IMPACT OF SEEDLING REMOVAL ON NATURAL REGENERATION IN THE SOUTHERN ATLANTIC FOREST REMNANT

ABSTRACT The use of a forest seedling bank has been recommended as an alternative to increase species richness in forest nurseries, as well as to produce seedlings of species that are diffi cult to propagate, especially those that belong to the late secondary and climax successional groups, which are not as commercially available. However, little is known about the impact of this method on forest dynamics. Thus, the present study aimed to examine the resilience and dynamics of a seedling bank in a remnant of a subtropical seasonal forest belonging to the Atlantic Forest Biome when subjected to different intensities of seedling removal. The experiment was conducted in a random block design in a factorial scheme (5 × 4), with treatments composed of fi ve intensities of removal of individuals from the seedling bank and the four seasons. The treatments were distributed into 18 blocks and the experimental units were composed of 1 m × 2.5 m plots. The resilience of the seedling community was assessed by examining effects of the fi ve removal intensities. The dynamics between the evaluation periods within each treatment were verifi ed by comparing the number of species and seedlings present before the treatments with those in the other evaluation periods. After one year, we found that tree-shrub vegetation had a partial capacity for restoration after withdrawal of individuals from the seedling bank. Our results show that the impact on the regeneration community can absorb the effects of up to 25% seedling removal. The technique of seedling transplantation may be recommended for species that have abundant regeneration, such as Actinostemon concolor, Eugenia rostrifolia, Trichilia claussenii and Nectandra megapotamica.

摘要 森林幼苗库（forest seedling bank）已被推荐为提升森林苗圃物种丰富度的替代方案，同时可培育难以繁殖的物种幼苗，尤其是隶属于晚期次生演替与顶极演替群落类群、且商业可获取性较低的物种。然而，目前学界对该方法对森林动态的影响仍知之甚少。因此，本研究旨在探究隶属于大西洋森林生物群区（Atlantic Forest Biome）的亚热带季节性森林残遗群落中，幼苗库在经受不同强度幼苗移除后的恢复力与动态特征。本实验采用5×4析因方案的随机区组设计，处理组由5种幼苗库个体移除强度与4个季节组合构成。实验共设置18个区组，实验单元为1 m × 2.5 m的样地。研究通过分析5种移除强度的效应，评估幼苗群落的恢复力；通过比较处理实施前与其余评估周期内的物种数量与幼苗个体数，验证各处理组内不同评估周期间的动态变化。一年后研究结果显示，乔灌植被在幼苗库个体移除后具备部分恢复能力。本研究结果表明，该操作对更新群落的影响可承受最高达25%的幼苗移除比例。针对拥有充足更新量的物种，如Actinostemon concolor、Eugenia rostrifolia、Trichilia claussenii及Nectandra megapotamica，可推荐采用幼苗移植技术进行培育。