北热带喀斯特季节性雨林凋落物组分构成及时空动态 / Composition and spatio-temporal dynamics of litter fall in a northern tropical karst seasonal rainforest in Nonggang, Guangxi, southern China

森林凋落物是森林生态系统的重要组成部分, 在森林生态系统的物质循环和养分平衡中起重要作用。自2012年5月开始, 我们在弄岗北热带喀斯特季节性雨林15 ha森林动态监测样地中布设了90个凋落物收集器进行凋落物收集。本文选取2013-2014年期间相关数据, 研究了凋落物的组分特征、物种组成、时间动态和空间分布特征等。结果表明, 2013年和2014年凋落物总量分别为4,858.0 kg/ha和4,928.8 kg/ha; 凋落物组分以凋落叶为主且高达85%以上, 其他组分所占比例较小。凋落物总量和凋落叶均有两个高峰期, 分别发生在每年的春季(3-4月)和秋冬季(8-11月), 凋落果的高峰期在8月左右; 其他组分由于凋落量较少, 年际动态并不明显。不同生态因子对凋落物总量分布格局的影响差异显著, 且存在年际变化, 但总体表现出凋落物总量受凋落物收集器所在样方的坡向和样方内所有DBH ≥ 1 cm个体的平均胸径影响最为显著。喀斯特季节性雨林凋落物的组分构成和时空动态特征反映了不同生物和非生物因素影响下的物质循环规律, 为深入揭示喀斯特独特地质、地貌背景下物质循环和能量流动的特殊性提供了基础。

Litter fall is a significant component of forest ecosystems and has important ecological functions in material cycling and nutrient balance of forest ecosystems. In this study, we studied litter fall production, composition, spatial and temporal dynamics in a 15-ha northern tropical karst seasonal rainforest dynamics plot in Nonggang National Nature Reserve, Guangxi. We set up 90 litter fall traps, and collected litter fall weekly since May 2012. All litter fall in each trap was dried, classified and weighed. We used litter fall data from January 2013 to December 2014. The total annual litter production in 2013 and 2014 was 4,858.0 kg/ha and 4,928.8 kg/ha, respectively. Litter fall of leaves accounted for 85% while other components made up a small amount. Fruit litter fall was significantly higher in 2013. There were two litter fall peaks in each year, one in spring (March and April) and the other occurring in autumn to early winter (between August and November). The peak of fruit litter fall peak occurred in August. There were no significant inter-annual fluctuations in other litter fall components. The prevailing ecological factors of litter fall production were significantly different between 2013 and 2014. Litter fall production was significantly influenced by aspect and mean DBH (diameter at breast height). Composition and spatio-temporal dynamics of litter fall reflected material cycles affected by multiple biotic and abiotic factors. Our results provide basic information to reveal the unique characteristics of material circulation and energy flows in the geological background and geomorphology of karst.

Abstract in Chinese and English; article in Chinese only.