The conservatism of prairie pollinators according to experts and empiricism

Abstract Ecological conservatism is a popular concept and tool for assessing the biological consequences of environmental change and degradation. However, conservatism has rarely been applied to insects because the requisite experience for assigning conservatism scores ( C values) is generally lacking for large swaths of regional insect diversity. We derived expert and empirical C values for 265 prairie pollinator species in an agriculturally intensive region. Four regional pollinator experts independently assigned species‐specific C values based on their field experience. Empirical C values were estimated from exhaustive field observations and fidelity to remnant versus non‐remnant prairie sites. Expert and empirical C values were weakly correlated (Spearman's 0.14–0.27) but differences were relatively small across the majority (52%–77%) of species. Expert‐based scores for remnants trended higher than expert‐based scores for non‐remnants but showed considerable overlap and limited statistical separation. Empirical C values were statistically independent of conservation status whereas expert C values trended lower for secure species and higher for at‐risk species. These results suggest that expert‐based C values can show redundancy with conservation ranks and may struggle to differentiate priority sites for prairie pollinators. We discuss how the advantages of empirical C values may outweigh their limitations and the complex ecology of pollinators. We recommend developing empirical C values to help facilitate pollinator‐based site assessment and prioritization in prairie regions.