Mesoclosures – increasing realism in mesocosm studies of ecosystem functioning

1. Experimental studies linking community composition to functioning are typically confined to small and closed micro- or mesocosms. Such restricted conditions may affect both species’ biology and their environment. Yet, targeting simple features in the behaviour of species may circumvent these constraints. Focusing on ecological functions provided by dung beetles, we test whether large, open-top cages – MESOCLOSURES – will intercept the flight trajectories of beetles, thereby allowing manipulation of local community composition. 2. MESOCLOSURES were built in both tropical forest (Brazil) and temperate grasslands (Finland), thus testing their general efficiency. Within the respective environments, we varied different aspects of MESOCLOSURE design: in the tropical forest, we examined the impact of MESOCLOSURE dimensions on exclusion efficiency, whereas in the temperate grassland, we assessed the potential for selectively excluding and including community members by different mesh sizes. ...