Herbicide Application Improves Plethodontid Salamander Habitat Conditions in Regenerating Clear-cut Forests

Abstract

Forestry activities, including harvesting and herbicide application, alter both overstory and understory vegetation communities, reshaping ecosystem structure and condition. These changes likely impact wildlife sensitive to environmental change, such as the Eastern Red-backed Salamander (Plethodon cinereus). We compared canopy cover, soil temperature, soil moisture, soil pH, and salamander abundance across unharvested reference stands and clear-cut harvest blocks treated and untreated with a glyphosate-based herbicide. Overall, reference stands exhibited the highest canopy cover and soil moisture, and lowest soil temperature. Herbicide-treated blocks showed decreasing soil temperature and increasing moisture with time since harvest, whereas untreated blocks exhibited the opposite trend. Salamander abundance in reference stands was 4 and 18 times higher than in herbicide-treated and untreated blocks, respectively, and 3 times higher in herbicide-treated than untreated blocks. Greater canopy cover and soil moisture in herbicide-treated blocks likely improve habitat suitability, promoting higher salamander abundance compared to untreated blocks during forest regeneration. Our study suggests that herbicide application in clear-cut forests may accelerate the recovery of microhabitat conditions to preharvest levels, partially mitigating the impacts of harvesting on forest specialists like salamanders. We emphasize the need for holistic approaches in forestry management to sustain biodiversity and ecosystem integrity in increasingly changing landscapes.