浙江省大叶榉树生境地群落数量分类与排序

【目的】探寻国家二级重点保护植物大叶榉树生境地的群落类型及群落结构,综合分析大叶榉树分布群落所在的环境特点,解释大叶榉树的生态学特征,明确影响大叶榉树分布的主要环境因子和群落特征,以期为大叶榉树种群恢复及浙江森林质量提升提供科学依据。【方法】基于包含3 420余个样地的浙江省生态监测样地数据库,经关键词搜索筛选出21个含有大叶榉树分布的样地,采用双向指示种分析(TWINSPAN)及典范对应分析(CCA)方法对浙江省大叶榉树生境群落进行了数量分类与排序。【结果】TWINSPAN结果显示浙江省大叶榉树生境所在的群落可分为8个类型。大叶榉树在研究区群落内的分布主要以阔叶林群落和杉木群落为主,21个样地中阔叶林群落达15个,杉木为主的群落为6个,但大叶榉树未出现在以马尾松为主的群落中。群落中主要出现了杉木、枫香、甜槠、大叶榉树、化香、木荷、香樟、白栎、柏木、山合欢等优势树种,其中杉木的重要值达到20.5%。在样地CCA排序图中8个群丛呈现一定的聚集分布,第1排序轴主要体现了海拔与枯落物厚度对群落及物种分布的影响,第2排序轴主要反映腐殖质厚度与坡度对群落及物种分布的影响。物种CCA结果显示:与大叶榉树生境选择最接近的树种是榔榆、黄连木、黄檀、化香、白栎,影响上述树种分布的主要环境因子是枯落物厚度和坡向。蒙特卡罗检验结果表明,影响浙江大叶榉树群落分布最主要的环境因子是海拔,其次为腐殖质厚度、坡度和土壤质地。【结论】浙江省森林中以白背叶、枫香、香樟、麻栎等树种为主的群落和杉木群落可作为大叶榉树种群恢复的载体。影响大叶榉树分布的主要环境因子是海拔、腐殖质厚度、坡度等条件。大叶榉树与榔榆、黄连木、黄檀、化香、白栎等树种对生境的选择趋于一致,在生态资源充足的情况下大叶榉树可与这些树种尝试混交造林。

Quantitative classification and ordination of Zelkova schneideriana habitat in Zhejiang Province

【Objective】 To provide the scientific basis for restoring Zelkova schneideriana , which is listed in the second class of protected plants in China, and to improve forest quality, we propose the following steps. We explored the community types and habitat-specific community structure of Z. schneideriana and comprehensively analyze the environmental characteristics of the Z. schneideriana community. In addition, we determined the ecological characteristics of Z. schneideriana, and identified the main environmental factors and community characteristics that affect the distribution of Z. schneideriana.【Method】In Zhejiang Province, based on its database of more than 3 420 ecological monitoring plots, and through comprehensive search, we selected 21 plots that contain Z. schneideriana. We applied TWINSPAN(two-way indicator species analysis)and CCA(canonical correspondence analysis)methods to quantitatively classify and ordinate the habitat community of Z. schneideriana in Zhejiang Province. 【Result】The result of TWINSPAN shows that the habitat-specific community of Z. schneideriana in Zhejiang Province can be divided into eight associations. The distribution of Z. schneideriana community in the study area is mainly in regions of broad-leaved forests and Cunninghamia lanceolata communities. There are 15 broad-leaved forests and 6 Cunninghamia lanceolata communities in the 21 plots studied. We found that Z. schneideriana was absent in communities dominated by Pinus massoniana. The dominant species in the research area were Cunninghamia lanceolata, Liquiolambar formosana, Castanopsis eyrei, Z. schneideriana, Platycarya strobilacea, Schima superba, Cinnamomum camphora, Quercus fabri, Cupressus funebris and Aabizia kalkora. The importance value of Cunninghamia lanceolata was up to 20.5%. We found 8 associations in the CCA ordination chart of samples plots, which showed inclination towards aggregated distribution. The first axis of CCA ordination mainly reflected the effect of altitude and litter-layer thickness on the distribution of communities and species; the second axis mainly reflected the effect of humus thickness and gradient on the distribution of communities and species. Species CCA showed that Ulmus parvifolia, Pistacia chinensis, Dalbergia hupeana, Platycarya strobilacea and Q. fabri had habitats most similar to that of Z. schneideriana. The main environmental factors affecting the distribution of these species were litter thickness and slope direction. Results of Monte Carlo test showed that the most important environmental factor affecting the distribution of Z. schneideriana in Zhejiang was altitude, followed by humus thickness, slope and soil type. 【Conclusion】Mallotus apelta, L. formosana, Cinnamomum camphora, Quercus acutissima and Cunninghamia lanceolata were found to be the main species in Zhejiang forests, and can be used as carriers for population restoration of Z. schneideriana. The main environmental factors affecting the distribution of Z. schneideriana are altitude, humus thickness and slope. Habitat selection of Z. schneideriana and other tree species such as Ulmus parvifolia, Pistacia chinensis, Dalbergia hupeana, Platycarya strobilacea and Q. fabri tends to be similar. Under the condition of sufficient ecological resources, we can try to mix Z. schneideriana with these tree species for reforestation.