Increasing Cupressaceae Pollen: A Growing Threat
Monday, March 7, 2016: 2:45 PM
Room 502A (Convention Center)
Estelle Levetin, PhD FAAAAI, ,
Rationale: The expansion of Juniperus populations throughout the Great Plains has been studied by ecologists for several decades. Although several Juniperus species are important aeroallergens, little is known about long-term changes in Juniperus (Cupressaceae) pollen concentrations. The current study examined trends in airborne Cupressaceae pollen since 1987 and the prospects for future increases based on computer models.  

Methods: The atmosphere in Tulsa, Oklahoma has been monitored with a Burkard sampler. Pollen concentrations were determined and pollen season metrics calculated for spring Cupressaceae pollen. Pearson correlations were used to examine changes over time. Current and future distributions of several Juniperus species were modeled using machine learning algorithms, based on available locality data and a suite of environmental parameters including climate, soil, and elevation.

Results: Analysis of spring Cupressaceae pollen data from 1987 to 2015 showed considerable variability in pollen metrics. Start date varied 6 weeks, season length from 18 to 62 days, cumulative season total (CST) pollen from 1,708 to 12,566, and peak concentrations from 442 to 2,699 pollen/m3. When analyzed over time, there were significant increases in both CST (r=0.67,p<0.0001) and peak concentration (r=0.57,p=0.001). Recent locality data for J.virginiana, J.ashei, J.pinchotii, and J.monosperma indicate the species' ranges are still expanding, and preliminary distribution models suggest this will be exacerbated under future climate change scenarios.

Conclusions: Cupressaceae pollen in the Tulsa atmosphere has shown significant increases over time paralleling Juniperus population increases in Oklahoma. Computer models of population distribution indicate continued expansion in the future, suggesting that airborne pollen levels will also continue to increase.