THE CONSERVATION STATUS OF BIRDS IN ARID AUSTRALIA

摘要: The impression has been given in previous studies that there are few bird conservation problems the arid zone, particularly because not one of a total 230 species become extinct. In stark contrast, almost half native terrestrial mammalian fauna Australian zone extinct on mainland since European occupation. Here we show status avifauna changed occupation, and conclude many threats to avian biodiversity at regional scale zone. There 19 (8%) classified as rare threatened nationally. Twelve more (5%) uncommon which have declined or risk two regions. A further 40 (17%) least region, although these remain common some increased elsewhere Australia. At 45 (20%) range abundance, including suite ground-feeding birds associated with degraded landscapes. Striking patterns emerged from analysis 29 declining species: • birds chenopod shrublands grassy, riparian floodplain environments most affected whereas mulga inhabitants canopy-dwellers woodland little affected; generally northem distribution south southern north contrast continental semiarid regions than within itself; feed ground low shrub height adversely • sedentary bushbirds (passerines) nomads their limited mobility seems be factor; • among non-passerines, parrots, cockatoos pigeons risk, while three passerine families stand out, namely wrens, quail-thrushes, thornbills allies; • contrary findings for mammals, size does appear an important factor. Land degradation habitat alteration such shifts abundance dominance plant caused by introduction exotic herbivores principal factors causing change provision reliable water sources pastoral districts is also important. Introduced predators implicated cases altered fire regimes may played part spinifex mallee habitats. Competitive interactions between increasing species, demonstrated, likely species. We documented hitherto unsuspected degree absence widespread regeneration dominant decline will accelerate dramatically. Also, unless better management ensues, next major drought could cause accelerated declines extinctions. advocate measures designed improve prospects birds, lower stocking rates properties, rehabilitation critical habitats protection herbivores, experimental research impact grazing predation, monitoring both sedentary passerines typically representative