Jf. Weltzin et al., PRAIRIE DOG EFFECTS ON PLANT COMMUNITY STRUCTURE IN SOUTHERN MIXED-GRASS PRAIRIE, The Southwestern naturalist, 42(3), 1997, pp. 251-258
Black-tailed prairie dogs (Cynomys ludovicianus) influence ecosystem s
tructure and function through their burrowing and grazing activities,
and reportedly increase plant species diversity relative to uncolonize
d portions of the landscape. Consequently, systematic eradication of p
rairie dogs-a widespread practice over much of the Great Plains-may ul
timately reduce plant species diversity. To determine the effects of p
rairie dogs and associated fauna on herbaceous vegetation in a souther
n mixed-grass prairie ecosystem, we quantified herbaceous standing cro
p, species composition, and plant species diversity on and off a prair
ie dog colony in north-central Texas in 1988 and 1989. Total live herb
aceous standing crop was 3 times to 4 times greater off the prairie do
g colony than on the prairie dog colony in 1988 and 1989, respectively
. Midgrass biomass was 6 and 15 times greater off-colony than on-colon
y in 1988 and 1989, respectively. Shortgrass biomass did not differ be
tween on-colony and off-colony zones in either year. Principal compone
nts analysis (PCA) revealed plant species distribution patterns attrib
utable to colonization by prairie dogs. Axis I sample scores were stro
ngly correlated with midgrass biomass bur not shortgrass biomass. Stat
istical analyses of jack-knifed Shannon's and Simpson's diversity indi
ces indicated that plant species diversity was greater off than on the
prairie dog colony. Thus, black-tailed prairie dogs and associated fa
una substantially altered the relative distribution, abundance, and co
mposition of herbaceous vegetation at this southern mixed-grass prairi
e site.