林线更新关键影响因子研究进展

Research advances in key factors affecting seedling regeneration above treeline

林线作为森林上限连接树种线的特殊生态过渡带,能够迅速地对气候变化做出反应,是理想的气候变化生态监测器。在全球变暖影响下,全球林线位置表现为一半上升,其余则保持相对稳定的趋势。林线能否上升取决于种子生产、向上扩散的能力及幼苗建成。大多学者从温度、降水、光照与干扰等方面分析林线更新及动态机制,主要认为低温限制林线上升,然而单一因素很难解释全球林线变化。国内外研究多关注于非生物因子对林线分布的作用机制,缺乏林线群落交错区基于种子扩散者等生物因子与幼苗定居,特别是林线交错带中种子扩散者对林线变化的作用。未来的研究可关注全球气候变暖下的林线幼苗幼树分布,如林线群落区分散贮食动物种子贮藏行为对林线幼苗更新的影响,为从种子扩散者与林线动态互作角度探究生物对气候变暖的响应提供科学依据。

Treeline is a special ecotone between the upper forest limit and tree species line. It is an ideal ecological indicator for climate change as it is sensitive to climate change. The position of half of global treelines is upward,with the rest maintaining relatively stable under the background of global warming. The treeline is strongly affected by seed production,dispersal and seedling establishment. Most studies have analyzed the mechanism of treeline structure from the aspects of temperature,precipitation,illumination,and disturbance,and found that low temperature limits treeline dynamics. However,single factor is hard to explain the global treeline variation. Most studies focused on the effects of abiotic factors on the distribution of treeline and little attention has been paid to the effects of seed dispersers on seedling establishment in treeline ecotones,especially on the treeline dynamics. Future studies should focus on the distribution of seedlings and saplings in treeline under global warming,such as the effects of seed caching behavior of animals in treeline community on the seedling regeneration of treeline,so as to provide scientific basis for exploring the biotic responses to climate warming from the perspective of interactions between seed dispersers and treeline dynamics.