两种修复方式对青藏高原取弃土场修复后草地盖度的影响

Effect of two restorations on the grassland coverage after remediation of take-abandon soil field on the Qinghai-Tibet Plateau

以公路工程建设为代表的人类活动和气候变化深刻影响高寒草地生态系统的功能。为探索不同修复方式对丧失主要功能的高寒草地生态系统的修复效果,选择青海省共玉高速旁因修路产生并经修复的取弃土场为研究对象,使用VegCover软件测定草地盖度,探讨了两种不同修复方式(种草法和草皮移植法)修复后青藏高原上低海拔(3012和3335m)、中海拔(4229和4302m)和高海拔(4433和4577m)样地的草地盖度差异及其与环境因子的关系。结果表明,使用草皮移植修复后的草地盖度(42.3%)显著高于使用种草法修复的草地盖度(16.8%)(P<0.05);使用种草法修复的草地盖度随海拔增加显著降低(P<0.05),而使用草皮移植修复的草地盖度在不同海拔样地间差异不显著(P>0.05)。两种修复方式下草地盖度的自然对数响应比随海拔的增加而增加(r=0.37,P<0.05)。研究结果说明,采用草皮移植法对于高寒草地群落盖度的修复效果优于种草法,种草法不适用于青藏高原高海拔区域取弃土场草地修复。

Human activities and climate change have important impacts on the alpine grassland ecosystem of the Qinghai- Tibet Plateau. Human activities represented by highway construction affect the function of alpine grassland ecosystem. In order to explore the recovery effects of different restoration methods on the alpine grassland ecosystem, we selected six grassland sites after two restorations (seeding method and turf method) along the elevational gradient. The coverage of the low (3 012 and 3 335 m), medium (4 229 and 4 302 m) and high (4 433 and 4 577 m) elevation sites after two restorations was measured by VegCover. We found that the coverage of turf treatment (42.3%) is significantly higher than that of the grass in the field of seeding (16.8%). The grass coverage of seeding treatment decreased significantly with the increase of elevation, but no statistic difference of the coverage of turf treatment was detected along the elevational gradient. As a result, the natural logarithm response ratio of the degree of grassland coverage under the two restorations increased significantly with the increase of elevation (r = 0.37, P < 0.05). These results suggest that turf is a better way to repair the gauntlet of the alpine meadow and the seeding method is not to be used for the temporary grassland repair in the high-altitude area.