Archive for the ‘yellow starthistle’ Category

Impact of the rosette weevil on yellow starthistle

March 13, 2017 Leave a comment

Yellow starthistle (Centaurea solstitialis L.) (YST) is an invasive weed native to the Mediterranean region with a geographical centre of diversity in Turkey. It is widely established in Chile, Australia, and western North America. It arrived in California as a contaminant in alfalfa seed in 1859 and, by 2002, had infested more than 7.7 million hectares in the U.S.A. Biological control of YST using capitula feeding weevils, picture wing flies and a foliar rust pathogen has been ongoing in the western U.S.A. for more than three decades with limited success. Modelling and field research suggest natural enemies that kill whole plants and/or reduce seed production of survivors are good candidates for successful biological control. A candidate species with some of these attributes is the rosette weevil Ceratapion basicorne (Illiger). In the present study, a model of the rosette weevil is added to an extant system model of YST and its capitula feeding natural enemies and, in a GIS context, is used to assess YST control in the Palearctic region and the weevil’s potential impact on YST in western U.S.A. The results obtained suggest densities of mature YST plants in western U.S.A. would be reduced by 70–80% in many areas.

Gutierrez A.P., Ponti L., Cristofaro M., Smith L., Pitcairn M.J., 2016. Assessing the biological control of yellow starthistle (Centaurea solstitialis L.): prospective analysis of the impact of the rosette weevil (Ceratapion basicorne (Illiger)). Agricultural and Forest Entomology,

The rosette weevil Ceratapion basicorne.

Invasive species and climate change: the PBDM approach

September 12, 2014 Leave a comment

Assessing the geographic distribution and abundance of invasive species is critical for developing sound management and/or eradication policies. Ecological niche modelling approaches (ENMs) that make implicit assumptions about biology and mathematics are commonly used to predict the potential distribution of invasive species based on their recorded distribution. An alternative approach is physiologically based demographic modelling (PBDM), which explicitly incorporates the mathematics and the observed biology, including trophic interactions, to predict the temporal phenology and dynamics of a species across wide geographic areas. The invasive weed, yellow starthistle (YST) (Centaurea solstitialis), and its interactions with annual grasses and herbivorous biological control agents is used to demonstrate the utility of the PBDM approach for analysing complex invasive species problems. The PBDM predicts the distribution and relative abundance of YST accurately across the western USA, and the results are used to assess the effects of temperature, rainfall, competition from grasses and the efficacy of biocontrol efforts. Such an effort could also be used to include the direct effects of rising carbon dioxide on YST biology. A bioeconomic model could be developed to show how the YST PBDM analysis can also be used to assess the biological and economic effects of climate change on YST infestation levels regionally. Finally, this chapter discusses the need for a unified system for assessing invasive species problems at the field, regional and global levels, with the goal of enhancing the development of efficacious policy and management decisions.

Gutierrez A.P., Ponti L., 2014. Assessing and managing the impact of climate change on invasive species: the PBDM approach. In: Ziska L.H., Dukes J.S., (eds.), Invasive Species and Global Climate Change. CABI Publishing, Wallingford, UK. ISBN: 978-1780641645.

Trophic interactions in the yellow starthistle PBDM system.