Caatinga Black-tyrant (Knipolegus franciscanus): Revise global status?

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4 Responses to Caatinga Black-tyrant (Knipolegus franciscanus): Revise global status?

  1. Diego Mendes Lima says:

    In the assessment of the risk of extinction of the Brazilian fauna carried out in 2018, the species was categorized as Vulnerable (VU) by criterion C2a(i).

    Evaluators: Crizanto Brito de Carvalho, Flávio Kulaif Ubaid, Gustavo Bernardino Malacco da Silva, Miguel Angelo Marini, Tarcisio Lyra dos Santos Abreu, Túlio Dornas de Oliveira and Wagner Nogueira Alves.

    Criterion A – In the 2018 assessment, we did not find long-term data from population estimates to track the decline by observed data (a) and the decline in AOO and EOO (c) do not reach the thresholds for a threat category. Habitat loss calculations performed with tools available on MapBioma (https://mapbiomas.org/) in the generational time of the species does not reach the population reduction threshold due to habitat loss in its range.

    Criterion B – The AOO (>2,000 km2) and EOO (235,542 km2) calculations do not meet the thresholds for the threatened categorization.

    Criterion C – The species is considered uncommon (Stotz et al., 1996) and the population trend appears to be declining (BirdLife International, 2017).
    The species is known from at most 40 locations where the total number of individuals should not exceed 10,000 individuals (Fitzpatrick, 2004). You can check records in 29 municipalities plus the Federal District (WiKiaves, 2020). Therefore, it is reasonable to assume, together with knowledge of the records evidenced on the species map, that there are at most 47 locations where the species is registered.
    The species is sensitive to environmental degradation due to its great habitat specificity. Need well-preserved forests. Furthermore, the fragmented habitat and the low mobility of the species in a non-forest matrix lead to severe population fragmentation. Threats due to habitat loss and fragmentation due to the expansion of agricultural activities and limestone mining have caused population decline. In a study carried out in the municipality of Jequitaí, Minas Gerais, 43 individuals were recorded in 31 days of sampling (Vasconcelos & D’Angelo Neto, 2018) and in the same area other researchers found 50 individuals of this species in a single hour of field sampling in November 1995 (Kirwan et al., 2004). However, such abundance was never found in other locations (Vasconcelos & D’Angelo Neto, 2018).
    Based on population data obtained in Minas Gerais and knowledge of the 47 places where the species occurs, it is inferred that the number of mature individuals per subpopulation is between 43-100 individuals and the population size is between 2,021-4,700 mature individuals.

    Criterion D – the number of mature individuals does not reach the threshold for criterion D1 and their AOO is greater than 20 km2

    Criterion E – in the 2018 assessment, we did not find PVA data.

    JUSTIFICATION: Knipolegus franciscanus is endemic to Brazil, occurring in the São Francisco valley, on the Bahia-Goiás-Tocantins border, in the Federal District and in Minas Gerais. There are clear threats due to the expansion of cattle ranching, irrigated crops, logging and limestone mining, causing population decline. In all known populations, the number of individuals reported is small, where it is inferred that there are less than 10,000 mature individuals in Brazil and no subpopulation has more than 1,000 individuals. In this context, K. franciscanus was categorized as Vulnerable (VU) by the C2a(i) criterion.

  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 2021 Red List would be to retain Caatinga Black-tyrant (Knipolegus franciscanus) as Least Concern.

    The Brazilian assessment is based on a study carried out in the municipality of Jequitaí, Minas Gerais, where 43 individuals were recorded in 31 days of sampling (Vasconcelos & D’Angelo Neto 2018). This total has been multiplied by the total number of localities at which the species has been recorded (D. M. Lima in litt. 2021). However, the referenced study (Vasconcelos & D’Angelo Neto 2018) used MacKinnon lists to evaluate the species richness of the site. This method uses lists of the first ten species observed at a location to assess which species are present and to estimate the species richness. The method does not gain an estimate of abundance at a site. The results of the study in Jequitaí cannot be interpreted as a subpopulation of 43 birds, and the frequency with which the species was detected in McKinnon lists indicates that it is one of the commoner species at the site.

    There is little direct quantitative information available on this species’s population size. No density estimate is available for this species or for any congener. Other population size estimates available for this species include 80,923 individuals based on a modelled density and an estimated extent of habitat (Santini et al. 2018) and 97,640 individuals based on a statistical approach applied to eBird records (Callaghan et al. 2021).

    Based on the above information, the available evidence does not indicate that the species’s population size is below, or close to 10,000 mature individuals, and so our preliminary decision is to retain the species as Least Concern. When further information about this species’s population size becomes available, the species may be recategorised.

    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.

    The final 2021 Red List categories will be published on the BirdLife and IUCN websites in December 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN.

    References:

    Callaghan, C. T., Nakagawa, S., & Cornwell, W. K. (2021). Global abundance estimates for 9,700 bird species. Proceedings of the National Academy of Sciences 118(21).

    Santini, L., Butchart, S. H., Rondinini, C., Benítez‐López, A., Hilbers, J. P., Schipper, A. M., … & Huijbregts, M. A. (2019). Applying habitat and population‐density models to land‐cover time series to inform IUCN Red List assessments. Conservation Biology 33(5): 1084-1093.

  4. Red List Team (BirdLife International) says:

    Recommended categorisation to be put forward to IUCN

    The final categorisation for this species has not changed. Caatinga Black-tyrant is recommended to be listed as Least Concern.

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

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