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ARS Home » Pacific West Area » Burns, Oregon » Range and Meadow Forage Management Research » Research » Publications at this Location » Publication #149836
Title: REVEGETATING WEED-INFESTED RANGELAND WITH NICHE-DIFFERENTIATED DESIRABLE SPECIES

Author
item Carpinelli, Michael
item SHELEY, ROGER - MONTANA STATE UNIV
item MAXWELL, BRUCE - MONTANA STATE UNIV

Submitted to: Journal of Range Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/7/2002
Publication Date: 1/20/2004
Citation: Carpinelli, M.F., Sheley, R.L., Maxwell, B.D. 2004. Revegetating weed-infested rangeland by maximizing niche occupation by desirable species. Journal of Range Management. 57(1):97-105.

Interpretive Summary: Revegetation of weed-infested rangeland often fails because weeds reestablish from seeds remaining in the soil seed bank. An experiment was conducted to develop the ecological basis for converting weed infestations to desirable, weed-resistant plant communities. Revegetating with a diverse mix of desirable species may maximize resource use, potentially preempting resources from weeds emerging from the soil seed bank. In a controlled field experiment, three desirable species with differing spatial and temporal growth patterns (crested wheatgrass, intermediate wheatgrass, and alfalfa) and one weed (spotted knapweed) were used to determine the potential for minimizing weed invasion by maximizing niche occupation and resource use by desirable species. All species were sown simultaneously in spring 1996, simulating revegetation of a site containing spotted knapweed seeds in the soil seed bank because of prior infestation. Species richness (number of species) of desirable species varied, while the total number of desirable seeds sown was held constant. Desirable species richness did not affect resource (soil water) use or spotted knapweed establishment in 1996 or 1997. These results suggest that revegetation of weed-infested rangeland must also include active control of weeds emerging from the soil seed bank. Only then can other strategies, such as maximizing niche occupation by desirable species, be expected to provide long-term success.

Technical Abstract: Revegetation of weed-infested rangeland often fails because weeds reestablish from seeds remaining in the soil seed bank. An experiment was conducted to develop the ecological basis for converting weed infestations to desirable, weed-resistant plant communities. Revegetating with a diverse mix of desirable species may maximize resource use, potentially preempting resources from weeds emerging from the soil seed bank. In a controlled field experiment, three desirable species with differing spatial and temporal growth patterns (crested wheatgrass, intermediate wheatgrass, and alfalfa) and one weed (spotted knapweed) were used to determine the potential for minimizing weed invasion by maximizing niche occupation and resource use by desirable species. All species were sown simultaneously in spring 1996, simulating revegetation of a site containing spotted knapweed seeds in the soil seed bank because of prior infestation. Species richness (number of species) of desirable species varied, while the total number of desirable seeds sown was held constant. Desirable species richness did not affect resource (soil water) use or spotted knapweed establishment in 1996 or 1997. These results suggest that revegetation of weed-infested rangeland must also include active control of weeds emerging from the soil seed bank. Only then can other strategies, such as maximizing niche occupation by desirable species, be expected to provide long-term success.