黑河中游湿地不同恢复方式对土壤和植被的影响——以张掖国家湿地公园为例

湿地是自然界最富生物多样性的生态景观和人类社会赖以生存和发展的环境之一,对维护生态系统功能和区域生态安全有着重要意义。为阐明不同湿地恢复方式对土壤和植被的影响,以黑河中游地区张掖国家湿地公园为研究对象,比较了自然恢复方式、恢复利用方式和恢复保护方式下植物多样性、植物生长状态、土壤pH、盐分、容重、水分含量、有机碳、全氮、全磷、速效氮、速效磷的变化特征,研究结果表明:在自然恢复方式下,湿地各层土壤全磷、土壤速效磷、土壤速效氮、物种多样性值最高,反映出自然恢复方式可能成为干旱区土壤磷固存的有效手段,适当干扰可能成为干旱区提高物种多样性的有效方法;恢复保护方式下,湿地植物多度最高165.67±25,表明恢复保护方式有助于植被的生长繁殖;恢复利用方式下,湿地各层土壤含水量、土壤有机碳、土壤全氮、植被盖度值最高,土壤盐分含量、土壤pH值最低,湿地物种多样性较高。表明恢复利用方式可以有效降低湿地土壤盐分,提高土壤碳、氮含量的潜力,适当人为管理可能成为干旱区湿地恢复过程中提高湿地物种多样性的有效管理方法。该研究结果对于干旱区湿地恢复、保护与重建的效应评估和恢复方式的选择提供一定的理论支持和决策参考。

Effects of different fallow and wetting methods on soil and vegetation properties in the middle reaches of the Heihe River: a case study of Zhangye National Wetland Park

Wetland is one of the most biologically diverse ecological landscapes in nature and the environment for the survival and development of human society. It is of great significance for the maintenance of ecosystem function and regional ecological security. The purpose of this study was to clarify the impacts of different wetland restoration methods on the physical and chemical properties of the soil and the vegetation characteristics. Inaddition, the application of different wetland restoration methods in arid areas was studied. We used Zhangye National Wetland Park, which is in the middle of the Heihe River, as the research object. Vegetation surveys and soil sampling were conducted in the summer of 2017 on three typical restoration modes in the main area of Zhangye National Wetland Park:natural restoration mode, restoration protection mode, and restoration and utilization mode. The size and road distribution of the area was such that 3-14 samples of 1 m² were used. A total of 25 samples were investigated and it was attempted to ensure that they were evenly distributed within the sample plot. The number and height of individual species were also recorded, and specimens of the individual species were brought back to the laboratory for identification. The soil samples from 0-10, 10-20, and 20-40 cm depth were collected from the center of the sample square by using the ring knife method; these were loaded into aluminum boxes and the fresh weight was measured. Another soil sample was taken from each sampling area and brought back to the laboratory. The litter and roots were collected and dried naturally. To determine the physical and chemical properties of the soil samples collected, they were passed through sieves with diameters of 1 mm, 0.25 mm, and 0.15 mm. The plant diversity, plant growth status, soil pH, soil temperature, and soil temperature under natural restoration, restoration utilization, and restoration protection were compared and analyzed. The variation in the characteristics of salinity, bulk density, water content, organic carbon, total nitrogen, total phosphorus, available nitrogen, and available phosphorus were also studied. The results showed that the soil total phosphorus, soil available nitrogen, and species diversity of each layer of wetland were the highest after natural restoration, which indicated that natural restoration could lead to soil phosphorus fixation in arid areas and that appropriate interference may be an effective method to improve species diversity in arid areas. Under the restoration protection mode, the wetland plants had the highest abundance (165.67±25), which indicated that the restoration protection method was conducive to the growth and reproduction of vegetation; the soil water content, soil organic carbon, soil total nitrogen and vegetation coverage were the highest, whereas the soil salt content and the soil pH value was the lowest, and the wetland species diversity was higher. It is shown that the recovery and utilization can effectively reduce the salt content of wetland soil and improve the potential soil carbon and nitrogen content. Appropriate human management may be an effective management method to improve wetland species diversity during the process of wetland restoration in arid areas. The results of this study have provided a theoretical basis and decision-making reference for the evaluation of wetland restoration, protection, and reconstruction effects and the selection of restoration methods in arid areas.