-) on the edge of a desert oasis in the Hexi Corridor in northwest China. We then investigated succession in this plant community and corresponding changes in soil physical and chemical characteristics over 10 years of fencing restoration to analyze the mutual feedback mechanisms. The results showed that: 1) The diversity of plant species in the community increased significantly over the study period, especially the number of herbaceous layer species, which increased from four in the early stage to seven in the late stage. The dominant species also changed, with the dominant shrub layer species shifting from in the early stage to in the late stage. The dominant herbaceous layer species changed from the annual herb in the early stage to and in the middle stage, and ultimately to and in the late stage. In the late stage, , , and began to invade, and the density of perennial herbs also increased significantly (from 0.01 m to 0.17 m for in year seven). 2) As the duration of fencing increased, the soil organic matter (SOM) and total nitrogen (TN) contents first decreased then increased, whereas the available nitrogen, potassium, and phosphorus contents showed the opposite trend. 3) Changes in community diversity were mainly affected by the nursing effects of the shrub layer, as well as soil physical and chemical properties. That is, fencing significantly increased the vegetation density of the shrub layer, which promoted growth and development of the herbaceous layer. However, community species diversity was positively correlated with SOM and TN. The diversity of the shrub layer was positively correlated with the water content of deep soil, whereas that of the herbaceous layer was positively correlated with SOM, TN, and soil pH. The SOM content in the later stage of fencing was 1.1 times that in the early stage of fencing. Thus, fencing restored the density of the dominant shrub species and significantly increased species diversity, especially in the herb layer. Studying plant community succession and soil environmental factors under long-term fencing restoration is highly significant for understanding community vegetation restoration and ecological environment reconstruction at the edge of desert oases.
围栏封育是恢复退化荒漠生态系统最经济的方法，在促进植物群落多样性和生产力以及稳定生态系统结构和功能方面发挥着重要作用。在本研究中，我们选择了中国西北河西走廊沙漠绿洲边缘一个典型的退化荒漠植物群落（-）。然后，我们调查了该植物群落的演替情况以及围栏封育10年间土壤理化性质的相应变化，以分析相互反馈机制。结果表明：1）在研究期间，群落中植物物种的多样性显著增加，尤其是草本层物种数量，从早期的4种增加到后期的7种。优势种也发生了变化，灌木层优势种从早期的 转变为后期的 。草本层优势种从早期的一年生草本 转变为中期的 和 ，最终在后期转变为 和 。在后期， 、 和 开始入侵，多年生草本的密度也显著增加（第7年时 从0.01 m增加到0.17 m）。2）随着围栏封育时间的增加，土壤有机质（SOM）和全氮（TN）含量先降低后升高，而速效氮、钾和磷含量则呈现相反的趋势。3）群落多样性的变化主要受灌木层的保育作用以及土壤理化性质的影响。也就是说，围栏封育显著增加了灌木层的植被密度，从而促进了草本层的生长发育。然而，群落物种多样性与SOM和TN呈正相关。灌木层的多样性与深层土壤含水量呈正相关，而草本层的多样性与SOM、TN和土壤pH呈正相关。围栏封育后期的SOM含量是围栏封育早期的1.1倍。因此，围栏封育恢复了优势灌木物种的密度，并显著增加了物种多样性，尤其是在草本层。研究长期围栏封育恢复下的植物群落演替和土壤环境因素，对于理解沙漠绿洲边缘的群落植被恢复和生态环境重建具有重要意义。
