中国地理科学(英文版) ›› 2013, Vol. 23 ›› Issue (3): 321-330.doi: 10.1007/s11769-013-0607-8

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Vegetation and Community Changes of Elm (Ulmus pumila) Woodlands in Northeastern China in 1983-2011

LIU Li1, WANG He2, LIN Changcun3, WANG Deli1   

  1. 1. Institute of Grassland Science, Key Laboratory of Vegetation Ecology, Northeast Normal University, Changchun 130024, China;
    2. College of Land and Environment, Shenyang Agricultural University, Shenyang 110161, China;
    3. Liaoning Academy of Environmental Sciences, Shenyang 110031, China;
    4. Research Center of Grassland Resource and Ecology, Beijing Forestry University, Beijing 100083, China
  • 收稿日期:2012-05-30 修回日期:2012-09-21 出版日期:2013-05-29 发布日期:2013-05-30
  • 通讯作者: WANG Deli. E-mail: Wangd@nenu.edu.cn E-mail:Wangd@nenu.edu.cn
  • 基金资助:

    Under the auspices of the Seventh Framework Programme (European Commission, No. 226818), National Natural Science Foundation of China (No. 31070294, 31072070, 31100331)

Vegetation and Community Changes of Elm (Ulmus pumila) Woodlands in Northeastern China in 1983-2011

LIU Li1, WANG He2, LIN Changcun3, WANG Deli1   

  1. 1. Institute of Grassland Science, Key Laboratory of Vegetation Ecology, Northeast Normal University, Changchun 130024, China;
    2. College of Land and Environment, Shenyang Agricultural University, Shenyang 110161, China;
    3. Liaoning Academy of Environmental Sciences, Shenyang 110031, China;
    4. Research Center of Grassland Resource and Ecology, Beijing Forestry University, Beijing 100083, China
  • Received:2012-05-30 Revised:2012-09-21 Online:2013-05-29 Published:2013-05-30
  • Contact: WANG Deli. E-mail: Wangd@nenu.edu.cn E-mail:Wangd@nenu.edu.cn
  • Supported by:

    Under the auspices of the Seventh Framework Programme (European Commission, No. 226818), National Natural Science Foundation of China (No. 31070294, 31072070, 31100331)

摘要:

Elm (Ulmus pumila), widely distributed in the north temperate zone, contributes to a special savanna-like woodland in typical grassland region in the northeastern China. This woodland performs a variety of ecological functions and environmental significance, such as decreasing soil erosion, stabilizing sand dunes, preserving species diversity. However, in the last approximate 30 years, the species composition, productivity and distribution area of elm woodland has decreased severely. A series of studies have been carried out to find out whether the climate changes or human disturbances caused the degradation of elm woodland and how these factors affected elm woodland. In this study, undisturbed, plowing and grazing elm woodland were investigated in 1983 and 2011 by using Point-Centered Quarter method. The relationship between vegetation changes and environmental factors was analyzed by Bray-Curtis ordination. The results show that in 2011, species diversity and understory productivity of undisturbed elm woodland decrease slightly compared to those of undisturbed elm woodland in 1983. However, nearly 60% of the species is lost in the plowing and grazing elm woodland relative to the species undisturbed elm woodland in 1983. Interestingly, plowing stimulates the growth of elm and certain understory species through furrowing soil and accelerating soil nutrient turnover rate. Grazing disturbance not only leads to species loss and productivity decrease, but also induces changes in elm growth (small, short and twisted). The mean age of the elm was 29 ± 2 yr in undisturbed and plowing elm woodland, while only 15 yr in the grazing elm woodland. The results of Bray-Curtis ordination analysis show that all sample stands clustered to three groups: Group I including the undisturbed sample stands of 83UE (undisturbed elm woodland in 1983) and 11UE (undisturbed elm woodland in 2011); Group II including sample stands of PE (elm woodland disturbed by plowing); Group III including samples stands of GE (elm woodland disturbed by grazing). The results indicate that the long time disturbance of the plowing and grazing have converted elm woodland to different community types. Climate change is not the primary reason causing the degradation of elm woodland, but plowing and grazing disturbance. Both plowing and grazing decrease the vegetation composition and species diversity. Grazing further decreases vegetation productivity and inhibits the growth of elm tree. Therefore, we suggest that reasonable plowing and exclusive grazing would be favorable for future regeneration of degraded elm woodland.

关键词: Elm (Ulmus pumila) woodland, species diversity, plant distribution, Bray-Curtis ordination

Abstract:

Elm (Ulmus pumila), widely distributed in the north temperate zone, contributes to a special savanna-like woodland in typical grassland region in the northeastern China. This woodland performs a variety of ecological functions and environmental significance, such as decreasing soil erosion, stabilizing sand dunes, preserving species diversity. However, in the last approximate 30 years, the species composition, productivity and distribution area of elm woodland has decreased severely. A series of studies have been carried out to find out whether the climate changes or human disturbances caused the degradation of elm woodland and how these factors affected elm woodland. In this study, undisturbed, plowing and grazing elm woodland were investigated in 1983 and 2011 by using Point-Centered Quarter method. The relationship between vegetation changes and environmental factors was analyzed by Bray-Curtis ordination. The results show that in 2011, species diversity and understory productivity of undisturbed elm woodland decrease slightly compared to those of undisturbed elm woodland in 1983. However, nearly 60% of the species is lost in the plowing and grazing elm woodland relative to the species undisturbed elm woodland in 1983. Interestingly, plowing stimulates the growth of elm and certain understory species through furrowing soil and accelerating soil nutrient turnover rate. Grazing disturbance not only leads to species loss and productivity decrease, but also induces changes in elm growth (small, short and twisted). The mean age of the elm was 29 ± 2 yr in undisturbed and plowing elm woodland, while only 15 yr in the grazing elm woodland. The results of Bray-Curtis ordination analysis show that all sample stands clustered to three groups: Group I including the undisturbed sample stands of 83UE (undisturbed elm woodland in 1983) and 11UE (undisturbed elm woodland in 2011); Group II including sample stands of PE (elm woodland disturbed by plowing); Group III including samples stands of GE (elm woodland disturbed by grazing). The results indicate that the long time disturbance of the plowing and grazing have converted elm woodland to different community types. Climate change is not the primary reason causing the degradation of elm woodland, but plowing and grazing disturbance. Both plowing and grazing decrease the vegetation composition and species diversity. Grazing further decreases vegetation productivity and inhibits the growth of elm tree. Therefore, we suggest that reasonable plowing and exclusive grazing would be favorable for future regeneration of degraded elm woodland.

Key words: Elm (Ulmus pumila) woodland, species diversity, plant distribution, Bray-Curtis ordination