The Internet of Things (IoT) continues to expand undeniably fast to reach billions of connected heterogeneous devices. This is changing the way systems are built: new applications integrating software and physical devices are emerging in different domains, such as health, smart building, and smart cities. This brings opportunities to enable new added value services. Nevertheless, building and managing such highly dynamic and heterogeneous infrastructures built upon a multitude of mobile and resource-limited devices is challenging. In this paper, we propose a semantic based autonomic management approach for service oriented IoT systems. The aim is to support building and managing highly dynamic new value added IoT services. The proposed approach relies on a semantic based model to characterize the system properties and then enables semantic reasoning, and graph grammars to enable its management and evolution. A use case is proposed to show the related features of the proposed approach and an evaluation study is presented.