Aeolian process effects on vegetation communities in an arid grassland ecosystem.
Aeolian process effects on vegetation communities in an arid grassland ecosystem.
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DOI：
10.1002/ece3.205
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发表时间：
2012-04
影响因子：
2.6
通讯作者：
Okin, Gregory S.
中科院分区：
文献类型：
--
作者：
Alvarez, Lorelei J.;Epstein, Howard E.;Li, Junran;Okin, Gregory S.
许多干旱草地群落正从禾本科优势向灌木优势转变，但这一转变过程的机制尚不完全清楚。风成过程可能促成了这种从草地到灌木地的转变。本研究的目的是提供关于干旱草原上的植被变化是如何由于风沙运输而发生的信息。试验设计包括3个处理区，每个处理区有25 × 50 m的区域，所有的草、半灌木和多年生草本植物都被人工去除；一个25 × 50 m的控制区，不操纵植被覆盖；另外两个10 × 25 m的试验区在去除草和控制区的正风方向，东北方19°，用于测量植被覆盖。在每个处理区和下风样地监测风沙通量、土壤养分和土壤种子库。在除草后的4年内，沿着连续样线测量每个除草、控制和下风样地以及每个下风区域内5 × 10 m的子样地的草和灌木覆盖。在除草区，泥沙通量显著增加，土壤养分和种子库枯竭，毛豆灌木盖度较对照增加。此外，在植被清除区和控制区的下风样地，观察到草和灌木覆盖的差异变化。尽管观测期间降水高于平均水平，但植被清除区下风样地草盖度随时间的推移呈下降趋势（2004-2007年），而对照区下风样地草盖度呈上升趋势；草皮盖度在清退区顺风区增加，在对照区顺风区减少。植被变化与风沙通量之间的关系显著，最好用对数函数来描述，草地覆盖减少，灌木覆盖增加，风沙通量小幅增加。
Many arid grassland communities are changing from grass dominance to shrub dominance, but the mechanisms involved in this conversion process are not completely understood. Aeolian processes likely contribute to this conversion from grassland to shrubland. The purpose of this research is to provide information regarding how vegetation changes occur in an arid grassland as a result of aeolian sediment transport. The experimental design included three treatment blocks, each with a 25 × 50 m area where all grasses, semi-shrubs, and perennial forbs were hand removed, a 25 × 50 m control area with no manipulation of vegetation cover, and two 10 × 25 m plots immediately downwind of the grass-removal and control areas in the prevailing wind direction, 19° north of east, for measuring vegetation cover. Aeolian sediment flux, soil nutrients, and soil seed bank were monitored on each treatment area and downwind plot. Grass and shrub cover were measured on each grass-removal, control, and downwind plot along continuous line transects as well as on 5 × 10 m subplots within each downwind area over four years following grass removal. On grass-removal areas, sediment flux increased significantly, soil nutrients and seed bank were depleted, and Prosopis glandulosa shrub cover increased compared to controls. Additionally, differential changes for grass and shrub cover were observed for plots downwind of vegetation-removal and control areas. Grass cover on plots downwind of vegetation-removal areas decreased over time (2004–2007) despite above average rainfall throughout the period of observation, while grass cover increased downwind of control areas; P. glandulosa cover increased on plots downwind of vegetation-removal areas, while decreasing on plots downwind of control areas. The relationships between vegetation changes and aeolian sediment flux were significant and were best described by a logarithmic function, with decreases in grass cover and increases in shrub cover occurring with small increases in aeolian sediment flux.
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影响因子：
8.8
作者：
Eldridge DJ;Bowker MA;Maestre FT;Roger E;Reynolds JF;Whitford WG
通讯作者：
Whitford WG
影响因子：
2.7
作者：
Guo, QF;Rundel, PW;Goodall, DW
通讯作者：
Goodall, DW
影响因子：
3.7
作者：
Okin, Gregory S.;D'Odorico, Paolo;Archer, Steven R.
通讯作者：
Archer, Steven R.
影响因子：
10.1
作者：
Luo, Y;Su, B;Field, CB
通讯作者：
Field, CB
影响因子：
2.8
作者：
Bestelmeyer, Brandon T.;Kalil, N. I.;Peters, Debra P. C.
通讯作者：
Peters, Debra P. C.