The NW/SW European population of Greylag Geese has increased more than seven-fold since the 1980s, resulting in substantial increases in conflicts with agricultural and in the risk of aircraft strikes. The International Single Species Management Plan for the Greylag Goose (Anser anser) (ISSMP) (Powolny et al. 2018) mandated the development of an Adaptive Flyway Management Programme (AFMP) to help address the growing socio-economic concerns associated with this population and to provide for sustainable hunting opportunities. This project will address a key element of the AFMP, which is to “establish an internationally coordinated population management programme for both management units, including offtake under hunting and, if necessary, under derogations, encompassing monitoring, assessment and decision-making protocols.”
In the absence of population models to guide decisions about offtake, the European Goose Management International Working Group agreed in 2020 to reduce population size by 15% over 10 years by increasing the level of offtake. However, the info-gap analysis used to support this decision (Johnson and Koffijberg 2021) does not take into account special needs and population trajectories of the two management units, and thus it carries a high risk of not meeting the population targets if not replaced by a more reliable decision-making tool. The use of the info-gap analysis is scheduled to be discontinued in 2023.
This project involves development of a flyway-wide decision model for use in investigating population-management strategies for Greylag Geese. This decision model will consist of three primary elements: (a) a flyway model of population dynamics; (b) a set of decision alternatives (i.e., varying levels of offtake in each management unit); and (c) a value model: