局域生态过程对吉林蛟河阔叶红松林群落相似度的影响

Effects of Local Ecological Processes on Community Similarity in the Jiaohe Broadleaved Korean Pine Forests in Jilin Province

【目的】研究局域生态过程对群落构建的相对作用,对解释和预测植被对干扰的响应,理解群落多样性变化具有重要意义,为研究群落物种共存机制以及生物多样性保护提供理论支撑。【方法】以吉林蛟河阔叶红松林3块大样地为研究对象,对样地中所有胸径≥1 cm的木本植物进行挂牌标记和长期监测,并根据地形将样地划分为不同生境类型。通过零模型构建生境间和生境内随机分布群落,分别计算实际群落和随机群落的相似度,比较实际群落相似度和随机群落相似度的差异,分析生境异质性和生境内空间隔离对群落结构的影响。具体验证以下4个假设:1)生境间随机群落相似度与实际群落相似度是否具有显著差异;2)生境内随机群落相似度与实际群落相似度是否具有显著差异;3)生境间随机群落相似度与生境内随机群落相似度是否具有显著差异;4)生境间随机群落相似度与生境内随机群落相似度的差值表示生境异质性的作用大小,生境内随机群落相似度与实际群落相似度的差值表示生境内空间隔离作用的大小,二者是否具有显著差异。【结果】实际群落的相似度与生境间随机群落相似度具有极显著差异,表明生境异质性和生境内空间隔离共同对群落构建具有极显著作用;实际群落的相似度与生境内随机群落相似度具有极显著差异,表明生境内空间隔离单独作用极显著;生境间随机群落相似度与生境内随机群落相似度具有极显著差异,表明生境异质性单独作用极显著;生境间随机群落相似度与生境内随机群落相似度的差值和生境内随机群落相似度与实际群落相似度的差值具有极显著差异,且前者小于后者,表明生境内空间隔离对群落构建的作用极显著高于生境异质性。【结论】在吉林蛟河阔叶红松林群落构建过程中,生境异质性作用和生境内空间隔离共同影响群落结构,分别对群落构建具有显著作用,且群落构建过程中扩散限制作用显著大于生境异质性作用。研究结果对维持和保护东北地区温带森林生物多样性具有重要意义,未来应结合大尺度过程做进一步分析。

【Objective】 Studying the relative effects of local ecological processes on community similarity is important for explaining and predicting the responses of vegetation to disturbances,as well as for understanding the dynamics of community diversity,which provides supports for species coexistence mechanisms and biodiversity conservation.【Method】We used the data of three large permanent sample plots,where all trees with a diameters at breast height（ DBH） ≥1 cm were identified,measured and georeferenced,and we divided the community into different habitat types according to topographical factors. By using null models,we established randomized-among-habitat communities and randomizedwithin-habitat communities. We calculated the community similarity of observed and randomized communities and compared the differences between the two types of communities to reveal the effects of habitat heterogeneity and spatial segregation on community structure. Specifically,we tested four hypotheses. 1） Whether the community similaritysignificantly differed between observed and randomized-among-habitat communities？ 2） Whether the community similarity significantly differed between the two types of communities？ 3） Whether the community similarity significantly differed between the two types of communities？ 4） The difference of community similarity between the two types of communities represents the effects of habitat heterogeneity,and the difference of community similarity between the two types of communities represents the effects of spatial segregation within habitat,are they significantly different from each other？【Result】The difference of community similarities between the observed and randomized-among-habitat communities was significant,indicating that the community assembly was obviously affected by the combined effects of habitat heterogeneity among habitats and spatial segregation within habitats. The difference of community similarity between the observed and randomized-within-habitat communities was significant,indicating that spatial segregation within habitats had a remarkable influence on community assembly. The difference of community similarity between the randomized-within-habitat and randomized-among-habitat communities was significant,indicating that habitat heterogeneity separately had notable effects on community assembly. The difference of community similarity between randomized-among-habitat and randomized-withinhabitat communities（ Pwh ＋ ah-Pwh） was significantly lower than that of community similarity between randomized-withinhabitat-and observed communities（ Pwh-Pob）,indicating that the effects of within-habitat spatial segregation had a stronger influence on community assembly than habitat heterogeneity. 【Conclusion】We conclude that in the process of community assembly of the broad-leaved Korean pine forest in Jiaohe temperate forests,the community structure was affected by both habitat heterogeneity and within-habitat spatial segregation,besides,the effects of spatial segregationon community assembly was greater than that of habitat heterogeneity. This study is important for the biodiversity conservation of temperate forests in Northeastern China,broad-scale process should be considered for further studies in the future.