CONCLUSIONS
This study represents a valuable case of integrating field observations, laboratory approaches and molecular tools for species and interaction identification. An additional relevance is given by the study system, which comprises small oceanic islands offering unique conditions to investigate direct ecological issues in isolated conditions with limited dispersal of individuals elsewhere. Moreover, the presence of usually simplified island communities makes it easier to quantify effects and causes of land-uses on indigenous biodiversity (Picanço et al., 2017; Jupiter, Mangubhai & Kingsford 2014). Overall, these features make small oceanic islands efficient model systems to comprehend the multi-level impacts of green area fragmentation. These could offer the possibility to transfer the obtained results to mainland contexts threatened by human activities and then to address proper mitigation solutions or to predict the effects of land-use alterations.
In the Maldives the rapid development of tourism and human settlement expansion represent the main drivers of change in the landscape composition and configuration (Fallati, Savini, Sterlacchini, & Galli, 2017). These changes highlight the need to find and promote suitable solutions to support biodiversity and ecological functioning. Indeed, we proved that a moderate green area fragmentation could even promote the biodiversity of pollinators, suggesting the need to assess tolerable disturbance thresholds in specific environmental contexts to develop local land-use planning aimed at promoting pollinator biodiversity. Moreover, we stress for a higher mitigation of harmful land-uses and favouring pollinator friendly interventions (e.g., promoting floral resources and availability of heterogeneous nesting sites). This would increase pollination success and thus improve the efficiency of the pollination service. Furthermore, as species-specific responses often take place in spite of community-averaged trends, the heterogeneity of pollinator life histories should be considered when choosing how to mitigate the effect of landscape alteration. In this view, the implementation of modern molecular tools such as DNA metabarcoding in ecological studies is of growing interest in the study of mutualistic interactions. As demonstrated by this study, it provides suitable information that can be easily integrated with field data to improve the efficiency of monitoring programs even in those contexts largely neglected by ecological research.