半干旱黄土小流域不同恢复方式对生态系统多功能性的影响

在黄土高原大规模退耕还林（草）背景下,植被恢复对生态系统功能会产生极大影响。以往研究多为比较不同恢复方式或植被类型的单一生态系统功能,对生态系统多功能性的研究亟待加强。因此,基于甘肃定西龙滩流域3种恢复方式（天然荒草、自然恢复、人工恢复）6种植被类型（长芒草草地、赖草草地、苜蓿草地、柠条灌丛、油松林、山杏林）38个样地调查数据,选取与土壤养分储存与循环、水源涵养、初级生产力、多样性维持等相关的23个功能指标利用平均值法量化生态系统多功能性。研究结果显示,（1）除营养物转化与循环功能外,其余土壤相关的生态系统功能在不同恢复方式与植被类型间均具有显著性差异（P<0.05）。人工恢复植被的土壤肥力显著高于自然恢复植被;人工恢复植被中土壤肥力从高到低依次为柠条灌丛、苜蓿草地、山杏林、油松林。自然恢复植被的水源涵养功能显著高于人工恢复植被。（2）除植物生长策略外,其余植物相关的生态系统功能在不同恢复方式与植被类型间均具有显著性差异（P<0.05）。人工恢复植被中地上初级生产力从高到低依次为山杏林、油松林、柠条灌丛、苜蓿草地,并显著高于自然恢复植被。人工恢复植被中植物养分吸收能力从高到低依次为苜蓿草地、柠条灌丛、油松林、山杏林,并显著高于自然恢复植被。自然恢复植被的物种多样性显著高于人工恢复植被。（3）生态系统多功能性在不同恢复方式与植被类型间均具有显著性差异（P<0.05）。生态系统多功能性表现为人工恢复植被高于自然恢复植被,但人工恢复植被的水源涵养功能与物种多样性均低于自然恢复植被,不利于生态系统的可持续发展。研究认为,在植被恢复具体实践中,应针对不同的恢复目标,根据各植被类型的功能特征,制定因地制宜的植被恢复战略。

Effects of different restoration methods on ecosystem multifunctionality in the semi-arid loess small watershed

Along with the large-scale "Grain for Green" in the Loess Plateau, vegetation restoration significantly affected ecosystem functions. Previous studies have mostly compared the functions of a single ecosystem with different restoration methods or vegetation types, and the research on ecosystems multifunctionality needs to be strengthened urgently. We conducted an ecosystem multifunctionality study in Longtan watershed of Dingxi, Gansu Province, China, based on survey data from 38 plots, which included 3 restoration methods (native grassland, natural restoration and artificial restoration) and 6 vegetation types (Stipa bungeana grassland, Leymus secalinus grassland, Medicago sativa grassland, Caragana korshinskii shrubland, Pinus tabuliformis forestland and Armeniaca sibirica forestland), We selected 23 functional indexes related to soil nutrient storage and transformation cycle, water conservation, primary productivity, and diversity maintenance to quantify ecosystem multifunctionality by averaging approach. The results showed that (1) except for nutrient transformation and recycling, the soil single ecosystem function had significant differences among different restoration methods and vegetation types (P<0.05). The soil fertility function of artificial restoration vegetation was significantly higher than that of natural restoration vegetation (P<0.05). The soil fertility of artificial restoration vegetation was in the order Caragana korshinskii shrubland, Medicago sativa grassland, Armeniaca sibirica forestland and Pinus tabuliformis forestland from high to low. The water conservation functional of natural restoration vegetation was significantly higher than that of artificial restoration vegetation (P<0.05). (2) Except for plant growth strategies function, the plant single ecosystem function had significant differences among different restoration methods and vegetation types (P<0.05). The above ground primary productivity of artificial restoration vegetation was significantly higher than that of natural restoration vegetation (P<0.05). The above ground primary productivity of artificial restoration vegetation was in the order Armeniaca sibirica forestland, Pinus tabuliformis forestland, Caragana korshinskii shrubland, Medicago sativa grassland from high to low. The plant nutrient absorption function of artificial restoration vegetation was significantly higher than that of natural restoration vegetation (P<0.05). The plant nutrient absorption of artificial restoration vegetation was in the order Medicago sativa grassland, Caragana korshinskii shrubland, Pinus tabuliformis forestland and Armeniaca sibirica forestland from high to low. The species diversity maintenance of natural restoration vegetation was significantly higher than that of artificial restoration vegetation (P<0.05). (3) Ecosystem multifunctionality had significant differences among different restoration methods and vegetation types (P<0.05). Ecosystem multifunctionality of artificial restoration vegetation was significantly higher than that of natural restoration vegetation, but the water conservation and species diversity of the artificial restoration vegetation were lower than that of the natural restoration vegetation, which was not conducive to the sustainable development of the ecosystem. It is considered that in the practice of vegetation restoration, vegetation restoration strategy should be formulated according to the different restoration objectives and the functional characteristics of each vegetation type.