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Aichi Target 12 of the Convention on Biological Diversity (CBD) aims to ‘prevent extinctions of known threatened species’. To measure its success, we used a Delphi expert elicitation method to estimate the number of bird and mammal species whose extinctions were prevented by conservation action in 1993 - 2020 (the lifetime of the CBD) and 2010 - 2020 (the timing of Aichi Target 12). We found that conservation prevented 21–32 bird and 7–16 mammal extinctions since 1993, and 9–18 bird and 2–7 mammal extinctions since 2010. Many remain highly threatened, and may still become extinct in the near future. Nonetheless, given that ten bird and five mammal species did go extinct (or are strongly suspected to) since 1993, extinction rates would have been 2.9–4.2 times greater without conservation action. While policy commitments have fostered significant conservation achievements, future biodiversity action needs to be scaled up to avert additional extinctions.
The Black-winged Myna (Acridotheres melanopterus) is a Critically Endangered passerine endemic to the islands of Java and Bali, Indonesia. Illegal trapping to supply the cage-bird trade has led to its near-total extinction, with the global population estimated to number fewer than 100 individuals. We estimated the current range and population size of the species at Baluran National Park, which supports Java’s last known population, and used species distribution modelling to evaluate potential suitability of currently unoccupied areas across the park to identify priorities for management intervention. We estimate that the Black-winged Myna population numbers 179 individuals (95% CI: 111–288; density: 14.3 ± 3.5 individuals km–2) and that its current range is 12.3 km2. Our model indicated that some 72 km2 of the park (30% of total area) has potentially suitable habitat for the species, and we infer that the principal cause for the disparity between its current and potential range is trapping, compounded by savanna loss and degradation due to illegal domestic cattle grazing and the spread of invasive thorny acacia (Vachellia nilotica). The partial clearance of acacia in recent years appears to have assisted a modest population recovery by the myna. Its further population growth and range expansion in Baluran depends on effective management of illegal poaching, further clearance of acacia, and easing domestic cattle grazing pressure on areas of savanna, particularly through engagement with communities living inside the park. Any actions that increase the size of the Black-winged Myna population are likely to benefit other threatened savanna-dependent wildlife in the park, notably banteng (Bos javanicus) and Green Peafowl (Pavo muticus). While our models and recommendations may be applicable to other protected areas in Java, and indeed other threatened myna species, trapping and habitat change may have site-specific dimensions, especially outside of protected areas, and thus demand local bespoke solutions.
Grey-backed myna (Acridotheres tricolor) is a critically endangered endemic bird of East Java with populations in nature fewer than 250 individuals. Baluran National Park is one of the last natural habitats of Grey-backed myna. This study aims to determine the relative abundance and habitat use of Grey-backed myna populations in several habitats in Baluran National Park. The relative abundance of bird populations was calculated using the encounter rates formula, while habitat use was analyzed using PCA. The study was conducted from October to November 2018 in savanna, forest-savanna, restoration-savanna, monsoon forest, acacia forest, and coastal forest. The results showed that the savanna habitat had the highest encounter rates of 11.16, while the beach forest habitat is the habitat with the lowest encounter rates of 0. PCA analysis shows the habitat use of Greybacked myna tends to be determined based on the presence of Brachiaria reptans, Acacia nilotica, Corypha utan, dead tree trunks, and abundant trees with large diameter, also the few of Tamarindus indica and leaf litter. An understanding of the relative abundance and habitat use is important for the grey-backed myna conservation.
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