摘要 : 2017年12月12日，国际期刊《Journal of Ecology》杂志在线发表了浙江大学生命科学学院生态所于明坚教授的一篇研究论文，研究报道了常绿阔叶林叶片寿命与资源利用关联关系。
Effects of light and topography on reGENEration and coexistence of evergreen and deciduous tree species in a Chinese subtropical forest
1.Evergreen broad-leaved forests are widely distributed in eastern Asia with evergreen (EBL) and deciduous (DBL) broad-leaved tree species coexisting under the same climatic regime, raising questions as to the underlying mechanisms. Since EBL and DBL species differ in leaf Lifespan, a key component of resource economic strategies, their coexistence might be attributed to regeneration niche partitioning across habitats varying in resource supply.
2.We investigated the effects of variation in insolation and topography on regeneration of EBL and DBL species in a subtropical evergreen broad-leaved forest of eastern China after an ICE storm that caused severe canopy disturbance.
3.Using a mixed-effects modeling framework and census data from 2011 to 2014 on 8548 wild seedlings of 123 species, we quantified habitat preferences of EBL and DBL species during post-disturbance regeneration and how their survival and height relative growth rates varied among habitats.
4.The relative density of DBL seedlings (proportional to all seedlings) was greater in habitats with greater (canopy gaps) compared to lesser (understory) insolation and increased with canopy gap size. However, DBL seedlings were not more frequent in higher (valleys) compared to lower (ridges) fertility habitats. Although DBL seedlings exhibited larger differences in growth between higher and lower resource habitats than EBL seedlings, their growth rates did not increase with canopy gap size. Seedlings of EBL species had high survival in all habitats, but larger DBL seedlings survived equally well on ridges. Consequently, the relative density of DBL seedlings declined in valleys, so that by 2014 it became more similar in valley and ridge habitats, whereas it remained higher in gaps than in the understory, and especially in larger gaps.
5.Synthesis. Specialization on contrasting topographic habitats is considered the primary mechanism mediating coexistence between DBL and EBL species. Our results, however, suggest this may not always be true, since seedlings of DBL and EBL species partitioned regeneration niches based on light more so than topography. We propose that coexistence of DBL and EBL species can strongly depend upon canopy disturbance to create a mosaic of habitat patches, including high light gaps favoring regeneration of DBL species.