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黄土高原刺槐人工林林下植物多样性对模拟降水变化的响应
1,2, 3,4, 1,4, 1,4

(1.zhongguokexueyuan shuilibu yaboappsuo huangtugaoyuanturangqinshiyuhandinongyeguojiazhongdianshiyanshi, shanxi yangling 712100; 2.zhongguokexueyuandaxue, beijing 100049; 3.xibeinonglinkejidaxue linxueyuan, shanxi yangling 712100; 4.xibeinonglinkejidaxue huangtugaoyuanturangqinshiyuhandinongyeguojiazhongdianshiyanshi, shanxi yangling 712100)

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Effects of Manipulative Precipitation on Plant Species Diversity in the Understory of Planted Robinia pseudoacacia Forest on the Loess Plateau, China
DENG Qiang1,2, LIU Di3,4, SHI Xinrong1,4, YUAN Zhiyou1,4

(1.state key laboratory of soil erosion and dryland farming on the loess plateau, institute of soil and water conservation, chinese academy of sciences and ministry of water resources, yangling, shaanxi 712100, china; 2.university of chinese academy of sciences, beijing 100049, china; 3.college of forestry, northwest a&f university, yangling, shaanxi 712100, china; 4.state key laboratory of soil erosion and dryland farming on the loess plateau, northwest a&f university, yangling, shaanxi 712100, china)

;;;; planted Robinia pseudoacacia forest;

备注

气候变化对物种多样性具有重要影响,探究物种多样性对未来气候变化的响应规律是生态学研究的重点之一,但目前亚博app森林生态系统林下植物多样性对降水变化的响应研究仍然较少。利用野外控制穿透雨试验,观测了9个降水梯度处理(减雨80%,60%,40%,20%和增雨20%,40%,60%,80%及对照)对黄土高原刺槐人工林林下植物物种组成、群落结构和物种多样性的影响。结果 表明:随着降水量的增加,土壤含水量呈增加趋势,减雨80%处理0—20 cm和20—40 cm土层土壤含水量分别比对照处理低23.6%和16.1%,增雨80%处理0—20 cm和20—40 cm土层土壤含水量分别比对照处理高26.2%和13.0%。不论降水减少或增加,都提高了蔷薇科和杂类草物种的重要值,但降低了豆科和禾本科物种的重要值,降水量的增加也提高了菊科物种的重要值。降水减少处理降低了物种多样性指数和均匀度指数,减雨80%和60%的物种多样性指数和均匀度指数显著低于对照组,而增雨20%和40%增加了物种多样性指数和均匀度指数,但增雨60%和80%降低了物种多样性指数和均匀度指数,增雨80%的物种多样性指数和均匀度指数显著低于对照组。群落物种丰富度、多样性和均匀度指数与0—20 cm土层土壤含水量呈显著正相关关系,Simpson指数与20—40 cm土层土壤含水量呈显著正相关关系(R2=0.630)。上述结果说明,黄土高原刺槐人工林林下多为一年生植物,主要受浅层土壤含水量的影响,不同生活型和水分生态类型植物对降水变化的响应存在差异,降水变化不利于水分胁迫耐受性低的物种生存,进而影响群落物种多样性。研究结果有助于深入了解降水对物种多样性的影响以及对气候变化背景下的黄土高原植被建设和生态恢复具有重要意义。

climate change has a significant impact on species diversity and it remains unclear that how species diversity responds to projected precipitation change, especially for understory communities in forest ecosystems. we investigated the effects of precipitation changes on species composition, community structure and species diversity in the understory of planted robinia pseudoacacia forest on the loess plateau via a manipulative throughfall experiment. soil moisture content increased with the increase of precipitation. -80% precipitation treatment reduced the soil moisture contents in 0—20 cm and 20—40 cm soil layers by 23.6% and 16.1%, respectively. +80% precipitation treatment enhanced the soil moisture contents in 0—20 cm and 20—40 cm soil layers by 26.2% and 13.0%, respectively. the precipitation treatments enhanced the importance values of rosaceae species and forbs, but reduced the importance values of leguminosae and gramineae species. the importance value of compositae species increased with increase of precipitation. compared with the control, both +20% and +40% precipitation manipulations increased the species diversity index and evenness index, while -60% and -80% precipitation treatments decreased the species diversity index and evenness index. meanwhile, the species diversity index and evenness index under -80%, -60% and +80% precipitation treatments were significantly lower than those of the control. the community species richness, diversity and evenness indices were all significantly positively correlated to the soil water content of 0—20 cm soil layer, while the simpson index was significantly positively correlated to the soil water content of 20—40 cm soil layer(r2=0.630). these results indicated that understory community mainly composed by annual plants was more susceptible to the change of water content in shallow soil layer. the response of plant species to precipitation change varied depending upon life forms and water ecological types. precipitation change was not conducive to the living of species with low water stress tolerance, which affected the species diversity. these results revealed that it was of great significance to explore the influence of precipitation change on species diversity for vegetation construction and ecological restoration of the loess plateau.

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