Weed eradication feasibility: lessons of the 21st century

Abstract

SummaryThe past decade has seen strong controversy concerning the upper bounds for weed eradication. Over this period, two of the most ambitious weed eradication attempts ever have failed. These have, however, provided rich data sets that have supported a productive and highly collaborative research effort. I review this research and present a new algorithm for assessing eradication feasibility, based upon time to maturation, seedbank persistence and membership of one of two contrasting dispersal functional groups. Eight ‘eradication syndromes’ are identified and their relative eradication feasibilities indicated. The syndrome with the highest feasibility includes species that combine long juvenile periods and low seedbank persistence with short‐distance and/or human‐mediated dispersal. At first glance, this may not be a common syndrome. The syndrome with the lowest feasibility comprises plants that combine a short juvenile period and high seedbank persistence with abiotic or non‐human‐mediated biotic dispersal. It includes a number of aquatic perennials that can be dispersed over large distances by floodwaters. Projected costs for a programme targeting a plant species should reflect its syndrome membership. Improved cost estimates will support better decision‐making with regard to programme initiation, maintenance and termination; models are available that can provide estimates of eradication programme duration and cost. Whether eradication has much of a future as a weed invasion management strategy will likely rest upon more timely, better‐informed and shrewder target selection.