Lu Meng-Zhen, Zeng Fu-Ping, Song Tong-Qing, Peng Wan-Xia, Su Liang, Liu Kun-Ping, Tan Wei-Ning, DU Hu
Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China.
Guangxi Key Laboratory of Karst Ecological Processes and Services, Huanjiang Observation and Research Station of Karst Ecosystem, Huanjiang 547100, Guangxi, China.
Ying Yong Sheng Tai Xue Bao. 2022 Oct;33(10):2679-2686. doi: 10.13287/j.1001-9332.202210.002.
Tree mortality is an important ecological process in forests. It is crucial to understand how tree mortality affects spatial patterns and interspecific associations for revealing the mechanisms of tree mortality and community dynamics. We employed the correlation method of spatial point pattern analysis to analyse the variations in spatial patterns and interspecific relations before and after mortality using data obtained from two surveys of a 25 hm plot in the Mulun National Natural Reserve, China. The results showed that most species had an aggregated distribution both pre- and post-mortality. The proportion of species with aggregated distribution reduced slightly post-mortality compared with that for pre-mortality. Increases in the number of species with random distribution at small scale indicated that tree death was not random. At the species level, there were significant positive associations between dead and live trees of the 13 common species at different levels of 0-30 m range, suggesting weak intraspecific and interspecific competition among dominant species. Pre- and post-mortality interspecific associations were mostly positive, which remained stable during the period of two surveys for most species, indicating that the community had reached a rather stable stage. Following tree mortality, the number of species with positive associations increased at 1-30 m scales, whereas the number of species with negative and no associations decreased at most scales. These results indicated that the pressure of interspecific competition was relieved to some extent after individual death.
树木死亡是森林中一个重要的生态过程。了解树木死亡如何影响空间格局和种间关联对于揭示树木死亡机制和群落动态至关重要。我们采用空间点格局分析的相关方法，利用在中国木论国家级自然保护区一块25公顷样地的两次调查所获数据，分析了死亡前后空间格局和种间关系的变化。结果表明，大多数物种在死亡前后均呈聚集分布。与死亡前相比，死亡后聚集分布物种的比例略有下降。小尺度上随机分布物种数量的增加表明树木死亡并非随机。在物种水平上，13个常见物种在0 - 30米不同距离水平的死树和活树之间存在显著正相关，表明优势物种之间种内和种间竞争较弱。死亡前后的种间关联大多为正相关，大多数物种在两次调查期间保持稳定，表明群落已达到相当稳定的阶段。树木死亡后，1 - 30米尺度上正相关物种数量增加，而负相关和无关联物种数量在大多数尺度上减少。这些结果表明个体死亡后种间竞争压力在一定程度上得到缓解。
