中国森林叶片功能属性的纬度格局及其影响因素

为了探究森林植物叶片功能属性的地理格局及其影响因素,在2013年7-8月期间系统调查了中国东部南北样带9个森林生态系统的847种植物的叶片面积（LA）、叶片厚度（LT）、比叶面积（SLA）和叶片干物质含量（LDMC）,并结合群落结构计算了各属性的群落加权平均值（LA_CWM、SLA_CWM、LT_CWM和LDMC_CWM）。结果显示：847种植物的LA、LT、SLA和LDMC的平均值（±标准误）分别为2860.01±135.37 mm²、0.17±0.003 mm、20.15±0.43 m² kg^-1和 316.73±3.81 mg g^-1。SLA和LDMC表现出了明显的纬度格局,随着纬度增加,SLA逐渐增加,LDMC降低;然而,LA和LT沿纬度的变化趋势不明显（R² = 0.02 ~ 0.06）。不同植物类型之间叶片属性的差异是影响LA、LT、SLA和LDMC空间变化的主要因素;叶片功能属性的群落加权值表现出了更加明显的纬度分布格局（R² = 0.46 ~ 0.71）,这主要受到了气候因素和土壤N含量的影响。本文结果完善了中国区域森林生态系统叶片功能属性地理分布的数据库,同时强调了在研究植物属性空间格局时,考虑群落结构在尺度扩展中的重要性。

Latitudinal patterns and influencing factors of leaf functional traits in Chinese forest ecosystems

To explore the large-scale changes in leaf functional traits from the species level to community level and their influencing factors in Eastern China, we investigated leaf area (LA), leaf thickness (LT), specific leaf area (SLA) and leaf dry matter content (LDMC) across 847 species from nine typical forest ecosystems along the North-South Transect of Eastern China (NSTEC) between July and August in 2013, and we also calculated the community weighted means (CWM) of leaf traits on the basis of the relative dominance of each species within the community. Our results showed that, for all 847 species, the means (± SE) of LA, LT, SLA, and LDMC were 2860.01 ± 135.37 mm², 0.17 ± 0.003 mm, 20.15 ± 0.43 m² kg^-1 and 316.73 ± 3.81 mg g^-1, respectively. In addition, SLA increased and LDMC decreased with the increasing latitude, whereas no clear latitudinal trends of LA and LT were found (R² = 0.02-0.06), as latitudinal changes were mainly affected by plant functional types. At the community level, more significant spatial patterns of leaf traits were observed (R² = 0.46-0.71). Generally, as latitude increased, LA_CWM and SLA_CWM varied nonlinearly, while LT_CWM increased and LDMC_CWM decreased linearly, which were influenced by climate and soil N. This study improved the biogeographical database of leaf functional traits from tropical to cold-temperate forests in eastern China and emphasized the importance of scaling-up in the study of plant traits.