The Farmland Refuge of the Last Andalusian Buttonquail Population

Global Ecology and Conservation 17 (2019) e00590 Contents lists available at ScienceDirect Global Ecology and Conservation journal homepage: http://www.elsevier.com/locate/gecco Original Research Article The farmland refuge of the last Andalusian Buttonquail population * Carlos Gutierrez-Exp osito a, , Ruth García-Gorria b, Abdeljebbar Qninba c, Miguel Clavero a, Eloy Revilla a a Conservation Biology Department, Estacion Biologica de Donana,~ Avenida Americo Vespucio 26, 41092, Isla de la Cartuja, Sevilla, Spain b Ibn Khaldoun 1, El Jadida, Morocco c Laboratoire de Geo-Biodiversite et Patrimoine Naturel (GEOBIO), Institut Scientifique, Mohammed V University in Rabat, Avenue Ibn Battouta, BP 703, 10090, Agdal, Rabat, Morocco article info abstract Article history: The last populations of threatened taxa usually survive in low-impacted areas, whose Received 8 November 2018 protection and management is critical for its conservation. However, they can also be Received in revised form 27 February 2019 located in humanized and highly dynamic areas, whose management can be extremely Accepted 7 March 2019 challenging. The Andalusian buttonquail (Turnix sylvaticus sylvaticus) is the critically endangered nominal subspecies of the common buttonquail, a largely unknown species due Keywords: to its secretive habits. Here, we show how the last Andalusian buttonquail population is Refugee species restricted to a small, intensively used agricultural area (4,675 ha) in the Atlantic coast of Agriculture intensification Andalusian buttonquail Morocco, where the birds adapt their life cycle to a fast crop rotation. Buttonquails occupy fl Turnix sylvaticus crops in the owering and fruiting stages, thus changing the preferred crop types along the year, although Alfalfa fields were occupied in all seasons. We used estimated occupancy rates in different crops to obtain seasonal (2017) and year-to-year population estimates (2011, 2014 and 2017). Numbers showed wide seasonal fluctuations between the lowest in winter and the maximum in summer (112e719 individuals). Year-to-year summer estimates also showed wide variations and large uncertainties, ranging between a maximum 1,890 estimated in 2011 and a minimum in 2014 with 492 individuals. The last population estimate available was 596 in 2017. The area is suffering a rapid shift from traditional irrigation farming towards practices more akin to commercial industrial agriculture. The conservation of this critically endangered taxon is highly dependent on the maintenance of traditional farming practices and a rational on-site agricultural modernization. © 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction In the current human-induced mass extinction and land transformation (Allan et al., 2017), declining species tend to find refuge in remnant unaltered patches of their natural habitats (Dirzo et al., 2014; Ceballos et al., 2017). These areas are characterised not only by the presence of the habitats that fulfil the ecological requirements of species (Kerr and Deguise, 2004), but also for being large enough to hold self-sustaining populations and not being affected by direct threats (e.g. * Corresponding author. E-mail addresses: [email protected] (C. Gutierrez-Exp osito), [email protected] (R. García-Gorria), [email protected] (A. Qninba), miguel. [email protected] (M. Clavero), [email protected] (E. Revilla). https://doi.org/10.1016/j.gecco.2019.e00590 2351-9894/© 2019 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). 2 C. Gutierrez-Exposito et al. / Global Ecology and Conservation 17 (2019) e00590 Woodroffe and Ginsberg, 1999). However, there are cases in which the extant populations of declining species do not survive in patches of their original habitat, but in suboptimal or marginal environments, a situation that gave birth to the concept of refugee species (Kerley et al., 2012). Some refugee species can use human-made habitats, such as waste water treatment plants and irrigation ponds (Murray and Hamilton, 2010; Sebastian-Gonz alez et al., 2010). The use of human-made environments is particularly noteworthy among steppe and grassland birds, many of which currently occupy open farmland habitats (O'Connor and Shrubb, 1986). The current agricultural intensification and industrialization occurring at a global scale are behind the dramatic population declines of farmland birds (Donald et al., 2002; Arroyo et al., 2002, Inchausti and Bretagnolle, 2005). The implementation of conservation measures in these intensively managed areas is conditioned by non-biological factors associated with human land-uses. For example, the choices that farmers make on crop and cropping practices are determined by factors such as market demand, price or agricultural policies, which can only be modified at much larger scales. These factors eventually define the structure of agricultural landscapes (Donald et al., 2002; Wilson et al., 2009). Buttonquails (Turnicidae) form a family of ground-dwelling small birds most often linked to grassy or low shrubby habitats. However, a few species (i.e. barred buttonquail Turnix suscitator, Madagascar buttonquail Turnix nigricollis or common buttonquail Turnix sylvaticus) can also live in farmland habitats, occupying crops, fallow land or pastures (Debus, 1996, Madge and McGowan, 2002). As for other species, the historical loss of natural habitats in favour of agriculture has been an opportunity for these adaptable buttonquail species. However, the intensification of agricultural practices poses a threat to those populations that inhabit agricultural systems. Due to the unobtrusive nature of buttonquails, there is a notable lack of field-based studies (Lee et al., 2017) and thus most of the knowledge about their basic biology has originated from observations on captive individuals (i.e. Bell and Bruning, 1974; Flieg, 1973). Buttonquails have a sequential polyandry breeding system, in which females lead the courtship, while parental care is performed by males. Chicks have a very fast development being fertile and able to breed a few months after hatching (i.e. Bell and Bruning, 1974; Butler, 1905; Flieg, 1973; Cramp and Simmons, 1980). The common buttonquail has a wide distribution range, from the Philippines in the East, through south Asia to sub- Saharan Africa and the South-Western Palearctic (Madge and McGowan, 2002). The Andalusian buttonquail (Turnix sylvaticus sylvaticus) is the largest common buttonquail subspecies and is an endemism of the Western Mediterranean (Madge and McGowan, 2002). It formerly inhabited lowlands of up to seven countries, being present in Sicily (Italy) and the Iberian Peninsula (Spain and Portugal) and from Libya to Morocco in North Africa. The Andalusian buttonquail is currently highly threatened, officially considered extinct in Europe and with the only population known to persist being confined to a small area in Morocco (Gutierrez-Exp osito et al., 2011). In this work we aim to 1) define the current global range of the Andalusian buttonquail; 2) describe its habitat selection along the annual cycle; and 3) analyse possible inter-annual variability in habitat selection. Finally, using all this information, we estimate the population size of the Andalusian Buttonquail, both seasonally and on a yearly basis, and evaluate the conservation status of this subspecies living in a human-dependent refuge. 2. Material and methods 2.1. Study area Our study area covers the shire where the Andalusian Buttonquail is known to occur in the Doukkala-Abda region (Morocco, Fig. 1). It includes a narrow coastal sandy agricultural area between Sidi Abed (33.047 N, 8.688 W) and Cape Bedouzza (32.571 N, 9.243 W) (hereafter cultivated strip; Fig. 2) and some remnants of Mediterranean scrubland, hereafter scrubland, characterised by palmetto (Chamaerops humilis), bridal broom (Retama monosperma) and Moroccan spiny broom (Chamaecytisus mollis), embedded within a calcareous plateau of highly degraded arid pastureland (Fig. 3; see Gutierrez- Exposito et al., 2011 for more information). 2.2. Buttonquail and habitat surveys We sampled the presence of the Andalusian buttonquail by walking the area and scanning the ground for its faeces, together with other signs, such as feeding platelets, footprints or feathers (Lees and Smith, 1998; Gutierrez-Exp osito and Qninba, 2010). Very rarely by direct sight or hearing the typical female booming call (Madge and McGowan, 2002). Searching was performed until all walkable area was visited at least by one observer. Given the high effectiveness of this sampling method, no false negatives have considered to occur in our data base (see S1 for details on sampling effort). In the cultivated areas, we used whole individual cultivated fields, hereafter plots, as sampling units (Fig. 2), while in the scrubland we performed linear transects. Our sampling was based in non-systematic and systematic surveys. Non-systematic buttonquail searches consisted in plot or transect searches in sites selected in the field where presence of buttonquails was expected. Between 2010 and 2015, 627 plots were surveyed within the cultivated strip, plus 40 agricultural sites outside this cultivated strip, where the species was suspected to be present. Scrubland sites were visited 32 times in total between 2006 and 2014. Together with our

Load more