A technique to monitor growth and spread of early-stage variable-leaf watermilfoil in a shallow impoundment

Abstract

We describe an approach to measure the invasiveness of Myriophyllum heterophyllum (variable leaf watermilfoil) in a shallow dystrophic impoundment at the early stages of an invasion. Over an eight-week observation period, dry weight measurements show a biomass specific rate growth rate of 0.0048·day⁻¹, consistent with other studies of invasive watermilfoil growth, and a diffusion rate (biomass spread) of D = 9.2 cm²·d⁻¹, which describes the horizontal encroachment into plant-free sediment.