Archived 2010-2011 topics: Fuerteventura Stonechat (Saxicola dacotiae): reclassify as Near Threatened or Least Concern?

Link to current BirdLife species factsheet for Fuerteventura Stonechat

Fuerteventura Stonechat Saxicola dacotiae is endemic to Fuerteventura in the Canary Islands (Spain). It is currently listed as Endangered on the IUCN Red List under criterion C2, because when last assessed it was considered to have a small declining population (1,000-2,500 mature individuals).

A recent study (Seoane et al. in press), based on extensive surveys during 2005-2006, produced a much larger population estimate of 14,436 individuals (CI 95%: 13,376 – 15,492) and suggested that the species is present in a much larger area of the island than previously thought. It prefers steep terrain above 200 m, but also occurs at lower densities in lower, flatter areas which extend across large parts of Fuerteventura.

Although differences in methods from the only previous census (Bibby & Hill 1987) make it impossible to calculate a population trend from this revised estimate, it seems unlikely that the species has undergone a significant overall population decline. There is some suggestion that it may even have increased during the last 25 years, although local extinctions have probably also occurred due to urban expansion in some parts of the island, e.g. tourism developments in the south (Illera 2004; Seoane et al. in press).

Ongoing local threats include habitat degradation and destruction as a result of development for tourism, and predation by invasive species. However, the revised population estimate, improved knowledge of its habitat preferences, and lack of any evidence for overall decline, suggest that the global status of the species ought to be revised to either Near Threatened (nearly meeting the threshold under criterion C2a[ii]) or Least Concern. Comments on this proposal, and particularly any quantitative information that might justify a projected or inferred future decline, are welcomed.

Bibby, C. J. and Hill, D. A. (1987) Status of the Fuerteventura Stonechat Saxicola dacotiae. Ibis 129: 491-498.

Illera, J.C. (2004) Saxicola dacotiae. In: Madroño, A., González, C. and Atienza, J. C., eds. (2004) Libro Rojo de las aves de España. Madrid: Dirección General de Conservación de la Naturaleza and SEO/BirdLife.

Seoane, J., Kouri, A., Illera, J.C., Palomino, D., Alonso, C.L. and Carrascal, L.M. (in press) New data on the population, distribution and habitat preferences of the Canary Islands stonechat (Saxicola dacotiae). Ardeola.

Related posts:

  1. Archived 2010-2011 topics: Lesser Kestrel (Falco naumanni): downlist to Near Threatened or Least Concern?
  2. Archived 2010-2011 topics: White-tailed Laurel Pigeon (Columba junoniae): downlist to Near Threatened or Least Concern?
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3 Responses to Archived 2010-2011 topics: Fuerteventura Stonechat (Saxicola dacotiae): reclassify as Near Threatened or Least Concern?

  1. Andy Symes says:

    The Seoane et al. paper has now been published:
    Seoane, J., Kouri, A., Illera, J.C., Palomino, D., Alonso, C.L. and Carrascal, L.M. (2010) NEW DATA ON THE POPULATION, DISTRIBUTION AND HABITAT PREFERENCES OF THE
    CANARY ISLANDS STONECHAT SAXICOLA DACOTIAE / NUEVOS DATOS SOBRE EL TAMAÑO POBLACIONAL,
    LA DISTRIBUCIÓNY LAS PREFERENCIAS DE HÁBITAT
    DE LA TARABILLA CANARIA SAXICOLA DACOTIAE
    Ardeola 57(2), 387-405

    Abstract available at: http://www.ardeola.org/pubs/volume/57%282%29/article/387-405?lang=en

  2. Andy Symes says:

    Ana Iñigo (SEO) has commented:

    Although recently published data estimate the population larger than previously published data, we can’t affirm that the population has increased during the last 25 years. Some authors suggest that previous data were infra estimated, meaning that we can’t compare population size. We can’t compare the previous census with the recent published by Seoane et al., because the methodology has been different. We can’t ensure this increase. There may be increased but not as we know. But more important is that the habitat is continuous losing. Has probably decreased the construction, but unfortunately goat farms are increasing. At present, the Canary Government rewards primary production in the islands, which are agricultural and livestock products, as cheese, for example. This has led to an increase in the number of heads of cattle and farms. Some of these goat farms are built in SPA, and unfortunately are not taken into account the accumulative impact of these farms, and their environmental impact is analyzed independently without taking into account the impact that all together. The effect of livestock on birds in the Canary Islands has been published by several authors (Carrete et al. 2009). Fuerteventura Stonechat is a very vulnerable species, its population size isn’t very high (being a passerine) and especially it has a small and restricted endemic distribution. And we know the extinctions in Alegranza and Montaña Clara in the early twentieth century, after has been described in 1913 as a possible subspecies (S. d. mureliae) (Illera et al., 2006). Therefore we believe that downlist the species to NT or LC is very risky. In the Red Book of birds of Spain the species is listed as EN. The last population census in 2005 and 2006 led us to revise the status of the species. The island of Fuerteventura has only 1,658 km2 and we know that there is a decline in area of occupancy. In the monograph of the species (in litt) we proposes the inclusion of the species at VU, attending the UICN criteria B1b(ii).

    BirdLife response:
    However, the Red List assessment hinges not on whether the species is increasing or not, but whether a decline is still suspected. As far as can be determined, there is no evidence that the species is declining. Habitat loss due to goat grazing is potentially very relevant information, but in order to infer that it is having negative impacts on Fuerteventura Stonechat habitat, some species-specific evidence is needed to demonstrate this. Inherent vulnerability of the species is dealt with through the Red List under criterion D2, but there is no plausible threat that could rapidly drive the species Extinct or Critically Endangered in a short time frame.

    Ana Iñigo (SEO):
    http://www.gobcan.es/agricultura/otros/estadistica/index.htm
    This link evidence that the goat-farms are increases since 2003. I can summary this information:
    2007: 151935
    2008: 152011
    2009: 131903 (decreases as economical crisis consequences, I think)

    But the most important is that the government is providing the farmers, situation that unquestionable will increase the number of cattle in the islands.

    Unfortunately for the instant anybody has studied the real and actual impact of the number of cattle on the Fuerteventura Stonechat but that does not means that the impact doesn’t exists. We know, in the experience, that is an important threat for the species, as you know. Overgrazing leads to a loss of vegetative cover (Carrete el at., 2009), this produced an decrease in the abundance of birds that uses this habitats (Carrete el at., 2009), but this study was carried out on a plain, were not present Fuerteventura Stonechat. The cited work publish by Osborne (attach) arrives to similar conclusions.
    We also know that the Fuerteventura Stonechat prefers hillsides with shrub cover medium and large size, which has a direct bearing on food availability (Illera, 2001. Biological Conservation). If herbaceous shrub cover decreasing, as consequence goats pressure (overgrazing), it is easy to deduce that the Fuerteventura Stonechat (that we know that it is absent or in fewer number in habitats with low shrub and grass) will be affected negatively.

    No one has performed an experiment to see if the indiscriminate use of insecticides, for example, could affect this species and no one would doubt (I hope) of their negative effects.

    And:
    (a) severely fragmented or restricted to <10 locations *Please, define location*
    (b) continuing decline: observed, inferred or projected
    Observed: part of Vinamar, Butihondo, Fimapaire and Mal Nombre valleys and ravines (excellent areas for the CIS have been destroyed) and CIS pairs living there have disappeared (J.C.Illera pers.obs.)
    (c) extreme fluctuations. The range of Fuerteventura Chat is not severely fragmented (it is only partly so) I agree, it is not severely fragmented yet. We will see in a short and medium time.

    BirdLife:
    Please see the extract below which is taken from the IUCN guidelines for interpreting the Red List criteria, available to view at: http://intranet.iucn.org/webfiles/doc/SSC/RedList/RedListGuidelines.pdf

    “The term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat.

    Justification for the number of locations used in Red List assessments should include reference to the most serious plausible threat(s). For example, where the most serious plausible threat is habitat loss, a location is an area where a single development project can eliminate or severely reduce the population.”

    For species such as the Stonechat, for which the key threatening process is habitat loss and degradation through the increase in goat grazing, it is difficult to accurately measure the number of locations, but to be consistent with the guidelines we would consider a location to be on the scale of a single goat farm or a single town/village, depending on the scale and nature of the farming. This is consistent with our application of the criteria for many other species threatened by relatively small-scale habitat loss and degradation around the world, and on the basis of this I cannot see any way that the number of locations sensu IUCN could be <10 for this species.

    Consequently, given the population estimate in Seoane et al. and the forthcoming monograph, even with evidence of ongoing habitat degradation, the species could at most qualify as Near Threatened under both B1a+b(iii) (nearly meeting criteria for Endangered but not severely fragmented and number of locations not <10) and C2a(ii) (nearly meeting the criteria for Vulnerable but >10,000 mature individuals according to latest population estimates).

  3. Andy Symes says:

    I think the estimated value oft he population size of Saxicola dacotiae in Ardeola 57(2) („New data on the population, distribution and habitat preferences oft he Canary Islands Stonechat“)(during reproductive seasons 2005/06) is very optimistically and at best under optimal conditions. My estimation in Limicola 24(1) was later (2008/09; before reproductive season 2010) and after a drought! Because of this my estimation value is not unrealistic low [600 pairs could be after one breeding period more than 3-4000 individuals!]. Besides I think the population of this species could do very strong fluctuations in short times [more than 1:2 per year seems possible].

    Best regards
    Bernd Nicolai

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