浑善达克退化沙地草地生态恢复试验研究

选择草地退化十分严重的浑善达克沙地腹地开展恢复生态学研究 ,试图寻求沙地草地生态恢复的新途径。采取“以地养地”模式 ,在小范围的土地上 ,建立高产饲草基地 ,使牲畜的压力逐步向高效地集中 ,同时改变畜群结构 ,解决当地牧民生活出路 ;而大面积的退化草地 ,主要借助自然力恢复。结果表明 ,自然力在浑善达克沙地退化生态系统恢复中起到巨大的作用 ,群落生物量、平均高度和总盖度 2年后均随恢复时间增加而增加 ( P<0 .0 5 )。流动沙丘的裸沙 ,经 2 a自然恢复后 ,生物量达 1 0 1 2 g/m,总盖度高达 60 %。与对照相比 ,封育 2 a后固定沙地群落盖度增加近 3倍 ;滩地群落生物量提高了 9倍 ,平均高度增加 4倍。植被组成方面 ,恢复前固定沙地以冷蒿 ( Artemisia frigida)、糙隐子草 ( Cleistogens squarrosa)和寸草苔 ( Carexduriuscula)等为主 ,恢复 2 a后冰草 ( Agropyron cristatum)、褐沙蒿 ( Artemisia intramongolica)等占优势 ;滩地植被中 ,羊草 ( L eymus chinensis)、披碱草 ( Elymus dahuricus)等逐步取代了灰绿藜 ( Chenopodiumglaucum)和尖头叶藜 ( Chenopodium acuminatum)等。生态恢复不仅使自然生态系统得以保护 ,而且带动了社会经济的发展 ,项目中的正蓝旗巴音胡舒嘎查牧民 ,在实验示范前后

An experimental and demonstrational study on restoration of degraded ecosystems in Hunshandak Sandland

Many practices dealing with restoration of degraded ecosystems have been conducted around the world since 1920s.However, such practices came to being only after 1980s in China. Although a number of measures have been applied on various degraded ecosystems, methods used in China mainly focus on vegetation establishment while neglected the ability of natural process. Meanwhile, less attention had been paid to the production and livelihood requirements of the local people. Therefore, it is hard to maintain the positive effects of the practices in the point of sustainable development view. As one of the four largest sand lands in China, Hunshandak Sandland was once the flourish grassland, but now it has been degraded seriously, with shifting sand dune accounting 50 % of the whole. The area of shifting dune is 20 folds of that 50 years ago. The strong wind, occurring always in the winter and the spring with an average speed of 4~5 m/s and the strongest 30m/s, greatly intensified the degradation. Furthermore, heave windy storms directly threaten the ecological environment of Beijing and Tianjin. So, it is urgent to restore such degraded ecosystems for the sake of both ecological security and survivals of local society. The aim of this paper is to probe the probability of restoration of degraded grassland through natural process. The main methodology we utilized was to intensively plant forages for the animals in a small part of the lands (only 1%) of the village we chose, while the large part of the lands (99%) was enclosed for recovering by natural processs, without planting any trees or grasses via aerial seeding. Changes of natural vegetation, economic development and the changes of ideality of local people during the experimental period in a small village of Bayinhushu, Zhenglan Banner, were also investigated. The results showed that biomass, height and coverage of plant community in most of the habitats have been significantly increased after 2 years regeneration (P<0.05). The average biomass was 1012 g/m~(2) and the mean coverage reached 60 % in shifting sand dunes where it was bare sand dunes before enclosing. In fixed sand dunes, total community coverage was 3 fold of that of control. The original dominated species Artemisia frigida and Artemisia commutata were replaced by Artemisia intramongolica and Agropyron cristatum,etc. The biomass in lowland was increased by 9 fold of control. Before experiment, the predominant species was Chenopodium glaucum and Chenopodium acuminatum, but now Festuca ovina and Elymus dahuricus are the ascendant species in the lowland. Economy of local society has developed greatly as well. For example, young stocks survival rate has increased by 10% and milk production by 200% from 1998 to 2002. This study reveals that degraded ecosystems in Hunshandak Sandland might be regenerated by natural process as long as the pasturing stress has been alleviated. In order to achieve this, however, planting higher efficient forage was vital so as to assure sustainable economic development and prevent further grassland degradation. Through this case study, we may suggest that the ecological restoration of Hunshandak degraded sand land should mainly depend largely on nature process rather than artificial vegetation reconstructions in the natural sand lands.