The Shy albatross (Thalassarche cauta): Population trends, environmental and anthropogenic drivers, and the future for management and conservation

摘要: Despite recent global conservation efforts, albatrosses remain amongst the most threatened groups of birds. Worldwide, they are affected on land and at sea by a range of processes, particularly fisheries bycatch. In spite their high profile, present challenges for monitoring recovery actions because long-lived, spend life and return to breed colonies that often located remote, relatively inaccessible islands. This thesis offers comprehensive assessment population status trends Australia’s endemic shy albatross, Thalassarche cauta, which breeds exclusively three Tasmanian offshore islands. The main anthropogenic, physical environmental processes influence each the three breeding populations examined shape key demographic parameters assessed in four analytical chapters follow introductory chapter. Chapter two compiles analyses available demographic data provide first comprehensive individual albatross colonies and species as whole. This chapter shows Albatross Island has recently stabilised following period sustained increase post-harvest this change trajectory appears driven decrease juvenile survival. small Pedra Branca is declining, likely due reduced success associated with increasing Australasian gannets island. While for Mewstone, largest population, unknown, it is shown birds from colony have greater exposure commercial fisheries, therefore at higher risk fishing-related mortality and, consequently, survival rates likely lower than counterparts. Collectively, these results suggest current status of likely be stable best quite possibly decreasing.The third uses satellite tracking investigate at-sea distribution post-fledging shy albatrosses. Data show colony-specific dispersal behaviour subsequent post-fledging range. Accordingly, differ extent juveniles overlap commercial fisheries consequent by-catch. supporting evidence band recoveries also highest immediately after fledging, with population differences frequency apparent. Post-fledging likely related foraging failure naive observed may related to proximity food resources. Considering combined impact and fisheries influences, it probable southern populations, and Mewstone particular, lower northern, well-studied, Island population. In line focus managers researchers understanding climate impacts on threatened species, assesses efficacy existing long term monitoring Albatross Island detecting performance population. This study sampling design biased towards older, more experienced breeding individuals, better able buffer effects variability thereby obscure signals. Modifications protocols suggested, including the deliberate younger sensitive effective ecological indicator of the population. The fifth takes breeding-success time-series investigates relationship of this important life-history parameter local regional variables. The strongest relationships were found conditions during chick-rearing, including rainfall maximum temperature site, sea-surface height anomalies increased upwelling primary areas both incubation chick-rearing phases. implications climate-biology relationships given future predictions considered. These findings synthesised produce first report overall conservation status conclusion research not secure as previously believed. addition contributing our this thesis highlights threatening underlying mechanisms provides clear guidance management can extended to other seabird species.