White-bearded Antshrike (Biatas nigropectus): downlist from VU to NT?

This discussion was first published as part of the 2016 Red List update. At the time a decision regarding its status was pended, but to enable potential reassessment of this species as part of the 2018 Red List update this post remains open and the date of posting has been updated.

BirdLife species factsheet for White-bearded Antshrike

White-bearded Antshrike is found in southern Brazil from Espirito Santo to Santa Catarina, and in Misiones, north-east Argentina. The species is listed as Vulnerable under A2c+3c+4c; B1ab(i,ii,iii,iv,v)c(iv); C2a(i)b. The population is estimated to number 2,500-9,999 mature individuals. The species’s population is suspected to be declining rapidly, in line with rates of habitat loss within its range. The species’s extent of occurrence (EOO) is estimated to be 18,800 km2 and the population is severely fragmented. The species inhabits forested areas where tall stands of bamboo are present.

In Brazil, there has been rapid destruction and fragmentation of Atlantic forest for agriculture, mining, and coffee, banana and rubber plantations (Fearnside 1996). Remaining forest in Brazil suffers from urbanisation, associated road-building and agricultural expansion (Dinerstein et al. 1995). In Argentina, the species depends on Guadua trinii bamboo (Bodrati and Cockle 2006), which has a 30 year cycle of growth, mast seeding, and massive die-off (Parodi 1955). It is not known how White-bearded Antshrike responds to these bamboo cycles, but strong population fluctuations are suspected, with bottlenecks during periods of bamboo die-off, increasing the species’s vulnerability to stochastic extinction (A. Bodrati in litt. 2007). It is a species that could easily “fall through the cracks” of current conservation policies, because its bamboo habitat is rarely contemplated in conservation strategies for the Atlantic forest. In Misiones, most Guadua trinii, and hence most records of White-bearded Antshrike, are outside of parks, often near houses, plantations and roads, where the bamboo has colonised degraded forest and is at considerable risk of being cleared (A. Bodrati in litt. 2007, A. Bodrati and K. Cockle in litt. 2012).

In the Brazilian Red List assessment for birds (MMA 2014) this species is listed as Near Threatened. Brazil holds a large proportion of the species’s range. For the species to be listed as Near Threatened the past/future/past+future population reduction must be <30% over three generations (for criterion A); the species’s extent of occurrence would have to be >20,000 km2 or no longer severely fragmented and no longer continuing to decline in area or quality (for criterion B); and the number of mature individuals would have to be >10,000 or not undergoing a continuing decline, with either more than 1,000 mature individuals in each subpopulation or with no fluctuations in the number of mature individuals (criterion C).

Up-to-date information is requested on the species’s population size and trends in Brazil and Argentina. Is the global population size >10,000 mature individuals? Is the population reduction <30% in three generations (14 years)? Is the population undergoing a continuing decline? Is the area of suitable habitat continuing to decline?

Comments on the proposed downlisting and any additional information are welcome.

 

References:

Bodrati, A.; Cockle, K. 2006. Habitat, distribution and conservation of Atlantic forest birds in Argentina: notes on nine rare or threatened species. Ornitologia Neotropical 17: 243-258.

Dinerstein, E.; Olson, D. M.; Graham, D. J.; Webster, A. L.; Primm, S. A.; Bookbinder, M. P.; Ledec, G. 1995. A conservation assesssment of the terrestrial ecoregions of Latin America and the Caribbean. World Bank, Washington, D.C.

Fearnside, P. 1996. Brazil. In: Harcourt, C.S.; Sayer, J.A. (ed.), The conservation atlas of tropical forests: the Americas, pp. 229-248. Simon & Schuster, New York and London.

MMA (2014) Lista Nacional Oficial de Espécies da Fauna Ameaçadas de Extinção. Portaria No 444, de 17 de dezembro de 2014. Diário Oficial da União – Seção 1. Nº 245, quinta-feira, 18 de dezembro de 2014.

Parodi, L. R. 1955. La floración de la tacuara brava (Guadua trinii). Revista Argentina Agronomia 22: 134-136.

 

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3 Responses to White-bearded Antshrike (Biatas nigropectus): downlist from VU to NT?

  1. James Westrip (BirdLife) says:

    Based on available information, our proposal for the 2016 Red List would be to pend the decision on this species and keep this discussion open until 2017, while leaving the current Red List category unchanged in the 2016 update.

    Final 2016 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  2. Hannah Wheatley (BirdLife) says:

    Preliminary proposals

    Based on available information, our proposal for the 2017 Red List would be to pend the decision on this species and keep this discussion open until 2018, while leaving the current Red List category unchanged in the 2017 update.

    Final 2017 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  3. Claudia Hermes (BirdLife International) says:

    Based on available information, our preliminary proposal for the 2018 Red List would be to list:
    White-bearded Antshrike as Vulnerable under criterion C2a(i)b.
    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 the initial proposal.
    The final 2018 Red List categories will be published on the BirdLife and IUCN websites in November, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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