Demographic matrix model for knapweeds (Centaurea spp.)

Authors: Milbrath, Lindsey; Biazzo, Jeromy

Submitted to: International Symposium on Biological Control of Weeds
Publication Type: Proceedings
Publication Acceptance Date: 6/12/2018
Publication Date: 8/23/2019
Citation: Milbrath, L.R., Biazzo, J. 2019. Demographic matrix model for knapweeds (Centaurea spp.). International Symposium on Biological Control of Weeds. 15:136.

Interpretive Summary:

Technical Abstract: Plant demographic models, such as stage-based matrix models, are useful in identifying life stage transitions that contribute the most to population growth of an invasive plant and hence should be targeted for disruption by biological control and/or other control tactics. This information can inform the selection of effective biological control agents in either a prospective or retrospective manner. We are in the process of parameterizing a four life-stage matrix model (seeds, seedlings, vegetative juveniles and flowering plants) in order to quantify reductions in various demographic or vital rates that are needed to cause population decline in two Centaurea species in the northeastern United States. Spotted knapweed (C. stoebe subsp. micranthos) is a short-lived perennial that is widespread in North America although not as common in New York State. Meadow knapweed (C. x moncktonii) is a long-lived perennial hybrid that is abundant in New York State in moist pastures and grasslands. Biological control agents currently established in the region are ineffective. We are quantifying demographic transitions over 3 years of both knapweed taxa in New York State (N = seven populations). Vital rates being estimated include survival, germination, transitions to other life stages, and fecundity (filled seeds produced per plant). Data will be presented on model parameters derived to date.