Local- and landscape-scale management for threatened breeding wader populations

• Main Author: Ewing, Harry
• Format: Thesis
• Language: English
• Published: University of East Anglia. School of Biological Sciences 2023
• Subjects: Eurasian Curlew; Numenius arquata
• Online Access: https://ueaeprints.uea.ac.uk/id/eprint/94888/; https://ueaeprints.uea.ac.uk/id/eprint/94888/1/HE%20240223%20Final%20PhD%20Thesis.pdf

Persistent declines of widespread, formerly common species are threatening global biodiversity and ecosystem services, but actions to tackle such declines have so far been insufficient. New strategies are required to facilitate species recovery and must include targeted actions capable of boosting low demographic rates (survival and/or productivity). A group of species for which such actions are increasingly required are waders Charadriiforms spp., of which the Eurasian curlew Numenius arquata is a particularly widespread but vulnerable species, with unsustainably low rates of breeding productivity contributing to ongoing population declines across Europe. In this thesis, intensive, field-based monitoring of demographic variation in a lowland curlew population in Breckland, eastern England, is used to inform the development of conceptual frameworks and simulation models to identify appropriate conservation actions and explore the benefits that such approaches could deliver. Curlew breed at very low densities across a range of habitats in Breckland, but consistently high rates of nest predation across the landscape mean that sustainable levels of breeding productivity were not achieved in any of the four study years. However, access to cover vegetation (> 40 cm height) was associated with an increased probability of chicks fledging, and the use and benefits of cover vegetation increased with chick age. Most curlew in Breckland breed in open, grassland habitats, but breeding successes were more frequent for the few curlew breeding in arable-dominated areas, highlighting the need for habitat-specific conservation actions. Simulation modelling suggested that the most efficient and effective actions to boost curlew breeding productivity would involve a combination of predator-exclusion fencing and maintenance or provision of cover vegetation in the few remaining areas with large numbers of breeding curlew. Such actions are likely to require multi-stakeholder nature recovery programmes to save this iconic but ...