Effects of prescribed fire and timber harvest on terrestrial salamander abundance, behavior, and microhabitat use

Abstract

The goal of my dissertation was to assess how terrestrial salamanders respond to two common forest management practices -- prescribed fire and timber harvest. Previous studies have reported that timber harvest adversely affects terrestrial salamanders, but there is not enough information to draw conclusions about the effects of prescribed fire. It is important to understand how prescribed fire affects wildlife, as it is increasingly being used to decrease wildfire risk and restore fire-adapted ecosystems. However, many fire management decisions are currently based on predicted plant responses, since there is more data available on plants than wildlife. To estimate terrestrial salamander population size (abundance) prior to treatments, I conducted surveys for three years and used a statistical modeling approach that accounted for the tendency of terrestrial salamanders to be belowground and unavailable for surveys. I found that terrestrial salamander density at our Missouri Ozark study site ranged from 0.4 to 1.6 salamanders per square meter. I found that salamanders were most likely to be on the forest floor surface during or following rainfall, and that they were more likely to be in leaf litter than under cover objects if it had recently rained. Following timber harvest and prescribed fire, salamanders were less likely to be on the surface. It appears that terrestrial salamander abundance is more adversely affected by timber harvest than by prescribed fire. I also tracked individual salamanders before and after a prescribed burn, and found that they stayed belowground much more frequently in burned areas than non-burned areas. However, I did not find evidence of direct salamander mortality due to the fire. My results indicate that terrestrial salamanders respond to post-fire and post-harvest conditions by spending more time belowground to avoid increased physiological stress. Though it appears that terrestrial salamanders can generally avoid direct consequences of prescribed fire, behavioral responses to post-fire micro-environmental conditions could affect salamander populations in ways that are not yet apparent.