Mechanical Aeration Effects on Mammifauna, Herpetofauna and Vegetation on a South Texas Shrubland

(December 2003)

Keith L. Krakauer, B.S., University of Colorado Boulder.

Chairman of Advisory Committee:  Dr. Steve Smith

 

Five study plots were aerated in August 1998 on Texas Parks and Wildlife's Chaparral Wildlife Management Area, Dimmit and LaSalle counties, Texas.  Each season, over a two-year period, rodents were Sherman trapped on the aerated and treated plots.  During late spring and summer 1999 and 2000, drift-fences on the aerated and control plots were monitored.  Herperofauna, and small mammal numbers were collected.  During summer 1999 and 2000, woody vegetation line-transects were surveyed and density and percent cover data were collected. In fall and spring 1999, herbaceous vegetation cover and density data were collected on the treated and control plots.  The impacts of aeration depended on the rodent species. The great plains narrowmouth toad (Gastrophryne olivacea), the Texas spotted whiptail (Cnemidophorus sexlineatus) numbers were higher in the control plots and the Texas toad (Bufo speciosus) numbers were similar in the control and treated plots.  Woody vegetation densities were similar on the control and aerated plots during summer 1999 and 2000, and vertical cover was higher on the control plots in both years.  Grass densities were similar on the aerated and control plots in both spring and fall 1999 and grass percent cover values were higher on the treated plots during the fall.  Forb densities and percent cover values were higher on the control plots during spring 1999.