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Integrative taxonomy reveals Europe’s rarest songbird species, the Gran Canaria Blue Chaffinch Fringilla polatzeki
Abstract
The conservation of endangered taxa often critically depends on accurate taxonomic designations. The status of the Gran Canaria population of the Blue Chaffinch Fringilla t. polatzeki has not been reevaluated since the early 1900s when this taxon was described as a subspecies and combined with the much more common Tenerife Blue Chaffinch F. t. teydea in a single species. We show that multiple diagnostic differences in plumage, songs, calls and morphometrics distinguish F. t. polatzeki from F. t. teydea. Preliminary playback experiments suggest that F. t. polatzeki is able to discriminate between songs of both taxa. Along with previously reported differences in mitochondrial DNA, these findings show that the blue chaffinches on Gran Canaria and Tenerife represent two distinctive species: F. polatzeki and F. teydea. Gran Canaria Blue Chaffinch is Europe’s rarest passerine species and should be classified as Critically Endangered. Its long-term survival in the wild currently depends on a very small (<20 km2) area in southwest Gran Canaria. Reclassification of Gran Canaria Blue Chaffinch as a species increases the urgency of ongoing conservation efforts. Our study underscores the critical importance of taxonomic clarification of threatened taxa that are currently classified as ‘subspecies’.
... The Eurasian Stone-curlew Burhinus oedicnemus (hereafter Stone-curlew) is a polytypic species with five subspecies distributed in the Palearctic and described on the basis of morphological characters (Cramp & Simmons 1983) Recent genetic investigations confirmed the four subspecies described for the Western Palearctic and found a significant level of genetic differentiation between Mediterranean and Canary Island populations (Mori et al. 2014(Mori et al. , 2017. The status of the Canary Islands subspecies is particularly intriguing as several cases of cryptic differentiation of local birds have been discovered in recent years (Illera et al. 2016, 2018, Sangster et al. 2016. Accurate taxonomic designations are of critical importance for biodiversity conservation (Sangster 2018), especially for taxa of a high conservation concern such as B. o. insularum and B. o. distinctus (Spanish catalogue of threatened species, Real Decreto 139/2011). ...
... Species delineation can be done in many different ways, but the best strategy seems to be integrative taxonomy, i.e. the combination and integration of multiple types of evidence (Sangster 2018). Together with genetic and morphological information, acoustic data play a major role in taxonomic designation of birds, especially for oscine and suboscine passerines (Alström & Ranft 2003, Illera et al. 2014, 2018, Sangster et al. 2016, Sangster 2018 and references therein). The vocalizations of suboscines, which are assumed to have a strong genetic component (Kroodsma 2004), have been frequently used to assess species limits (Alström & Ranft 2003, Remsen 2005, Isler et al. 2012, Cooper & Cuervo 2017. ...
... We integrated acoustic analysis of some of the most frequently used call types with a preliminary playback experiment aimed at testing whether birds belonging to the nominate subspecies responded differently to calls belonging to their own or to the Canarian subspecies. Playback tests have been successfully used to study song discrimination in passerines (Tietze et al. 2011, Sangster et al. 2016, Freeman & Montgomery 2017, but they also have been employed to examine how subspecies or closely related species of non-passerines, including shorebirds, respond to calls recorded in different geographical locations (Douglas III 1998, Curé et al. 2010, Miyazaki & Nakagawa 2015. Our final aim is to provide useful data to better assess the taxonomic status of the Canarian subspecies, and in particular, whether the distinctus subspecies could be raised to full species status using an integrative taxonomic approach. ...
Capsule: Acoustic analysis does not support the elevation of Central and Western Canary Islands subspecies of the Eurasian Stone-curlew Burhinus oedicnemus distinctus to full species.
Aims: To verify whether the vocal repertoires of Eurasian Stone-curlew subspecies oedicnemus and distinctus show biologically significant quantitative and qualitative differences.
Methods: We carried out an acoustic analysis of some of the most frequently used call types of Eurasian Stone-curlew, recorded in Italy and in the Canary Islands. Additionally, we used playback experiments to test the response of the two subspecies to calls of their own and the other subspecies.
Results: The vocal repertoires of the individuals belonging to the two subspecies were rather similar, but the quantitative analysis of acoustic parameters showed some differences between the populations. In particular, the three most used call types showed higher frequency and faster utterance rhythm for distinctus than oedicnemus. Playback experiments indicated that individuals from the nominate subspecies responded in the same way to the playback of calls of individuals belonging to both subspecies.
Conclusion: Acoustic analysis supports the distinctiveness of Eurasian Stone-curlew populations from Central and Western Canary Islands, thus confirming the available morphological and genetic data. These results, however, do not suggest that distinctus should be elevated to a full species.
... For in-depth breeding biology studies RFID readers with paired antennas may be considered, but study burrows will likely provide the most detailed data on the South Georgian Diving Petrel in particular and small, burrowing seabirds in general. (May 1990, Sangster et al. 2016. If common, polytypic taxa (i.e., clusters of distinct and diverged species; Griffiths 1974), include unclassified taxonomic units warranting species status, their significance remains "hidden". ...
... If common, polytypic taxa (i.e., clusters of distinct and diverged species; Griffiths 1974), include unclassified taxonomic units warranting species status, their significance remains "hidden". Valuable time to implement conservation management may consequently be lost if composite "species" ameliorate the actual conservation status of threatened taxa (Sangster et al. 2016). Therefore, the "hidden" rare taxa are unlikely to receive the management required to conserve them. ...
... This phenomenon of "hidden" but endangered taxa is common on archipelagos and many distinct and endemic taxa on (single) islands are consequently underappreciated (Sangster et al. 2016). For instance, the taxonomy of many species complexes on the archipelago of New Zealand remains unresolved (e.g., May 1990, Hay et al. 2010. ...
Procellariiformes diverse order of seabirds under considerable pressure from onshore and offshore threats. New Zealand hosts a large and diverse community of Procellariiformes, but many species are at risk of extinction. In this thesis, I aim to provide an overview of threats and conservation actions of New Zealand’s Procellariiformes in general, and an assessment of the remaining terrestrial threats to the South Georgian Diving Petrel (Pelecanoides georgicus; SGDP), a Nationally Critical Procellariiform species restricted to Codfish Island (Whenua Hou), post invasive species eradication efforts in particular. I reviewed 145 references and assessed 14 current threats and 13 conservation actions of New Zealand’s Procellariiformes (n = 48) in a meta-analysis. I then assessed the terrestrial threats to the SGDP by analysing the influence of five physical, three competition, and three plant variables on nest-site selection using an information theoretic approach. Furthermore, I assessed the impacts of interspecific interactions at 20 SGDP burrows using remote cameras. Finally, to address species limits within the SGDP complex, I measured phenotypic differences (10 biometric and eight plumage characters) in 80 live birds and 53 study skins, as conservation prioritisation relies on accurate taxonomic classification. The results from the meta-analysis revealed that New Zealand’s Procellariiformes are at risk from various threats (x̅ = 5.50 ± 0.34), but species also receive aid from several conservation actions (x̅ = 7.19 ± 0.33). Results from a logistic regression showed that smaller species are more threatened onshore than offshore. The majority of the conservation actions appear in place where needed. However, habitat management, native predator control and the mitigation of risks associated with environmental stochasticity may need improvement. Analysis of SGDP nest-site selection showed dependency on mobile, steep, seaward-facing foredunes. Invasive plant species, the presence of conspecifics, or the presence of other seabird species did not influence SGDP nest-site selection. Assessment of interspecific interactions at SGDP burrows showed seven species occurring at burrows, but only Common Diving Petrels (P. urinatrix; CDP) interfered with SGDP breeding success. Assessment of phenotypic differences within the SGDP revealed that the New Zealand SGDP population differs in five biometric and three plumage characters from all other populations and warrants species status based on a species delimitation test with quantitative criteria. I propose to name this Critically Endangered species Pelecanoides taylorii sp. nov. These findings indicate that P. taylorii is of considerable conservation concern and additional measures, even after successful eradication of invasive species, may be required to safeguard this species. Based on the habitat preference, stochastic events, such as storms and storm surges, appear a major threat to P. taylorii. The assessed interspecific interactions at nest-sites, indicate competition with CDPs to be a minor threat. I propose a translocation as a potential strategy to relieve the pressure on P. taylorii, but further monitoring and research is needed to enable the implementation of such a conservation strategy.
... Conservation biology remains focussed on species as distinct and single ecological and taxonomic units and accurate nomenclature and taxonomic placement of threatened species is thus crucial to effective conservation management [1,2]. If common, polytypic taxa (i.e., clusters of distinct and diverged species [3]), encompass unclassified taxonomic units warranting species status, their biodiversity value remains "hidden". ...
... If common, polytypic taxa (i.e., clusters of distinct and diverged species [3]), encompass unclassified taxonomic units warranting species status, their biodiversity value remains "hidden". Valuable time to implement conservation management may consequently be lost if composite "species" ameliorate the actual conservation status of threatened taxa [2]. Therefore, the "hidden" rare taxa are unlikely to receive the management required to conserve them. ...
... Therefore, the "hidden" rare taxa are unlikely to receive the management required to conserve them. This phenomenon of "hidden" but endangered taxa is common on archipelagos and many distinct and endemic taxa on isolated islands are consequently underappreciated [2]. For instance, the taxonomy of many species complexes on the archipelago of New Zealand remains unresolved e.g., [1,4,5]. ...
Unresolved taxonomy of threatened species is problematic for conservation as the field relies on species being distinct taxonomic units. Differences in breeding habitat and results from a preliminary molecular analysis indicated that the New Zealand population of the South Georgian Diving Petrel (Pelecanoides georgicus) was a distinct, yet undescribed, species. We measured 11 biometric characters and scored eight plumage characters in 143 live birds and 64 study skins originating from most populations of P. georgicus, to assess their taxonomic relationships. We analysed differences with principal component analyses (PCA), factorial ANOVAs, and Kruskal-Wallis rank sum tests. Results show that individuals from New Zealand differ significantly from P. georgicus from all other populations as following: 1) longer wings, 2) longer outer tail feathers, 3) deeper bills, 4) longer heads, 5) longer tarsi, 6) limited collar extent, 7) greater extent of contrasting scapulars, 8) larger contrasting markings on the secondaries, 9) paler ear coverts, 10) paler collars, and 11) paler flanks. Furthermore, we used a species delimitation test with quantitative phenotypic criteria; results reveal that the New Zealand population of P. georgicus indeed merits species status. We hereby name this new species Pelecanoides whenuahouensis sp. nov. Due to severe reductions in its range and the very low number of remaining birds (~150 individuals limited to a single breeding colony on Codfish Island/Whenua Hou) the species warrants listing as 'Critically Endangered'. An abstract in the Māori language/Te Reo Māori can be found in S1 File. PLOS ONE | https://doi.org/10.1371/journal.pone.
... polatzeki) in the Canarian archipelago, are phenotypically distinct in male plumage [34], as well as in morphometrics and vocalizations [35,36]. A recent study confirmed the statistical significance of these measures and suggested lifting the taxa to species rank [37]. There is also some evidence that the taxa are divergent in mtDNA [38,39] and nuclear microsatellites [40]. ...
... The largest effect size was estimated for bill length of males (Table 4), which scores as a medium divergence (score = 2). For scoring the acoustics, we used Table 5. the quantitative measurements of temporal and spectral variables presented in Sangster et al. [37]; Table 4. The stable pitch in the first phrase of the teydea song versus the gradually decreasing pitch in polatzeki qualifies for a score of 3, whereas the increased amplitude of phrase 2 (crescendo) in teydea and reduced amplitude in polatzeki, gives a score of 2 (Table 9). ...
... We have also shown that the two Blue Chaffinch taxa are reciprocally monophyletic in mitochondrial and nuclear DNA, and are divergent in sexual traits, like song and sperm, that are presumably important traits in mate choice and fertilization success. In a recent paper, Sangster et al. [37] indicated a qualitatively similar divergence in male plumage characters and documented non-overlapping body size distributions in adult males, using a similar PCA approach as we have presented here. They also analysed song and calls, and found strong divergences between the two taxa. ...
Background
One of the biggest challenges in avian taxonomy is the delimitation of allopatric species because their reproductive incompatibility cannot be directly studied in the wild. Instead, reproductive incompatibility has to be inferred from multiple, divergent character sets that indicate a low likelihood of allopatric populations amalgamating upon secondary contact. A set of quantitative criteria for species delimitation has been developed for avian taxonomy. ResultsHere, we report a broad multi-trait comparison of the two insular subspecies of the Blue Chaffinch Fringilla teydea, endemic to the pine forests of Tenerife (ssp. teydea) and Gran Canaria (ssp. polatzeki) in the Canary Islands. We found that the two taxa were reciprocally monophyletic in their whole mitogenomes and two Z chromosome introns. The genetic distance in mitogenomes indicates around 1 Mya of allopatric evolution. There were diagnostic differences in body morphometrics, song and plumage reflectance spectra, whose combined divergence score (=11) exceeds the threshold level (=7) set for species delimitation by Tobias et al. (Ibis 152:724–746, 2010). Moreover, we found a marked divergence in sperm lengths with little range overlap. Relatively long sperm with low intra- and intermale CV compared to other passerines suggest a mating system with high levels of sperm competition (extrapair paternity) in these taxa. Conclusion
The large and diagnostic divergences in multiple functional traits qualify for species rank, i.e., Tenerife Blue Chaffinch (Fringilla teydea) and Gran Canaria Blue Chaffinch (Fringilla polatzeki). We encourage a wider use of sperm traits in avian taxonomy because sperm divergences might signal reproductive incompatibility at the postcopulatory prezygotic stage, especially in species with sperm competition.
... The analysis of evolutionary patterns and taxonomic status of taxa underrepresented in biological collections is often unclear (Sangster et al. 2016) because variation may be underestimated in small series. The Mexican D. s. sheffleri is represented by less than eight specimens, so our conclusions are based on a large proportion of the avail-able individuals. ...
... The Mexican D. s. sheffleri is represented by less than eight specimens, so our conclusions are based on a large proportion of the avail-able individuals. In such circumstances, molecular information has proven to be a useful tool to understand the status and phylogenetic relationships of these poorly known taxa Sangster et al. 2016). ...
Humid tropical forests in Mesoamerica are distributed along the Atlantic slope and, in scattered locations, along the Mexican Pacific slope. These poorly explored Mexican forests include microendemic bird species. Two species in the genus Dendrocolaptes occur in lowland and foothill humid tropical forests of Mesoamerica. One of these, D. sanctithomae, is comprised of four subspecies, of which the two that occur in Mexico, D. s. sanctithomae and D. s. sheffleri, are distinctly different morphologically, and the latter is a poorly known microendemic taxon of the Mexican Pacific humid tropical forest in the Sierra Madre del Sur. We used both nuclear (nDNA) and mitochondrial DNA (mtDNA) to evaluate the genetic variation of D. sanctithomae in Mexico, and complemented this with a quantitative analysis of phenotypic traits. We also conducted analyses of environmental niche models to test the hypothesis of niche differentiation of D. s. sheffleri from other taxa of D. sanctithomae. Our phylogenetic reconstructions of mtDNA consistently recovered D. s. sheffleri and D. s. sanctithomae as reciprocally monophyletic, while they shared alleles of nDNA. These mtDNA differences are comparable with differences reported between other Dendrocolaptes sister-taxa pairs. Our analysis of phenotypic traits also indicated that the taxa differ in measurements of hallux and feather barring. In contrast, niche differentiation tests suggest that the niches of both taxa are more similar than expected by chance. Our evidence leads us to propose species status for D. sheffleri. This is an additional example of recent speciation in Mexico that indicates active and peripatric evolutionary differentiation in the northern Neotropics.
... Taxa (Manegold, 2012). # Recently split taxa (Sangster et al., 2016). ◊ Taxa proposed to be split (this study). ...
... See Illera et al. (2012) (Manegold, 2012). # Taxones nuevos (Sangster et al., 2016). ◊ Taxones propuestos para ser considerados como especies verdaderas (este estudio). ...
... In this context, it happens that species that were described before the application of molecular tools frequently need to be divided into several new taxonomic units. Examples are widespread in animals and plants; a large number of the species described in Europe in the past decade are the product of splitting larger species complexes that appeared arguably homogeneous (Recuero et al. 2012, Ghielmi et al. 2016, Sangster et al. 2016, Criado Ruiz et al. 2021. In smaller organisms with fewer morphological features, such as protists, this case should be, at least, equally widespread (e.g. ...
Accurate species delimitation based on an integrative approach is indispensable for biodiversity evaluation. Accordingly, species that were formerly only described morphologically often need to be split into several evolutionary independent units. However, taxonomic actions often lag behind, even when the required data are already available. As a result, invalid species names are carried over the years, with negative implications on ecology, biogeography, and conservation; we designate these entities as ‘shadow species’. This is particularly common in protists, due to the lack of specialized taxonomists and the difficulties of working with microscopic organisms. Here, we resolve the case of the testate amoeba shadow species Cyphoderia ampulla (Rhizaria: Cercozoa: Euglyphida: Cyphoderiidae), a known polyphyletic taxon. Purposely, we integrated the current ecological, genetic, and morphological data on the family Cyphoderiidae with its described evolutionary history. Subsequently, we took the required taxonomic actions to resolve the taxonomy of the family, erecting four new genera (Psammoderia gen nov., Knarr gen. nov., Ichthyosquama gen. nov., and Oleiformis gen. nov.), emending Cyphoderia and describing four new species (Ichthyosquama sanabriensis sp. nov., Ichthyosquama catoirensis sp. nov., Ichthyosquama loricaria sp. nov., and Oleiformis carmelae sp. nov.). Finally, we discuss the extension and relevance of the ‘shadow species’ issue in eukaryotic taxa, and differentiate it from species complex concept.
... Erithacus marionae is the second endemic taxon on Gran Canaria to be raised to species rank. Gran Canaria Blue Chaffinch Fringilla polatzeki is currently treated as a species based on differences from Tenerife Blue Chaffinch F. teydea in plumage, songs, calls, sperm morphology and mitochondrial and nuclear DNA sequences (Lifjeld et al., 2016;Pestano et al., 2000;Sangster et al., 2016). Two other endemic taxa are also phylogenetically distinct but have not been shown to differ diagnosably in song from their closest relatives. ...
The European Robin Erithacus rubecula is currently treated as a single species with eight subspecies. A previous molecular study and new molecular, morphometric and bioacoustic data reported here strongly support the recognition of three species in this complex: E. rubecula (Europe, North Africa and Macaronesia except the central Canary Islands), E. superbus (Tenerife) and a recently described subspecies on Gran Canaria which we raise to species rank as E. marionae. The taxa on Tenerife and Gran Canaria have previously been lumped as a single taxon but differ from each other and from E. rubecula in territorial songs, tic calls, seep calls and wing length. All three species are characterised by moderate to high levels of interspecific mitochondrial DNA sequence divergence (mean 4.2–4.8%). Phylogenetic analysis indicates that E. marionae is sister to E. superbus + E. rubecula. Recognition of Gran Canaria and Tenerife Robins as separate species adds two single-island endemics to the Canary Islands avifauna.
... The Gran Canaria Blue Chaffinch Fringilla polatzeki is an endemic taxon of the Canary Islands, recently separated from its former sister species, the Tenerife Blue Chaffinch (Fringilla teydea; Lifjeld et al. 2016, Sangster et al. 2016. While the species from Tenerife is classified on the IUCN Red List as 'Near Threatened' (BirdLife International 2017a), the one from Gran Canaria is assessed as 'Endangered' (BirdLife International 2017b). ...
The Gran Canaria Blue Chaffinch Fringilla polatzeki is a threatened, endemic, forest‐dwelling bird species of the Canary Islands, whose core population at the end of the 20th century was restricted to the pine forests of Inagua Nature Reserve (38 km ² ). A translocation programme released birds from a breeding centre into the nearby (<3 km) pine forests of La Cumbre in the years following 2010. From 2015 to 2019 the La Cumbre population was reinforced by translocation of wild juveniles from the source population of Inagua. We estimate the population size, the spatial variation of abundance, and recent temporal changes in density of the species in Inagua and La Cumbre by means of line transects, distance sampling, and habitat suitability modelling using random forests. The average density of the Blue Chaffinch in Inagua Nature Reserve was 10.2 birds/km ² in spring 2019, with a population estimated at 362 birds (95% CI: 257–489). The most important variables affecting the distribution of the Blue Chaffinch in Inagua were the amount of precipitation during the summer (July–September), the solar radiation in June, and the northern position in the reserve, highlighting the importance of abiotic factors related to thermal and hydric stress during the breeding season. The density was considerably lower in the translocated population inhabiting 21 km ² of pine forests in La Cumbre (3.3 birds/km ² ), with an estimate of 68 Blue Chaffinches (35–141) breeding freely in the wild. The translocation programme successfully contributed to the establishment of a second viable nucleus, accounting for 16% of the total population within a time span of 10 years. This result reinforces the role of translocations in preventing extinctions of endangered species with very low population sizes restricted to only one isolated area.
... En Baleares, así, ha habido varios estudios sobre currucas, como la balear, sarda y subalpina (esta última antes considerada una subespecie de la curruca carrasqueña) [291,292] , papamoscas gris [293][294][295] o piquituerto común [239] . En el caso de Canarias, también hay numerosos trabajos referentes a sus especies endémicas o de distribución muy restringida, especialmente paseriformes: bisbita caminero [296] , tarabilla canaria [257] , mosquitero canario [297,298] , pinzón azul de Tenerife y pinzón azul de Gran Canaria [255,[299][300][301][302][303] , herrerillo canario [304,305] y el reciente estudio que propone la separación del pinzón canario del pinzón vulgar [306] . En el ámbito peninsular, una de las especies que más trabajos ha generado en los últimos años a nivel taxonómico y también a efectos de identificación es el mosquitero ibérico [206,254,[307][308][309][310] , considerada subespecie del mosquitero común hasta el año 2000 [311] . ...
... We concur with previous studies on this system (Marshall and Baker, 1999;Suárez et al., 2009, Rodrigues et al., 2014, Illera et al., 2016, Perktaş et al., 2017, Clement, 2018 Recognizing the new proposed species should be consistent with most species concepts that take into account evidence for independent evolving lineages and phenotypic differentiation (De Queiroz, 2007, Sangster, 2013, Gill, 2014. The taxonomic upgrade from subspecies to species is likely to have important conservation implications, as species tend to receive more conservation attention than subspecies (Winker, 2010;Sangster et al. 2016). Specifically, species status would guarantee that the conservation status of each chaffinch taxon is evaluated by the International Union for Conservation of Nature (IUCN), taking into account their distribution area and population size independently, making the difference especially for the more restricted insular populations (Martín 2009). ...
Oceanic archipelagos are excellent systems for studying speciation, yet inference of evolutionary process requires that the colonization history of island organisms be known with accuracy. Here, we used phylogenomics and patterns of genetic diversity to infer the sequence and timing of colonization of Macaronesia by mainland common chaffinches (Fringilla coelebs), and assessed whether colonization of the different archipelagos has resulted in a species-level radiation. To reconstruct the evolutionary history of the complex we generated a molecular phylogeny based on genome-wide SNP loci obtained from genotyping-by-sequencing, we ran ancestral range biogeographic analyses, and assessed fine-scale genetic structure between and within archipelagos using admixture analysis. To test for a species-level radiation, we applied a probabilistic tree-based species delimitation method (mPTP) and an integrative taxonomy approach including phenotypic differences. Results revealed a circuitous colonization pathway in Macaronesia, from the mainland to the Azores, followed by Madeira, and finally the Canary Islands. The Azores showed surprisingly high genetic diversity, similar to that found on the mainland, and the other archipelagos showed the expected sequential loss of genetic diversity. Species delimitation methods supported the existence of several species within the complex. We conclude that the common chaffinch underwent a rapid radiation across Macaronesia that was driven by the sequential colonization of the different archipelagos, resulting in phenotypically and genetically distinct, independent evolutionary lineages. We recommend a taxonomic revision of the complex that takes into account its genetic and phenotypic diversity.
... Important and informative as such a perspective is, it cannot be the whole story. 'Integrative taxonomy', the use of as many lines of evidence as possible in making decisions on species limits, has become something of a mantra in modern systematics (Dayrat 2005, Padial et al. 2010, Yeates et al. 2011, Sangster et al. 2016, Conix 2018. Many researchers who make extensive use of molecular methods recognize the benefits of an integrative approach: 'levels of sequence divergence alone', observed Shultz and Burns (2013), 'should not be used for describing species', and Drovetski et al. (2018) cautioned 'against the out-ofhand dismissal of traditional taxonomy in cases when mtDNA appears to contradict it'. ...
Taxonomists now usually recognize 10 extant species of oystercatcher Haematopus, plus the extinct Canary Islands Oystercatcher Haematopus meadewaldoi. Molecular data, however, have recently been used to propose meadewaldoi as either a morph or a subspecies of Eurasian Oystercatcher Haematopus ostralegus. The morph option is untenable for multiple reasons, but we also find subspecies rank problematic given (a) the all-black plumage and (based on our examination of all known specimens) significantly larger bill of the Canarian taxon, and (b) the global acceptance of species rank for Variable Haematopus unicolor and South Island Oystercatchers Haematopus finschi, which are genetically as close as and morphologically closer than meadewaldoi is to ostralegus but which despite their sympatry rarely inter-breed. This case illustrates the difficulties of assessing species rank in shallowly divergent, morphologically conservative groups of birds such as the oystercatchers.
... Species like the Common Chaffinch(Rodrigues et al. 2014b), Common Blackbird(Rodrigues et al. 2016), European Robin (Dietzen et al. 2003Rodrigues et al. 2013) and the Goldcrest(Rodrigues et al. 2014a) show island or archipelago unique haplotypes across Macaronesia, which are not shared with the continental conspecific population. Furthermore, due to recent molecular studies, island taxa which were previously considered subspecies have been elevated to species level: the Cape Verde Shearwater(Gómez-Díaz et al. 2006) and both the Tenerife and Gran Canaria Blue Chaffinches(Lifjeld et al. 2016;Sangster et al. 2016). Taking into consideration that the current taxonomic trend is to split species which have geographically distinct lineages, we expect to reach an increased number of approximately 18 thousand bird species(Barrowclough et al. 2016), from the 11 thousand currently recognized. ...
A plethora of studies have offered crucial insights in the phylogeographic status of Western Palearctic bird species. However, an overview integrating all this information and analyzing the combined results is still missing. In this study, we compiled all published peer-reviewed and grey literature available on the phylogeography of Western Palearctic bird species. Our literature review indicates a total number of 198 studies, with the overwhelming majority published as journal articles (n = 186). In total, these literature items offer information on 145 bird species. 85 of these species are characterized by low genetic differentiation, 46 species indicate genetic variation but no geographic structuring i.e. panmixia, while 14 species show geographically distinct lineages and haplotypes. Majority of bird species inhabiting the Western Palearctic display genetic admixture. The glaciation cycles in the past few million years were pivotal factors in shaping this situation: during warm periods many species expanded their distribution range to the north over wide areas of Eurasia; whereas, during ice ages most areas were no longer suitable and species retreated to refugia, where lineages mixed.
Supplementary information:
The online version contains supplementary material available at 10.1007/s10336-021-01893-x.
... However, we acknowledge that the Calandrella larks are poorly differentiated morphometrically (Figure 1), and we stress that other types of data, in combination with dense taxon sampling, are necessary for confident taxonomic revisions. Here, we lack substantive data from nuclear DNA markers, vocalizations, other behaviours, ecology etc., to take the fully integrative taxonomic approach [108][109][110] that is becoming more common, e.g., [111][112][113][114][115][116][117][118][119][120] and which we argue should be the gold standard. Yet, while we emphasize that taxonomic decisions should never rest on mitochondrial trees alone [101,106], we here make use of available morphometric data and evaluate a recent tool for single-locus molecular species delimitation [54], which has been used to propose avian taxonomic revisions based solely on mitochondrial data [121] or in combination with morphometry [65]. ...
Larks constitute an avian family of exceptional cryptic diversity and striking examples of convergent evolution. Therefore, traditional morphology-based taxonomy has recurrently failed to reflect evolutionary relationships. While taxonomy ideally should integrate morphology, vocalizations, behaviour, ecology, and genetics, this can be challenging for groups that span several continents including areas that are difficult to access. Here, we combine morphometrics and mitochondrial DNA to evaluate the taxonomy of Calandrella larks, with particular focus on the African C. cinerea and the Asian C. acutirostris complexes. We describe a new range-restricted West African taxon, Calandrella cinerea rufipecta ssp. nov. (type locality: Jos, Plateau State, Nigeria), with an isolated relic population 3000 km from its closest relative in the Rift Valley. We performed molecular species delimitation, employing coalescence-based multi-rate Poisson Tree Processes (mPTP) on cytochrome b sequences across 52 currently recognized lark species, including multiple taxa currently treated as subspecies. Three species-level splits were inferred within the genus Calandrella and another 13 across other genera, primarily among fragmented sub-Saharan taxa and taxa distributed from Northwest Africa to Arabia or East Africa. Previously unknown divergences date back as far as to the Miocene, indicating the presence of currently unrecognized species. However, we stress that taxonomic decisions should not be based on single datasets, such as mitochondrial DNA, although analyses of mitochondrial DNA can be a good indicator of taxa in need of further integrative taxonomic assessment.
... Until 2016, Blue Chaffinch was classified as a "nearthreatened" species, because the range size and population numbers of the Tenerife taxon (now F. teydea) overwhelmed those of the much rarer Gran Canaria taxon (now F. polatzeki). After two studies showed that the two taxa differed in plumage, morphometrics, vocalizations, response to playback, sperm morphology, and nuclear DNA (Lifjeld et al. 2016;Sangster et al. 2016b), F. polatzeki was classified as an endangered species. Photographs courtesy of Jolanda A. Luksenburg (upper) and Ian Merrill (lower) ...
Species are the basic currency in biodiversity studies, but what constitutes a species has long been controversial. Since the late 1990s, debates over species have shifted from theoretical questions (e.g., What is a species? Which species concept is best?) to empirical questions (How can we document species both efficiently and accurately?). A growing number of taxonomists agree that species can be discovered and documented in many different ways, preferably by employing and combining multiple types of evidence (“integrative taxonomy”). This chapter examines how and why avian taxonomy has become integrative, how species hypotheses are documented and falsified, and how the growth of taxonomic knowledge provides new and valuable insights into the speciation process, biogeography, and conservation biology.
... Such findings supported the description of a new subspecies (R. r. ellenthalerae), occurring in the western islands of La Palma and El Hierro, meanwhile the former subspecies (R. regulus teneriffae) inhabits the islands of Tenerife and La Gomera. In addition, similar scenarios have been documented to occur with the robin Erithacus rubecula, and the blue chaffinch Fringilla teydea in the Canary Islands (Dietzen et al. 2003, Lifjeld et al. 2016, Sangster et al. 2016. Overall, all these results show an interesting pattern at species level of independent but repeated bouts of colonisation from the continental areas to the Canaries, with subsequent processes of genetic isolation (and sometimes of extinction) producing new taxa over time. ...
The common chaffinch (Fringilla coelebs) is the extant avian species with the highest level of differentiation across North Atlantic archipelagos. Such a degree of diversification has been traditionally recognised within the subspecies category, with one endemic subspecies occurring in Azores (F. c. moreletti), one in Madeira (F. c. maderensis), and three in the Canary Islands (F. c. canariensis, F. c. palmae and F. c. ombriosa). Recent genetic, acoustic, and sperm morphology studies informed us about the significant differentiation of the Gran Canaria population, which is traditionally included within F. c. canariensis subspecies. The goal of this study is to examine the similarity of the Canarian chaffinches, with the objective of determining if the Gran Canaria chaffinches represent an isolated and distinct population. In order to achieve this aim, we used a double approach: (1) we analysed new morphological and genetic data from the Canary Islands, and (2) we reviewed and synthesised the vast acoustic, morphological and genetic information available for these taxa in Macaronesia, with special emphasis on the Canary Islands. Genetic, acoustic, and sperm morphological data, and to a lesser extent phenotypic data, strongly support the existence of a cryptic taxon in Gran Canaria. Moreover, our findings also reveal an incipient speciation process on going in the Canary Islands, mostly driven by genetic differentiation. Overall, our synthesis suggests that individuals occurring in Gran Canaria should be considered as a novel taxon that we formally described as Fringilla coelebs bakeri ssp. nov.
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... Die Gesamtschau der Merkmale veranlassen Sangster et al. (2016), beiden Populationen Artrang einzuräumen, F. teydea s. str. und F. polatzeki E. Hartert, 1905 Die Ergebnisse sind insofern alarmierend, als die Population von polatzeki heute sehr klein ist und auf ein Areal von 25 km 2 beschränkt ist und auch dort infolge von Biotopveränderungen nur noch lokal vorkommt, im Jahr 2008 nur noch 122 Individuen. ...
This report is the twelfth of a series and presents the results of a comprehensive literature screening in search for new bird taxa described in 2016, namely new genera, species and subspecies worldwide. We tracked names of 16 new genera, six species and seven subspecies new to science, which were correctly described according to the International Code of Zoological Nomenclature. The new genera are within Psittaculidae, Thraupidae and Muscicapidae. The new species refer to Turdidae, Muscicapidae and Thraupidae; all are Passeriformes. In 2016, one species of Thraupidae was described twice by different authors. New subspecies were named within Rallidae (1), Psittaculidae (1), Acrocephalidae (1), Muscicapidae (2), Nectariniidae (1), Leiotrichidae (1; in addition to the 2015 report) und Pellorneidae (1; addition to 2015) und Maluridae (1). In several cases, the populations in question now considered to represent a new species were known since long. But only substantial studies of type specimens of related species, songs, genetics and/or ecology led to description of new formerly unrecognized species. The descriptions of most new taxa concern the Neotropics (eleven new genera, two new species, one new subspecies), Indo-Malaya (three new genera, one new species, two new subspecies, the latter as addenda to 2015) and the Afrotropics (2 new genera, 2 new species, 1 new subspecies). The distributional areas of new species often are minute, consequently also the size of the populations concerned. Due to their limited ranges, species new to science are often already endangered when detected or newly defined. In the North African/European fauna elevation to species rank is most prominent in populations of the finch genus Fringilla from the Canary Islands and of the flycatcher genus Muscicapa from Corsica in this report. In a sequence by family/genus/species/subspecies the newly described taxa have the following origins: Palaearctic (-/-/-/1), Neotropics (-/11/2/1), Indo-Malaya (-/3/1/2), Afrotropics (-/2/3/1) and Australian-Papua (-/-/-/2). Multiple splits of widely distributed species refer to Palaearctic and Southeast Asian flycatchers (Muscicapa, Calliope, Cyornis), an Southeast Asian bulbul (Pycnonotus) and an Indo-Malayan thrush (Zoothera). We suggest possible flaws in new descriptions and certain splits, regardless of the species concept addressed. In this respect, the Tobias concept for species delimitation is mentioned. However, this general report addresses documentation of new taxa, and is not a critical review of recent changes in bird taxonomy and bird descriptions.
... Die Gesamtschau der Merkmale veranlassen Sangster et al. (2016), beiden Populationen Artrang einzuräumen, F. teydea s. str. und F. polatzeki E. Hartert, 1905 Die Ergebnisse sind insofern alarmierend, als die Population von polatzeki heute sehr klein ist und auf ein Areal von 25 km 2 beschränkt ist und auch dort infolge von Biotopveränderungen nur noch lokal vorkommt, im Jahr 2008 nur noch 122 Individuen. ...
This report is the twelfth of a series and presents the results of a comprehensive literature screening in search for new bird taxa
described in 2016, namely new genera, species and subspecies worldwide. We tracked names of 16 new genera, six species and
seven subspecies new to science, which were correctly described according to the International Code of Zoological Nomenclature.
The new genera are within Psittaculidae, Thraupidae and Muscicapidae. The new species refer to Turdidae, Muscicapidae
and Thraupidae; all are Passeriformes. In 2016, one species of Thraupidae was described twice by different authors.
New subspecies were named within Rallidae (1), Psittaculidae (1), Acrocephalidae (1), Muscicapidae (2), Nectariniidae (1),
Leiotrichidae (1; in addition to the 2015 report) und Pellorneidae (1; addition to 2015) und Maluridae (1). In several cases,
the populations in question now considered to represent a new species were known since long. But only substantial studies of
type specimens of related species, songs, genetics and/or ecology led to description of new formerly unrecognized species. The
descriptions of most new taxa concern the Neotropics (eleven new genera, two new species, one new subspecies), Indo-Malaya
(three new genera, one new species, two new subspecies, the latter as addenda to 2015) and the Afrotropics (2 new genera,
2 new species, 1 new subspecies). The distributional areas of new species often are minute, consequently also the size of the
populations concerned. Due to their limited ranges, species new to science are often already endangered when detected or
newly defined. In the North African/European fauna elevation to species rank is most prominent in populations of the finch
genus Fringilla from the Canary Islands and of the flycatcher genus Muscicapa from Corsica in this report.
In a sequence by family/genus/species/subspecies the newly described taxa have the following origins: Palaearctic (-/-/-/1),
Neotropics (-/11/2/1), Indo-Malaya (-/3/1/2), Afrotropics (-/2/3/1) and Australian-Papua (-/-/-/2). Multiple splits of widely
distributed species refer to Palaearctic and Southeast Asian flycatchers (Muscicapa, Calliope, Cyornis), an Southeast Asian
bulbul (Pycnonotus) and an Indo-Malayan thrush (Zoothera). We suggest possible flaws in new descriptions and certain splits,
regardless of the species concept addressed. In this respect, the Tobias concept for species delimitation is mentioned. However,
this general report addresses documentation of new taxa, and is not a critical review of recent changes in bird taxonomy
and bird descriptions
... The level of endemism in this region is high; about 50% of the terrestrial invertebrates are endemic (Juan et al. 2000). Several endemic species and subspecies of birds are presently recognized on the islands and many previously recognized subspecies have recently been upgraded to species level due to their genetic, morphological and acoustic distinctiveness (Helbig et al. 1996, Dietzen et al. 2003, Kvist et al. 2005, Päckert et al. 2006, Illera et al. 2007, Barrientos et al. 2009, González et al. 2009, Sangster et al. 2016. ...
We studied genetic diversity and differentiation in island and nearby continental populations of a bird of prey, the common kestrel Falco tinnunculus. We sampled 11 islands in the eastern North Atlantic (Madeira and Canary Islands) and western Mediterranean archipelagos (Balearic Islands) and two continental sites (Iberian Peninsula and north-west Africa). We used microsatellite (9 loci, n = 470) and mitochondrial data (cytochrome b sequences, n = 244) and applied Bayesian clustering, multivariate frequentist statistics and coalescence analyses. We revealed two main genetic clusters; the first including populations from the Atlantic islands and the second comprising populations from the Balearic Islands, the Iberian Peninsula and north-west Africa, with additional finer scale structuring. The highest levels of genetic variation were found in Iberian Peninsula, north-west Africa and Lanzarote island. The lowest diversity was detected in La Palma, the most north-westerly island of the Canary Islands. The lowest levels of haplotype and nucleotide diversity were observed in Madeira and Gran Canaria and the highest in Menorca. We found evidence of decreasing genetic diversity with increasing severity of a past population bottleneck and, to some extent, with increasing geographic distance from the continent. The two Canary Island subspecies, F. t. dacotiae and F. t. canariensis, have diverged from each other to some degree and from the continental and Balearic conspecifics of F. t. tinnunculus. Samples from Madeira, representing F. t. canariensis, indicated affinities to both Canary Islands and Mediterranean clusters, depending on the marker and methods applied. Our results suggest stronger gene flow between close islands than between distant islands. The genetic structure of an endemic subspecies F. t. dacotiae in the easternmost Canary Islands is suggested to have an origin in a past hybridization between continental F. t. tinnunculus and insular F. t. canariensis.
... The Gran Canaria blue chaffinch (Fringilla polatzeki, Canary Islands) is a rare, threatened species that occupies an island-habitat within the island of Gran Canaria (Martín and Lorenzo, 2001 for the probable status of the species since the beginning of the 20 th century). Currently split from F. teydea according to genetic, morphological and behavioural data (Pestano et al., 2000;Lifjeld et al., 2016;Sangster et al., 2016), it is mainly restricted to the Strict Nature Reserve of Inagua-Ojeda-Pajonales (Inagua, hereafter; 39.2 km 2 ; Moreno and Rodríguez, 2007), although a few pairs have recently established elsewhere as a result of a translocation program (Delgado et al., 2016). The Gran Canaria blue chaffinch is a habitat specialist of the mature Canarian pine forests (Pinus canariensis), likely as a consequence of past competition with other Fringilla species and niche displacement (Illera et al., 2016). ...
Evidence regarding population trends of endangered species in special protection areas and their recovery ability from catastrophic disturbances is scarce. We assessed the population trend of the Gran Canaria blue chaffinch (Fringilla polatzeki), a habitat specialist endemic to the pine forest of Inagua in the Canary Islands, following a devastating wildfire in July 2007. Using a standardized census program that accounts for detectability, we have monitored the population trend of the species since Inagua was declared a Strict Nature Reserve in 1994. The breeding population density of the blue chaffinch remained stable in Inagua from the beginning of the monitoring program in 1994 until the year before the wildfire. However, in spring 2008, the population density decreased by half with respect to density in the preceding years. Since 2008, the population has gradually increased, reaching its highest recorded density in 2016 (15.8 birds/km2).This represents an average annual increase of 23.7%, indicating impressive resilience to catastrophic events. The creation of Inagua as a strict nature reserve did not therefore increase the global population or protect the blue chaffinch against a demographic crisis but probably prevented a deepening of the demographic crisis or further declines. Except for the two years immediately after the severe wildfire of 2007, the population density of the blue chaffinch in Inagua has remained relatively stable at around 9–16 birds/km2, the lowest recorded abundance for a small woodland passerine in the Western Palearctic.
... The blue chaffinch of the Gran Canaria island (Fringilla polatzeki, Canary Islands) is a recently established species on the basis of genetic, morphological and behavioural data (Pestano et al., 2000;Lifjeld et al., 2016;Sangster et al., 2016), mainly restricted to the Strict Nature Reserve of Inagua-Ojeda-Pajonales (Inagua, hereafter; 39.2 km 2 ; Moreno & Rodríguez, 2007). It inhabits mature pine forests, where nests are placed in tall trees; breeding success is very low for a Fringillidae, with only ca. ...
Background
Understanding constraints to the distribution of threatened species may help to ascertain whether there are other suitable sectors for reducing the risks associated with species that are recorded in only one protected locality, and to inform about the suitability of other areas for reintroduction or translocation programs.
Methods
We studied the Gran Canaria blue chaffinch ( Fringilla polatzeki ), a habitat specialist endemic of the Canary Islands restricted to the pine forest of Inagua, the only area where the species has been naturally present as a regular breeder in the last 25 years. A suitability distribution model using occurrences with demographic relevance (i.e., nest locations of successful breeding attempts analysed using boosted classification trees) was built considering orographic, climatic and habitat structure predictors. By means of a standardized survey program we monitored the yearly abundance of the species in 100 sectors since the declaration of Inagua as a Strict Nature Reserve in 1994.
Results
The variables with the highest relative importance in blue chaffinch habitat preferences were pine height, tree cover, altitude, and rainfall during the driest trimester (July–September). The observed local abundance of the blue chaffinch in Inagua (survey data) was significantly correlated with habitat suitability derived from modelling the location of successful nesting attempts (using linear and quantile regressions). The outcomes of the habitat suitability model were used to quantify the suitability of other natural, historic, pine forests of Gran Canaria. Tamadaba is the forest with most suitable woodland patches for the species. We estimated a population size of 195–430 blue chaffinches in Inagua since 2011 (95% CI), the smallest population size of a woodland passerine in the Western Palearctic.
Discussion
Habitat suitability obtained from modelling the location of successful breeding attempts is a good surrogate of the observed local abundance during the reproductive season. The outcomes of these models can be used for the identification of potential areas for the reintroduction of the species in other suitable pine forests and to inform forest management practices.
... Even though plumage and vocal traits are important pre-mating barriers in birds, analyses of differences in plumage and vocalisations frequently assume that the traits measured are the same that birds use in mate recognition, but this inference might not be valid for all cases (Pegan et al. 2015). Behavioural responses of birds to these differences are most relevant, and playback experiments provide useful (but underused) tools to evaluate the role of vocal traits as barriers to gene flow (Lanyon 1963;Ábalos and Areta 2009;Areta and Pearman 2013;Burbidge et al. 2015;Sangster et al. 2016). ...
Species limits in the Poospiza nigrorufa/whitii complex are not well understood. Three taxa formally
described as species are now considered as subspecies (nigrorufa, whitii and wagneri) of a widespread
species. The heavier nigrorufa has longer bill, tarsus and wings, is slightly dimorphic with
males showing tawny rufous throat, breast and flanks, and brownish grey upper parts with a slate
tinge, while females differ in the orange tinge of ventral parts and in the more olivaceous upper
parts; inhabits shrubby open areas and wetlands with reeds and bulrushes in eastern southern
South America, and gives a simple three-note pattern that repeats to form the song and diagnostic
calls. The lighter whitii (including wagneri as a synonym) has a shorter bill, tarsus and wings, is
highly dimorphic with males having dark chestnut throat, breast and flanks, and slate upper parts,
while females exhibit tawny pale-orange ventral parts, and olivaceous light-brown upper parts;
inhabits closed to semi-closed xerophytic to semi-humid scrub and woodlands in the western
highlands, and has a complex multi-noted song and diagnostic calls. Reciprocal playback experiments
indicate that both taxa are able to discriminate each other’s songs. Locality data and
ecological niche modelling show that nigrorufa and whitii are narrowly allopatric or parapatric in
central Córdoba province (Argentina).This integrative evidence and the ~2.5% divergence in
mtDNA show that nigrorufa and whitii possess different Specific Mate Recognition Systems and
should be afforded full species status under any species concept.
... According to some authors (e.g., Illera et al. 2016), the Common Chaffinches of each archipelago are better treated as full species (i.e., F. moreletti, F. maderensis and F. canariensis). Two of these birds, the Blue Chaffinch of Gran Canaria and the Priolo, are threatened species, the former being the rarest songbird in Europe (Sangster et al. 2015;BirdLife International 2013). In addition, the three extinct known passerines of the Canary Islands were granivorous, and in Madeira the extinction of at least two species (Coccothraustes coccothraustes and one or several species related probably to Acanthis) has been reported (Pieper 1985). ...
A new species of extinct bullfinch, Pyrrhula crassa n. sp., is described from bones found in Furna do Calcinhas, a small cave situated at Caldeira, a volcano located in the southeastern portion of the Graciosa Island (Azores archipelago, North Atlantic Ocean). It is the first extinct passerine bird to be described from this archipelago. Both skull and post-cranial bones are larger in the new species than in its relatives, the Eurasian Bullfinch (P. pyrrhula) and the Azores Bullfinch or “Priolo” from São Miguel Island (P. murina), the new species being the largest known in this genus. The morphology of its humerus and the estimated wing length and surface area seem to indicate a flying ability similar to that of the extant P. murina. The possible sources of colonization of the genus into Azores, causes and chronology of extinction of the new species are discussed
... These limitations can increase ambiguity in specimen identifications from DNA barcodes and thereby complicate conservation efforts. However, there are numerous examples in the literature where there exists close correspondence between species recognized through traditional means and DNA barcode clusters, making barcoding useful for biodiversity surveys (Sangster et al. 2015;Wijayathilaka et al. 2016;Hiebert and Maslakova 2015;etc.). ...
Biological diversity is depleting at an alarming rate. Additionally, a vast amount of biodiversity still remains undiscovered. Taxonomy has been serving the purpose of describing, naming, and classifying species for more than 250 years. DNA taxonomy and barcoding have accelerated the rate of this process, thereby providing a tool for conservation practice. DNA barcoding and traditional taxonomy have their own inherent merits and demerits. The synergistic use of both methods, in the form of integrative taxonomy, has the potential to contribute to biodiversity conservation in a pragmatic timeframe and overcome their individual drawbacks. In this review, we discuss the basics of both these methods of biological identification- traditional taxonomy and DNA barcoding, the technical advances in integrative taxonomy, and future trends. We also present a comprehensive compilation of published examples of integrative taxonomy that refer to nine topics within biodiversity conservation. Morphological and molecular species limits were observed to be congruent in ~41% of the 58 source studies. The majority of the studies highlighted the description of cryptic diversity through the use of molecular data, whereas research areas like endemism, biological invasion, and threatened species were less discussed in the literature.
... As pointed out by Illera et al. (2016), the taxonomic status of all endemic subspecies recognised on the Canary Islands should be revised using an integrative taxonomic approach, as it is likely that several of them could be raised to full species status (see e.g. Sangster et al. 2016). Given the genetic distinctiveness of Canary Stonecurlews recorded in our analysis, it seems necessary to plan future investigation on morphological and behavioural characters and to sample population from nearby areas (e.g. ...
Full text: http://rdcu.be/mE9F
The Stone-curlew Burhinus oedicnemus, a steppe bird species, is mainly distributed in the Mediterranean and Macaronesian regions, which are considered hotspots of biodiversity with priority for animal and plant species richness conservation. In this study, we investigated the genetic diversity of the Stone-curlew in the Mediterranean basin and in the Canary Islands by applying a multilocus approach. We analysed mitochondrial and nuclear markers in order to evaluate the genetic structure and the congruence between morphological subspecies and geographic samples. We found a significant level of genetic differentiation between Mediterranean and Canary Island populations with all markers. Both in the Mediterranean basin and in the Canary Islands, we found a significant level of genetic diversity with nuclear markers only. We identified seven population groups, including insular populations. The four subspecies described for the Western Palaearctic were confirmed with some changes in distribution range. In spite of habitat fragmentation and negative population trend, the Stone-curlew showed a significant level of genetic diversity and gene flow among continental populations. However, islands constitute important reservoirs of genetic diversity and a potential for the evolution of the species.
... The Blue Chaffinch Fringilla teydea is a specialist passerine of thick upland Canary Island Pine Pinus canariensis forest on Tenerife and Gran Canaria (Canary Islands). One subspecies exists in each of these islands, although some authors have recently suggested that these represent two distinct species: the Gran Canaria Blue Chaffinch Fringilla polatzeki and the Tenerife Blue Chaffinch F. teydea (Sangster et al. 2015, Lifjeld et al. 2016. The reclassification of Gran Canaria Blue Chaffinch as a single-island endemic species would make it Europe's rarest passerine species. ...
Capsule: The endangered Gran Canaria Blue Chaffinch Fringilla teydea polatzeki has been bred in captivity with the aim of reinforcing wild populations. We released and monitored 26 males and 15 females between 2010 and 2012. Survival and reproductive success were similar between the reinforced population and a stable reference population, suggesting that the process could be useful for the conservation of the species.
... We suggest that the number of endemic Canarian species is underestimated and that a number of known endemic subspecies could be raised to full species status (e.g. Pratt, 2010;Sangster et al., 2016). There are currently more than 30 endemic subspecies described from the Canary Islands (Supplementary Electronic Material), some of which have been intensively studied since the 1990s (Martín and Lorenzo, 2001;Illera et al., 2012). ...
Oceanic islands are excellent systems for allowing biologists to test evolutionary hypotheses due to their relative simplicity of habitats, naturally replicated study design and high levels of endemic taxa with conspicuous variation in form, colour and behaviour. Over the last two decades the Canary Islands archipelago has proved an ideal system for evolutionary biologists who seek to unravel how biodiversity arises and disappears. In this review we have evaluated the contribution of the study of Canarian birds to our understanding of how and why species occur and change over time. We focus our attention on both extant and extinct Canarian taxa, and describe how research on these species has filled gaps in our understanding of avian speciation and extinction. In addition, we discuss the necessity of revising the current taxonomy in the Canarian avian taxa, especially the status of the endemic subspecies, some of which might be better treated as full species. An accurate classification of Canarian birds is not only necessary for testing evolutionary, biogeographic and ecological hypotheses, but also for effective decision making about conservation and environmental management. Finally we introduce future avenues of research that we feel will yield the most exciting and promising findings on island evolution in the coming years.
Basic population information is often lacking for recently recognized species, yet such information is essential for conservation and management. This study provides a detailed assessment of population size and habitat association in the Madeira Firecrest (Regulus madeirensis). Species abundance and habitat data were collected using a point transect distance sampling method. Estimates of density per habitat type were made, in conjunction with presence and absence data derived from the Madeira bird atlas, to estimate population size and habitat associations. We estimate the population size of the Madeira Firecrest to be 698,300 (95% CI: 523,540–869,960), which greatly exceeds the 10,000 individuals threshold for the IUCN “Vulnerable” category. Distribution and abundance were strongly associated with laurel and heath forest, with 56% of the population found in these 2 habitats. Historically, much of the native laurel and heath forest was lost on Madeira, but these remnant native forest habitats are now protected. Based on the large population size and successful management of the laurel forest habitat, our results suggest there is no immediate risk of a change in conservation status for the Madeira Firecrest.
Basic population information is often lacking for recently recognized species, yet such information is essential for conservation and management. This study provides a detailed assessment of population size and habitat association in the Madeira Firecrest (Regulus madeirensis). Species abundance and habitat data were collected using a point transect distance sampling method. Estimates of density per habitat type were made, in conjunction with presence and absence data derived from the Madeira bird atlas, to estimate population size and habitat associations. We estimate the population size of the Madeira Firecrest to be 698,300 (95% CI: 523,540–869,960), which greatly exceeds the 10,000 individuals threshold for the IUCN “Vulnerable” category. Distribution and abundance were strongly associated with laurel and heath forest, with 56% of the population found in these 2 habitats. Historically, much of the native laurel and heath forest was lost on Madeira, but these remnant native forest habitats are now protected. Based on the large population size and successful management of the laurel forest habitat, our results suggest there is no immediate risk of a change in conservation status for the Madeira Firecrest.
Background . Understanding constraints to the distribution of threatened species may help to ascertain whether there are other suitable sectors for reducing the risks associated with species that are recorded in only one protected locality, and to inform about the suitability of other areas for reintroduction or translocation programs.
Methods . We studied the Gran Canaria blue chaffinch ( Fringilla polatzeki ), a habitat specialist endemic of the Canary Islands restricted to the pine forest of Inagua, the only area where the species has been naturally present as a regular breeder in the last 25 years. A suitability distribution model using occurrences with demographic relevance (i.e., nest locations of successful breeding attempts analysed using boosted classification trees) was built considering orographic, climatic and habitat structure predictors. By means of a standardized survey program we monitored the yearly abundance of the species in 100 sectors since the declaration of Inagua as a Strict Nature Reserve in 1994.
Results . The variables with the highest relative importance in blue chaffinch habitat preferences were pine height, tree cover, altitude, and rainfall during the driest trimester (July-September). The observed local abundance of the blue chaffinch in Inagua (survey data) was significantly correlated with habitat suitability derived from modelling the location of successful nesting attempts (using linear and quantile regressions). The outcomes of the habitat suitability model were used to quantify the suitability of other natural, historic, pine forests of Gran Canaria. Tamadaba is the forest with most suitable woodland patches for the species. We estimated a population size of 195-430 blue chaffinches in Inagua since 2011 (95% CI), the smallest population size of a woodland passerine in the Western Palearctic.
Discussion . Habitat suitability obtained from modelling the location of successful breeding attempts is a good surrogate of the observed local abundance during the reproductive season. The outcomes of these models can be used for the identification of potential areas for the reintroduction of the species in other suitable pine forests and to inform forest management practices.
Background . Understanding constraints to the distribution of threatened species may help to ascertain whether there are other suitable sectors for reducing the risks associated with species that are recorded in only one protected locality, and to inform about the suitability of other areas for reintroduction or translocation programs.
Methods . We studied the Gran Canaria blue chaffinch ( Fringilla polatzeki ), a habitat specialist endemic of the Canary Islands restricted to the pine forest of Inagua, the only area where the species has been naturally present as a regular breeder in the last 25 years. A suitability distribution model using occurrences with demographic relevance (i.e., nest locations of successful breeding attempts analysed using boosted classification trees) was built considering orographic, climatic and habitat structure predictors. By means of a standardized survey program we monitored the yearly abundance of the species in 100 sectors since the declaration of Inagua as a Strict Nature Reserve in 1994.
Results . The variables with the highest relative importance in blue chaffinch habitat preferences were pine height, tree cover, altitude, and rainfall during the driest trimester (July-September). The observed local abundance of the blue chaffinch in Inagua (survey data) was significantly correlated with habitat suitability derived from modelling the location of successful nesting attempts (using linear and quantile regressions). The outcomes of the habitat suitability model were used to quantify the suitability of other natural, historic, pine forests of Gran Canaria. Tamadaba is the forest with most suitable woodland patches for the species. We estimated a population size of 195-430 blue chaffinches in Inagua since 2011 (95% CI), the smallest population size of a woodland passerine in the Western Palearctic.
Discussion . Habitat suitability obtained from modelling the location of successful breeding attempts is a good surrogate of the observed local abundance during the reproductive season. The outcomes of these models can be used for the identification of potential areas for the reintroduction of the species in other suitable pine forests and to inform forest management practices.
Half a century ago, MacArthur and Wilson proposed that the number of species on islands tends toward a dynamic equilibrium diversity around which species richness fluctuates [1]. The current prevailing view in island biogeography accepts the fundamentals of MacArthur and Wilson’s theory [2] but questions whether their prediction of equilibrium can be fulfilled over evolutionary timescales, given the unpredictable and ever-changing nature of island geological and biotic features [3; 4; 5; 6 ; 7]. Here we conduct a complete molecular phylogenetic survey of the terrestrial bird species from four oceanic archipelagos that make up the diverse Macaronesian bioregion—the Azores, the Canary Islands, Cape Verde, and Madeira [8 ; 9]. We estimate the times at which birds colonized and speciated in the four archipelagos, including many previously unsampled endemic and non-endemic taxa and their closest continental relatives. We develop and fit a new multi-archipelago dynamic stochastic model to these data, explicitly incorporating information from 91 taxa, both extant and extinct. Remarkably, we find that all four archipelagos have independently achieved and maintained a dynamic equilibrium over millions of years. Biogeographical rates are homogeneous across archipelagos, except for the Canary Islands, which exhibit higher speciation and colonization. Our finding that the avian communities of the four Macaronesian archipelagos display an equilibrium diversity pattern indicates that a diversity plateau may be rapidly achieved on islands where rates of in situ radiation are low and extinction is high. This study reveals that equilibrium processes may be more prevalent than recently proposed, supporting MacArthur and Wilson’s 50-year-old theory.
Este informe agrupa información de 190 especies, siguiendo la secuencia taxonómica y los nombres de la última edición de la Lista de las Aves de España (Gutiérrez et al., 2012). Entre otras citas de interés, continúa la reproducción de buitre leonado Gyps fulvus en Mallorca y se registra un récord de cría de milano real Milvus milvus en Baleares, nuevas localidades de cría del ganso de Egipto Alopochen aegyptiacus, citas de carricerín cejudo Acrocephalus paludicola en Madrid, concentraciones posnupciales de cernícalo primilla Falco naumanni, así como cifras máximas de algunas especies invernantes en el delta del Ebro.
Socotra Sparrow Passer insularis is the only Socotran endemic landbird that occurs on the other islands of the Socotra archipelago. It is widely reported to occur on Abd 'Al Kuri, but the populations on Samha and Darsa were unknown until very recently. We present genetic data to support a recent call to elevate the Abd 'Al Kuri population to species level, Abd 'Al Kuri Sparrow P. hemileucus. Sequence divergence in two mitochondrial genes between hemileucus and insularis is 1.3-1.7%. The evolutionary history of the sparrows on Socotra cannot be inferred reliably until other taxa in the P. motitensis superspecies have been sampled. Sparrows on Samha are not genetically distinct from those on the main island of Socotra, but are appreciably smaller and should be recognised subspecifically. Birds on nearby Darsa were not caught, but photographs suggest they are similar to those on Samha. The Abd 'Al Kuri Sparrow qualifies as Vulnerable, due to its small population (<1,000 mature birds) and limited range (<100 km 2).
El Pinzón azul es una especie muy escasa en Inagua, Ojeda y Pajonales, donde alcanza una densidad media de 3,51 pinzones / km2. El grueso de la población se localiza en esta zona en el sector norte, y en el sur por encima de los 1.150 m de altitud, que cubren el 45% de toda la superficie de los pinares analizados y acogen el 73% de todos los efectivos de la especie. La distribución del Pinzón azul en Inagua, Ojeda y Pajonales no se ve afectada por la del Pico picapinos (i.e., ausencia de patrón excluyente). El Pinzón azul no fue detectado en Tamadaba, en donde, de existir, tendría una densidad inferior a 0,36 pinzones / km2.
El esfuerzo de muestreo realizado para el seguimiento poblacional del Pinzón azul en Inagua, Ojeda y Pajonales ha sido suficiente a lo largo de todos estos años, incluso en escenarios de abundancia tan bajos como los registrados en 2008 y 1994. No se han encontrado diferencias significativas en la detectabilidad de la especie entre observadores-años. La distancia eficaz de censo media del Pinzón azul en esta región fuertemente montañosa y abarrancada ha sido de unos 82 m (rango 65 – 110 m al 90% de confianza). Se recomienda seguir utilizando la red de sendas empleadas desde 1994 para efectuar el seguimiento de los efectivos de la especie.
La red fija de transectos utilizada desde 1994 sobre-estima considerablemente la densidad y el tamaño de población de la especie en todo Inagua, Ojeda y Pajonales (por un factor que en 2008 sería x1,49). Esto es debido a la gran heterogeneidad espacial del reparto de la abundancia de la especie dentro de esta zona. Se recomienda cautela dando crédito a las estimas previas del tamaño de población del Pinzón azul. El tamaño de población en los 34,85 km2 de Inagua, Ojeda y Pajonales es muy pequeño, estimándose en unos 122 individuos (intervalo de confianza al 90%: 75 – 176 pinzones). El Pinzón azul ha disminuido significativamente su abundancia desde 2004 a 2008 en la zona sobre la que se han establecido los transectos control, con una magnitud relativa del descenso muy notable y preocupante (promedio del -49%). La estima de abundancia en 2008 es consistentemente la más baja registrada para la especie en Inagua, Ojeda y Pajonales desde 1994, siendo al menos un 35% inferior que la menor observada previamente.
El Pinzón azul no ha manifestado cambios significativos en su abundancia relativa en Inagua, Ojeda y Pajonales desde 1994, año en que se crea la figura de Reserva Integral, hasta 2004, ni siquiera en el periodo de cambios más acusados en su abundancia relativa (1998-2002). Globalmente, el Pinzón azul ha aumentado su abundancia un 3,4% por año desde 1994 a 2004, aunque tal magnitud de cambio es indistinguible de lo que podría esperarse por puro azar. De seguir utilizando el esfuerzo de muestreo efectuado hasta la fecha (22,9 km de transectos realizados una sola vez al año) sólo serían detectables disminuciones significativas a p<0,1 superiores al 29,2% e incrementos superiores al 40,4% entre dos años consecutivos. Se recomienda repetir 3-4 veces al año el censo del Pizón azul sobre la red fija de transectos iniciada en 1994 para seguir sus efectivos poblacionales.
La distribución del Pinzón azul en Mayo de 2008 en Inagua, Ojeda y Pajonales fue un fenómeno fácilmente explicable y altamente predecible y coherente, aunque la ausencia de la especie se predijo más fácilmente (92% de clasificaciones correctas) que su presencia (57%). Las características ambientales y geográficas que maximizan la probabilidad de adecuación del territorio para la especie son:a localización en el tercio occidental de la reserva, en áreas con cobertura de pinos superior al 24% (y en zonas situadas a más de 1.345 m s.n.m. en el resto de la reserva). La intensidad de quema del pinar en Mayo-Junio de 2008, derivada del incendio de Julio de 2007, ha afectado en muy escasa medida a su distribución actual en la reserva. Es altamente probable que la filopatría sea un importante determinante de la distribución actual de la especie en Inagua, Ojeda y Pajonales.
El área de distribución preferente del Pinzón azul en Inagua, Ojeda y Pajonales tiene una elevada carga térmica durante el verano. Durante una alta proporción del tiempo del día la temperatura está por encima de lo que suele ser la temperatura crítica máxima en pequeñas aves forestales (unos 35 ºC). Estos resultados muestran el carácter tórrido de Inagua, Ojeda y Pajonales en verano, a pesar de ser un ambiente forestal y tener una elevada altitud.
El Pinzón azul es mucho más frecuente en los pinares de Tenerife que en los de Gran Canaria (las frecuencias de aparición son de 49% y 23%, respectivamente). La distribución del Pinzón azul en Tenerife puede describirse con precisión (80% de clasificación correcta) con un modelo que la asocia positivamente con la altura y cobertura del arbolado (a partir de 16,5 m y 33% de cobertura), la altitud sobre el nivel del mar (por encima de 1590 m) y el índice de vegetación (valor de NDVI entre 146 y 192). Los pinares estudiados en Gran Canaria (Tamadaba y reserva integral de Inagua) tienen unas características en general poco favorables para el Pinzón azul, si atendemos a las preferencias de hábitat de la subespecie tinerfeña teydea. Las áreas más adecuadas serían aquellas a más de 1206 m de altitud, con un índice NDVI mayor de 141, con una altura media de los pinos superior a 16,9 m, una cobertura de arbolado mayor del 24%, y una cobertura del matorral superior al 10%. Las localidades más adecuadas en Tamadaba serían aquellas localizadas a más de 1116 m de altitud, con un índice NDVI mayor de 168, con una altura media de los pinos superior a 15 m, una cobertura de arbolado mayor del 35% y una cobertura del matorral superior al 9%. A estas zonas se les debería conferir el máximo estatus de protección.
This volume deals with the passerines (6063 spp. in pp. i-lii, 1-752. Joel Cracraft provided and explains the sequence of families. 15 expert colleagues assisted with this volume. The accompanying CD includes an editable spreadsheet version of the two-volume checklist as well as the volume reference list (over 3000 references) and appendices 5 to 9 (1 to 4 being in the book). Five new family-group names are introduced.
En Peligro Crítico; CR B1ab(ii,v); C2a(ii) Autores: Felipe Rodríguez y Ángel Moreno El Pinzón Azul de Gran Canaria, endémico de Canarias, se encuentra restringido a dos masas boscosas de pinar, una de las cuales, con una superficie de unas 3.700 ha, alberga más del 95% de su población global, la cual no supera los 250 ejemplares. La destrucción del hábitat y la colecta de ejemplares fueron las cau-sas que han llevado a este taxón a su situación de amenaza. Actualmente los altos riesgos de extinción vienen dados por el reducido tamaño poblacional y su ex-tremada localización.
Leapfrog patterns are a peculiar and little-understood phenomenon in which similar populations at either end of a geographic continuum are divided by dissimilar intervening populations. Leapfrog patterns may be important in allopatric speciation. Most documented cases of biological leapfrog patterns refer to morphological traits in passerine birds, and only few have been reported from outside the Andean region. More importantly, the biological basis of leapfrog patterns continues to elude biologists. We document a vocal leapfrog pattern—possibly the second such case documented— in the Maroon-chinned Fruit Dove (Ptilinopus subgularis) complex, adding to the few known examples of leapfrog patterns from outside the Neotropics and in non-passerines. P. subgularis is a Wallacean pigeon whose three taxa occur in a longitudinal continuum from Sulawesi in the west to the Sula Islands in the east. We used discriminant analysis and other statistical methods to demonstrate that terminal members of the complex differ in song from the geographically intermediate taxon but resemble each other more closely. Plumage in P. subgularis does not exhibit the same geographic distribution of variability, a pattern that agrees with the only other study reporting a vocal leapfrog pattern, and supports an earlier hypothesis that leapfrog patterns arise from stochastic phenotypic changes in geographically intermediate taxa. We combine the new insights on the distribution of vocal trait variation in P. subgularis with Pleistocene earth-historic information to revise species in the complex.
We reconstructed the phylogeographic relationships of the Variable Dwarf-Kingfisher (Ceyx lepidus) using DNA sequence data. Maximum likelihood and Bayesian analysis methods were used to reconstruct trees from a multilocus data set of all 15 named subspecies of the Ceyx lepidus species complex. The concatenated data-set length was 2,471 base pairs and included two mitochondrial genes and two noncoding nuclear introns. Support for the monophyly of C. lepidus was equivocal. We instead found support for a clade including all C. lepidus subspecies plus two endemic Philippine taxa: C. argentatus and C. cyanopectus. Relationships among subspecific taxa were not well resolved, and many nodes were collapsed into polytomies suggesting a rapid and widespread colonization. In situ diversification likely played a role in generating current diversity within four archipelagos: the Philippines, Malukus, Bismarcks, and Solomons. Some biogeographic patterns recovered for the Solomon Islands taxa match those seen in other bird species, such as the close relationship of taxa on Bougainville, Choiseul, and Isabel. By contrast, the sister relationship between populations on Guadalcanal and the New Georgia Group is novel. We discuss species limits and make taxonomic recommendations to treat all 15 subspecies of C. lepidus as species. Received 31 May 2012, accepted 5 November 2012.
Taxonomists have largely ignored biodiversity questions in the Bahamas, so many distinct species of flora and fauna remain to be described as full species. Some of these previously overlooked species are highly endangered, warranting high-priority conservation status because distinct species receive higher priority than subspecies or local races. Their discovery in an era when new species are rarely described can generate considerable publicity, igniting efforts to save them and the habitats they require and improving public and decision-maker attitudes toward the environment. Thus, conservation taxonomy—the study of organismal classification to clarify conservation priorities—should be pursued vigorously, before many unrecognized species become extinct. There are a number of overlooked species candidates among birds, a group that engenders considerable public interest and sympathy. Recognizing some or all of these candidate taxa as distinct and (in many cases) endangered species may increase up to fourfold the number of endemic bird species in The Bahamas and dramatically alter conservation priorities. As ‘flagship’ species, protected birds can help to save other flora and fauna that depend on the same threatened habitats.
The present study represents the third in a series of papers that seeks to re-examine the taxonomic status of avian forms described from the Socotran archipelago. It follows publica-tions concerning the population of Nubian Nightjar Caprimulgus nubicus, which was previously regarded as an endemic subspecies, jonesi (Kirwan 2004), and a re-evaluation of species limits in Golden-winged Grosbeak Rhynchostruthus socotranus (Kirwan & Grieve 2007). These notes seek to stimulate renewed interest in taxonomic studies of Socotran birds, specifically to meet the challenge set by Martins (1996), who stated: 'There is a clear need for a review of the avifauna of Socotra which reflects contemporary systematic thinking.' All originally described as species, the six allopatric groups (and nine constituent taxa) within the almost exclusively Afrotropical Rufous Sparrow Passer motitensis complex have suffered a rather checkered taxonomic history of late. Following their demotion to sub-species, this arrangement persisted through Moreau & Greenway (1962), White (1963) and Hall & Moreau (1970). Thus, despite the contrary opinions of van Someren (1922), Lynes (1926), Grant & Mackworth-Praed (1944), Bannerman (1948) and Macdonald (1957) con-cerning some or all of these taxa, it was not until Wolters (1982), who split P. insularis, from the island of Socotra, off north-east Africa, and Summers-Smith (1984, 1988), who separat-ed P. iagoensis, from the Cape Verde archipelago, at the level of species that more than one species tended to be recognised by major works. This notwithstanding the riposte of Bourne (1986) to Summers-Smith (1984) wherein Bourne could find little to recommend the advancement of iagoensis to specific status beyond the need for 'a tiresome change of name'. Thus, Sibley & Monroe (1990) recognised the following specifically: P. iagoensis, P. insu-laris, P. rufocinctus (including cordofanicus and shelleyi), from East Africa, and P. motitensis, from South Africa north to southern Angola (which arrangement was followed by Gill & Wright 2006). In contrast, Dowsett & Dowsett-Lemaire (1993), followed by Dickinson (2003) in his important world checklist, preferred to recognise just motitensis and iagoensis as species, and pointed to errors and inconsistencies in the work of Wolters and Sibley & Monroe. However, the relevant volume of the influential The birds of Africa elected to recog-nise P. shelleyi (spottily in Ethiopia and Somalia south to Kenya) and P. cordofanicus (from west-central Sudan to eastern Chad), in addition to the four taxa separated by Sibley & Monroe, specifically (Urban in Fry & Keith 2004), albeit not without criticism (Leonard & Demey 2006). Thus, in recent years, only motitensis and iagoensis have received reasonably widespread recognition as being meritorious of specific status (Cramp & Perrins 1994 and Hazevoet 1995 also afforded iagoensis such treatment). Passer [motitensis] insularis Sclater & Hartlaub, 1881, was unsurprisingly (given its abun-dance, which is currently placed at c.230,000 individuals: R. F. Porter in litt. 2007) amongst the initial wave of taxa endemic to the ancient island of Socotra to be described, following boc1282-080509:BOC Bulletin 5/9/2008 7:22 AM Page 83 the first scientific visit to the archipelago, by Sir Isaac Bayley Balfour, who spent almost seven weeks there in 1880. It was not until the considerably more extensive survey by Ogilvie-Grant & Forbes, in 1898–99, that Passer [motitensis] hemileucus Ogilvie-Grant & Forbes, 1899 (hereafter referred to as P. hemileucus), was discovered. The latter is endemic to Abd 'Al Kuri, a rather inhospitable island with no permanent running water, c.36.5 km east to west and a maximum of c.5 km north to south, which lies c.145 km west of the main island and rises to a maximum 743 m (Cheung & DeVantier 2006). Abd 'Al Kuri covers 133 km 2 , whereas Socotra is 3,625 km 2 in area. Our knowledge of insularis has increased substan-tially (see, e.g., Kirwan et al. 1996) since even the work of Summers-Smith (1988), who was able to make scarcely even the most basic comments about the bird's natural history, but hemileucus has remained a mysterious taxon known almost solely from specimens, namely the type series and seven birds collected by Alec Forbes-Watson in spring 1964. In report-ing on the latter collection, Ripley & Bond (1966), in an immense understatement, referred only to hemileucus being paler than insularis. In consequence the taxon's obvious distinctive-ness has gone unappreciated, though its describers (Ogilvie-Grant & Forbes 1899) were clearly aware of this as their manuscript makes plain (even allowing for the fact that all such novelties were then afforded species status). Summers-Smith (1988) opined that 'although paler and slightly smaller the differences are not great enough to warrant their separation from the birds on Socotra even as a different race.' Clement et al. (1993), presumably impressed by Summers-Smith's statement as to the weak distinction, simply ignored hemileucus. Urban (2004), in contrast, noted it as being 'Much paler than insularis, under-parts nearly pure white, black patch on chin of % smaller, & without dusky patch on throat', and also remarked on the overall smaller size of hemileucus (something which had not escaped, but apparently failed to impress, Summers-Smith). None of these commentators, with the exception of Dillon Ripley and Bond, appears to have examined the Forbes-Watson specimens, and it might be wondered whether the first two authors looked carefully at the, admittedly limited, material to hand in The Natural History Museum (Tring). In fact, Passer hemileucus appears as easily diagnosable as any other member of the Rufous Sparrow com-plex admitted to species status by Urban (2004).
The Blue Chaffinch (Fringilla teydea) is endemic to the Canary Islands and restricted to the pine forests on Tenerife (ssp. teydea) and Gran Canaria (ssp. polatzeki). While the teydea population is large and stable, the polatzeki population underwent a dramatic decline in the twentieth century and currently numbers less than 200 individuals. Here, we show that microsatellite allelic diversity is lower in polatzeki than in teydea, consistent with a genetic bottleneck scenario. Our genotyped polatzeki individuals, which were wild-caught but currently used in a captive breeding programme, have the same allelic diversity as free-ranging birds. However, the captive polatzeki males seem to have reduced sperm motility as compared with captive teydea males, which could be an effect of reduced genetic diversity. Because polatzeki and teydea are phylogenetically distinct, they should be recognized as Evolutionarily Significant Units by conservation authorities. We also recommend maintaining the captive polatzeki population as a pre-emptive measure against extinction in the wild.
The Indo-Pacific region has arguably been the most important area for the formulation of theories about biogeography and speciation, but modern studies of the tempo, mode and magnitude of diversification across this region are scarce. We study the biogeographic history and characterize levels of diversification in the wide-ranging passerine bird Erythropitta erythrogaster using molecular, phylogeographic and population genetics methods, as well as morphometric and plumage analyses. Our results suggest that E. erythrogaster colonized the Indo-Pacific during the Pleistocene in an eastward direction following a stepping stone pathway, and that sea-level fluctuations during the Pleistocene may have promoted gene flow only locally. A molecular species delimitation test suggests that several allopatric island populations of E. erythrogaster may be regarded as species. Most of these putative new species are further characterized by diagnostic differences in plumage. Our study reconfirms the E. erythrogaster complex as a 'great speciator': it represents a complex of up to 17 allopatrically distributed, reciprocally monophyletic and/or morphologically diagnosable species that originated during the Pleistocene. Our results support the view that observed latitudinal gradients of genetic divergence among avian sister species may have been affected by incomplete knowledge of taxonomic limits in tropical bird species.
Western Palearctic Yellowhammer and eastern Palearctic Pine Bunting are considered a pair of young sister species. A huge area of sympatry is in western Siberia where they hybridize extensively despite striking plumage differences. The somehow dominant Yellowhammer pushes the hybrid zone further east. Territorial songs of the two taxa are almost indistinguishable. We tested 15 song types from both species from various localities inside and outside the hybrid zone in playback experiments on German Yellowhammer males. All songs elicited territorial behavior in almost every experiment. Reaction intensity depended on one out of 25 investigated sonagraphic parameters and was the weaker the further away the recording site of the playback was from the experimental site regardless of the taxon. Songs from the hybrid zone elicited disproportionately strong response so that a reinforcement of reproductive isolation through song can be excluded. Song seems to be more conserved than morphological features and has thus prevented a complete genetic divergence in this pair of subspecies groups.
The Blue Chaffinch is a passerine endemic to the Canary Islands and comprises two subspecies, one found on Tenerife (Fringilla teydea teydea) and the other on Gran Canaria (F. t. polatzeki). Even though the status of the Gran Canaria subspecies is endangered due to habitat loss and fragmentation, knowledge of its life history is anecdotal. We studied its breeding ecology during the years 1991-2004. New data are presented on breeding phenology, number of broods per year, egg biometrics, nest-site characteristics, breeding site fidelity and breeding success. In general, the breeding biology of the two subspecies were similar, with discrepancies in some previously reported traits, such as egg laying interval and frequency of second clutches. The Blue Chaffinch breeds earlier on Gran Canaria than on Tenerife: nests were begun mainly in the second fortnight of May. We did not find any relationship between the onset of egg laying and rainfall in March. However, the onset of the breeding period was negatively correlated with mean April temperature. The Blue Chaffinch showed preferences for a south-easterly nest orientation and for nest placement at the end of branches, where the nest is hidden by pine needles. Nests were located at various heights, from 5.5 to 23.8 m above the ground. 33% of females produced two broods a year. We found no differences in nest site characteristics between successful and unsuccessful nests, which suggests that other factors may be affecting the vulnerability of nests. The main cause of nesting failure (73.9%) was predation, due mostly to the Great Spotted Woodpecker.
The recently introduced term ‘integrative taxonomy’ refers to taxonomy that integrates all available data sources to frame species limits. We survey current taxonomic methods available to delimit species that integrate a variety of data, including molecular and morphological characters. A literature review of empirical studies using the term ‘integrative taxonomy’ assessed the kinds of data being used to frame species limits, and methods of integration. Almost all studies are qualitative and comparative – we are a long way from a repeatable, quantitative method of truly ‘integrative taxonomy’. The usual methods for integrating data in phylogenetic and population genetic paradigms are not appropriate for integrative taxonomy, either because of the diverse range of data used or because of the special challenges that arise when working at the species/population boundary. We identify two challenges that, if met, will facilitate the development of a more complete toolkit and a more robust research programme in integrative taxonomy using species tree approaches. We propose the term ‘iterative taxonomy’ for current practice that treats species boundaries as hypotheses to be tested with new evidence. A search for biological or evolutionary explanations for discordant evidence can be used to distinguish between competing species boundary hypotheses. We identify two recent empirical examples that use the process of iterative taxonomy.
Aim In birds, differentiation of acoustic characters is an important mechanism of reproductive isolation that may lead to an ethological–acoustic barrier, resulting in the formation of new species. We examined acoustic variation in mainland citril and insular Corsican finch populations, with the aim of assessing the degree of acoustic differentiation between both members of the superspecies Carduelis [ citrinella ] and documenting possible variation between local subpopulations that are geographically isolated.
Location We chose study sites throughout the geographical ranges of citril and Corsican finches. For the citril finch, we obtained samples from the Black Forest (Germany), the Cevennes (France) and the Pyrenees (Spain); for the Corsican finch, we obtained samples from the islands Capraia and Sardinia (Italy) and Corsica (France).
Methods We analysed frequent contact calls and elements of the perch song. Vocalization patterns of the study populations were compared by means of discriminant and hierarchical cluster analyses.
Results There were significant differences in vocalization characteristics of perch songs and contact calls, which permitted unambiguous discrimination of citril and Corsican finch populations. However, we also detected significant differences in contact calls between mainland citril finch subpopulations. There was a pattern of clinal variation in vocalization: short, steeply modulated signals in the northern part of the geographical range (Black Forest) and long, shallowly modulated signals in the southern part (Pyrenees).
Main conclusions Acoustically, mainland citril and insular Corsican finches separate well in their contact calls and perch songs. However, variation in the two vocalization patterns between subpopulations of mainland citril finches indicates that acoustic characteristics can evolve very quickly, not only on islands but also on the mainland. Local habitat differences may play a crucial role in the rapid evolution of these signals under full or partial isolation of small subpopulations. To judge the importance of signal variation as a pre‐mating isolating barrier, future studies will have to determine whether members of the distinct subpopulations are able to match their signals to each other if they re‐meet, and whether intraspecific species recognition is still possible.
The elepaio (Chasiempis sandwichensis) is a monarch flycatcher endemic to the Hawaiian Islands of Kauai, Oahu, and Hawaii. Elepaio vary in morphology among and
within islands, and five subspecies are currently recognized. We investigated phylogeography of elepaio using mitochondrial
(ND2) and nuclear (LDH) markers and population structure within Hawaii using ND2 and microsatellites. Phylogenetic analyses
revealed elepaio on each island formed reciprocally monophyletic groups, with Kauai ancestral to other elepaio. Sequence divergence
in ND2 among islands (3.02–2.21%) was similar to that in other avian sibling species. Estimation of divergence times using
relaxed molecular clock models indicated elepaio colonized Kauai 2.33 million years ago (95% CI 0.92–3.87 myr), Oahu 0.69
(0.29–1.19) myr ago, and Hawaii 0.49 (0.21–0.84) myr ago. LDH showed less variation than ND2 and was not phylogenetically
informative. Analysis of molecular variance within Hawaii showed structure at ND2 (fixation index=0.31), but microsatellites
showed no population structure. Genetic, morphological, and behavioral evidence supports splitting elepaio into three species,
one on each island, but does not support recognition of subspecies within Hawaii or other islands. Morphological variation
in elepaio has evolved at small geographic scales within islands due to short dispersal distances and steep climatic gradients.
Divergence has been limited by lack of dispersal barriers in the extensive forest that once covered each island, but anthropogenic
habitat fragmentation and declines in elepaio population size are likely to decrease gene flow and accelerate differentiation,
especially on Oahu.
Keywords
Chasiempis
–Elepaio–Hawaii–Phylogeography–Population structure–Relaxed clock
Background:
Evolutionary studies of insular biotas are based mainly on extant taxa, although such biotas represent artificial subsets of original faunas because of human-caused extinctions of indigenous species augmented by introduced exotic taxa. This makes it difficult to obtain a full understanding of the history of ecological interactions between extant sympatric species. Morphological bill variation of Fringilla coelebs and F. teydea (common and blue chaffinches) has been previously studied in the North Atlantic Macaronesian archipelagos. Character displacement between both species has been argued to explain bill sizes in sympatry. However, this explanation is incomplete, as similar patterns of bill size have been recorded in F. coelebs populations from islands with and without F. teydea.
Methodology/principal findings:
The discovery of a new extinct species in Tenerife (Canary Islands), here named Carduelis aurelioi n. sp. (slender-billed greenfinch), provides the opportunity to study ancient ecological interactions among Macaronesian finches. To help understand the evolutionary histories of forest granivores in space and time, we have performed a multidisciplinary study combining: (1) morphological analyses and radiocarbon dating (11,460±60 yr BP) of the new taxon and, (2) molecular divergence among the extant finch species and populations in order to infer colonization times (1.99 and 1.09 My for F. teydea and F. coelebs respectively).
Conclusion/significance:
C. aurelioi, F. coelebs and F. teydea co-habited in Tenerife for at least one million years. The unique anatomical trends of the new species, namely chaffinch-like beak and modified hind and forelimbs, reveal that there was a process of divergence of resource competition traits among the three sympatric finches. The results of our study, combined with the presence of more extinct greenfinches in other Macaronesian islands with significant variation in their beak sizes, suggests that the character displacement has influenced patterns of divergence in bill size and shape on other Macaronesian islands as well.
Taxonomy is the biological discipline that identifies, describes, classifies and names extant and extinct species and other taxa. Nowadays, species taxonomy is confronted with the challenge to fully incorporate new theory, methods and data from disciplines that study the origin, limits and evolution of species.
Integrative taxonomy has been proposed as a framework to bring together these conceptual and methodological developments. Here we review perspectives for an integrative taxonomy that directly bear on what species are, how they can be discovered, and how much diversity is on Earth.
We conclude that taxonomy needs to be pluralistic to improve species discovery and description, and to develop novel protocols to produce the much-needed inventory of life in a reasonable time. To cope with the large number of candidate species revealed by molecular studies of eukaryotes, we propose a classification scheme for those units that will facilitate the subsequent assembly of data sets for the formal description of new species under the Linnaean system, and will ultimately integrate the activities of taxonomists and molecular biologists.
The widespread common chaffinch (Fringilla coelebs) inhabits five of the seven Canary Islands. Sequences of the mitochondrial cytochrome b gene (1002bp) revealed new insights into the systematics and phylogeography of this taxon. Additionally, a set of microsatellite loci were analyzed to examine the structure of these populations. Our results suggest that a new species of the genus Fringilla is present in the Canary Islands, which comprises at least three subspecies, but with a different distribution to that which has been morphologically accepted. The specimens from Gran Canaria are genetically distinct from those of La Gomera and Tenerife (F. c. canariensis), which suggests the existence of an undescribed taxon. Furthermore, nuclear microsatellite data suggest an ongoing incipient speciation process in this population. This study provides both important conservationist implications and a basis for re-evaluating the taxonomic status of the Canarian Fringilla coelebs populations.
The impact and significance of modern taxonomy on other fields in biology have been subjects of much debate. It has been proposed that increasing numbers of vertebrate species are largely owing to 'taxonomic inflation'. According to this hypothesis, newly recognized species result from reinterpretations of species limits based on phylogenetic species concepts (PSCs) rather than from new discoveries. Here, I examine 747 proposals to change the taxonomic rank of birds in the period 1950-2007. The trend to recognize more species of birds started at least two decades before the introduction of PSCs. Most (84.6%) newly recognized species were supported by new taxonomic data. Proposals to recognize more species resulted from application of all six major taxonomic criteria. Many newly recognized species (63.4%) were not based exclusively on PSC-based criteria (diagnosability, monophyly and exclusive coalescence of gene trees). Therefore, this study finds no empirical support for the idea that the increase in species is primarily epistemological rather than data-driven. This study shows that previous claims about the causes and effects of taxonomic inflation lack empirical support. I argue that a more appropriate term for the increase in species is 'taxonomic progress'.
Citril finches Carduelis c. citrinella and Corsican finches Carduelis c. corsicana represent two closely related forms, endemic to European mountains and some Mediterranean Islands. Their taxonomic status has recently been disputed based on the results from mitochondrial genes. We show that the use of different genetic markers may lead to different results in these two putative species. Using the mitochondrial ATP8+6 we found a clear difference between C. c. citrinella and C. c. corsicana (3.2%) suggesting a divergence time of 1.2MYR. In contrast, no clear difference was found using two nuclear genes. The mismatch between the different markers suggests that the separation of C. c. citrinella and C. c. corsicana is likely to be a rather recent event, involving bottlenecks, which have enhanced the divergence in the mtDNA. Our results call for caution when using mtDNA alone for assessing times of divergence and rates of evolution. We did not find any support for the view that C. c. corsicana is more related to Carduelis carduelis than C. c. citrinella as proposed by previous studies.
The blue chaffinch (Fringilla teydea) is found only on the two central Canary Islands of Gran Canaria and Tenerife, where it is restricted to pine forest habitat. It is reasonably abundant on the latter island but endangered on the former. Here, sequence variation was studied in a fragment spanning domains I and II of the mitochondrial DNA (mtDNA) control region. Phylogenetic analysis of all haplotypes with a F. coelebs outgroup indicated the two island populations were reciprocally monophyletic, supporting their individual conservation. Unlike in other species, most within-island haplotype diversity was due to mutations in the domain II region. Surprisingly, genetic diversity was greater in the smaller Gran Canarian population. We suggest that this is unlikely to be maintained under current population sizes although it may be mitigated by incorporating genetic information into the captive breeding programme.
Animals often exhibit predictable geographic variation in morphology, and such ecogeographic patterns reflect local adaptation to varying environmental conditions. The most common of these patterns are termed Bergmann's, Allen's, and Gloger's rules. I studied morphological variation in the Hawaii Elepaio (Chasiempis sandwichensis) and the Oahu Elepaio (C. ibidis), forest birds endemic to the Hawaiian Islands. I measured body size and plumage color of 223 live elepaios captured at 36 sites on Hawaii and 132 live elepaios captured at 23 sites on Oahu, and I examined 132 museum specimens from an additional 22 locations on Hawaii. I used multiple regressions to examine relationships of elepaio body size and plumage color to elevation and annual rainfall on each island. Size of Hawaii Elepaios varied among sites and was related to elevation and rainfall. Wing chord, tail length, and body mass had positive relationships with elevation, as predicted by Bergmann's rule. Proportional bill length and proportional tarsus length were inversely related to elevation, as predicted by Allen's rule. In Hawaii Elepaios, 17 of 20 plumage color variables were related to rainfall. Elepaios in wetter areas were more heavily pigmented and had fewer and smaller white markings, as predicted by Gloger's rule. Plumage color of Oahu Elepaios showed similar but weaker patterns and only two of 20 plumage characters were related to rainfall. All body-size and plumage-color measurements had smoothly clinal distributions, with no large gaps with respect to elevation or rainfall. Putative subspecies of the Hawaii Elepaio differed in mean value of several plumage characters, but there was overlap in plumage color among subspecies and variation within them, and none of the three subspecies was diagnosable from both other subspecies by any plumage character using the 75% rule. Elepaios differed morphologically among sites only a few kilometers apart because of their sedentary behavior and the steep gradients in temperature and elevation and limited climatic variation of the tropical environment of the Hawaiian Islands. Morphological variation in elepaios is smoothly clinal because there are few dispersal barriers and elepaios inhabit areas with a range of climates and vegetation. Although my results did not support the designation of subspecies within the Hawaii Elepaio, morphological and underlying genetic variation is important, and conservation of elepaios with varying phenotypes would preserve evolutionary potential and ability to adapt to climate change.
The debate over species concepts has produced a huge body of literature on how species can, may or should be delimited. By contrast, very few studies have documented how species taxa are delimited in practice. The aims of the present study were to (i) quantify the use of species criteria in taxonomy, (ii) discuss its implications for the debate over species concepts and (iii) assess recent claims about the impact of different species concepts on taxonomic stability and the ‘nature’ of species. The application of six species criteria was examined in taxonomic studies of birds published between 1950 and 2009. Three types of taxonomic studies were included: descriptions of new species (N=329), proposals to change the taxonomic rank of species and subspecies (N=808) and the taxonomic recommendations of the American Ornithologists’ Union Committee on Classification and Nomenclature (N=176). In all three datasets, diagnosability was the most frequently applied criterion, followed by reproductive isolation and degree of difference. This result is inconsistent with the popular notion that the Biological Species Concept is the dominant species concept in avian taxonomy. Since the 1950s, avian species-level taxonomy has become increasingly pluralistic and eclectic. This suggests that taxonomists consider different criteria as complementary rather than as rival approaches to species delimitation. Application of diagnosability more frequently led to the elevation of subspecies to species rank than application of reproductive isolation, although the difference was small. Hypotheses based on diagnosability and reproductive isolation were equally likely to be accepted in a mainstream checklist. These findings contradict recent claims that application of the Phylogenetic Species Concept causes instability and that broader application of the Biological Species Concept can stabilise taxonomy. The criteria diagnosability and monophyly, which are commonly associated with Phylogenetic Species Concepts, were used throughout the study period. Finally, no support was found for the idea that Phylogenetic Species Concepts have caused a change in the ‘nature’ of species taxa. This study demonstrates that there is a discrepancy between widely held perceptions of how species are delimited and the way species are actually delimited by taxonomists. Theoretically oriented debates over species concepts thus may benefit from empirical data on taxonomic practice.
The two chaffinch species on Tenerife (Fringilla teydea and F. coelebs tintillon) were tested with playback of their own and the other species song in areas where only one of the two occurs. They were also tested in this non-overlap zone with the song of the European chaffinch (F. c. gengleri was used) to test the hypothesis that they would respond more to it than to the competing species as their songs appear to have diverged from the European form in opposite directions. The results were broadly in line with this prediction. Playback of teydea and tintillon song in the zone of overlap between the two species led to heterospecific response in only a few cases, indicating that they are not usually interspecifically territorial. Response to the other species song was less strong than outside the area of overlap, suggesting that habituation may lead birds to respond to less to the other species where it is present.
Maps of the territories of the two species of chaffinches in an area of sympatry on Tenerife (Fringilla coelebs and F. teydea) show that they are not interspecifically territorial. Playback experiments of heterospecific song show that both species tend to respond in areas of allopatry, but only rarely in sympatry. There is no clear difference in song structure in either species between areas of sympatry and allopatry. Although a comparison of common chaffinch song among 14 samples in the Atlantic region shows significant amounts of differentiation among regions, there is no clear evidence of character displacement. The divergence of blue chaffinch song can best be explained by the
I used inter-island song playbacks and information on geology, ecology, and behavior to investigate biogeography and species limits in the `Elepaio (Chasiempis sandwichensis), a monarch flycatcher (Monarchidae) endemic to the Hawaiian Islands. `Elepaio occur on Kaua`i, O`ahu, and Hawai`i, but are absent on the four islands of the Maui Nui group in the center of the Hawaiian Archipelago. It is unlikely that `Elepaio became extinct on Maui Nui or were excluded by the presence of competing species. `Elepaio are absent in the fossil record on all four islands of Maui Nui, but occur in the fossil record on all three islands they currently inhabit. They have adapted to a variety of forested habitats and are more resistant to alien diseases than other bird species that have persisted on Maui Nui. `Elepaio on each island responded most strongly to songs from their own island. Response to foreign songs was asymmetrical. Hawai`i `Elepaio responded to songs from Kaua`i, suggesting that `Elepaio on Kaua`i and Hawai`i share a more recent common ancestry. The sequence of colonization events that led to the current distribution was most likely: (1) Kaua`i to O`ahu and (2) Kaua`i to Hawai`i. Geologic and genetic evidence indicate the `Elepaio lineage arrived in the Hawaiian Islands 1.5–1.9 million years ago. `Elepaio probably were blown from Kaua`i to Hawai`i during storms, skipping several of the stepping-stones in the Hawaiian chain. The low level of foreign song recognition indicates song could inhibit interbreeding and might serve as an isolating mechanism.
Discusses the pros and cons of using qualitative (nonmathematical) descriptors of strength of association and effect size in data interpretation. Proposed is an extension of J. Cohen's (1988) classification scheme through the addition of a "very large" descriptive category. Discussed are the advantages of the odds ratio for the analysis of categorical data, as well as the development of qualitative descriptors of effect size for the odds ratio. Where treated as flexible guidelines rather than rigid rules and where sensitive to context and substantive area, qualitative description facilitates data interpretation and communication, particularly for the nonstatistical audience: beginning students, administrators and practitioners. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Chaflinches have differentiated within the last million years on the Canary Islands and the Azores. All island populations differ more from mainland relatives than from each other. The characteristics of island birds are large body size, short wings, long legs and beaks, and blue dorsal colour. Beak depth and width have increased on the Azores but not on the Canaries. As a consequence the Azores chaffinch has evolved more in the direction of the Canary Island F. teydea than have Canary Island chaflinches. Character displacement may have occurred on the Canaries. Most of the evolutionary shifts are not predicted from a knowledge of clinal variation on the mainland. Populations have differentiated more on the Canaries than on die Azores, but are less variable regardless of whether ecologically restricted (by teydea) or not. Similarly, within the Azores archipelago the most differentiated populations are die least variable. On the Azores, but not on the Canaries, differentiation increases with isolation, whereas wimin-population variation decreases with isolation and increases with elevation. A model for diese patterns is proposed in terms of gene flow between populations, which reduces differentiation but enhances variation, and directional selection and random genetic processes which have the opposite effects.
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