AUTHORS: Allison Sacerdote-Velat, Chicago Academy of Sciences
ABSTRACT: Smooth Greensnakes (Opheodrys vernalis) are small-bodied, oviparous, grassland dependent colubrids, that are declining throughout much of the Midwest due to grassland loss and degradation. We used a before-after-control-impact (BACI) approach to examine effects of prescribed fire, burn interval, and mowing for shrub control, on Smooth Greensnake detection, and nesting activity. This approach parses out temporal effects from management effects. Pre-management data were collected in two grassland sites from multiple long-term monitoring plots. Prescribed fire and mowing were implemented across study plots in both grasslands while maintaining unmanaged plots as controls. Smooth Greensnake detection was greater in post-burn plots than in the control or mowed plots. However, nest abundance decreased following burning, and did not reach pre-management levels until after two to three years of post-burn recovery. In contrast, Smooth Greensnakes continued to nest in post-mow plots with no difference in nest abundance pre- and post-mowing. In Site 1, snake detection and nest abundance did not differ between the control and the mowed plot. In Site 2, willow encroachment in the control plot reduced Smooth Greensnake activity overall. Subsequent burns occurred in Site 2, one year after the initial burn, and in Site 1, three years after the initial burn, allowing further examination of the effects of fire interval. Again, we observed greater snake detection, but reduced nest abundance following the burns. Burning significantly reduced nesting activity for Smooth Greensnakes, which we attribute to the loss of vegetative thatch, which may help retain critical moisture in nesting sites. These results have conservation implications for recruitment based on fire intervals and the extent of burn units. Snake responses to habitat management may be influenced by aspects of reproductive requirements, reiterating the need for a mosaic-approach to management, and including variation in fire intervals in managed grasslands.
