TY - JOUR
T1 - Impacts of Cattle, Deer, Small Mammals, and Drought on Bur Oak (Quercus macrocarpa Michx.) Seedling Survival in Remnant Savannas in Central Nebraska
AU - Granger, Joshua J.
AU - Rothenberger, Steven J.
AU - Buckley, David S.
AU - Zobel, John M.
PY - 2017/1
Y1 - 2017/1
N2 - Oak savanna remnants contribute substantially to the biodiversity of graminoid-dominated landscapes in the Great Plains Region. Most of these ecologically important ecosystems have either been altered or lost altogether since the arrival of Europeans in the early to mid-1800s. Changes in land use have been accompanied by reduced oak regeneration, which may be attributable to grazing and other management practices. At present, numbers of surviving oak seedlings are insufficient for sustaining the recruitment of oaks into savanna overstory strata. Herbivore exclosures were used to distinguish sources of mortality in first-year bur oak (Quercus macrocarpa) seedlings to determine the impacts of large mammalian herbivores, small mammals, and drought on oak regeneration in savanna remnants in Custer County, Nebraska. Results suggested an uncertain future for extant oak savannas on private land in central Nebraska. Seedlings without exclosures exhibited 97% mortality over the first growing season, and 100% mortality was observed during the subsequent dormant season in seedlings without exclosures that had survived the growing season. Although drought and small mammals contributed to overall oak seedling mortality, cattle and deer impacts were the leading causes of mortality in seedlings without exclosures. Trampling, grazing, and browsing may compromise efforts to restore and sustain these ecologically valuable ecosystems. However, effects of these factors may be reduced through management involving exclosures and limiting grazing to seasons when young oaks are less susceptible to damage.
AB - Oak savanna remnants contribute substantially to the biodiversity of graminoid-dominated landscapes in the Great Plains Region. Most of these ecologically important ecosystems have either been altered or lost altogether since the arrival of Europeans in the early to mid-1800s. Changes in land use have been accompanied by reduced oak regeneration, which may be attributable to grazing and other management practices. At present, numbers of surviving oak seedlings are insufficient for sustaining the recruitment of oaks into savanna overstory strata. Herbivore exclosures were used to distinguish sources of mortality in first-year bur oak (Quercus macrocarpa) seedlings to determine the impacts of large mammalian herbivores, small mammals, and drought on oak regeneration in savanna remnants in Custer County, Nebraska. Results suggested an uncertain future for extant oak savannas on private land in central Nebraska. Seedlings without exclosures exhibited 97% mortality over the first growing season, and 100% mortality was observed during the subsequent dormant season in seedlings without exclosures that had survived the growing season. Although drought and small mammals contributed to overall oak seedling mortality, cattle and deer impacts were the leading causes of mortality in seedlings without exclosures. Trampling, grazing, and browsing may compromise efforts to restore and sustain these ecologically valuable ecosystems. However, effects of these factors may be reduced through management involving exclosures and limiting grazing to seasons when young oaks are less susceptible to damage.
KW - Grazing
KW - Great Plains
KW - Quercus macrocarpa Michx
KW - oak savannas
KW - regeneration
UR - http://www.scopus.com/inward/record.url?scp=85010193025&partnerID=8YFLogxK
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U2 - 10.3375/043.037.0109
DO - 10.3375/043.037.0109
M3 - Review article
AN - SCOPUS:85010193025
SN - 0885-8608
VL - 37
SP - 58
EP - 68
JO - Natural Areas Journal
JF - Natural Areas Journal
IS - 1
ER -