| Resource & environmental sciences |
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| Response of community distribution and biodiversity of grassland plants to environmental factors based on a “3circles” paradigm |
| WANG Xing1, SONG Naiping1,2*, YANG Xinguo2 |
| (1. School of Agriculture, Ningxia University, Yinchuan 750021, China; 2. Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration of North-western China/Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in North-western China of Ministry of Education, Ningxia University, Yinchuan 750021, China) |
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Abstract To obtain the relationship between the pattern of plant community biodiversity and distribution and environmental factors, we conducted a study in a “3-circles” paradigm, which included grassland, sand, and beach land. Based on the “3-circles” paradigm, a 11.7 km land belt was selected, including three land types of girder land, slope land and beach land, which represented grassland, sandy land and wet land, respectively, and located in the ecotone area of grassland and sandy land in Wanjigou and Shabianzi villages of Yanchi County, Ningxia, China. Vegetation characteristics, soil water content at different layers, litter biomass and faeces counts on the ground and elevation were surveyed in August 2012. We conducted a clustering analysis by the important value of dominate species and then analyzed the relationship among the spatial distribution of community and biodiversity and different environmental factors (soil water content, litter biomass, faeces counts and elevation) by redundancy analysis (RDA).
Results showed that: 1) A total of 56 plant species were recorded, including 14 families and 38 genera. The grasses, legumes and weeds were shown as the main species. The average coverage of plant showed a good restoration effect in comparison with that before enclosure and grazing prohibition, but the community structure did not change significantly, and psammophytic species were still the dominant species. The value (0.2-2) of plant diversity was lower, and the interferential factors (litter biomass and faeces counts on the ground) had significant effects, which were primary factors for the changes of plant biodiversity along the belt. 2) The plant communities were classified into 12 groups at the fifth level of division by twoway indicator species analysis (TWINSPAN) and were classified into five groups by detrended correspondence analysis (DCA). The results of TWINSPAN and DCA were similar in the level of vegetation type in the desert steppe. The soil water content (60-80 cm) had a significant influence and it controlled the spatial distribution patterns of the plant community.
In summary, under the “3-circles” belt condition, the spatial distribution of water resource in deep soil layer and interferential factors on the ground lead to the distinguished patch features of grassland. In the landscape level, the spatial distribution of soil water resource influenced the spatial distribution of plant community, and the interferential factors drived the change of plant diversity. There existed arduousness and feasibility in the restoration process of desert steppe, and the integration of geography and biology provide a new way for the restoration of desert steppe. Based on the redistribution of soil water resource in the zone of “3-circles”, future studies would focus on the spatial relationship between the soil water resource and community type, which will help make sure a reasonable and scientific program in ecological restoration and reconstruction in the desert steppe.
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Published: 19 November 2016
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Corresponding Authors:
SONG Naiping （http://orcid.org/0000-0003-0444-498X），E-mail:songnp@163.com
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基于“3圈”模式的草地植物群落分布及多样性对环境因子的响应
为了解“3圈”模式下草地-湿地-沙地群落交错带植被分布格局及多样性与环境因子间的关系，2012年在宁夏盐池县皖记沟村与沙边子村的草原向沙地过渡区设置一条长11.7 km的“3圈”样带，贯穿硬梁、坡地、滩地3种地貌，调查并分析植物群落及多样性与土壤水分、海拔、地表羊粪量、枯落物量间的关系。结果表明：1）研究区共记录草本植物56种，隶属于14科38属，以禾本科和豆科植物以及农田杂草类为主；草本植物盖度较禁牧前有所提高，但植物群落结构简单，仍然以沙生植物为主，植物多样性较低；地表枯落物量、地表羊粪量等干扰因素对其具有显著影响，是植物多样性的首要控制因子。2）双向指示种分析法(two-way indicator species analysis，TWINSPAN)在第5级分类水平上将植被划分为12个群落类型，除趋势对应分析法（detrended correspondence analysis，DCA）排序将植被划分为5个群系，且DCA排序结果是TWINSPAN 5级分类在植被型层次上的空间体现；深层（60~80 cm）土壤水分含量和地表枯落物含量显著影响植物群落分布，是植物群落分布格局的控制因子。总之，在“3圈”模式下，土壤水分资源的空间分布和外在干扰作用导致草地群落空间变异性较强，斑块化特征较为明显。其中，深层土壤水分资源的再分配影响着植物群落在景观上的空间分布特征，而外在干扰因素则驱动了植物多样性的变化。未来的草地植被恢复应基于“3圈”地带土壤水分异域性基础上展开，深入认识土壤水分资源再分配与植被空间分布关系，合理、科学地恢复和重建荒漠草原生态环境。
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