Global change and plant-pollinator communities in Mediterranean biomes

AimOccurring in five distinct global regions, Mediterranean-type ecosystems (MTEs) include both centres of agricultural production and hotspots of extratropical biodiversity - particularly for plants and bees. Considerable research has addressed the persistence of highly diverse biological communities within MTEs, despite their typically long histories of anthropogenic and natural disturbance. However, important questions remain, especially regarding the limits of ecological resilience in the face of accelerating environmental change. Here, we explore current knowledge regarding the effects of disturbance on MTE plant-pollinator communities.LocationMediterranean Basin, California, Cape Province in South Africa, Central Chile and Southern South-Western Australia.Taxa StudiedFlowering plants and pollinators (insects, birds and mammals).MethodsWe reviewed the available literature about MTE plant-pollinator communities via a systematic search that yielded 234 case studies. We analysed this dataset to quantify research efforts across regions and taxonomic groups, the proportion of surveys addressing ecological interactions (i.e. rather than only taxonomic diversity) and the availability of work addressing community responses to specific stressors (viz. climate change, landscape alteration, fire, farming, grazing, urbanization and species introductions).ResultsCurrent knowledge on MTE plant-pollinator communities is dominated by work from the northern Mediterranean Basin, while the Southern Hemisphere and California are markedly understudied by comparison. Taxonomic coverage is similarly uneven, with 58% of studies focusing only on a single pollinator group. Furthermore, less than half of the surveys address ecological networks. Finally, despite some pioneering work addressing fire, climate and species introductions, only 13% focus on the impact of stressors on interaction networks.OutlookBased on our findings, we identify a need for coordinated international research efforts focusing on (i) community-level studies, observational and experimental, (ii) ecological networks, (iii) functional traits mediating post-disturbance recovery and (iv) impacts of combined/synergistic stressors. Progress in these areas will facilitate predictions about the long-term impacts of global change on MTE plant-pollinator communities.