三峡水库消落区植被在差异性水淹环境中的分布格局

人工水库修建引发的差异性水文节律是决定消落区植被群落格局的主要因素,高强度水淹环境中水淹胁迫是影响植被的重要因子而低强度水淹环境中物种竞争是影响植被的重要因子。为了探究差异性水淹环境中三峡水库消落区植物的水淹耐受能力及光资源竞争能力(植物株高)对植被群落分布格局的影响,对三峡水库典型消落区不同水淹强度下生长的植被进行了研究,结果表明:(1)典型消落区调查共发现有植物41种,其中高耐淹低竞争能力型植物4种,其生物量在所有物种生物量中的占比达70.99%,低耐淹高竞争能力型植物23种,其生物量占比为28.02%,低耐淹低竞争能力型植物14种,生物量占比不足1%,消落区内无高耐淹高竞争能力型植物物种分布;(2)高耐淹低竞争能力型植物在水淹强度大的消落区区域占优,低耐淹高竞争能力型植物在植物物种竞争压力大的消落区区域占据主导,低耐淹低竞争能力型植物在消落区中仅有零星分布;(3)消落区植被生物量格局随着高程增加呈现出先增加后减少的趋势。研究差异性水淹环境对三峡水库消落区植被分布的影响,可以为深入理解消落区植被分布格局的形成机制和大型水库消落区植被恢复与重建提供理论依据。

Distribution pattern of vegetation in water-level fluctuation zone of the Three Gorges Reservoir as affected by differential flooding regimes

The different hydrological regimes caused by artificial reservoir construction is the main factor affecting the patterns of community vegetation in the water-level fluctuation zone. The flooding stress in the high-intensity flooding area is an important factor affecting vegetation, but species competition in the low intensity flooding area is a key stress factor affecting vegetation. Plants growing under different flooding regimes in the typical water-level fluctuation zone of the Three Gorges Reservoir were studied in order to explore the effect of plant flooding tolerance and optical resource competitiveness (plant height) on vegetation distribution patterns. The results showed the following:(1) A total of 41 plants species were distinguished and analyzed in the studied area, including 4 plants with high submergence tolerance and low competitiveness, making up 70.99% of total biomass; 23 plants with low submergence tolerance and high competitiveness, making up 28.02% of total biomass; 14 plants with low submergence tolerance and low competitiveness, making up less than 1% total biomass; and no plants with high submergence tolerance and high competitiveness in the water-level fluctuation zone; (2) The plants with high tolerance and low competitiveness dominated in the water-level fluctuation zone with high flooding intensity, those with low tolerance and high competitiveness dominated in the water-level fluctuation zone with high competitive pressure, and plants with low tolerance and low competition were only sporadically distributed at the shorelines; (3)The biomass pattern of vegetation along an inundation gradient showed a tendency to increase first and then decrease. This study could help us understand the mechanisms of vegetation distribution patterns at the water-level fluctuation zone of the Three Gorges Reservoir and provide basic knowledge on vegetation restoration and reconstruction in this zone.