Ex situ conservation of the Bengal florican 909
TABLE 3 Step 5: plan for harvest of eggs of the Bengal florican. Year
Stoung-Chikreang 2019 2020 2021
Only collect eggs from July onwards; monitor powerline mortality
Only collect eggs from July onwards; monitor powerline mortality
Only collect eggs from July onwards unless powerline mortality is high, & then consider collecting eggs earlier; monitor powerline mortality
2022 onwards
Monitor the situation& act accordingly
Baray
Only collect eggs from July onwards; monitor field situation
Only collect eggs from July onwards; monitor field situation
Monitor the situation & act accordingly
Sankor
Collect all eggs immediately; monitor field situation
Collect all eggs; monitor field situation
Monitor the situation & act accordingly
Bakan
Monitor field situation
Collect all eggs; monitor field situation
Monitor the situation & act accordingly
Koup Preah Buong Trea
Collect all eggs immediately; monitor field situation
Collect all eggs; monitor field situation
Monitor the situation & act accordingly
Monitor the situation & act accordingly
Monitor the situation & act accordingly
per year for 5 years). In this context, identification and miti- gation of practical risks associated with ex situ conservation are critical to ensure that parameters match those in the above-average or best possible scenarios. Of the two risks that we rated high (Table 2), refusal of governmental per- mission to collect eggswasmanaged by beginning to request permits before the assessment, as a precautionary measure, given the time constraints, and to allow time to resubmit or modify the application if needed. Although at the time of writing, permits have been granted, this risk was rated high during the assessment because permission had not then been granted and ex situ conservation cannot begin without it (permission to harvest and transport eggs has since been granted).We rated risks associated with harvest of eggs from the wild as high because nests will have to be found by community members, and it is impossible to elim- inate the possibility they will misunderstand instructions to leave eggs in the nest until ACCB staff arrive, and instead may take eggs to their homes, in an attempt to assist the pro- ject but inadvertently causing them to spoil.Wealso consid- ered rating knowledge of husbandry techniques relevant to the species as high because the Bengal florican has rarely been kept in captivity, and captive breeding has never before been attempted. Good husbandry should aim to minimize adult mortality, because sensitivity analysis showed that probability of extirpation of the captive population was most heavily affected by changes in adult mortality (Supplemen- tary Fig. 1). In our risk assessment we noted there is consid- erable global expertise in ex situ management and breeding of other bustard species on which we can draw; for instance the Asian houbara Chlamydotis macqueenii is bred exten- sively by the International Fund for Houbara Conservation, and the little bustard and great bustard Otis tarda are bred at Centro de Cría deAves Esteparias in Spain.Wehave already begun receiving technical advice from the latter, which a
Monitor the situation & act accordingly
Monitor the situation & act accordingly
staff member of the Angkor Centre for the Conservation of Biodiversity visited in early 2019 and again in early 2020 to learn about captive bustard husbandry. We plan to continue to expand our advisory network and formalize it through creating an advisory panel of relevant experts. Demographic modelling indicates there is little chance
that ex situ management will produce a sufficient number of Bengal floricans to reintroduce birds within 50 years (Fig. 3). Even under the best possible scenario with egg harvest rates of 10 per year for 5 years, there are unlikely to be sufficient birds to release for 20–30 years, by which time the species will almost certainly be extinct in the wild. Participants considered this information as they worked through the decision tree to assess biological risks associated with ex situ management (Fig. 1), but concluded that, given the relatively low risk of extirpation of a well- managed captive population and the very high risk of extir- pation of the wild population, embarking on a programme of ex situ management was prudent (Fig. 3). Based on the assessment of risks described above, the
participants re-examined Tables 1&2, and used them to de- velop a plan for ex situ management of the Bengal florican (Table 3), which is summarized here, with notes on what eventuated. It was hoped that as many eggs as possible would be harvested from the unprotected population at Sankor in the 2019 breeding season (April–September), but none were found. This population is declining rapidly and is likely to be extirpated within a year because the habi- tat has been transformed from grassland to rice (Table 3). At all sites, any eggs laid during July or later will be harvested, because these probably represent late or second breeding at- tempts that are likely to fail because of heavy rain and rising floodwater at this time. Mortality caused by the power trans- mission line (completed in May 2019) that bisects the stable, protected, population at Stoung-Chikreang Bengal Florican
Oryx, 2021, 55(6), 903–915 © The Author(s), 2021. Published by Cambridge University Press on behalf of Fauna & Flora International doi:10.1017/S0030605319001510
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