Shrub encroachment occurring worldwide in savannas and grasslands has commonly been hypothesized to result from anthropogenically altered environments. Two disturbance-based approaches to restoration have involved: (1) application of selective herbicides to reduce density/cover of shrubs; (2) reinstatement of natural fire regimes to generate environmental conditions favoring herbaceous species. We studied short-term responses of native shrubs, vines, and grasses in a Louisiana pine savanna to herbicides followed by a prescribed fire and fire alone. Plots established in the summer, 2013, were hand-sprayed in the fall with Imazapyr and Triclopyr, Triclopyr alone, or no herbicide, then prescribed burned the following spring. Numbers of species of shrubs and vines at scales of 1 and 100 m 2 , numbers of stems and regrowth of stems produced by six common species of shrubs, and the number of flowering culms of perennial C 4 grasses were assessed postfire in 2014. Compared with fire alone, herbicides followed by fire resulted in (1) small reductions in species richness of shrubs and no effects on vines, (2) fewer stems comprising shrub genets, but similar postfire regrowth of resprouting shrub stems, and (3) fewer flowering culms of C 4 grasses. Underground storage organs of savanna shrubs and vines survived both aboveground disturbances. Thus, single applications of herbicides followed by fires reduced, but did not reverse shrub encroachment and negatively affected grasses. Because effects of herbicides overrode those of prescribed fires, these disturbances did not act synergistically, suggesting that reinstating natural fire regimes should be a priority in restoration of savannas and grasslands.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.