Archived 2020 topic: Dupont’s Lark (Chersophilus duponti): Revise global status?

BirdLife International factsheet for Dupont’s Lark.

This discussion was first published as part of the 2018 Red List update. At the time, a decision regarding the status of this species was pended and the post remained open. Following experts’ review of the species factsheet, the topic has now been updated to reflect the most recent information. The initial topic on this analysis can be found here.

Dupont’s Lark inhabits open shrub-steppe plains, and has a patchy, fragmented range from Spain across North Africa, including Morocco, Algeria and Tunisia. It has a 0.61 male-biased sex ratio, which makes estimating population size difficult, but the global estimate is currently placed between 25,000-35,000 individuals (J García pers. comm., 2020; J Traba pers. comm., 2020). Assuming that two thirds of the population are of breeding age, this makes 16,750 – 23,450 individuals able to breed. When the sex ratio is applied, there is an estimated 6,533 – 9,145 mature females. Assuming that pairs are strictly monogamous, this equates roughly to 13,000 – 18,300 mature individuals.

Dupont’s Lark is threatened by ongoing habitat loss and degradation resulting from development in Spain, reforestation in Tunisia, and increasing agricultural pressures in Morocco. It has previously been listed as Near Threatened, approaching classification as threatened under criterion A2bc +3bc + 4bc. However, new information, particularly from African populations, may warrant a change in Red List category. We have therefore reviewed Dupont’s Lark here against all the criteria.

Criterion A: Recent figures show that this species may be undergoing larger declines than the previously suspected 20-30%.IUCN guidelines stipulate that rates of decline should be measured over the longer of 10 years or 3 generations (IUCN Standards and Petitions Committee, 2019). The generation length for Dupont’s Lark has been recalculated to 3 years (Bird et al., 2020)*. Therefore, the rates of reduction for this species are calculated over 10 years.

Recent studies in Spain have recorded declines of at least 40% between 2004 and 2015 (Gómez-Catasús et al., 2018), equalling a decline of 37% over 10 years. In Morocco, countrywide trends are difficult to gauge. Some subpopulations experienced a reduction of 20-30% between 2008 and 2020, equating to a 17-25% 10-year reduction, while others demonstrated a slight increase. The countrywide trend is suspected to be closer to a 10% reduction over the same period, but more precise population data is required to confirm these trends (J García pers. comm., 2020).  In Tunisia, Isenmann et al. (2005) produced an estimated range of 89,000 km² for Dupont’s lark, corresponding to data records from ornithological expeditions c.1950 by (Heim de Balsac & Maynaud, 1962). Intensive surveys in 2007 by Suárez, García and Viñuela(in litt. 2020) throughout the range discovered that it had decreased to 70 km², and that suitable habitat outside of this had been lost. Assuming that habitat is still being lost at the same rate, and that the population declines at the same rate as habitat loss, this equates to a suspected decline of 55% in 10 years for the Tunisian population.

It is believed the populations in Spain, Morocco and Tunisia make up a large proportion of the global distribution for Dupont’s Lark (BirdLife International, 2020). Despite the uncertainty of the rate of Moroccan declines, the new information from Spain and Tunisia suggest that the global population is undergoing a decline of >30% over 10 years, and that Dupont’s Lark may therefore be listed as Vulnerable under criterion A2bc+3bc+4bc.

Criterion B: The Extent of Occurrence for Dupont’s Lark is believed to be 2,640,000 km² (BirdLife International, 2020). This is far too large to trigger the threatened categories under criterion B. This species may therefore be considered Least Concern under this criterion.

Criterion C: The global population size is difficult to quantify precisely, but it has been estimated as 13,000 – 18,300 mature individuals. This is greater than the <10,000 mature individuals threshold required for full classification as threatened under criterion C (García et al., 2008; Traba et al., 2019; Suárez, García and Viñuela, in litt. 2020). However, the population is undergoing an estimated continuing decline of at least 10% in 10 years, which would qualify Dupont’s Lark for listing as Near Threatened under criterion C1. This species does not experience extreme fluctuations, nor does it exist in a single subpopulation. The rest of the subpopulation structure is not fully understood, so this species cannot be listed under criterion C2. Overall, Dupont’s Lark may be considered Near Threatened, approaching the threshold for listing as threatened under criterion C1.

Criterion D: The global population size is estimated to be much higher than the <1000 mature individuals threshold required to classify as threatened under criterion D. Dupont’s Lark is therefore considered Least Concern under this criterion.

Criterion E: To the best of our knowledge, no quantitative analysis has been conducted for this species, so we are unable to assess it against this criterion.

We therefore propose that Dupont’s Lark (Chersophilus duponti) be listed as Vulnerable under criterion A2bc+3bc+4bc. 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., Şekercioğlu, Ç.H. and 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: Chersophilus duponti. Downloaded from http://www.birdlife.org on 21/04/2020.

García, J.T., Suárez, F., Garza, V., Justribó, J.H., Oñate, J.J., Hervás, I., Calero, M. and Morena, E.L.G. 2008a. Assessing the distribution, habitat, and population size of the threatened Dupont’s Lark Chersophilus duponti in Morocco: lessons for conservation. Oryx 42(4): 592-599.

Gómez-Catasús, J.; Pérez-Granados, C.; Barrero, A.; Bota, G.; Giralt, D.; López-Iborra, G.M.; Serrano, D.; Traba, J. 2018. European population trends and current conservation status of an endangered steppe-bird species: the Dupont’s lark Chersophilus duponti. PeerJ 6:e5627.

Heim de Balsac H and Mayaud N1962. Les oiseaux du Nord- Ouest  de  l’Afrique.  Ed.  Paul  Lechevalier.  Collection Encyclopédique d’Ornithologie X, Paris, 486pp

Isenmann, P., Gaultier, T., El Hili, A., Azafzaf, H., Dlensi, H. & Smart, M. (2005) Les Oiseaux de Tunisie. Birds of Tunisia. SEOF Editions, Paris, France.

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.

Traba, J.; Garza, V.; García-Antón, A.; Gómez-Catasús, J.; Zurdo, J.; Pérez-Granados, C.; Morales, M.B.; Oñate, J.J.; Herranz, J., Malo, J. 2019. Criterios para la gestión y conservación de la población española de alondra ricotí Chersophilus duponti. Fundación Biodiversidad, Ministerio para la Transición Ecológica. Madrid.

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5 Responses to Archived 2020 topic: Dupont’s Lark (Chersophilus duponti): Revise global status?

  1. Morocco: According to recent data from the Moroccan expedition of TRABA & AL. (pers. comm.): decrease rates of -65%, -54%, -4% and + 25% in the last 12-15 years in some populations. Although comparisons are difficult, this suggests a decrease in Moroccan populations of around 16% in the last 12-15 years that could be associated with changes in land use and increases in the intensity of livestock use.

    Criterion E: To the best of our knowledge, no quantitative analysis has been conducted for this species, so we are unable to assess it against this criterion.

    For this criterion:
    The Iberian population has been evaluated by AVP (TRABA & AL., 2019). The main result is that the Probability of Extinction in 20 years is P = 0.897, and the total Extinction of the population is estimated at 35 years.
    Currently, this has motivated the request to recatalog in Spain to Endangered.

  2. Jose Rafael Garrido López says:

    My experience working with birds conservation in North Africa showed me that though there still are enough available habitat in Morocco, it is changing because increase in pastoralism and human populations, specially in the East of the country. Though more good populations surveys are necessary, El Agbani & Qninba (2011) estimated only 2.000-3.000 pair, less than 11.200-20.200 males estimated by Suárez (2010). Data seem to indicate that it is the same in Tunisia, but habitat could still be well preserved in Algeria and Libya. However, it should also be considered that climate change projections indicate loss of >70% potential area in Spain (Huntley et al., 2007; Araujo et al., 2011), which could be extrapolated to Mediterranean areas of North Africa. So, species could be listed as Vulnerable under criterion A3c because population reduction of at least > 30% in the near future, at least in Spain, Morocco and Tunisia.

  3. 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

  4. 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

  5. Red List Team (BirdLife International) says:

    Recommended categorisation to be put forward to IUCN

    The final categorisation for this species has not changed. Dupont’s Lark is recommended to be listed as Vulnerable under Criterion A2bc+3bc+4bc.

    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.