Conservation management conflict in the Greenland barnacle goose

Abstract

Human population expansion into natural environments has resulted in an increase in human-wildlife conflict. To mitigate these conflicts, numerous management strategies have been implemented worldwide. Several strategies depend on lethal approaches either for population control, or lethal scaring. These impact populations directly through mortality and indirectly through disturbance. Understanding the effect of these strategies is vital to determine their efficacy and ensure the long-term viability of managed populations. In recent decades, population expansion of several European-wintering goose populations into agricultural areas has resulted in goose-agricultural conflict. This thesis evaluates how shooting management impacts the East Greenland flyway population of Barnacle geese (Branta leucopsis). In chapter two I summarise the effectiveness of scaring for conflict mitigation and identify key factors in maximising success of scaring schemes. Chapter three evaluates the cumulative impact of harvest on flyway-scale population dynamics. I then assess the effect of shooting disturbance on i) foraging site selection (chapter four), ii) movement (chapter five) and iii) foraging behaviour (chapter six). Lastly, I address the cryptic consequences of shooting management including the impact on non-quarry species and the use of lead shot (chapters five and seven). This review highlights the importance of understanding of species ecology and landscape dynamics when implementing a scaring scheme. Furthermore, scaring is best implemented as a push-pull strategy, balancing scaring at key sites with the provision of suitable refuges for successful redistribution. Declines in global abundance are associated with increasing harvest rates throughout the flyway. Most notable changes to harvest have occurred on Islay, suggesting that localised Islay-management is the primary cause of flyway decline in abundance. Finally, I identify refuges as important provisions for effective population management. Refuges are preferentially selected foraging sites in response to direct shooting disturbance, where geese can forage undisturbed. They are also associated with reduced anti-predation behaviour and allow geese to redistribute and recoup energetic losses undisturbed. As human-wildlife conflict will continue to pose a key conservation issue, effective, evidence-based management strategies will be vital to ensure their efficacy in mitigating conflict and maintaining viable populations. This thesis provides a case study, that assesses the cumulative impact of local shooting on global population dynamics. This can inform future management policies and assist in coordinating international management to prevent overexploitation and highlights important avenues for further research and management.