Internationally, the importance of a coordinated effort to protect\nboth biodiversity and public health is more and more recognized.\nThese issues are often concentrated or particularly challenging in\nurban areas, and therefore on-going urbanization worldwide raises\nparticular issues both for the conservation of living natural resources\nand for population health strategies. These challenges include significant\ndifficulties associated with sustainable management of urban ecosystems,\nurban development planning, social cohesion and public health. An\nimportant element of the challenge is the need to interface between\ndifferent forms of knowledge and different actors from science and\npolicy. We illustrate this with examples from Belgium, showcasing\nconcrete cases of humanâ€“nature interaction. To better tackle these\nchallenges, since 2011, actors in science, policy and the broader\nBelgian society have launched a number of initiatives to deal in\na more integrated manner with combined biodiversity and public health\nchallenges in the face of ongoing urbanization. This emerging community\nof practice in Belgium exemplifies the importance of interfacing\nat different levels. (1)Â Bridges must be built between science and\nthe complex biodiversity/ecosystemâ€“human/public healthâ€“urbanization\nphenomena. (2) Bridges between different professional communities\nand disciplines are urgently needed. (3)Â Closer collaboration between\nscience and policy, and between science and societal practice is\nneeded. Moreover, within each of these communities closer collaboration\nbetween specialized sections is needed.