LC
Spix's Antwarbler Hypocnemis striata



Justification

Justification of Red List Category
This species has an extremely large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (extent of occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very large, and hence does not approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.

Population justification
The species is described as fairly common to common throughout most of its extensive range, although it is apparently uncommon and very local at the eastern edge of its range (del Hoyo et al. 2003, 2020). Based on the area of tree cover with at least 30% canopy cover within the species's range in 2010 (931,000 km2; Global Forest Watch 2020), the minimum recorded density of a congener (2 individuals per km2; Terbough et al. 1990) and assuming 25-40% of habitat within the range is occupied, the population size is tentatively suspected to fall within the range 465,500 - 744,800 individuals, roughly equating to 310,333 - 496,533 mature individuals and here placed in the band 100,000 - 499,999 mature individuals. There are three subspecies, so there are at least three subpopulations.

Trend justification
Remote-sensed data on forest loss indicates a loss of approximately 7% of tree cover with at least 30% canopy cover within the species's range from 2009-2019 (Global Forest Watch 2020). The population size is inferred to be undergoing a continuing decline. 

An analysis of the impact of disturbance on forest species in Pará found that in private lands or sustainable-use reserves, the impact of disturbance on biodiversity was equivalent to that of an additional 51% loss of forest, with disturbance in areas with 83% forest loss causing 147% the expected level of biodiversity loss (Barlow et al. 2016). However, the species is thought to be tolerant of forest that has survived fire (del Hoyo et al. 2020). Assuming that the population size is proportional to forest area, and taking into account the potential additional impact of disturbance, the population size is suspected to have undergone a reduction of 7-17% over the past decade.

In the three years from 2017-2019, approximately 2.8% of forest within the range was lost (Global Forest Watch 2020). If this rate of forest loss were to occur over ten years, this would equate to a loss of 9%. Assuming that the population size is proportional to forest area, and that disturbance may increase the impact of deforestation by up to 147%, a population reduction of 7-22% is suspected over the next decade. Taking 51% as a best estimate of the additional impact of disturbance, and assuming 9% forest loss, the best estimate of population reduction over the next decade is 14%.

Distribution and population

The species is endemic to Brazil, where it occurs in the Amazon basin, in the states of Pará, Mato Grosso and Amazonas. Its range is bounded by the Roosevelt and lower Madeira rivers to the west, the Amazon river to the north and the Tocantins river to the East (Isler et al. 2007, del Hoyo et al. 2020).

Ecology

It occurs in the understorey to midstorey of humid evergreen-forest borders (terra firme, transitional and seasonally flooded areas), especially in densely vegetated light-gaps (e.g., around treefalls) and streams within forest, as well as adjacent tall second-growth woodland (del Hoyo et al. 2020). It is found below c. 800 m (del Hoyo et al 2020).

Threats

The species is threatened by forest loss and disturbance, largely resulting from agriculture, grazing and selective logging. Forest loss has been extensive in Pará and Mato Grosso (INPE 2019, Global Forest Watch 2020). A study has indicated that the disturbance from fire and logging can double the biodiversity loss caused by deforestation (Barlow et al. 2016), however, the species is thought to be tolerant of forest areas that have survived fire (del Hoyo et al. 2020).

Conservation actions

Conservation and Research Actions Underway
It occurs in a number of protected areas, including the Serra dos Carajás mosaic of conservation units, Tapajós National Park, Tapajós National Forest and Rio Cristalino Private Natural Heritage Preserve (del Hoyo et al. 2020).

Conservation and Research Actions Proposed
Carry out surveys to estimate population size and trends. Continue to monitor forest loss across the species's range. Enforce protected areas and legislation against deforestation.

Acknowledgements

Text account compilers
Wheatley, H.

Contributors
Lees, A. & Symes, A.


Recommended citation
BirdLife International (2022) Species factsheet: Hypocnemis striata. Downloaded from http://www.birdlife.org on 03/07/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 03/07/2022.