CR
Rio Branco Antbird Cercomacra carbonaria



Justification

Justification of Red List Category
This species, which has a small range and moderately small population, is listed as Critically Endangered because a model of future deforestation in the Amazon basin predicts that its population will decline extremely rapidly over the next three generations as land is cleared for cattle ranching and soy production, facilitated by expansion of the road network.

Population justification
Vale et al. (2007) extended the extent of available habitat to 723 km2. Assuming a population density of 80 individuals / km2 gives a total population estimate of c.15,000 individuals, so it is placed in the band 10,000-19,999 individuals. This equates to 6,667-13,333 mature individuals, rounded here to 6,000-15,000 mature individuals.

Trend justification
This species is suspected to lose 100% of suitable habitat within its distribution over three generations (20 years) based on a model of Amazonian deforestation (Soares-Filho et al. 2006, Bird et al. 2011). Given the susceptibility of the species to fragmentation and/or edge effects, it is therefore suspected to decline by ≥80% over three generations.

Distribution and population

Cercomacra carbonaria is limited to middle sections of the rio Branco and some of its tributaries in Roraima, extreme north Brazil, and adjacent Guyana. It ranges from Caracarai in the south, along the rio Branco and rio Tacutu to the Ireng river in Guyana, less than 2 km from its confluence with the rio Tacutu (Zimmer et al. 1997). It has been found on the rio Mucajaí, and also along the rio Parime and the rio Uraricoera (Grosset and Minns 2002, Vale et al. 2007). Given the recent increase in records from a wider geographic area, the estimated extent of available habitat has been increased to 723 km2. It is fairly common within this range, (c.80 individuals per km2) and extrapolations indicate that the population is c.15,000 individuals (Vale et al. 2007).

Ecology

On the mainland, it apparently only occurs in dense thickets along the river edge, where suitable habitat is restricted to within 0.5 km2 of the rivers (Zimmer et al. 1997). On Ilha São Jose, it largely inhabits interior, densely wooded forest, with trees 20-30 m in height (Zimmer et al. 1997). It has also been found in dense second growth, consisting mostly of overgrown manioc plantations with widely scattered, 20-30 m trees (Zimmer et al. 1997). The diameter of territories is 100-150 m, and breeding is probably in the wet season (Zimmer et al. 1997).

Threats

There has been some conversion to agriculture, especially rice cultivation, some trees in the gallery forest are selectively logged (Zimmer et al. 1997), and burning of habitat may be a significant threat. In 1998, c.75% of Ilha São Jose was burnt, and widespread fires in Roraima in 1999 probably had a severe impact on its river-edge habitats (A. Whittaker in litt. 1999). The primary threat is now thought to be accelerating deforestation in the Amazon basin as land is cleared for cattle ranching and soy production, facilitated by expansion of the road network (Soares-Filho et al. 2006, Bird et al. 2011, Zimmer et al. 2014). Proposed changes to the Brazilian Forest Code reduce the percentage of land a private landowner is legally required to maintain as forest (including, critically, a reduction in the width of forest buffers alongside perennial steams) and include an amnesty for landowners who deforested before July 2008 (who would subsequently be absolved of the need to reforest illegally cleared land) (Bird et al. 2011).

Conservation actions

Conservation Actions Underway
Occurs within Viruá National Park, where it is common (Laranjeiras et al. 2014). Surveys have clearly delimited the species's range (Zimmer et al. 1997, Vale et al. 2007), but no other measures have been taken.

Conservation Actions Proposed
Assess the impact of recent fires on the species. Protect river-island habitat, especially Ilha Boa Água and Ilha São Jose with adjacent gallery forest on the mainland. Expand the protected area network to effectively protect IBAs. Effectively resource and manage existing and new protected areas, utilising emerging opportunities to finance protected area management with the joint aims of reducing carbon emissions and maximizing biodiversity conservation. Conservation on private lands, through expanding market pressures for sound land management and preventing forest clearance on lands unsuitable for agriculture, is also essential (Soares-Filho et al. 2006). Campaign against proposed changes to the Brazilian Forest Code that would lead to a decrease in the width of the areas of riverine forest protected as Permanent Preservation Areas, which function as vital corridors in fragmented landscapes.

 

Identification

15 cm. Mid-sized, long-tailed, black antbird. Male is mostly black with indistinct white streaking on throat and breast, white fringes to wing-coverts and tips to tail feathers. Female is dark slate-grey with white throat streaked dark grey and otherwise ochraceous underparts. Black wings and tail with white markings as in male. Voice Series of up to 20 defined pook or faster kikuk notes.

Acknowledgements

Text account compilers
Westrip, J., Mahood, S., Pople, R., Capper, D., Sharpe, C.J., Symes, A.

Contributors
Silveira, L.F., Vale, M. & Whittaker, A.


Recommended citation
BirdLife International (2020) Species factsheet: Cercomacra carbonaria. Downloaded from http://www.birdlife.org on 15/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 15/08/2020.