Archived 2020 topic: Madagascar Jacana (Actophilornis albinucha): Revise global status?

BirdLife International factsheet for Madagascar Jacana.

The Madagascar Jacana is a wetland bird endemic to Madagascar, inhabiting shallow lake margins and freshwater marshes (BirdLife International, 2020). A new population estimate puts the global population at 975-2,064 individuals (D’Urban Jackson et al., 2019). An observation survey found an 80% proportion of birds to be mature (D’Urban Jackson et al., 2019). Therefore, the number of mature individuals here is estimated to be 708-1,643. The population is suspected to still be declining because of its main threats: wetland habitat degradation, and hunting.

Madagascar Jacana has been considered Near Threatened, approaching classification as Vulnerable under criterion A2cd+3cd+4cd. However, recent new information about the species may warrant a change in Red List category. We have therefore reviewed this species here against all the criteria.

Criterion A: The Madagascar Jacana is suspected to have been declining for some years. The rate of decline is measured over the longer of 10 years or three generation lengths of the species. The generation length for the Madagascar Jacana has been recalculated to 4.6 years (Bird et al., 2020)*. Rates of decline for this species are therefore calculated over 14.8 years.

Direct data on population trends are not available, and while this new population figure falls at the lower end of the previous population estimate range, it is not directly comparable and therefore cannot be used to calculate a population trend. However, the main threats to this species are believed to be habitat loss and hunting. There are no quantitative data available for exploitation levels. D’Urban Jackson et al., (2019) did not observe hunting during their surveys, but locals reported that hunting was common. Between 1950 and 1994, 60% of the Madagascan wetlands were lost (Kull, 2012), and the degradation is still ongoing (D’Urban Jackson et al., 2019). Both of these threats are likely to continue into the future. If the Madagascar Jacana is commonly hunted, then it is likely to be a frequent food source, and it currently receives no legislative protection (D’Urban Jackson et al., 2019).  Additionally, the wetlands are being degraded and converted into agricultural land, which is linked to the expanding human population, but whether the rate of conversion is likely to increase over the next three generations is not clear. Assuming that habitat loss and hunting rates remain the same, and that the species declines at the same rate, the population size reduction is suspected to be between 20-29% in three generations. This does not meet the threshold for Vulnerable (population size reduction >30%), however this species can be considered Near Threatened, approaching a threatened status under criterion A2cd+3cd+4cd.

Criterion B: The Extent of Occurrence for this species is 415,000 km². This is too large to trigger the Vulnerable threshold (EOO <20,000 km²), so the Madagascar Jacana can be considered Least Concern under this criterion.

Criterion C: The estimated population size of 708-1,643 mature individuals meets the initial threshold for listing as Endangered (<2,500 mature individuals). In order to fully qualify as threatened under this criterion, other sub-criteria must be met.

The population size must be undergoing an observed, estimated, projected or inferred continuing decline (IUCN Standards and Petitions Committee, 2019). As the Madagascar Jacana is restricted to wetland habitats which are known to be declining in extent and quality, a decline in the population size can be inferred. However, as the rate of population decline is based on habitat loss, and is therefore only suspected, the conditions for C1 are not met. This species is not believed to experience extreme fluctuations in the number of mature individuals, so sub-criterion b is not met. During the genetic analysis detailed in D’Urban Jackson et al., (2019), no genetic sub-populations were identified (J. D’Urban Jackson pers. comm., 2018), so 100% of the mature individuals can be considered to exist in one sub-population. This meets the requirements of sub-criterion a(ii). Therefore, Madagascar Jacana may be considered Endangered under Criterion C2a(ii).

Criterion D: A new population size estimate puts the global population at 708-1,643 mature individuals (D’Urban Jackson et al., 2019). Assuming the true population size is at the lower end of the estimate, this meets the threshold for classification as Vulnerable under criterion D1.

Criterion E: To the best of our knowledge, no quantitative analyses have been conducted for this species, so the Madagascar Jacana cannot be assessed against this criterion.

Therefore, it is proposed that the Madagascar Jacana (Actophilornis albinucha) be listed as Endangered under criterion C2a(ii). We welcome any comments to the proposed listing.

Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of the species’ Red List status. Therefore, please make sure your comments are relevant to the species’ Red List status and the information requested. By submitting a comment, you confirm that you agree to the Comment Policy.

*Bird generation lengths are estimated using the methodology of Bird et al. (2020), as applied to parameter values updated for use in each IUCN Red List for birds reassessment cycle. Values used for the current assessment are available on request. We encourage people to contact us with additional or improved values for the following parameters; adult survival (true survival accounting for dispersal derived from an apparently stable population); mean age at first breeding; and maximum longevity (i.e. the biological maximum, hence values from captive individuals are acceptable).

An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.

References

Bird, J. P.; Martin, R.; Akçakaya, H. R.; Gilroy, J.; Burfield, I. J.; Garnett, S.; Symes, A.; Taylor, J.; Šekercioğlu, Ç.; Butchart, S. H. M. (2020). Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology online first view.

BirdLife International (2020) Species factsheet: Actophilornis albinucha. Downloaded from http://www.BirdLife.org on 16/04/2020. 

D’Urban Jackson, J., Zefania, S, Moehy, S. Bamford, A. J., Bruford, M. W. and Székely, T. 2019. Ecology, conservation, and phylogenetic position of the Madagascar Jacana Actophilornis albinucha. Ostrich 90: 315–326.

IUCN Standards and Petitions Committee, 2019. Guidelines for Using the IUCN Red List Categories and Criteria. Version 14. Prepared by the Standards and Petitions Committee. Downloadable from http://www.iucnredlist.org/documents/RedListGuidelines.pdf.

Kull C. 2012. Aerial photo evidence of historical land-cover change in the highlands: wetlands and grasslands give way to crops and woodlots. Madagascar Conservation and Development 7: 144–152.

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5 Responses to Archived 2020 topic: Madagascar Jacana (Actophilornis albinucha): Revise global status?

  1. Josephine D'urban Jackson says:

    Thank you, on behalf of myself and my co-authors (from D’Urban Jackson et al. 2019, Ostrich) we support the proposed uplisting of the Madagascar jacana to Endangered according to your assessment. Comments are made below.

    More detailed explanation of wetland bird threats in Madagascar can be found in

    Bamford, A.J., Razafindrajao, F., Young, R.P. and Hilton, G.M., 2017. Profound and pervasive degradation of Madagascar’s freshwater wetlands and links with biodiversity. PLoS One, 12(8).

    Please cite this paper.

    Our survey observed 75% adult birds (immatures were 27/108, 25%) so the estimate adult population should be adjusted accordingly.

    Population trend data: Durrell Wildlife Conservation Trust/ Wildfowl and Wetlands Trust/ The Peregrine Trust have repeat bird survey data for Madagascar wetlands. These sources may be able to provide population trend information that is needed to for Criterion A.

    Criterion D: Madagascar is restricted to wetlands. Therefore the current range extent does not truly represent the species’ actual extent, as this is very patchy and occupancy of jacana in these wetlands can be highly variable throughout the year. The actual extent is likely far smaller than shown here.

    Genetic analysis finding of no substructuring in D’urban Jackson et al 2019, is supported by genomic data investigated in:

    D’Urban Jackson, J. 2018. Population Genetic Consequences of Mating Systems and Dispersal. University of Bath (PhD Thesis).

    Please cite this (as: D’Urban Jackson 2018) rather than pers comms.

    Please edit my name in the citation and full reference of the Ostrich paper, this is the correct name: D’Urban Jackson et al. and D’Urban Jackson, J. for the full reference (rather than Jackson and Jackson, J. d’U.)

  2. Red List Team (BirdLife International) says:

    Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested by so many people in commenting. The window for consultation is now closed. We will analyse and interpret the new information and post a preliminary decision on this species’s Red List status on this page in early July.

    Thank you once again,
    BirdLife Red List Team

  3. Red List Team (BirdLife International) says:

    Preliminary proposal

    Based on available information, our preliminary proposal for the 2020 Red List would be to adopt the proposed classifications outlined in the initial forum discussion.

    There is now a period for further comments until the final deadline in mid-July, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from those in the initial proposal.

    The final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN. The final publication date will be publicised by IUCN here: https://www.iucnredlist.org/assessment/updates

  4. RENE DE ROLAND Lily Arison says:

    I support Josephine’s idea as the Madagasacar Jacana’s population declined. This decline is due mostly of wetland degration. For example, surrounding of Mampikony wetland areas, during the last 10 years, I always made an observation in three differents places and the individuals number decreased almost three times before. But, the population of this species is stable at Las sariaka, Baie de Baly protected area.

  5. Red List Team (BirdLife International) says:

    Recommended categorisation to be put forward to IUCN

    The final categorisation for this species has not changed. Madagascar Jacana is recommended to be listed as Endangered under Criterion C2a(ii).

    Many thanks for everyone who contributed to the 2020 GTB Forum process. The final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN.

Comments are closed.