Study on the Recovery of the Intertidal communities on Seawall from the Environmental Disturbances caused by Unusual Hot weather

1998年，我们对海堤潮间带群落从异常高温天气造成的环境干扰中恢复进行了研究，重点研究了潮间带藤壶、半钩藤壶及其生态作用。在岩手县奥基莱伊湾的樱叶海堤进行了实地研究。2004-2006年间。在离墙不同距离的墙上设置了聚氯乙烯测试板，以防止海胆和蜗牛等捕食者。我们还用不同凹凸度的混凝土面板研究了表面粗糙度对固着生物补充的影响。在实验室条件下，研究了中间链霉菌对藤壶和贻贝的捕食作用。作为野外实验的结果，我们首先发现，如果能够控制海胆、中间圆中心线虫和蜗牛等捕食者，潮间带群落是有可能恢复的。实验室实验证明，如果猎物很小，中间链球菌就会捕食藤壶和贻贝。其次，潮间带藤壶(Semibalanus Cariosus)是北太平洋沿岸的优势种，对于在海堤上建立潮间带群落是必要的，因为它是贻贝、褐藻、裙带藻和红藻等次生固着生物的亚种。第三，凹凸体可以有效地促进固着生物体的招募，但凹陷体往往被苔藓虫和锯齿动物等栖息的小型动物填充。在适当的季节在海堤上设置或放置凹陷，以形成持久的潮间带群落似乎是重要的。对于未来的研究，重要的是发明一种易于管理的消除中间海胆的方法来形成和保护潮间带群落。这一概念将适用于潮下群落，并可能为从岩岸剥蚀中恢复提供线索。

We have studied to aim recovery of the Intertidal communities on seawall from the environmental disturbances caused by unusual hot weather in 1998, especially focusing on intertidal barnacle, Semibalanus carious and its ecological role. Field studies have been conducted at Sakihama seawall in Okkirai Bay, Iwate Prefecture. during 2004-2006. PVC test plates have been set on the wall with different distances from wall to prevent predators such as sea-urchin and snails. We also investigated the effect of surface roughness for recruitment of sessile organisms by using concrete panels with different convexo-concavities. Effect of pedation by S. intermedius was investigated for barnacles and mussels in laboratory conditions.As a result of field experiments, first we found that recovery of the intertidal communities will be possible if predators such as sea-urchin Strongyrocentrotus intermedius and snails could be controlled. Laboratory experiments proved that S. intermedius preys on barnacles and mussels if the preys are small. Second, intertidal barnacle Semibalanus cariosus which is a dominant species in northern Pacific coast is essential to build up intertidal communities on the seawalls as a subsuate for secondary sessile organisms such as mussel Mytilus galloprovincialis brown alga Undaria pinnatifida, and red alga Analypus japonicus. Third, convexo-concavities are effective to facilitate recruitment of sessile organisms, but concavities tends to be filled by small sedentary animals such as bryozoans and serpulids. It seems important to set or put concavities on seawalls at an appropriate season to form long-lasting intertidal communities.For future study, it is important to invent a way to eliminate sea-urchin S. intermedius with easy to manage to form and preserve intertidal communities. This concept will be applicable for subtidal communities and may give a hint to recover from rocky-shore denudation.