Managing exotic grasses and conserving declining species
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Authors: D. J. Germano, G. B. Rathbun, and L. R. Saslaw
Date: 2001
Journal: Wildlife Society Bulletin
Volume: 29
Number: 2
Pages: 551-559
Summary of Methods: This is a scientific opinion paper that uses 61 studies to present the use of targeted livestock grazing to decrease the cover of exotic annual grasses in an effort to benefit many threatened and endangered wildlife and plant species.
Article Summary / Main Points:
• Initial classification of the San Joaquin Valley in California was a bunchgrass prairie, though in recent years this has been challenged.
• Examination of the native plants and animals, it is now thought the southern portion of the San Joaquin Valley was originally an open desert saltbrush shrubland habitat.
• The introduction of annual exotic grasses has created a very dense herbaceous habitat that is detrimental to native kangaroo rats, antelope squirrel, lizards, birds and plants that require more open, sparsely vegetated areas for survival.
• Many of these species are listed as state or federal threatened and endangered species.
• Removal of livestock grazing has been shown to only accelerate the detrimental effects of the annual grasses and not lead to native perennials out competing exotic annuals.
• Without management action these annual grasslands will not recover to the native saltbrush shrublands.
• Fires decrease herbaceous cover, but also kill all native shrubs and are costly to manage.
• Herbicides are costly, and mechanical treatments would likely destroy the burrows and habitats of the species of concern, leaving prescription grazing as the last viable option to manage these exotic annual grasses.Vegetation Types: California Grasslands (including all annual grasslands)
MLRA Ecoregions: 17 Sacramento and San Joaquin Valleys
Agrovoc Control Words: Weeds Annual Grasses Grazing
Article Review Type: Peer Reviewed
Article Type: Scientific Opinion
Keywords: conservation, endangered species, exotic plants, livestock grazing
Annotation: This paper presents a very compelling argument for the use of well managed, targeted grazing to control the exotic annual grasses in the San Joaquin Valley of California that was originally dominated by saltbrush. The authors believe for any grazing prescription to work here it has to be flexible in grazing dates, stocking rates, frequency. This is consistent with the steps outlined by Frost and Launchbaugh in 2003 (Rangelands, 25:43-47, available in the RSIS database).
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