Mediterranean drylands face increasing drought frequency and severity under climate change, yet the effects on pollinator resources and plant-pollinator interactions remain poorly understood. At the Matta Long-Term Ecological Research Station, in the Jerusalem Mountains, we implemented a multi-year rainfall manipulation experiment using rainout shelters. Treatments simulate a 66% reduction in rainfall via natural exclusion or scheduled irrigation pulses with low or high rainfall frequency simulating changes in rainfall distribution.
We examined drought effects at two levels: community-scale assessments of floral resources, pollinator preferences and nesting substrates, and species-level interactions with two native, nectar-rich plant species, Salvia fruticosa and Asphodelus ramosus. At the community level, early results suggest a potential reduction in floral richness and abundance under drought, with notably higher wild pollinator visitation observed in control plots during peak bloom. These resource constraints may limit pollinator foraging and network connectivity.
At the species level, early results show that S. fruticosa under drought exhibited delayed onset of bloom, reduced nectar standing crop and replenishment, and delayed germination timing. Preliminary results on A. ramosus indicate that treatment influences variation in mean flower size, pest incidence, and inflorescence characteristics. These preliminary findings suggest that altered rainfall regimes can reduce floral resources and disrupt pollinator activity at both community and species levels. Such cascading effects highlight the vulnerability of Mediterranean pollination networks under future drought scenarios.
