TY - JOUR
T1 - Invasion by an exotic, perennial grass alters responses of a native woody species in an arid system
AU - Alexander Eilts, J.
AU - Huxman, T. E.
PY - 2013/1/1
Y1 - 2013/1/1
N2 - Grass growth has been encouraged in arid communities globally to improve grazing. Often exotic species are planted, subsequently spreading beyond their plantings to drastically alter cover and negatively impact native species. We evaluated the effects of the invasive, perennial grass Cenchrus ciliaris on the native woody species Cercidium microphyllum over two growing seasons: 2002 and 2003. To determine if C. ciliaris alters seasonal responses of C. microphyllum, we measured predawn water potential, photosynthesis, and branch sacrifice on C. microphyllum growing with either native cover or C. ciliaris. In 2003 a removal treatment of C. ciliaris was applied to assess responses in C. microphyllum during the summer. In both years, C. microphyllum water potentials closely tracked seasonal rainfall, suggesting dependence on shallow soil water. In 2002, we observed few negative impacts when C. microphyllum grew with C. ciliaris. However, the trees growing with C. ciliaris exhibited greater branch sacrifice, a typical response to drought, which likely complicated interpretation of the treatment effects. Removal of C. ciliaris resulted in increased water potentials and photosynthesis. This study suggests that exotic grasses, such as C. ciliaris, can reduce both water potential and photosynthetic rates in mature woody shrubs, like C. microphyllum, in aridland systems.
AB - Grass growth has been encouraged in arid communities globally to improve grazing. Often exotic species are planted, subsequently spreading beyond their plantings to drastically alter cover and negatively impact native species. We evaluated the effects of the invasive, perennial grass Cenchrus ciliaris on the native woody species Cercidium microphyllum over two growing seasons: 2002 and 2003. To determine if C. ciliaris alters seasonal responses of C. microphyllum, we measured predawn water potential, photosynthesis, and branch sacrifice on C. microphyllum growing with either native cover or C. ciliaris. In 2003 a removal treatment of C. ciliaris was applied to assess responses in C. microphyllum during the summer. In both years, C. microphyllum water potentials closely tracked seasonal rainfall, suggesting dependence on shallow soil water. In 2002, we observed few negative impacts when C. microphyllum grew with C. ciliaris. However, the trees growing with C. ciliaris exhibited greater branch sacrifice, a typical response to drought, which likely complicated interpretation of the treatment effects. Removal of C. ciliaris resulted in increased water potentials and photosynthesis. This study suggests that exotic grasses, such as C. ciliaris, can reduce both water potential and photosynthetic rates in mature woody shrubs, like C. microphyllum, in aridland systems.
KW - Branch sacrifice
KW - Cenchrus ciliaris
KW - Cercidium microphyllum
KW - Exotic species
KW - Pennisetum ciliare
KW - Sonoran desert
UR - http://www.scopus.com/inward/record.url?scp=84868230138&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84868230138&partnerID=8YFLogxK
U2 - 10.1016/j.jaridenv.2012.08.002
DO - 10.1016/j.jaridenv.2012.08.002
M3 - Article
AN - SCOPUS:84868230138
SN - 0140-1963
VL - 88
SP - 206
EP - 212
JO - Journal of Arid Environments
JF - Journal of Arid Environments
ER -