Portal to the Lesser White-fronted Goose

Literature type: Scientific

Journal: Biological Conservation

Volume: 281

DOI: 10.1016/j.biocon.2023.110028

Language: English

Download:

Full reference: Marolla, F., Aarvak, T. Hamel, S., Ims, R.A., Kéry, M., Mellard, J.P., Nater, C.R., Schaub, M., Vougioukalou, M., Yoccoz, N.G. & Øien, I.J. 2023. Life-cycle analysis of an endangered migratory goose to assess the impact of conservation actions on population recovery. Biological Conservation 281. https://www.dx.doi.org/10.1016/j.biocon.2023.110028

Keywords: Goose management, State-space model, Management evaluation, Lesser white-fronted goose, Unmarked individuals, Non-breeding dynamics, migration

Abstract:

Evaluating the effectiveness of conservation actions is challenging for migratory species because a population can be impacted anywhere along its route. Conservation actions for the critically endangered Fennoscandian lesser white-fronted goose population include culling of red foxes in the breeding area and habitat improvements and reduction of illegal hunting in the non-breeding areas. One goal of the predator control strategy is to prevent adult birds from using an autumn migration route through western Asia, where mortality is believed to be higher than on the migration route through eastern Europe. We used 23 years of count data obtained at different staging areas to parameterize a seasonal state-space model describing the full-annual cycle dynamics of this population and evaluate whether the recent population recovery was linked to these conservation efforts. The results did not provide evidence that predator control influenced population recovery, as survival on the European route did not appear higher than on the allegedly riskier Asian route. However, adult survival at staging areas on both routes and at wintering sites may have improved in the last decade, suggesting a positive effect of the other conservation initiatives. These results emphasize the importance of including the non-breeding dynamics in population assessments of migratory species and highlight the challenge of evaluating the efficacy of separate conservation actions when a proper experimental design is unfeasible. Our study, which is a unique case of cross-national, coordinated conservation efforts, exemplifies how to model complex population dynamics to assess the influence of costly conservation initiatives.

Literature type: Report

Language: Norwegian In norwegian with english abstract

External Link:

Download:

Full reference: Kvalnes, T., Follestad, A., Krange, O. & Tombre, I.M. 2023. Evaluering av norsk handlingsplan for dverggås. [Evaluation of the Norwegian action plan for the Lesser White-fronted Goose.] , NINA Rapport 2349. Norsk institutt for naturforskning.

Keywords: dverggås, national action plan, Norway, priority species, conservation actions

Abstract:

The lesser white-fronted goose (Anser erythropus) is a critically endangered species in Norway. Due to a rapid decline in population size since the 1940s the population is now at very low numbers. In the previous three generations, the population has several times consisted of less than 50 reproducing individuals. In addition, the Norwegian breeding population constitutes almost the entire remaining Fennoscandian population of the species. Because of this situation, the lesser white-fronted goose is classified as a priority species with its own regulations in Norway. BirdLife Norway (formerly the Norwegian Ornithological Association) has since 1985 monitored the species annually in Finnmark, northern Norway. Geese have been individually ringed with neck-bands and leg rings, including GPS-loggers, which have identified migration routes from Norway to their wintering areas in Greece. Commissioned by the Norwegian Environment Agency, NINA has conducted an overall evaluation of the implementation of the Norwegian action plan for the lesser white-fronted goose which was launched in 2009. The aims of this evaluation has been 1) to evaluate the achievements of the management goals, 2) to evaluate whether knowledge from the monitoring is organized and disseminated appropriately for practical use, 3) to evaluate how the financial structures and conservation measures have been organised, and 4) to provide input for further knowledge acquisition and implementation of actions. The evaluation was based on relevant published results, such as reports from BirdLife Norway, scientific articles, and other information developed in the project. Informants from various relevant stakeholder groups and end-users have been interviewed. Additionally, a so-called red to green method was applied to evaluate the need for future knowledge needs and management actions. Stopping the ongoing population decline by 2015 and a long-term increase of the population size to a target of 1000 individuals, were the main objectives of the action plan. The second objective has not yet been achieved. However, the earlier population decline has been stopped and the population have displayed a slight positive growth rate. Thus, that the first objective has been achieved. In our evaluation, the change in population growth rate is considered to be an effect of the overall measures which have been made to preserve the species. A revision of the action plan is recommended. New achievable objectives for population size should be implemented as steps on the way towards a viable population size. The red list criteria can be used to define objectives and aid the choice of measures. To reduce adult mortality and increase the reproductive success, several conservation measures have been implemented. No entry zones have been established at important staging sites, such as Valdakmyra in Porsanger municipality and Rørholmen in Alta municipality. Annual culling of red foxes (Vulpes vulpes) in and around the breeding area have been carried out to reduce egg and gosling predation. Bans on hunting for greylag geese (Anser anser) have been imposed in large parts of Finnmark to prevent accidental harvest of lesser white-fronted geese. Extensive international cooperation with Finland, Russia and other countries has been important. Cooperations have included efforts to monitor, reduce illegal hunting and secure important functional sites along the migration routes and in the wintering sites. The conservation measures are in general met with support from the informants. They express that most people are concerned with the conservation of the lesser white-fronted goose. Staff in nature management and at museums use the knowledge generated by the monitoring and various research projects to a large extent. However, there is a lack of knowledge about the conservation efforts among other users of the areas where staging and breeding sites for the lesser white-fronted goose are found. We also observed a need for more accessible dissemination of the knowledge which is generated. Some of the informants expressed that several stakeholders do not agree with the ban on hunting of greylag geese in local areas. The established boundaries for where the hunting ban should apply are especially considered problematic. Several stake-holders also claimed that hunter skills are underrated when the underlying assumption for this ban is that it is difficult for hunters to distinguish lesser white-fronted geese from greylag geese during the hunt. This evaluation recommends that also farmers and hunters are included in the dialogue involved in the management of the lesser white-fronted goose. Enhancing communication will facilitate discussions on potential changes that can be implemented to meet their needs while at the same time mitigating the risk of harming the geese. A discussion on adjusting the boarders of the hunting ban should be part of such a dialogue. Our evaluation indicates that much of the conservation effort carried out has been important and should be prolonged in the years ahead. In addition, some new objectives for the species and conservation measures are suggested. However, the lesser white-fronted goose has a long migration route across many countries. Thus, there is a limit to what can be achieved with unilateral national efforts in Norway. To ensure a high probability of success, it will be extremely important that international efforts are also prioritized. Moreover, the evaluation reveals some knowledge gaps that will be important to fill such that more precise conservation measures can be implemented and the effect of measures, such as red fox removal, can be evaluated in more detail. Internationally, it is particularly important to secure stop-over and wintering sites against illegal hunting, degradation and disturbance. Continued monitoring during wintering, along the migration route and at staging sites in Norway is essential to assess the effects of the conservation measures. Based on information from the interviews, it should also be considered whether a dialogue group should be established. With joint meetings among the representatives from nature management, participants in the conservation measures and other affected stakeholders. A forum is likely to improve communication, allow for exchange of experience and knowledge, and contribute to an increased understanding and acceptance of the conservation measures. Hence, it can contribute to achieving the management goals.