The role of dioecious species on the regeneration dynamics and species

雌雄异株物种对再生动态和物种的作用

• 批准号: 08660189
• 负责人: KAWAGUCHI Hideyuki
• 金额: $ 1.47万
• 依托单位: Shimane University (1998)Kyoto University (1996-1997)
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08660189/
• 关键词: Coexistence; Community structure; Dioecy; Population structure; Forest regeneration; Seed dispersal; Spatial heterogeneity; Spatial pattern; 成長速度; 分布相関

1. Spatial patterns of two co-dominant dioecious tree species, Podocarpus nagi and Neolitsea aciculata, were analyzed at Mt. Mikasa, Nara City, Japan. Podocarpus nagi has a higher shade tolerance but a narrower seed dispersal range than N.aciculata. We examined the effects of dioecy on regeneration and coexistence of the two species.2. Seeds of F.nagi are dispersed by gravity around female trees. Young plants of P.nagi were clumped and showed significant attraction to large female trees and significant repulsion from large male trees. Dioecy therefore affected the spatial heterogeneity of plant density in the P.nagi population.3. Seeds of N.aciculata are widely dispersed by birds and young plants of N.aciculata therefore showed no significant attraction to female trees. This wide dispersal of seeds moderated the effects of dioecy on the spatial pattern in N.aciculata.4. Large N.aciculata trees were clumped and showed significant attraction to large male P.nagi trees, suggesting that growth of N.aciculata is facilitated, where young P.nagi plants are uncommon and competition is therefore less intense.5. One effect of dioecy may be to produce a population structure for P.nagi which promotes its coexistence with N.aciculata.

1.对山上两种共优雌雄异株乔木--罗汉松和针叶新铁杉的空间格局进行了分析。米卡萨，日本奈良市。罗汉果具有较高的耐荫性，但种子传播范围比针叶罗汉松小。我们研究了雌雄异株对这两个物种的再生和共存的影响。F.nagi的种子在重力的作用下散布在雌株周围。长白杨幼株丛生，表现出对高大雌株的显著吸引和对大雄株的显著排斥。因此，雌雄异株影响了白杨种群植物密度的空间异质性。针叶菊的种子被鸟类广泛散布，其幼苗对雌株没有明显的吸引力。种子的这种广泛传播缓和了雌雄异株对针叶菊属空间格局的影响。针叶松大树聚集，对雄性大树有明显的吸引作用，这表明针叶杨的生长更容易，因为针叶杨幼树不常见，竞争不那么激烈。雌雄异株的作用之一可能是产生一种种群结构，促进其与针叶夜蛾共存。