Data from: Genet dynamics of a regenerating dwarf bamboo population across heterogeneous light environments in a temperate forest understorey

Despite the advantage of plant clonality in patchy environments, studies focusing on genet demography in relation to spatially heterogeneous environments remain scarce. Regeneration of bamboos in forest understoreys after synchronous die-off provides an opportunity for assessing how they come to proliferate across heterogeneous light environments. In a Japanese forest, we examined genet demography of a population of Sasa kurilensis over a 7-year period starting 10 years after die-off, shortly after which some genets began spreading horizontally by rhizomes. The aboveground biomass was estimated and genets were discriminated in 9-m2 plots placed under both canopy gaps and closed canopies. Overall, the results suggest that the survival and spread of more productive genets and the spatial expansion of genets into closed canopies underlie the proliferation of S. kurilensis. Compared to canopy gaps, the recovery rate of biomass was much slower under closed canopies for the first 10 years after the die-off, but became accelerated during the next seven years. Genet survival was greater for more productive genets (with greater initial number of culms), and the spaces occupied by genets that died were often colonized afterward by clonal growth of surviving genets. The number of genets decreased under canopy gaps due to greater mortality, but increased under closed canopies where greater number of genets colonized clonally from outside the plots than genets died. The colonizing genets were more productive (having larger culms) than those originally germinated within the plots, and the contribution of colonizing genets to the biomass was greater under closed canopies. Our study emphasizes the importance of investigating genet dynamics over relevant spatio-temporal scales to reveal processes underlying the success of clonal plants in heterogeneous habitats.

尽管植物克隆性在斑块状生境中具备优势，但针对与空间异质环境相关的基株（genet）种群动态的研究仍较为匮乏。森林林下竹类在同步枯死后的更新过程，为探究其如何在异质光照环境中实现增殖扩散提供了绝佳的研究契机。本研究在一处日本温带森林中，针对库页笹（Sasa kurilensis）种群的基株动态开展了为期7年的追踪调查，调查起始于该种群枯死后的第10年——枯死后不久便有部分基株通过根状茎启动水平扩散。研究人员在林窗与郁闭林冠下设置的9平方米样地内，估算了地上生物量并区分了不同基株。综合来看，研究结果显示，高生产力基株的存活与扩散，以及基株向郁闭林冠区域的空间扩张，是库页笹得以种群增殖的核心驱动机制。相较于林窗生境，枯死后的前10年郁闭林冠下的生物量恢复速率显著更缓，但在后续7年中恢复进程明显加快。高生产力基株（初始秆茎数量更多）的存活率更高，死亡基株占据的空间往往会被存活基株的克隆生长所占据。林窗生境中，因基株死亡率更高，种群基株总数有所下降；而郁闭林冠下，从样地外通过克隆定植的基株数量多于死亡基株数量，基株总数呈上升趋势。定植基株的生产力高于样地内最初萌发的基株（秆茎更为粗壮），且在郁闭林冠下，定植基株对群落地上生物量的贡献占比更大。本研究强调，需在匹配研究对象的时空尺度下开展基株动态研究，方能揭示克隆植物在异质生境中成功定植与扩散的内在生态过程。