Economic Impacts of Yellow Starthistle on California Ranchers

While the significant ecosystem damage caused by invasive weeds has been well documented, the economic impacts of specific invasive weed species are poorly understood. Yellow starthistle (Centaurea solstitialis L., hereafter YST) is the most widespread non-crop weed in California, resulting in serious damage to forage on natural range and improved pasture. A survey was administered to California cattle ranchers to investigate YST infestation rates, loss of forage quantity and value, and control or eradication efforts. The results were used to estimate county-wide economic losses for three focus counties, as well as state-wide economic losses, due to YST in California. Total losses of livestock forage value due to YST on private land for the state of California are estimated at $7.96 million/year, with ranchers’ out-of-pocket expenditures on YST control amounting to$9.45 million/year. Together, these costs are the equivalent of 6-7% of the total annual harvested pasture value for the state. Therefore, while the impacts are relatively small within the statewide total agricultural production system, costs due to YST infestation significantly constrain California’s livestock grazing sector.nonnative species, invasive weeds, yellow starthistle, ranching profitability, forage, livestock

Yellow starthistle continues its spread in California

Yellow starthistle is an exotic invasive weed that is estimated to infest over 14 million acres in California and is considered the most common exotic weed statewide. We reviewed several previous studies and conducted a township survey to provide an up-to-date analysis of the weed's rapid spread throughout the state. A county-by-county comparison between 1985 and 2002 showed increases in yellow starthistle in all regions of the state except for northeast California and the southeast desert region. Currently, most infestations occur in Northern California, but future invasions and spread will likely occur in the coastal counties of Southern California

Yellow starthistle continues its spread in California

Yellow starthistle is an exotic invasive weed that is estimated to infest over 14 million acres in California and is considered the most common exotic weed statewide. We reviewed several previous studies and conducted a township survey to provide an up-to-date analysis of the weed’s rapid spread throughout the state. A county-by-county comparison between 1985 and 2002 showed increases in yellow starthistle in all regions of the state except for northeast California and the southeast desert region. Currently, most infestations occur in Northern California, but future invasions and spread will likely occur in the coastal counties of Southern California

Vascular Plants of Northern Death Valley National Park (Death Valley, Last Chance Range, and Eureka Valley), Inyo County, California

The northern portion of Death Valley National Park closely (but not entirely) corresponds to the northernmost portion of the Mojave Desert in California. From 2014 through 2019 we surveyed the vascular plants in the Eureka Valley, northern Last Chance Range, and northern Death Valley. This study area covers 1735 sq km and ranges in elevation from 810 to 2577 m; it contains the tallest sand dunes in California, a calcium-rich mountain range, and alkaline seeps. These features provide specialized habitats for narrowly and regionally endemic plants. Fossil data from packrat middens suggest that the local climate has become warmer and drier during the Holocene and the assemblage of plants currently observed has only been in place for a few thousand years. During six years of fieldwork, we documented 542 specimens of minimum-rank taxa, including 51 special concern taxa and 25 non-natives. We were unable to relocate 45 taxa known from historic collections. Fifty-one collections were the first for the study area; these include 24 range extensions. Observations from our collections are combined with those from historic collections and other collectors in an annotated checklist

The Fern-Leaved Monkeyflower (Phrymaceae), a New Species from the Northern Sierra Nevada of California

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Economic Impacts of Yellow Starthistle on California Ranchers

While the significant ecosystem damage caused by invasive weeds has been well documented, the economic impacts of specific invasive weed species are poorly understood. Yellow starthistle (Centaurea solstitialis L., hereafter YST) is the most widespread non-crop weed in California, resulting in serious damage to forage on natural range and improved pasture. A survey was administered to California cattle ranchers to investigate YST infestation rates, loss of forage quantity and value, and control or eradication efforts. The results were used to estimate county-wide economic losses for three focus counties, as well as state-wide economic losses, due to YST in California. Total losses of livestock forage value due to YST on private land for the state of California are estimated at $7.96 million/year, with ranchers’ out-of-pocket expenditures on YST control amounting to$9.45 million/year. Together, these costs are the equivalent of 6-7% of the total annual harvested pasture value for the state