Nature-based solutions (NBSs) for urban resilience. Introduction

Ecosystem services are "the direct and indirect contributions of ecosystems to human wellbeing" and they can help to cope with the major challenges that cities are facing nowadays. In fact, healthy ecosystem are able to regulate city temperature reducing the heat island effect, reduce water run off, and improve human health and the overall resilience of urban areas. At the same time, urbanisation has increased the pressure on natural resources, generating several impacts on the ecosystems and on the services provided by them at local, regional, national and global scales. This phenomenon has been exacerbated by the impacts of climate change, increasing vulnerability to natural disaster risks. At international and national level several policies for the protection of ecosystems has been defined. Indeed regional and local authorities can improve integrated spatial planning and coordinated management between sectors to reduce the pressures on natural system. In order to do this it is fundamental to understand the value of the ecosystem to introduce regulatory and market instruments that are able to protect them.