The 2008 Joint Meeting of the Society for Range Management and the America Forage and Grassland Council. |
Wednesday, January 30, 2008
52
Breeding Chronology and Success of Grasshopper Sparrows and Eastern Meadowlarks on A Military Training Landscape: Implications for Management
Donald P. Althoff, Divison of Biology, Kansas State University, 206 Leasure Hall, Kansas State University, Manhattan, KS 66506 and Philip S. Gipson, U.S. Geological Survey, Kansas Cooperative Fish & Wildlife Research Unit, 206 Leasure Hall, Kansas State University, Manhattan, KS 66506.
Grassland ecosystems can be influenced by variety of natural and anthropogenic disturbances. Understanding chronology of breeding activities of small landbird species is critical to development and refinement of management plans—especially where local populations may be considered at risk. We documented territory occupancy and breeding success of grasshopper sparrows (Ammodramus savannarum) and eastern meadowlarks (Sturnella magna) on the Fort Riley Military Installation, Kansas, from 2003-2005. Prescribed burning, haying, and mechanized maneuver training were relatively common disturbances on Fort Riley. Using an indirect method based on breeding behaviors, we determined timing of reproductive success for both species (grasshopper sparrow: 98 territories in 2003, 82 territories in 2004, 76 in 2005; eastern meadowlark: 43 territories in 2003, 22 in 2004, 33 in 2005). We observed that the peak production of fledglings was earlier in 2003 and 2005 than 2004 by 4-5 weeks (mid-June vs. mid-July, respectively) for both species and appeared to be more influenced by rainfall events (more in number and greater intensity in 2004) than any disturbances from military training. During years when rainfall events mimic those we observed in 2004, disruptive activities such as haying, which is typically initiated in mid-July, should be delayed ³2 weeks to improve reproductive success by grasshopper sparrows and to a lesser extent eastern meadowlarks.