Effects of artificial disturbance of river on the biodiversity of the river forest

为了探讨滨江林生物多样性的机制，对日本温带地区几种保存完好的滨江林中几种优势树种的繁殖策略和交配系统进行了研究。在雌雄异株树种柳属中，我们揭示了有性生殖和无性生殖在林龄上的相对重要性。在柳属中，雌性投入更多的资源用于繁殖，但它们有一些上级的生理、形态和物候机制来补偿繁殖成本。我们还发现了一种滨江种--这两种类型对男性和女性功能的投资相等。利用稳定同位素技术揭示了从山地河边森林凋落物到海洋鱼类的食物链。本研究为保护滨江天然林对维持生物多样性的重要性提供了依据。

To evaluate the mechanisms of bio-diversity of riverside forests, we investigated the reproductive strategies and mating systems of several dominant tree species in several well-preserved riverside forests in temperate region of Japan. In the dioecious tree species, Salix sp., we revealed the relative importance of sexual and asexal reproduction in relation to stand ages. In Salix sp., female invest much more resource to reproduction, but they have several superior physiological, morphological, and phenological mechanisms to compensate the reproductive cost. We also revealed that a riverside species, Jugalns ailanthifolia, is a heterodichogamous species, which have two type of flowering phenolgies. Both types invest equally to each of male and female function. Male reproductive success was also almost identical to that of females.We revealed the food chain from litter fall in mountaneous river side forest to fish in sea by using stable isotope. This study provide the evidences of importance of the preservation of natural riverside forests to maintain the bio-diversity.