成都生物所在林下植被对皆伐的响应研究中取得进展

摘要 : 中国科学院成都生物研究所恢复生态学学科组长期致力于青藏高原东部亚高山森林生态系统经营管理与采伐迹地生态恢复研究。该组研究生刘鑫在导师包维楷研究员的指导下利用BACI(Before-After, Control-Impact)的方法对青藏高原东部近林线区云杉林林下植被对森林皆伐的响应进行研究，分析了林下维管植物与苔藓植物在森林皆伐后短期内物种组成、多样性和群落结构的变化及其驱动机理。

林下植被是森林生态系统的重要组成部分，在生态系统的能量流动、物质循环，维持生态系统生产力、稳定性和生态系统服务功能等方面发挥着重要作用。森林皆伐会显著改变林下植被的物种组成、群落结构以及生物多样性。青藏高原东部的亚高山针叶林处于我国多条重要江河的源头或上游地区，具有重要的生态屏障功能。但是长期以来，皆伐使这里的森林生态系统逐步演替为灌草丛，导致生态系统功能和生物多样性严重衰退。

森林皆伐主要通过两个过程对林下植被产生影响：其一是皆伐作业过程中对林下地表植被的物理破坏;其二是皆伐过后，迹地的气候和养分等环境因素变化对林下植被造成的影响。

目前，虽然对森林采伐的环境变化与迹地人工造林恢复重建开展过许多研究，但是绝大多数研究只关注林下维管植物，对于苔藓植物在森林采伐后的变化了解很少;而且尚不明确上述两种过程对林下植被的影响。

中国科学院成都生物研究所恢复生态学学科组长期致力于青藏高原东部亚高山森林生态系统经营管理与采伐迹地生态恢复研究。该组研究生刘鑫在导师包维楷研究员的指导下利用BACI(Before-After, Control-Impact)的方法对青藏高原东部近林线区云杉林林下植被对森林皆伐的响应进行研究，分析了林下维管植物与苔藓植物在森林皆伐后短期内物种组成、多样性和群落结构的变化及其驱动机理。

青藏高原东部亚高山针叶林林下植被

青藏高原东部亚高山针叶林林下常见植物

青藏高原东部亚高山针叶林皆伐迹地

研究发现，森林皆伐后两年内，林下植被群落结构变化比多样性变化更加剧烈。不同种组的植物对森林皆伐表现出截然不同的反应，其中苔藓植物和禾草是最敏感的种组，其盖度分别出现显著下降和显著上升。森林采伐过程中的物理破坏作用和采伐后环境因子的变化在驱动不同种组的植物变化方面分别表现出重要作用。

研究结果发表于最新一期的CanADIan Journal of Forest Research 。

原文摘要：

Understory plant assemblages present distinct short-term responses to the clear-cutting of an old-growth spruce forest near an alpine timberline

Xin Liu, W.K. Bao

Forest clear-cutting is a prominent disturbance influencing understory plant communities. We implemented a before–after, control–impact (BACI) designed experiment in a high-elevation, old-growth spruce forest in the eastern Tibetan Plateau to understand the response in cover and species richness of the understory plant community and its assemblages, as well as the driving roles of environmental alteration (e.g., radiation, temperature, humidity, and nutrients), physical disturbance (e.g., direct damage by trampling and tree-felling), and interplay effects (e.g., shading or burial from logging residue) during a 2-year period. The decrease in cover for the understory vegetation was predominantly due to a decrease in bryophytes; the grass cover, however, increased. While bryophyte species richness decreased, the total number of understory and vascular plants changed minimally. Furthermore, the environmental alteration drove the increase in grass cover, as well as the cover and species richness decline for bryophytes and its two species groups. It was also found that physical disturbances and interplay effects caused the decrease in cover for bryophytes. The total effects influenced the understory community and bryophytes in terms of cover, but not in terms of species richness. We conclude that the short-term responses of understory vegetation to clear-cutting are distinct across different assemblages due to various mechanisms. Bryophytes are more sensitive than vascular plants, and cover percentage responded more swiftly than species richness to clear-cutting.

作者：成都生物所

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