COS 148-1 - Potential co-benefit of prescribed fire for blacklegged tick control in mid-Atlantic forests

Wednesday, August 9, 2023

8:00 AM – 8:15 AM PDT

Location: E141

Presenting Author(s)

OS

Olivia Spencer

Graduate Student
The Pennsylvania State University - Department of Geography, United States

Coauthor(s)

ES

Erica AH Smithwick

Distinguished Professor of Geography
The Pennsylvania State University
University Park, PA, United States
EM

Erika Machtinger

Assistant Professor
The Pennsylvania State University - Department of Entomology, United States
JE

Jesse Ray Evans

Graduate Student
The Pennsylvania State University - Department of Entomology, United States
JK

Jesse Kreye

Assistant Research Professor
The Pennsylvania State University - Department of Ecosystem Science and Management, United States

Abstract: Fire suppression over the past century has led to multiscale structural and compositional changes in eastern U.S. landscapes. Long term shifts in microclimate conditions, vegetation composition, and forest structure may relate to increasing habitat suitability of disease-carrying ticks. In recent decades, prescribed fire has become increasingly common for addressing mesophication concerns, but knowledge of forest response related to ticks and their pathogens has been limited, particularly in the mid-Atlantic where blacklegged ticks (Ixodes scapularis) are becoming more abundant and Lyme disease rates continue to grow under climate and landscape change. The efficacy of prescribed burning for tick control is not well established due to conflicting results among existing studies, lacking implications for regions where blacklegged ticks are highly abundant, and limited findings on ecological mechanisms guiding tick-fire relationships through time. To understand the effects of prescribed fire on blacklegged ticks, we collected and analyzed data on tick abundance, microclimate, vegetation composition, forest structure, and animal activity in central Pennsylvania where prescribed fire has become increasingly common for restoring ecosystems and promoting wildlife habitat in the last decade. We collected data from 24 total sampling plots and using a non-parametric ANOVA found significantly fewer blacklegged nymph ticks in recently burned areas (0-2 years post-burn) compared to unburned and distantly burned (3-7 years post-burn) plots. Additionally, using bidirectional stepwise regression on the basis of AIC, we found statistically significant (p < 0.05) negative correlations between nymph tick abundance with fire presence, relative humidity variation, ground temperature, forbs and fern cover, tree density, and deer activity. We revealed positive correlations (p < 0.05) between nymph abundance and ground humidity, temperature variation, grass and moss cover, and sapling density. Our work is the first in the region to empirically showcase the potential co-benefit of prescribed burning for tick control while simultaneously exploring ecological mechanisms driving these trends. These co-benefits must be weighed against other co-benefits of prescribed fire including vegetation restoration, hazard reduction, and game species management objectives that are already developing in the region. Questions regarding the role of fire in sustainable land management, ecological restoration, and mitigating vulnerabilities associated with climate and landscape change are particularly important as fire regimes continue shifting in the future.