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假臭草入侵对土壤养分与微生物群落功能多样性的影响

全国明1,2,代亭亭1,章家恩1*,徐嘉琳1#br#   

  1. 1华南农业大学热带亚热带生态研究所, 农业部华南热带农业环境重点实验室, 广东省现代生态农业与循环农业工程技术研究中心, 广州 510642; 2广州城市职业学院城市建设工程系, 广州 510405)
  • 出版日期:2016-11-10 发布日期:2016-11-10

Impacts of Praxelis clematidea invasion on soil nutrient and microbiological characteristics.

QUAN Guo-ming1,2, DAI Ting-ting1, ZHANG Jia-en1*, XU Jia-lin1#br#   

  1. (1Institute of Tropical and Subtropical Ecology, South China Agricultural University/Key Laboratory of AgroEnvironment in the Tropics, Ministry of Agriculture/Guangdong Engineering Research Center for Modern Ecoagriculture and Circular Agriculture, Guangzhou 510642, China; 2Department of Urban Construction Engineering, Guangzhou City Polytechnic, Guangzhou 510405, China).
     
  • Online:2016-11-10 Published:2016-11-10

摘要: 假臭草(Praxelis clematidea)是华南地区的主要外来入侵杂草之一,已对当地的生物多样性、农业生产和生态安全造成严重威胁。采用野外样方法研究了假臭草入侵(入侵年限4~5年)对土壤养分、土壤微生物生物量、土壤酶活性以及土壤微生物群落代谢活性、碳源利用特征与功能多样性的影响。结果表明,与土著灌木丛对照区相比,假臭草入侵使土壤有机质、全氮、碱解氮、速效钾含量显著降低,全磷、速效磷含量的变化不明显,但全钾含量显著上升;土壤微生物生物量碳、氮、磷显著下降;土壤脲酶、蛋白酶、蔗糖酶和过氧化氢酶活性亦显著降低,但土壤纤维素酶活性显著增加;假臭草入侵显著降低土壤微生物群落的功能多样性,平均孔颜色变化率(AWCD)、碳水化合物和羧酸类碳源的利用率以及土壤微生物群落的McIntosh指数(U)、丰富度指数(S)显著下降,Pielou均匀度指数(E)则显著上升,但两处理间的Shannon指数(H)、Simpson优势度指数(Ds)的差异不明显。这说明假臭草入侵造成土壤养分的大量损耗,土壤酶活性与土壤微生物群落功能多样性降低,土壤质量下降。

关键词: 水生植被, 微型无人机影像, 面向对象分类, 监督分类, 可见光植被指数, ESP

Abstract: Praxelis clematidea is one of the nastiest invasive exotic weeds in southern China and poses lots of serious threats to biodiversity, agricultural production and ecological security of native ecosystems. In order to explore impacts of P. clematidea invasion (with an invasion period of 4 to 5 years) on soil ecosystem, we investigated the changes of soil chemical and microbiological properties, including soil nutrient, soil microbial biomass, soil enzyme activity, and metabolic activity, carbon substrate utilization and function diversity of soil microbial community from invaded and native sites in Hainan Island using field plot experiments. The results showed that compared with the native bush sites, the contents of soil organic matter, total nitrogen, alkaline nitrogen and available potassium were significantly decreased while the content of total potassium was significantly increased in the P. clematidea invasion sites. However, there was no significant difference in the contents of total phosphorus and available phosphorus between the invaded and native sites. Soil microbial biomass carbon, nitrogen, and phosphorus, as well as the activities of soil urease, protease, invertase and hydrogen peroxidase in the invaded sites were significantly lower than those in the native bush sites, while the activity of soil cellulase was significantly increased by the P. clematidea invasion. Functional diversity of soil microbial community, calculated from the average well color development (AWCD) of 31 carbon sources in a Biolog EcoPlate, was significantly decreased by the P. clematidea invasion. Compared with the native bush sites, AWCD, microbial utilization efficiency of carbohydrates, carboxylic acids, McIntosh index (U), and  richness index (S) of soil microbial community were significantly decreased, while Pielou index (E) was significantly increased in the P. clematidea invasion sites. There was no significant difference in Shannon’s index (H) and Simpson’s dominance index (Ds) between the invaded and native sites. Our results suggested that P. clematidea invasion could consume enormous soil nutrients and cause soil degradation in the invaded region.

Key words: mini-UAV image, estimation of scale parameter, supervised classification, visible vegetation index, object-oriented image classification., aquatic vegetation