Potential impact of neonicotinoid use on Northern bobwhite (Colinus virginianus) in Texas: A historical analysis

Abstract

The widespread use of neonicotinoid insecticides in recent years has led to increasing environmental concern, including impacts to avian populations. In Texas and across their range, Northern bobwhite (Colinus virginianus) habitat frequently overlaps cultivated cropland protected by neonicotinoids. To address the effects of neonicotinoid use on bobwhites in Texas, we conducted a historical analysis from 1978-2012 in Texas' ecological regions using quail count data collected from North American Breeding Bird Survey and Texas Parks and Wildlife Department, and neonicotinoid use data from the U.S. Geological Survey. We considered bobwhite abundance, neonicotinoid use, climate, and land-use variables in our analysis. Neonicotinoid use was significantly (p<0.05) negatively associated with bobwhite abundance in the High Plains, Rolling Plains, Gulf Coast Prairies & Marshes, Edwards Plateau, and South Texas Plains ecological regions in the time periods following neonicotinoid introduction (1994-2003) or after their widespread use (2004-2012). Our analyses suggest that the use of neonicotinoid insecticides may negatively affect bobwhite populations in crop-producing regions of Texas.

Fig 1. Distribution of Breeding Bird Survey and Texas Parks and Wildlife Department driving transects within Texas ecoregions.

1) Trans Pecos, 2) High Plains, 3) Rolling Plains, 4) Cross Timbers & Prairies, 5) Piney Woods, 6) Edwards Plateau, 7) Gulf Coast Prairies & Marshes, 8) South Texas Plains.

Fig 2. Temporal trend in neonicotinoid use in Texas.

USGS ePest High estimates for total neonicotinoid use in the state of Texas from 1978–2012. Statistical analysis was split into three time periods based on overall levels of neonicotinoid use: prior to neonicotinoid introduction (Pre), directly following neonicotinoid introduction (Light), and after the widespread use of neonicotinoids (Heavy).