Signals of Paleotemperature in the Age Structure and Seasonal Distribution of Pollination Syndromes Across a Temperate Region

ABSTRACT

Across the planet, angiosperm diversification has been shaped by palaeoclimates and biotic interactions, particularly with pollinators, leaving signatures in the angiosperm age structure. Regional floras represent biased samples of this global diversification shaped by dispersal, extinction and environmental filtering, yet it remains unclear whether floristic age structure reflects pollination strategies or their interaction with palaeoclimates. We constructed a 93% resolved phylogeny of all native 1178 angiosperms in the Netherlands and characterized age structure of eight pollination syndromes by standardized epoch‐specific lineage diversities (stELDs) quantifying the proportional increase in lineages per 10‐Myr interval. Overall, stELDs peaked under the coldest intervals and were lowest for intermediate‐temperature intervals (geological age alone had no effect). This age structure was strongest in wind‐pollinated species. Resolving insect pollination into six syndromes revealed strong heterogeneity: lepidoptera‐pollination was most strongly associated with warmest palaeotemperatures, bumblebee and wasp‐pollination under intermediate temperatures, and fly, lepidoptera and beetle‐pollination under coldest temperatures. Paleotemperature signatures correlated positively with contemporary seasonal flowering temperatures, indicating conserved thermal niches across ecological and macroevolutionary timescales. We suggest that temperate floras reflect both recent cold‐house diversification of wind‐ and certain insect‐pollinated lineages and earlier warm‐house radiations of lineages pollinated by older insect clades. Phylogenetic age structures permit detecting such patterns.