木麻黄海防林种子雨的时空动态

Spatial and Temporal Dynamics of Seed Rain of Casuarina equisetifolia Coastal Protection Forest

为了解木麻黄(Casuarina equisetifolia)种子雨的时空间分布格局和萌发性能对其天然更新的影响,对海口木麻黄海防林种子雨的时空分布特征和种子雨的萌发动态进行了研究。结果表明,木麻黄种子落雨时间始于7月中旬,结束于次年4月中旬,持续长达9个月,期间种子雨年际平均密度为1 764.63 grain m^-2a^-1;种子雨高峰期在12月上中旬,落种量占总散落量的43.38%;种子雨呈聚集分布,且种子雨密度与附近球果数量呈极显著正相关;种子雨萌发率较低,仅为11.31%,但由于种子雨密度较大,可萌发的种子雨密度仍然较大,为199.58grainm^-2a^-1。因此,种子数量和质量均不是制约木麻黄天然更新困难的主要障碍因子,但聚集分布特征使木麻黄种子在林内扩散能力十分有限。

In order to understand the spatial and temporal distribution patterns and germination of seed rain of Casuarina equisetifolia, the spatial-temporal distribution characteristics and germination dynamics of seed rain were studied in coastal protection forest of C. equisetifolia in Haikou, Hainan Province. The results showed that the seed rain of C. equisetifolia began in mid-July and finished in mid-April of next year, which was lasted for 9 months, with average density of seed rain for 1 764.63 grain m^(-2)a^-1. The peak of seed rain was in early-to mid-December, accounting for 43.38% of the total seed rain. Seed rain was aggregated distribution, and the seed rain density was positively correlated with the number of nearby cones. The germination rate of seed rain was low only with 11.31%, but the germinable seed rain density was still high with 199.58 grain m^(-2)a^-1, due to the high seed rain density. Therefore, the quantity and quality of C. equisetifolia seed rain were not the main factors in restricting its natural regeneration, but the aggregated distribution pattern made the diffusion ability of C.equisetifolia seeds very limited in the forest.