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气候变暖对领春木沿海拔分布潜在影响的实验模拟

Potential Impacts of Climate Warming on Distribution of Euptelea pleiospermum along Altitude:An Experimental Simulation

  • 摘要: 在神农架山地不同海拔高度进行领春木(Euptelea pleiospermum)种子萌发实验和萌发后实生幼苗的存活状况研究,模拟气候变化对领春木分布的潜在影响。结果显示:(1)林窗内种子萌发率显著高于林下,林下的幼苗全部死亡;(2)在领春木的分布上限(2090 m)和以上区域种子萌发率高,且幼苗死亡率低,在领春木的分布下限(900 m)和以下区域种子萌发率低,且除620 m阳坡林下以外,幼苗均全部死亡;(3)种源对领春木种子萌发率和幼苗死亡率均无显著影响;(4)冬季播种的种子比春季播种种子萌发率低,萌发后幼苗死亡率高。研究结果表明,珍稀植物领春木具备向高海拔地区迁移的潜能,但向高海拔的迁移扩散可能会受到一定的限制;在低海拔区域,领春木幼苗更新受到威胁,但一些小生境可以缓冲气候变暖带来的威胁。

     

    Abstract: Climate change has already triggered species distribution shifts along the elevation gradient in many mountainous regions.Seed germination and seedling survival of Euptelea pleiospermum with different seed sources were examined under different elevations,aspects,in the forest or in the gap,and in spring or winter.The results showed that gaps were necessary for seedling survival and establishment.Furthermore,seed germination rate and seedling survival rate were not significantly different between the population at higher elevations(2090 m and 2350 m)and population from intermediate elevation(1600 m),but populations at 2220 m were lower.Seed germination rate and seedling survival of the population at lower elevations(900 m and 750 m)were lower than at the intermediate elevations,but at 620 m were as high as intermediate elevation.In addition,seed sources and aspect had no significant effect on seed germination and seedling survival rate.Cold stratification at high altitude had negative influences on seed germination and seedling survival.These ndings suggest that E.pleiospermum has the potential to move to higher elevation.Furthermore,forest gaps,which are not frequent,are necessary for seedling survival and establishment,indicating the limited population shift of E.pleiospermum to higher elevations.Finally,populations in lower elevations will be vulnerable to future climate change due to poor seedling recruitment,which may be mediated by some scattered suitable habitats.

     

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