The Long-Term Effects of Fire Seasonality on a Rolling Plains Small Vertebrate and Vegetation Community
Gutierrez, Joselyn Maree
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Fire is a natural process in grasslands, which makes prescribed burning an extremely important management tool that is widely used to replicate that natural process that is often missing from modern grasslands. However, most research addressing the impacts of prescribed fire have focused on short-term responses and studies examining the seasonality of fire are largely lacking. Prescribed burn studies on nongame wildlife are also generally lacking. Therefore filling in this data gap with longer-term studies will help us better-manage these species that are potentially in trouble and being ignored. In 2004, a project was initiated to evaluate the impacts of summer and winter burning on vegetation and small vertebrates in a sand sage prairie ecosystem within the southeastern Texas Panhandle. Although the initial project was designed to look at the short-term effects, I initiated a project to continue data collection to begin evaluating the longer-term effects on vegetation and small vertebrates. A randomized complete block design with 5 blocks and 3 treatments was established at the Matador Wildlife Management Area (WMA) in Cottle County, Texas. Each plot within a block was randomly assigned 1 of 3 treatments: winter burned, summer burned or unburned. Herpetofauna and small mammals were sampled using drift fence arrays with pitfall traps during the spring and summer of all years of sampling. Herbaceous vegetation cover and frequency was measured twice annually using quadrats and woody vegetation was measured during late summer using the line-intercept method. I regressed sample year against community metrics to evaluate longer-term responses to burning. In the early season, summer-burning increased species richness, evenness, and diversity of vertebrates over time, but individual species responses were variable. In contrast, treatment did not generally alter community metrics for vegetation. However, comparison of early season indices of similarity suggested that burning shifted the species composition of the herbaceous plant community over time, whereas during the late season, the small vertebrate community shifted in the unburned treatment, but not in either burn treatment. Thus, burning is shifting the plant community regardless of weather patterns, but it may be ameliorating the effects of long-term drought on the small vertebrate community. These trends were weak and interpretation has been made difficult because of the long-term severe drought that has persisted in the region for the duration of this project. However, my results generally suggest summer burning seems to have a greater positive benefit on small vertebrate communities in this system than winter-burning, and both burning treatments appear to improve conditions relative to lack of burning. Longer-term research on the effects of growing and dormant season burning on small vertebrate and vegetation communities, especially during wet and drought years, is needed to evaluate the effects of seasonal prescribed burns in the Rolling Plains of Texas.