Emerging pervasive computing scenarios require open service frameworks promoting situated adaptive behaviors and supporting diversity in services and long-term ability to evolve. We argue that this calls for a nature-inspired approach in which pervasive services are modeled and deployed as autonomous individuals in an ecosystem of other services, data sources, and pervasive devices. We discuss how standard service-oriented architectures have to evolve to tackle the above issues, present a general architecture based on a shared spatial substrate mediating interactions of all the individual services of the pervasive computing system, and finally show that this architecture can be implemented relying primarily on standard W3C Semantic Web technologies, like RDF and SPARQL. A use case of adaptive pervasive displays for crowd steering applications is exploited as reference example.