中国东部海岛森林和灌丛土壤碳氮磷养分库的纬度变化

虽然海岛结构相对简单,但在生物多样性和生态功能维持方面起重要作用.以中国东部暖温带、北亚热带、中亚热带和南亚热带的14个海岛为对象,研究森林土壤碳和氮磷养分库的纬度变化特征,并分析其与气候因子和植物多样性的关系.结果表明:土壤碳和氮磷养分库在温度带间差异显著,土壤碳库与氮库在暖温带最低,分别为49.35和1.08 t·hm^-2,在北亚热带最高,为137.25和4.63 t·hm^-2;磷库在南亚热带海岛最低,为1.3 t·hm^-2,在北亚热带最高,为5.19 t·hm^-2.各植被类型土壤碳氮磷库在不同温度带间存在显著差异,落叶林土壤碳氮磷库在亚热带高于暖温带;常绿阔叶林土壤碳和氮库不受温度带影响,磷库在北亚热带和中亚热带显著高于南亚热带.年均温、年降水量、土壤含水量和植物物种多样性间的交互作用对土壤碳氮磷库有显著正向影响;植物物种多样性对土壤氮库变化有正向影响,但对磷库具有负向影响.海岛森林土壤碳库的纬度变化趋势与大陆相反,土壤氮磷养分库变化格局与大陆相似;其中,水热和植物物种多样性是驱动中国东部海岛森林土壤碳氮磷库变化的主要非生物和生物因素.

Latitudinal variation in soil carbon,nitrogen and phosphorus pools across island forests and shrublands in eastern China

Despite its monotonous structure, sea-island plays a crucial role in sustaining biodiversity and ecosystem functioning. The objectives of this study were to explore the altitudinal variation of soil carbon (C), nitrogen (N), and phosphorus (P) pools in forests across 14 islands spanning temperate zone (TZ), northern subtropical zone (NSZ), mid-subtropical zone (MSZ), and sou-thern subtropical zone (SSZ) in eastern China. The relationships of soil C and nutrient pools with climatic factors and plant species diversity were examined across islands. Our results showed that soil C, N and P pools differed significantly across climatic zones. Soil C and N pools were the lowest in TZ (49.35 and 1.08 t·hm^-2) and the highest in NSZ (137.25 and 4.63 t·hm^-2). Soil P pool was the lowest in SSZ (1.3 t·hm^-2) and the highest in NSZ (5.19 t·hm^-2). There were significant difference in soil C, N and P pools among vegetation types. Soil C, N and P pools in deciduous forests were significantly higher in subtropical than in temperate islands. Soil C and N pools in evergreen broadleaved forests did not differ among sub-climatic zones, and soil P pool was lower in SSZ than that in NSZ and MSZ. The interactions across mean annual temperature, mean annual precipitation, soil water content, and plant species diversity positively affected latitudinal variation in soil C, N, and P pools. Plant species diversity positively associated with soil N pool, but negatively linked with soil P pool. In conclusion, the latitudinal trend of soil C pool is different, but that of soil N and P pools are identical between sea-island and mainland. The main abiotic and biotic dri-vers of soil C, N and P pools are water availability, temperature and plant species diversity across sea-islands in eastern China.