Date of Award
Master of Science
Natural Resource Ecology and Management
James R. Miller
Rolf R. Koford
Patch-burn grazing (PBG) is a management practice intended to benefit grassland-dependent wildlife. This practice relies on a fire-grazing interaction to create a habitat mosaic that is heterogeneous in terms of structure and composition, mimicking historic conditions. To assess effects of this, we studied nesting and postfledging survival of Grasshopper Sparrows (Ammodramus savannarum), in pastures under two treatments: PBG (grazed, 1/3 burned annually) or graze-and-burned (grazed, entire pasture burned every third year).The study was conducted in Ringgold County, Iowa, on public and private lands. We found 332 Grasshopper Sparrow nests in 2008 and 2009. In 2009 we attached 50 transmitters to randomly selected nestlings one day prior to fledging. We found that nests in graze-only pastures had a daily survival rate (DSR) of 0.90 (SEy 0.01), and nests found in PBG pastures had a DSR of 0.92 (SEy 0.007). Postfledging survival across treatments was low, with 10 chicks surviving >14 days. Mortality rates were highest within three days of fledging (>48%). We would caution against assessing management with nest survival alone due to high rates of mortality during the postfledging stage.
Torre James Hovick
Hovick, Torre James, "Survival of grasshopper sparrows (Ammodramus savannarum) during two important life stages in grassland managed with fire and grazing" (2010). Graduate Theses and Dissertations. 11227.